final manual coa 24-06-2020

i

MANUAL ON

POST HARVEST MANAGEMENT AND VALUE ADDITION OF FRUITS

Prepared and edited by Dr. P. K. Yadav Dr. R. K. Narolia Dr. R. S. Rathore Dr. N. K. Sharma

Department of Horticulture College of Agriculture,

Swami Keshwanad Rajasthan Agricultural University, Bikaner-334006

Sponsored by National Agricultural Higher Education Project, ICAR-New Delhi

ii

Published by:

Dr. I. P. Singh

Dean

College of Agriculture, Bikaner

Swami Keshwanand Rajasthan Agricultural University, Bikaner

Publication Number 02/2020

v

Contents

Exercise No. Particulars Page No.

1. Preparation of squash 1

2. Preparation of jam by different fruits 5

3. Preparation of Jelly 8

4. Preparation of value added tomato product sauce/ketchup

11

5. Preparation and preservation of juices 14

6. Preparation of candied fruits 17

7. Method of marmalade preparation 19

8. Value addition in Aonla 22

9. Value addition and processing of date palm 25

10. Processing and value addition of Ker 27

11. Post harvest and value addition of mandarin 29

12. Maturity indices for fruits 34

13. Effect of ethylene on ripening and chemicals used for hastening and delaying ripening of fruits

38

14. Different packaging material for some major fruits 45

15. Packaging of fresh fruits 49

16. Determination of PLW, TSS and Total Sugars in fresh Fruits

55

17. Causes of post harvest losses in fresh fruits and their control measures

61

18. Post-harvest treatments for shelf life extension of horticultural crops

65

1

Preparation of Squash

P. K. Yadav, Kishor Kumar Das and Priyanka Kumawat

S. K. Rajasthan Agricultural University, Bikaner

Fruits are highly perishable in nature and require immediate processing. The fruits like pineapple, grape, acid lime, sweet orange, aonla etc., are some of the fruits, which are grown in our country. Fruits and vegetables are seasonal and are grown all over the country. Losses can occur in fruits and vegetables at various stages in the process. In most of the horticultural advanced countries like U.S.A, Australia, Brazil and Israel, 40-60% of the total production of fruits and vegetables are processed into different products. In India among the various fruit based beverages mango, orange, lime, grapes and pineapple squash beverages occupied a prominent place in the fruit processing industry. Squash is a type of fruit beverage containing at least 25 per cent fruit juice or pulp and 40 to 50 percent total soluble solids, commercially. It is diluted before serving. Squash contains about 1.0 percent acid and 350 ppm sulphur dioxide or 600 ppm sodium benzoate as preservative.

All fruits are not for making squash suitable because of difficulties in extracting the juices or due to poor quality juice. Only fully ripe fruits are selected. Over ripe and unripe fruits adversely affects the quality of the juice. Most available squashes in Indian market from lime, lemon, pome fruits and stone fruits. Strawberry is one of the best fruits for squash preparation because of red colored anthocyanin as well as high flavor. In case of oranges there is need to remove the astringency from orange juices. Technological flow sheet for removal of astringency is given below:

Oranges

Peeling

Dipping segments in hot 2% NaOH for 2-3 minutes

Dipping in Citric acid solution

Use for Juice Extraction

Removal of astringency from citrus fruits

Selection of fruits is very important. Diseased, damaged or decayed fruits are rejected. Dirt and spray residues of arsenic, lead etc. are removed by washing with water or by using dilute hydrochloric (HCl) acid solution (0.5%) followed by washing in water. For the preparation of squash pulping of fruits or extraction of juice is very important and proper care should be taken. Generally, juice is extracted from fresh fruit by crushing and pressing them. Screw type juice extractor, basket presses or fruit pulpers are mostly used. According to Srivastava there are two types of extraction methods i.e., single and double operation system. In case of single operation, screw type, plunger type or roller type press is generally used to crush and press the prepared fruit to extract the juice. The screw type extractor is operated either manually or by using electricity depending upon the requirement. The juice extracted is generally thick and cloudy and contains a considerable amount of macerated pulp. Finally, the juice is strained through a thick cloth or a sieve to remove seeds and in the double operation, the fruits are crushed and then pressed separately. Fruits like apple, aonla, berries, grapes, jamun, phalsa etc. are crushed in fruit grater or crusher and the crushed mass is pressed by means of basket press and hydraulic press. Juices of fruits contains varying

1

2

amount of suspended matter consisting of broken fruit tissue, seed, skin, pectin substances which adversely affect the quality of juice, are removed by straining through a thick cloth or sieve. That clear and pure juice is used for preparation of squash. After measuring the juice, sugar syrup is added to fruit juice to make a fruit squash. It is added to give a final concentration of 12-14% sugar. The amount of sugar present in the fruit has to be taken into account when calculating the amount of sugar to add. The amount of sugar added to a fruit squash is also determined by consumer taste and demand for sweetness. The amount of sugar syrup to be added to the juice to give a final concentration of 12-14% can be calculated by using the Pearson Square. For making sugar syrup, require quantity of sugar boil with water till the total sugar dissolve. Citric acid adds to remove impurity of sugar from syrup. Sugar syrups should be filtered through a muslin cloth to remove particles of dirt that are present in the sugar. Sugar syrup mix with juice after cooling down at 25oC.

Addition of preservatives potassium meta bi sulphite and sodium benzoate are used as per specification. Bottles are thoroughly washed with hot water and filled leaving 1.5 cm head space. At the small-scale, containers can be filled simply using a funnel and a jug. The juice containers should be thoroughly washed and sterilized at 116oC temperature in autoclave or pressure cooker before filling. Bottles that are recycled should be checked for cracks and chips. Only new caps should be used for sealing the bottles.

FRUITS

WASHING

TRIMMING

CUTTING OR GRATING

JUICE EXTRACTION

STRAINING

JUICE MEASURING

PREPARATION OF SYRUP (Sugar + water + acid

Heating just to dissolve)

STRAINING

MIXING WITH JUICE

ADDITION OF PRESERVATIVE (0.6 g KMS or 1.0 g sodium benzoate/ litre squash)

BOTTLING

CAPPING

STORAGE

Flow sheet for preparation of squash

3

The fruit juice blended squashes such as papaya and mango, aonla and lime, aonla and pineapple in the ratio of 4:1 were prepared as per FPO specification. The enzyme clarified muskmelon juice was used to prepare squash as per FPO specification and enriched by fortifying with 100 mg of ascorbic acid per 100 g. The flow chart for the preparation of mixed fruit squash is given in Fig. 3. The fruit pulp was prepared by adding equal proportion of fruit pulp in the ratio of 1:1:1. Required amount of sugar and citric acid were taken in a vessel. Sugar syrup was prepared using required amount of sugar and citric acid. The prepared syrup was filtered and allowed to cool. The fruit juice was added to the syrup and mixed thoroughly. The required amount of KMS was mixed in a small quantity of fruit juice and added to the prepared squash and mixed well. The prepared squash was poured in a sterilized bottle (capacity 650 ml) leaving headspace (2 cm) and capped airtight.

Flow chart for preparation of mixed fruit squash-

Guava Banana Mango Sugar + citric acid + water

Selecting Selecting Selecting Boiling

Washing Peeling Washing Cooling

Peeling Cutting Peeling Filtering

Cutting Pulping Cutting Sugar syrup

Steam blanching Banana pulp Pulping

Mango pulp

Seed removal

Guava pulp

Mixing

Filtering

Filling the bottles (head space 2cm)

Capping

Storing at room and refrigeration temperature

Flow chart for the preparation of mixed fruit squash (guava, banana, mango)

4

Table 1: Squashes can be prepared in home according to the adding following ingredients

S. No.

Fruit

Ingredient for one liter pulp/ juice

Sugar

(kg)

Water (liter)

Citric acid (g)

Preservatives (g)

1. Aonla 1.75 1.0 25 2.5 KMS

2. Apricot 1.8 1.2 25 1.5 KMS

3. Bael 1.80 1.0 25 1.9 KMS

4. Guava 1.80 1.0 20 2.0 KMS

5. Jamun 1.80 1.0 15 3 Sodium Benzoate

6. Karonda 1.80 1.0 5.0 4.0 Sodium Benzoate

7. Lime 2.0 1.0 25 2.5 KMS

8. Litchi 1.25 0.75 30 1.8 KMS

9. Mango 1.75 1.0 20 2.5 KMS

10. Orange 1.8 1.2 30 3.0 KMS

11. Papaya 1.80 1.0 25 2.5 KMS

12. Phalsa 1.80 1.0 5.0 4.0 Sodium Benzoate

13. Pineapple 1.75 1.0 20 1.9 KMS

14. Plum 2 1.0 10 3.0 Sodium Benzoate

15. Water melon 0.50 0.25 10 1.5 Sodium Benzoate

Storage of Squash

As the storage period increased, a slight decline in color score. The TSS level of Squash increase significantly irrespective of the storage months. Hydrolysis of polysaccharides during storage results in increase of soluble sugars. The pH and ascorbic acid contain decrease irrespective of the storage duration due to hydrolysis of polysaccharides and non-reducing sugars where acid is utilized for converting them to hexose sugars. It can be store at 4oC temperature in refrigerator for 8-10 months.

Table for income/expenditure

S. No. Items Quantity Rate Total 1. Fruits 5kg 25/ 125 2. Sugar 3.5kg 40/ 140 3. Citric acid 50gm 10 10 4. Preservatives 5gm 5 5 5. Bottles 6No. 5/ 30 6. Other items - 50 50

Total cost 360 Net profit (Rs.) = Market price – Cost of production

= 600(100/bottle) -360 =240

Net profit (Rs.) = 240

5

Preparation of Jam by Different Fruits

R. K. Narolia and Aakanksha Sharma College of Agriculture, SKRAU, Bikaner

Jams can be made from one or two or more kind of fruits. This is a product of boiling of fruit’s pulp with sufficient sugar with a reasonably thick consistency having firm enough to hold the fruits tissues. Various fruits like apple, papaya, mango, sapota, strawberry etc. are used to prepare Jams. Jam contains 0.5-0.6 per cent acid, 68 per cent TSS and at least 45 per cent of fruit juice. Jam can be prepared in home according to the adding following ingredients (recipe) given below as per F. P. O. specification.

Fruits Ingredient for one kg pulp (recipe) Sugar (Kg) Citric acid (g) Water (ml)

Apple 0.75 2.0 100 Aonla 0.75 -- 150 Papaya 0.70 3.0 100 Mango 0.75 1.5 50 Sapota 0.75 3.0 150 Strawberry 0.75 2.0 100 Mixed jam (Pulp of pineapple, guava and mango or papaya and pineapple in equal amount)

0.80 2.5 100

Flow sheet for preparation of jam Ripe Firm Fruits

Washing

Peeling (removing of seed and core)

Pulping

Addition of sugar

Boiling (stir continuously)

Addition of citric acid

Judging of End-Point by further cooking up to 105oCor 68 to 70% TSS or by sheet test

Filling hot into sterilized bottles

Cooling

Waxing

Capping

Storage (at ambient temp.)

2

6

Materials required: Ingredients as per recipe, kitchen wares, stainless steel knife, peeling/coring knife,

pulper, pulp collecting utensil, oven for cooking, citric acid, crown corking machine, water, colour, bottles, labels etc.

Methods of preparation: Select firm ripe fruits.

Washing the fruits with clean tap water than RO water for removing dirt.

Peel the fruits and remove the seeds and core by cutting in small pieces.

Make the pulp by crushing the small pieces of fruits or heating them.

Add the sugar in pulp as given in recipe.

Stir continuously with boiling of contents and add preservative 2 gm citric acid.

Judging of End-Point by further cooking up to 105oC or measuring 68 to 70% TSS by hand refractrometer or by sheet test (small amount of jam is taken in a spoon or wooden ladle during boiling and cooled slightly. Allow it to drop. If the product falls in the form of a sheet or flakes instead of flowing in a continuous stream or syrup, it considered that the end-point has been reached and the product is ready, otherwise, boiling is continued till the sheet test is positive.)

Filing hot into sterilized bottles after judging of end point

Cooling, waxing and labelling (contains nutritional status, date of manufacture and expire date)

Storage at ambient temperature in cool and dry place.

Problems during apple jam preparation:- Premature Setting: This is due to low total soluble solids and high pectin content in the jam and can be prevented by adding more sugar. If this cannot be done a small quantity of sodium bicarbonate is added to reduce the acidity and thus prevent the pre-coagulation.

Crystallization: The final product should contain 30 to 50% invert sugar. If there is the percentage less than 30, cane sugar may crystallize out on storage, and if it is more than 50%, the jam will become honey-like mass due to formation of small crystals of glucose. Corn syrup or glucose may be added along with cane sugar to avoid crystallization.

Sticky or Gummy jam: Because of the high percentage of total soluble solids, jams tend to become gummy or sticky. This problem can be solved by the addition of pectin or citric acid or both.

Microbial spoilage: Sometimes moulds may spoil the jam during storage but they are destroyed if exposed in less than 90 per cent humidity. Hence, jams should be stored at 80 % humidity. Mould can be prevented by not sealing the filled jar and covering the surface of the jam with a disc of wax paper because mould does not grow under the open condition as rapidly as in a closed space. It is also advisable to add 40 ppm sulphur dioxide in the form of KMS. In the case of cans, sulphur dioxide should not add to the jam and it causes the blackening of the internal surface of the can. Yeasts are not a serious problem due to the high concentration of sugar.

Surface Graining and Shrinkage: This is caused by evaporation of moisture during the storage of jam. Storing in a cool place can reduce it.

7


S. No. Items Quantity Rate Total 1. Fruits 1.0 Kg 100/- 100.00 2. Sugar 750 gm 40/- 30.00 3. Citric acid 2 gm 2/- 2.00 4. Bottles 4 (500x4) 8/- 32.00 5. Other items --- 20/- 20.00

Total cost 184.00

Net profit (Rs.) = Market price – Cost of production

= 400 (100x4)-184 = 216.00

Net profit (Rs.) = 216.00

Jam Bottle Fruit Pulp Mixture and crusher

8

Preparation of Jelly

Komal Kathuria S.K. Rajasthan Agricultural University, Bikaner

A jelly is a semi-solid product prepared by boiling a clear, strained solution of pectin containing fruit extract, free from pulp, after the addition of sugar and acid.

It should be firm enough to retain a sharp edge but tender enough to quiver when pressed. It should not be gummy, sticky or syrupy or have crystallized sugar. The product should be free from dullness, with little or no syneresis (weeping), and neither tough nor rubbery and should have TSS 65%, 0.5 - 0.75% acid and 45% of fruit juice.

Fruits suitable for jelly preparation

Guava, Apple, Grapes, Orange, Jamun, Apricot, Peach, Pineapple, Karonda, Papaya, Loquat etc.

Material Required:

Stainless steel knife, juice extractor, juice containing utensil, broad mouthed bottles, capping machines, sugar, citric acid, colour, methylated spirit etc.

Technological process for preparation of jelly from guava fruits:

Selection of fruits (Firm and Ripe) washing of fruits cutting the fruits into thin pieces boiling the fruits in water for 20-30 minutes (250 ml of water for 1 kg) straining the extract for pectin test (Addition of Sugar) cooking Addition of citric acid judging the end point (Sheet and temperature test) removal of Scum or Foam filling hot into clean sterilized bottles waxing capping storage.

Reciepe for Jelly preparation : In the home, Jelly can be prepared using following recipes:

Fruit Ingredient for one litre Extract Sugar (Kg) Citric Acid (g)

Guava 0.75 3.0 Sour Apple 0.75-1.00 2.0 Karonda 0.75 - Jamun 0.75 1.0 Woodapple 1.00 - Plum 0.75 2.5 Loquat 0.80 2.0 Papaya 0.75 3.0 Important Consideration for Jelly Preparation

Pectin: Pectin substance present in the form of calcium pectate is responsible for the firmness of fruit. Pectin is the most important constituent of jelly. It is a commercial term of water soluble pectinic acid which under suitable conditions forms a jel with sugar and acid. The

3

9

setting of pectin is also dependent upon the pH and sugar concentration. Pectin concentration of 0.5-1.0 % pectin is sufficient to produced good jelly. Fruits can be divided into four groups according to their pectin and acid contents.

Rich in Pectin and Acid: Sour and crab apple, grape, sour guava, lemon, sour orange, sour plum, jamun. Rich in pectin but low in acid: Apple (low acid varieties), unripe banana, sour cherry, fig (unripe), pear, ripe guava, peel of orange, grapefruits. Low in Pectin but rich in Acid: Sour Apricot, sweet cherry, sour peach, pineapple, strawberry. Low in pectin and acid: Ripe apricot, Peach (ripe), pomegranate and Strawberry. Guava, sour apple, plum, karonda, woodapple, loquat, papaya and gooseberry are generally used for preparation of jelly. Apricot, Pineapple, Strawberry can be used but only after pectin powder because these fruits have low pectin content. Determination of pectin content: Alcohol test: In this method involving precipitation of pectin with alcohol. The ratio of alcohol and extract is 1:3. Extract rich in pectin a single, transparent lump or clot will form. Add equal amount of sugar. Extract contains moderate amount of pectin the clot will be less firm and fragmented. Add three fourths of sugar. Extract is poor in pectin, numerous small granular clots will be seen. One half the amount of sugar is added. Jelmeter test: The reading of the level of extract in the Jelmeter is noted and figure indicates how many parts of sugar are to be added to one part of juice. Acid: The jellying of extract depends on the amount of acid and pectin present in the fruit. The final jelly should contain at least 0.5 per cent but not more than 1 per cent total acids because a large quantity of acid may cause syneresis. pH of extract: Jelly strength increases with the increases in pH until optimum is reached and the optimum pH value for jelly is 3.2. Sugar: This is an essential constituent of jelly which imparts sweetness to jelly. If the concentration of sugar is high, the jelly retains less water resulting in a stiff jelly, probably because of dehydration. Judging of end point Sheet or flake test: A small portion of jelly taken out during boiling in a spoon. It is then allowed to drop, if the product falls off in the form of a sheet or flakes instead of flowing in a continuous stream or syrup, it means that the end point has been reached and the product is ready. Drop test: A drop of the concentration mass is poured into a glass containing water. Setting down of the drop without disintegration denotes the end point. Temperature test: A solution containing 65% total soluble solid boils at 105˚C. Heating of the jelly to this temperature would automatically bring the concentration of solids to 65 %. Characteristics of perfect jelly A perfect jelly should be transparent, well-set, but not too stiff, and should have original flavour of the fruit and land transplant. It should be attractive in colour and keep its shape when removed from the mould.

10


S. No. Items Quantity Rate Total 1. Fruits 2. Sugar 3. Citric acid 4. Bottles 5. Other items 6.

Total cost


Small packing of Jelly Hand refractometer

11

Preparation of Value Added Tomato Product Sauce/Ketchup

Deepak K. Sarolia ICAR-Central Institute for Arid Horticulture, Bikaner

Tomato is grown in India in abundance during summer and winter season in open field and in controlled condition round the year with desired quality. In open condition produces better quality in winter season than summer season with more total solids and ascorbic acid content. Fresh tomato fruits cannot be stored for long time and due to perishability nature more post harvest losses occurred approximately 25 per cent. These problems would be crated price fluctuation in market and alternate solution is these tomatoes require proper storage facilities or change the form/ product. In India tomato sauce, tomato ketchup, chutney is most common. As per FPO specification, tomato sauce/ketchup an free from its seed and 25 per cent minimum total soluble solids, 1.0 per cent acetic acid.

Recipe:

Tomato fruits : 2.5 kg Tomato pulp : 1 kg Sugar : 75 g Salt : 10g Onion (Chopped) : 50g Ginger (Chopped) : 10g Garlic (Chopped) : 5g Red chilli powder : 5g Clove (headless) : 5-6 numbers Cardamom big, mace, aniseed, cumin, black pepper mix : 10g Vinegar or Acetic acid : 25ml or 5ml Sodium benzoate : 0.25g/kg final product Materials required:

Ingredients as per recipe, kitchen wares, oven for cooking, preservative (SB & vinegar/acetic acid), bottles and labels etc.

Methods of preparation:

Select fully ripe red intense red coloured fruits from market that should be blemish free

Washing the fruits with clean tap water than RO water for removing dirt.

Sorting and trimming with proper watch with removal of calyx (if attached) and blemished or over ripe part should be trimmed.

Cutting and chopping with stainless steel knife at 2.5 cm pieces on chopping board and collect in cooking pan.

Heating this at 70-90 oC for 5 minutes till softening with proper messing it.

Pulping or extraction of pulp manually by tomato pulper. This will strain the pulp with removal of skin and seed part automatically.

Cooking pulp with addition of one third quantity of sugar for retention of lycopene.

4

12

Putting spice bag (Chilli, garlic, onion, cardamom, mace, black pepper, cumin, aniseed) in pulp and pressing occasionally 4-6 times till end point reaching.

Removal of spice bag with proper squeezing in pulp and addition of remaining sugar and in last salt.

Judging of end point (1 Hand refractometer reading 25 degree for sauce and 28 degree for ketchup, 2. Mass weight one third of its original 3. Put mass in plate and slight tilt no water reflect).

Addition of vinegar and preservative

Filing hot into bottles at about 88oC

Crown corking and pasteurization at 85-90oC for 30 minutes.

Cooling and labeling (contains nutritional status, date of manufacture and expire date).

Storage at ambient temperature in cool and dry place.

General considerations: Hot method generally prefer for pulp extraction due to pectin easily separates. Sugar

addition help in fixing the red colour (lycopene) so before start cooking should be added. Spices extraction true form to be added in industries directly but home scale bag slowly gave its squeeze in crude form slightly off colour develops in the product. Final product viscosity prevents the separation of pulp from juice. Hot filling prevent browning and loss of vitamins during subsequent storage. General addition of ingredients on final product basis like sugar varies with 10-26 %, salt about 1.3-3.4 %, acetic acid contains 1.25-1.5%, pectin about 0.1-0.2 % etc. Problem in the preparation of sauce/ketchup: Black neck: Formation of black ring in the neck of bottles is known as black neck. It is caused by the iron which gets in to the product from the metal of the equipment and the cap/crown cork through the action of the acetic acid. This iron coming into contact with tannins in spice forms ferrous tannate which is oxidized to black ferric tannate. This can be prevented by:

o Filling hot not temperature less than 85oC. o Leave little head space. o Use plastic lid in place of iron lid. o Partial replacement of sugar by corn syrup or glucose syrup. o Storing bottles in horizontal or inverted position.

Discoloration: Other that black neck some time whole product not looking red may be brownish probably due to extra squeezing of spices bag and addition of salt too early during cooking of the product. Care gently squeeze the bag as per required taste or pungency added in the product and salt addition at end of the final cooking of the product. Precautions:

1. Do not use iron and copper equipments/ utensils. 2. Clove with head and iron lid cause bottle neck disorder. 3. Leave head space 2 cm at top and the bottles are sealed or corked at once.

13

4. Best use of the product within one month of opening and see the date of manufacture and expiry.

5. Addition of artificial colour/chemical etc are dangerous for health so should not be used.

Cost of production tomato sauce:

S. No. Particular Quantity Rate per unit Cost (Rs.) A Ingredients

a Tomato 10 kg 20/-kg 200 b Sugar 375g 42/kg 15.75 c Salt 50g 10/kg 0.5 d Onion (Raw) 250g 25/kg 6.25 e Ginger 50g 100/kg 5 f Garlic 25g 100/kg 2.50 g Clove 2.5 g 1000/kg 2.5 h Condiments: Cardamom (big),

mace 10 + 2.5 g 1500/kg 18.75

Aniseed, cumin etc. 5 + 5 g 250/kg 6.25 Black pepper ,

cinnamon mix 5 + 2.5 g 500/kg 3.50

Red chilli powder 10-20 g 250/kg 2.50

h Vinegar 45ml 250/litre 11.25 i Sodium benzoate 1.25g 1250/kg 1.5

B Miscellaneous 1 Bottle/jar (1 kg capacity) 5 5 25 2 Label and print etc 1 5 5 3 Labour, pasteurization and

gas charges - - 125

Total cost - - 431.25


= 650 (130x5 bottle)-431 = 219.00

Net profit (Rs.) = 219.00

14

Preparation and Preservation of Juices

P. K. Yadav and Priyanka Kumawat S.K. Rajasthan Agricultural University, Bikaner

Definition: Extract of ripe fruit used to prepare drinks known as juice. Fruits for juice making: Lime, lemon, orange, grape fruit, apple, pulm, mango, pineapple, grapes, pomegranate, etc.

Material required:

Fruits, stainless steel knife, utensils, sieve, crown corking machine or can sealer, bottles, colour, flavor, sugar, citric acid, preservatives, etc.

Process of juice preparation:

Fruits

↓

Washing

↓

Trimming

↓

Cutting

↓

Juice extraction

↓

Straining

↓

Clarification

↓

Filtration

↓

Bottling

↓

Capping

↓

Pasteurization

↓

Cooling

↓

Storage

Flow chart of general fruit juice preparation

5

15

Apple juice: Wash the fruit → grating by apple grater → basket press for juice extraction → straining → clarification by enzyme or gelatin →filtration→heating at 82- 85 oC →filling in cans →sealing →process at 100 oC for 15 minutes → cooling → storage.

Grape juice: Wash the fruits →remove stalk → basket crush the fruits ( heat colored fruit crush at 60-65 oC for 10-15 min to better extraction of colour) → extract the juice → clarify by store the extract at low temperature for 3-4 months for settling of cream lartar → filtration →adding sodium benzoate →bottling → crown corking → pasteurization → cooling → storage.

Pomegranate juice: Washing the fruits → cut the fruit in pieces → separate the seeds → pressing the seeds → straining → bottling →capping → pasteurization → cooling → storage.

Pineapple juice: Remove the crown → peel the fruit → slicing → crushing → juice extraction → straining →heating at 82-85oC→ fill hot in plain cans → sealing → process at 100oC for 15 min. → cooling →storage.

Citrus juice: Wash the fruit → peel the fruit by hand → separate and cleaning of segments → juice extract by screw type extractor → straining → heat at 80oC → bottling or canning → crown corking → pasteurization → cooling → storage. (To avoid bitterness dip segments in 2% boiling NaOH for 2-3 Mins before juice extract or add 5-6 % sugar).

Mango juice: Wash the ripe mango → peeling → removing of stone → straining of pulp → adding water (half of the pulp) → add syrup (200 g sugar + 1 g citric acid + 800 ml water for 1 liter pulp) →homogenization → heating at 85oC → filling hot in cans → sealing → process at 100 oC for 20 min → cooling → storage.

Preservation Pasteurization: In this process juice is heated to 100oC or slightly below for a sufficient time to inactivate/kill the micro-organisms. Commonly fruit juices are pasteurized between 75 and 88oC with times ranging from 30 sec to 30 min depending on the type of heating system, the nature of the juice and the size of the container. Chemicals: Juice spoilage can be check by adding chemical preservatives. Colored fruit juice preserve by Sodium benzoate and it is most effective against yeast. Potassium Meta bi sulphite use in non-colored juice and it is more effective against mould spores and bacteria. Freezing: Commonly juice freeze at -18oC retains its freshness, colour, taste, flavor and aroma. It does not sterilize fruit juices, it merely reduces the temperature where microbes unable to multiply and chemical changes take place very slowly. Drying: Fruit juices can be preserved in the form of powder by various methods viz., spray drying, drum drying, freeze-drying, foam-mat drying etc. Fruit juice powder is highly hygroscopic and requires special care in packing. It checks microbial growth by removing water Carbonation: It is a process of mixing carbon dioxide @ 1 to 8 g/litre under pressure with water. It helps to remove air and creates anaerobic condition and reduces the oxidation of ascorbic acid. Lime, lemon, grape, apple juice can be carbonated by using carbonation process.

16

Aseptic processing: In this process products are packed in pre-sterilized container in a sterile environment. It is done by high temperature short time (HTST) sterilization at 90-110oC temperature for acid products (pH<4.6) and ultra-high temperature (UHT) sterilization at 121oC and above for low acid foods (pH>4.6). It helps in better retention of nutrients and excellent sensory quality. Apple, mango, litchi, pineapple drinks etc. in tetra pack are processed commercially using aseptic processing and packaging. Filtration: Particularly apple and grapes juices are passed through special filters, which are capable of retaining yeasts and bacteria. Precautions

o Fresh and ripe fruits should be use for juice. o Whole process takes place in clean environment. o Only require amount of chemicals use.


S. No. Items Quantity Rate Total 1. Fruits 2. Sugar 3. Citric acid 4. Preservatives 5. Bottles 6. Other items 7. Total cost


Citrus Juicer Aonla Juicer

The linked image cannot be displayed. The file may have been moved, renamed, or deleted. Verify that the link points to the correct file and location.

17

Preparation of Candied fruits

R. K. Narolia and Aakanksha Sharma College of Agriculture, SKRAU, Bikaner

A fruit impregnated with cane sugar or glucose syrup, and subsequently drained free of syrup and dried is known candied fruit. The most suitable fruits for candying are aonla, karonda, pineapple, cherry, papaya, apple, peach etc. The process of making candied fruits is practically similar to that of preserves. The only difference is that fruit is impregnated with syrup having a high percentage of glucose. A certain amount of invert sugar and glucose viz. confectioners glucose, dextrose or invert sugar is substituted for cane sugar.

Processing Flow Sheet for Manufacturing of Candy

Mature Fruits

Washing

Preparation for sugar treatment

Keeping fruit and sugar in alternate layers [1 kg fruit: 1kg sugar] or Steeping fruit in syrup of 40% TSS for a Day

Removal of fruit and increasing Consistency of syrup to 60% TSS by boiling

Steeping of fruit [for a day]

Repeating the process and raising strength by 5 to 75% TSS on alternate days

Steeping in 75% TSS for a week

Draining

Shade drying

Packing

Storage

Problems in preparation of preserves and candied fruits

[1] Fermentation: It is due to low concentration of sugar used in the initial stage of preserves. Sometimes fermentation also occurs during later stage due to low concentration of sugar and to insufficient cooking. This can be prevented by boiling the product of suitable intervals, by adding required quantity of sugar and by storage and cool dry place.

[2] Floating of fruit in jar: It is mainly due to filling the preserve without cooling and can be avoided by cooling the preserve prior to filling.

6

18

[3] Toughening of fruit skin or peel: It may be due to inadequate blenching and cooking of fruits hence blenching till tender is necessary. Toughness may develop when cooking is done in a large shallow pan with only a small quantity of syrup.

[4] Fruit shrinkage: Cooking of fruit in heavy syrup greatly reduces absorption of sugar and cause shrinkage. Therefore, fruits should be balanced first or cooked in low sugar syrup.

[5] Stickiness: It may develop after drying or during storage due to insufficient consistency of the syrup, poor quality packing and damp storage condition.

If candied fruits are stored under humid conditions, they lose some of their sugar due to absorption of moisture from the air. Further, they become mouldy if they are not sufficiently dried and are packed in wet container.


S. No. Items Quantity Rate Total 1. Fruits 2. Sugar 3. Bottles 4. Other items 5. 6. Total cost


19

Method of Marmalade Preparation

Ramkesh Meena ICAR-Central Institute for Arid Horticulture, Bikaner

It is a fruit jelly in which slices of the fruit (or) peel are suspended. The term is generally used for products prepared from citrus fruits like sweet oranges, kinnow and citrus fruits in which shredded peel is used as the suspended material. Citrus fruits marmalades are classified into (1) jelly marmalade (2) jam marmalade. The FPO specifications for marmalade are TSS- 65% and fruit juice - 45% of the prepared product.

Materials required:

Kinnow fruit- 1 Kg Lime – 1 Kg Ingredients Pectin extract- 1 litre Sugar - 750 gm Shredded peel -62 gm

Procedure of product preparation:

Jelly marmalade Selection of ripe fruits → Washing → Peeling outer yellow portion (Flavedo) thinly →

Cutting yellow portion into fine shreds (0.3 - 2.5 cm long and 0.8 – 0.12 cm thick) Cutting of 0.3-0.45 cm thick slices of peeled fruit → Boiling (in 2-3 times its weight of water for 40-

60 min.) Straining the extract Testing for pectin content → Addition of sugar (as required)

Cooking to 103-105oC (Continuous stirring) Addition of shreds shredded peel boiled for 10 to 15 min. in several changes of water for softening and removing bitterness and added @

about 62 g per kg of extract) Boiling g till (continuous stirring) Testing for end point -

88oC with continuous stirring) Flavoring Storage at ambient temperature.

Jam Marmalade

The method of preparation is basically the similar as that for jelly marmalade. In this case the pectin extract of fruit is not clarified and the whole pulp is used. Sugar is added according to the weight of fruit, generally in the proportion of 1:1. The pulp – sugar mixture is cooked till the TSS content reaches 65%.

7

Testing f

Genera

Chopp

Boiling (2-3

for pectin co

A

Boilin

Addition o

Boiling

Testing for

Cooli

Sealin

al flow cha

Selection

Was

Peeling th

ing the peel

3 times wei

Separating

ontent (Alco

Addition of

ng the juice

of prepared

g till jellyin

r end point

ng (82-88 o

Flavour

Sterlizing

ng and stora

20

art of marm

n of mature

shing of Jars

he fruits (fl

ls (0.3-0.45

ight of wate

g the juice fr

ohol test &

f sugar (As

e and pulp (

Shreds (62

ng point (con

( Sheet/ Dr

oC with cont

ring (orange

g the jars ot

age at ambi

malade prep

e fruits

s

avedo)

cm thick sli

er for 40-60

rom pulp

Jel test for

required)

103 to 105o

g per kg of

ntinous stirr

rop/temprat

tinous stirri

e oil)

bottles

ent temprat

pration

ices)

minutes)

addition of

oC)

f extract)

ring)

ture test)

ing)

ture

sugar)

21

Problems of marmalade preparation Browning: This is common problem in marmalade making which can be prevented by addition of KMS @ 900 ppm and not using tin containers. Spoilage: In proper use of KMS may cause this problem mainly due to moulds. Over this problem by use of required quantity of KMS dissolved in small quantity of water then added to the products. Cloudy or foggy marmalade: This problem appeared when scum not removed on time and faulty pouring. Precautions during product preparation:

o Always select mature and ripe fruit of good condition. o Require pectin rich fruit for jelly marmalade preparation eg. o Add sugar on the basis of Jel meter reading o Cooking the whole mass till end point with constant stirring. o Filling of final product in clean and sterilize jar/bottles o After filling proper labeling should be places with mentioning date of manufacture

and expire. o Stored the product in dry and cool place.


S. No. Items Quantity Rate Total 1. Fruits 2. Sugar 3. Pectin 4. Preservatives 5. Other items 6. Total cost Net profit = Market price – Cost of production

22

Value Addition in Aonla

R. K. Goyal CCS Haryana Agriculture University, Hissar

Aonla being easy adaptable and less care requiring is now a day gaining popularity. It can be grown very well on a marginal, waste land and salt affected soil. It is an indigenous fruit to Indian subcontinent and highly valued among indigenous medicines. Being a very rich source of ascorbic acid, i.e., 500 mg /100 g of pulp and other nutrients such as phenols, pectin, iron, calcium and phosphorus, the fruit is a potent antioxidant. Its fruit is acrid, cooling, diuretic and laxative. The fully mature fruits are used for the preparation of preserve, candy, pickle, chutney, jam, etc. Drying of aonla fruits is the oldest technique of preservation, where the moisture is brought down to a level at which microbial growth is not supported. Aonla is one of the three constituents of the famous ayurvedic preparation triphala, which is prescribed in many digestive disorders and other product are chavanprash & murabba. The edible fruit tissues of aonla contain about three times more protein and 160 times more vitamin C as compared to apples.

Fruit preserve (Murabba) Tender and/or transparent sugar-impregnated fruits or fruit pieces retain their shape

and do not break or pulped. The fruit preserve contains 68% TSS and 55% fruit portion.

Material required: Fruits (aonla), fork/aonla pricking machine, refractometer, sugar, citric acid, steel utensils, glass jars, etc.

Method of preparation of aonla preserve: The method of preparation is explained as under: 1. Disease free healthy aonla fruits are washed thoroughly, dried and then pricked with

the help of fork. 2. Soak the fruits in 2% salt solution and increase the salt concentration 2% on alternate

day up to 8%. 3. Wash the fruits after removal from the salt solution. 4. Keep the fruits in 2% alum solution. Dip the fruits in water. 5. Blanch the fruits for 6-10 minutes. 6. Prepare the sugar syrup of 40% and put the fruits in the syrup. 7. Increase sugar concentration of about 10% on alternate days until it reaches up to

68%, which is maintained for few days. 8. Fill it in sterilized jar or HDPE bag.

Precautions 1. Concentrate the syrup after removal of the fruits.

2. Blanching of the fruits should be uniform.

Aonla candy Drained, dried and impregnated with sugar fruits is called candy. It should be soft,

sweet and retain the flavour and shouldn’t be sticky. It is gaining popularity because of its convenient packing, good storage, eating friendly and source of vitamin C. The TSS of fruit candy is 70% and fruit portion is 100%.

Material required: Fruits (aonla), knife, steel utensils, refractometer, sugar, citric acid, glass jars, etc.

8

23

Method for preparation of aonla candy 1. Take firm mature, healthy, disease free aonla fruits, wash them thoroughly, dry and

cut them into pieces (diagonal). 2. Blanch the fruits for 2-3 minutes. 3. Prepare the sugar syrup of 40% and put the fruits in syrup. 4. Increase the sugar concentration on alternate days gradually up to 70% and maintain it

up for 10 days. 5. Remove the fruits from sugar syrup and drain out the remaining sugar syrup from the

fruits. 6. Keep the fruits in oven at 50+5°C for drying.

Precautions 1. Concentrate the syrup after removal of the fruits. 2. Blanching of fruits should be uniform.

Aonla chutney Chutney has mellow flavoured and is spicy. Chutneys are generally hot and sweet.

The only substances that may be added are fruit pulp, raisins, dry fruits, spices, salt, sugar, onion, garlic, vinegar/acetic acid and permitted colour. The minimum fruit portion and TSS is maintained 40 and 50%, respectively. Material required: Fruits (aonla), knives, pulper, refractometer, spices, vinegar, glass jars, steel utensils, etc. Recipe of aonla chutney

Ingredients Quantity Aonla 1.0 kg Sugar 750 g Salt 20-30 g Ginger 15 g Hot spices (Gram masala) 20 g Red chillies 4-6 g

Vinegar or 200 ml Acetic acid 5-8 ml

Method for Preparation of aonla chutney 1. Take fully mature fruits and wash them thoroughly. 2. Boil the fruits in pressure cooker. 3. Crush the fruits in the mixer. Place all the ingredients except vinegar in a pan and

cook it to a thick consistency. 4. Add glacial acetic acid. Pack the chutney while it is hot in a wide mouth sterilized

bottle. 5. Seal the bottle air tight and keep it in cool and dry place.

Precautions 1. Long gentle cooking should be done for mellow flavour. 2. Sugar should be added after the basic ingredients have cooked well.

Aonla Pickle

Material required: Aonla fruits, knife, spcices, salt, mustard oil, glass jars, steel utensils, etc.

24

Recipe aonla pickle: Ingradients Quantity Aonla 1.0 kg Mustard oil 250 ml Salt 20-30 g Turmeric 25 g Red chillies 4-6 g Nigella seeds 10 g Mustard seeds (Rai) 100 g Fenugreek 50 g Fennel seeds 50 g

Method for preparation of aonla pickle 1. Take fully mature/ripe fruits and wash them thoroughly. 2. Boil the fruits in water for 8-12 minutes so that the fruits may become soft. 3. Take mustard oil in the pan and boil, add small quantity of salt and water so that froth

may generate. Thereafter, add all the ingredients except fruits. 4. Mix the ingredients well, add the fruit slices, fill it in sterilized air tight jar and keep

the jar in the sun. 5. Occasional shake jar while it is kept in sun till it become ready to use. 6. Thereafter, keep it in cool and dry place.

Dehydration of aonla Dehydration of aonla is very common practice since long, which is used for ayurvedic preparations and other home remedies.

Method for dehydration of aonla

1. Take fully mature fruits and wash them thoroughly.

2. Blanch the fruits in water for 4-5 minutes. Sometime, sulphuring is done.

3. Dry the aonla fruit in oven at 50±5°C until the constant weight is achieved.

4. Fill it in sterilized air tight bottles or bags and keep it in cool and dry place.


S. No. Items Quantity Rate Total 1. Fruits 2. Sugar 3. Citric acid 4. Spices 5. Bottle 6. Other items Total cost


25

Value Addition and Processing of Date Palm

Rajendra Singh Rathore Agricultural Research Station, SKRAU, Bikaner

Date palm is one of the potential fruit crops for arid irrigated areas of western Rajasthan. The production of date palm in this region will be helpful in sustainability of income of farmers of the region. The unique agro climatic condition of the western arid Rajasthan makes it one of the most potential areas for successful production of date palm.

The date palm is grown extensively in arid and semi arid regions of the world. It provides food, shelter, timber products and all parts of the palm can be used. Because of its high nutritional value, productivity and long yield-life (100 years), the date palm is referred to as the "tree of life" in the Bible and highly regarded as a national heritage in many countries. Because of these qualities and its tolerance to harsh environmental desert conditions, areas under cultivation have increased tremendously in recent years. Dates are important fruits grown in Kutch district of Gujarat and western parts of Rajasthan. Dates from this region are general try harvested at Doka stage due to the onset of monsoon. Due to harvesting of date during glut period, farmers have to sell produce at lower prices. Thus, improvement in marketing and post harvest management are priorities for date palm growers. Date palm fruits can be utilized for making various value added products. The whole date fruits are traditionally used for preparation of a wide range of products such as dry dates (chhuhara), soft dates (pind khajoor), date juice concentrates (spread, syrup), liquid fermented date products (wine) and date pastes for different uses (e.g. bakery and confectionary) besides their direct consumption. Some of the uses are discussed below:

Date products:

1. Dry dates (Chhuhara):

The full doka stage fruits (with fruit cap intact) are washed and dipped in boiling water for 5 to 10 minutes and dried either in air circulating oven at 48 to 520C for 70 to 95 hours or through sun drying for 80 – 120 hours, if weather is dry. Variety Medjool was found most suitable for preparation of dry dates.

2. Soft dates (pind khajoor):

Soft dates are prepared by dipping dang fruits in boiling water for 20 to 30 seconds and dehydrating them in the air circulating oven at 38-400C, fully dang fruits can be converted into soft dates simply by drying them in air circulating oven.

Chhuhara Pind khajoor

9

26

3. Dehydrated date:

Fruits of date palm, widely cultivated in Kutch district of Gujarat and western part of Rajasthan are harvested at doka stage. These date fruits with less commercial value can be preferably be processed into dehydrated dates. Dehydration is carried out in special chambers. These chambers control the entry and flow of hot air and ensure the appropriate moisture level. The temperature must not rise above 700C in order to prevent "the burning of sugars"(caramelisation). High temperatures will also cause the fruit to darken. These conditions will preserve the quality of the fruit. Different temperatures suit different date varieties; Halawy 550C (and 20 % moisture during the process); Barhee and Medjool at 500C.

4. Date juice concentrate:

The date fruits with less commercial value are used for processing into date juice concentrate. Fruit crushed and then treat with 0.1 per cent pectinase enzyme for 120 min to obtain maximum juice. The prepared juice is then pasteurized at 850C to inactivate the enzyme, cooled and centrifuged at 3000 ppm to get clear juice. Prepared date juice is rich in reducing sugars (16.1%) and total sugars (18.3%).

5. Date paste:

A simple additional grinding operation will turn the macerated date into date paste. Date paste is also produced commercially in Saudi Arabia and used for bakery products. A curious non-food application of date paste is that it will, in combination with soap, efficiently stop leaks in gasoline tanks in automobiles. This will not open up large markets for date paste, but it may become a life saver on long desert journeys.

6. Date powder: Dates are put on trays and dried down to less than 5% moisture in tunnel or cabinet

dryers. The dried dates are ground and sold in various screen sizes. The product is used in prepared cake-, cookie- and muffin mixes etc.

7. Wine:

Wine can be also prepared from dates. The wine of dates is not so popular due to lack of typical flavor and astringency. Zahidi variety was found suitable to make good quality light colored wine.


S. No. Items Quantity Rate Total 1. Fruits 2. Other items 3. 4. Total cost Net profit (Rs.) = Market price – Cost of production

27

Processing and Value Addition of Ker

Mamta Singh, Namrata Jain and Vimla Dunkwal

College of Home Science, Bikaner

Ker (Capparis deciduas) is commonly known as karira is a useful plant in its marginal habitat. Its spicy fruits are used for preparing vegetables, curry and fine pickles and can attract helpful insectivores; the plant also is used in folk medicine and herbalism. It can be used in landscape gardening, afforestation and reforestation in semidesert and desert areas; it provides assistance against soil erosion.

Processing of ker Ker fruit harvested at three stages (immature, semi-mature and fully-mature) were

subjected to different processing treatment viz., blanching and curing. Then the fruit were sun dried and stored for six months. Fruit harvested at an immature stage (20 days after fruit set) and blanched for 3 min followed by curing in salt (5%) for the first 6 days and salt 10% + buttermilk 25% for the next 6 days proved significantly superior in terms of better rehydration ratio, ascorbic acid content and organoleptic quality.

Ker pickle

Ingredient Amount Ker 1 kg Salt 100 gm Turmeric powder 40 gm Red chilli powder 100 gm Fennel seeds 40 gm Yellow mustard seeds 60 gm Mustard oil 800 ml

Method: o Dry the processed ker for half an hour under sun and grind the fennel seed. o Mix all the spices in 20ml of preheated and cooled oil. o Add ker and fill in bottle for 3 days. o Add remaining oil and keep for 10 days before serve.

Ker vegetable

Ingredient Amount Ker 1 kg Salt 50 gm Turmeric powder 20 gm Mango powder 100 gm Red chilli powder 50 gm Cumin seeds 10 gm Fennel seeds 50 gm Yellow mustard seeds 50 gm Fenugreek seeds 50 gm Mustard oil 200 ml

10

28

Method: 1. Wash the previously soaked ker in the butter milk. 2. Heat oil in a pan, add whole spices. 3. Add ker and other spices and cook for 2 minutes.

Note: Dried ker can be used after soaking overnight. Ker can also be used with sangari and panchkutta vegetable.


S. No. Items Quantity Rate Total 1. Ker 2. Salt 3. Turmeric powder 4. Mango powder 5. Red chilli powder 6. Cumin seeds 7. Fennel seeds 8. Yellow mustard seeds 9. Fenugreek seeds 10. Mustard oil 11. Other items Total cost


29

Post Harvest and Value Addition of Mandarin

Shalini Pilania Department Horticulture, RCA, Udaipur

Citriculture is the third largest fruit industry in India next to mango and banana. The mandarin having largest area and maximum production constitutes about 41% of total area under citrus. In Rajasthan mandarin is mainly grown in Ganganagar and Jhalawar district. Presently, 95% the fruit is mainly utilized for fresh consumption only, since very meager processing option is available. Its juice and beverages are not trendy because of bitterness caused by oxidation of glycoalkaloid ‘Naringine’. The fruit consist of three layers:

o The outer yellow/ orange peel with oil glands which exude the essential oils, producing the typical orange odor.

o The whitish thread like mesocarp.

o The endocarp consisting of 8-10 segments filled with juice sacs (vesicles).

Composition of Mandarin (per 100 g of edible portion)

Mandarin (Citrus reticulate Blanco) is of three types:- Nagpur Mandarin, Coorg Mandarin and Kinnow (King x Willow Leaf)

Value addition of mandarin

o Peel 1. Oil (Distilation) α-Limonin 2. Pectin from albedo: Procedure of preparation- Take 25 gm dried peel blended 100ml

distilled water. The homogenate was transferred to a 1500 ml beaker, pH adjusted HCl (1, 1.5, 2, 2.5 and 3) after every 15 minutes and maintain temperature (80, 85, 90, 95, 100oC) respectively, care should be taken that if water evaporated replaced with water. Mixture rapidly cooled to 40oC in an ice bath. Filtered under vacuum. Filtrates coagulated using 95% ethanol different duration 60, 75, 90, 105 and 120 minutes. Pectin float on the surface. Filtered through cheese cloth. Dried at 60-70oC in an air forced oven. Yield of pectin is 12.93-29.05%. Maximum pectin is obtained at 95oC and 105 minutes, beyond which pectin yield levels off.

3. Face pack: It’s peel is also used for making face pack. o Endocarp 1. Marmalade: Citrus fruits are used for making marmalade.

Moisture 82.6-90.2 g Iron 0.17-0.62 mg Protein 0.61-0.215 g Carotene 0.013-0.175 mg Fat 0.05-0.32 g Thiamine 0.048-0.128 mg Fibre 0.3-0.7 g Riboflavin 0.014-0.041 mg Ash 0.29-0.54 g Niacin 0.199-0.38 mg Calcium 25.0-46.8 mg Ascorbic acid 13.3-54.4 mg Phosphorous mg

11

30

2. Jelly:

3. Squash: Squash is a type of fruit beverage containing at least 25 Per cent fruit juice or pulp and 40 to 50 per cent total soluble solids, commercially. It also contains about 1.0 per cent acid and 350 ppm sulphur dioxide or 600 ppm sodium benzoate. It is diluted before serving.

FRUIT

WASHING

CUTTING INTO THIN SLICES

BOILING WITH WATER

ADDITION OF CITRIC ACID DURING BOILING

STRAINING OF EXTRACT

PECTIN TEST

ADDITION OF SUGAR

BOILING

JUDGING OF END POINT

REMOVAL OF SCUM OR FOAM

COLOUR AND REMAINING CITRIC ACID

FILLING HOT INTO CLEAN STERILISED BOTTLES

WAXING

CAPPING

STORAGE AT AMBIENT TEMPERATURE

31

Flow sheet Fruits

Washing

Trimming

Cutting or grating

Juice extraction

Straining

Juice measuring

Preparation of syrup

(sugar + water + acid, heating just to dissolve)

Straining

Mixing with juice

Addition of preservative (0.6 g KMS or 1.0 g sodium benzoate/litre squash)

Bottling

Capping

Storage

4. Wine: It is undistilled alcoholic beverages usually made from grapes or other fruits. It has been safe and healthy drinks, besides an important adjunct to the diet. A typical wine contains ethyl alcohol, sugar, acids, higher alcohols, tannins, aldehydes esters, amino acids, minerals, vitamins, anthocyanin and flavouring compounds. Alcohol, a macronutrient present in wine acts as an energy source and provide calories for all the essential biological activities in the human cells. Different studies have shown the beneficial effects of wine consumption due to the presence of phenolic and alcohol in wine, which protects human body from free radical attack and increases high-density lipid level in the body.

Methodology: Juice from peeled mandarin fruit was extracted mechanically, added with sucrose to raised TSS to 20, 24, 20, and 32 % and 100 or 200 ppm SO2 to prevent wild yeasts. The must was added with dry yeast powder of Saccharomyces cereviseae after specified rehydration process. The fermentation was allowed to process at room temperature (25 ±5oC) in glass vessels with airlock assembly attached to create anaerobic condition. During

32

fermentation the TSS content gradually decrease; ethyl alcohol content increase and bubbles are visible in the airlock assembly. The fermentation was completed in 9-12 days which is indicated by cessation of carbon dioxide gas bubbles in the airlock assembly and a constant reading of TSS for 2-3 consecutive days.

After primary fermentation was over, the fermented juice was filtered to remove pulp and other colloidal substances and kept for sedimentation. After sedimentation the clear wine is siphoned off into sterilized glass bottles, sealed airtight as pasteurized at 55oC for 10-15 minutes. The bottles were stored at 10oC for 3-6 months for maturation (ageing). Jain observed that maximum TSS (9.30) of must having initial TSS of 32oBrix and 200 ppm SO2, while minimum TSS (5.73) in the must having initial TSS 20oBrix and 100 ppm SO2.

The steady deceased in the TSS during fermentation could be attributed to conversion of sugars to alcohol which is available in maximum amount in the beginning of fermentation. The yeast converts the sugars into alcohol by forming enzymes such as pyruvic decarboxylase and alcohol dehydrogenase.

The alcohol content of mandarin wine increased slightly during maturation in all the treatments. It is due to conversion of sugars into alcohol due to very slow secondary fermentation that occurred during ageing.

During maturation TSS, acidity, total sugars and total phenols decreased, whereas, as increase was observed in reducing sugar and pH content. Improvement in the aroma, taste and flavor might be due to the hydrolysis of non-reducing sugar into reducing sugar which is one of the desirable effects from taste point of view and formation of esters which is responsible for fruity flavor of wine. The decreased in astringency is correlated with decrease in total phenols and tannins which decreased during maturation and is responsible for improvement of palatability of the wine.

5. Canning: Mandarin whole segment are dipped in syrup 250Bix Recipe for canned mandarin; Ingredients-

o 18-20 mandrin oranges o 4 cup water o 1 cup sugar

Instructions 1. Peel mandarins and remove as much of the white pith as possible from the outside and

center of the oranges. Split into segments and remove any seeds that may be lurking in those “seedless” oranges.

2. Set aside oranges to prepare jars and simple syrup. 3. In small pot, bring water and sugar boil to dissolve sugar and create simple syrup. 4. Wash and heat jars and sealing lids (no need to sterilize). 5. Tightly pack as many oranges segments as possible into each hot jar. 6. Pour syrup over oranges leaving a ½ inch (1.2 cm) headspace. 7. Remove air bubbles by running a knife along inside edges of the jars. Add more syrup

as needed to keep headspace. 8. Wipe rim with a clean cloth and sealing with hot sealing lids. 9. Screw band on top and tighten finger tight.

33

10. Place jars in canner or large pot filled with hot water. Ensure jars are covered with 1 inch of water. Bring to boil, then continue boiling for 10 minutes.

11. Turn off heat and allow jars to rest in canner for 5 minutes, then remove and cool undisturbed for 12 hours.

12. These jars will last on a shelf for one year. 13. Makes 4-5 half pint (250 mL) jars.


S. No. Items Quantity Rate Total 1. Fruits 2. Sugar 3. Citric acid 4. Preservatives 5. Other items 6. Total cost


34

Maturity Indices for Fruits

R.R. Sharma

Division of Food Science & Postharvest Technology,

ICAR-Indian Agricultural Research Institute, New Delhi

India looses about 25 to 30% of the produce during post-harvest handling and mismatching harvest with proper maturity of fruits plays a great role. The harvesting of fruits at right maturity is therefore, essential to improve fruit quality and minimize post-harvest losses.

Maturity index and its importance Fruits should be harvested at a stage, which allows developing full size and acceptable

flavour and appearance and having adequate shelf life when it reaches the consumer.

Methods to assess maturity The following methods are mainly used to assess the maturity of different fruits:

1. Visual means: Peel colour and fruit size. 2. Physical means: Ease in peel separation, fruit firmness and specific gravity of fruit. 3. Chemical analysis: Determination of total soluble solids (TSS), solid to acid ratio,

starch and oil content, etc. 4. Computation: Days after full bloom, days after pollination, heat units etc. 5. Physiological methods: Respiration rate, ethylene evolution etc.

Maturity indices for some selected fruits: Considerable variations exist in maturity period among different fruit crops and

within different varieties of a fruit, which is even controlled by cultural practices and environmental factors (heat units, humidity, chilling etc.). Mango: Various maturity indices for harvesting mangoes have been suggested for several varieties, but on the whole little effort has been made to determine indices of practical significance. Maturity in mango is judged by (i) change in peel colour on the shoulders, (ii) falling down of some ripe fruits from the tree (tapka), and (iii) specific gravity of most of the fruits reaching between 1.01 and 1.02. However, the 3rd method is more reliable. Fruits are sampled from all directions of the tree and put in water to find out the specific gravity. Fruits, which sink fully in water, are indicative of the correct maturity stage. Number of days taken by the fruit to mature depends on the cultivar and the climatic condition and hence it cannot serve as a good index of maturity. Banana: Bananas are harvested while fully mature but green and transported to the markets, where these are ripened artificially under controlled conditions. However, for local markets, the banana should be harvested when the ridges on the surface change from angular to round. Fall of floral remnants, pulp to peel ratio (10:1), pH of fruit (5.2-5.6) etc. are also good harvest indices in banana. Citrus: Fruits of most citrus species are harvested at the full ripe stage with proper colour development. Physiological parameters of maturity in citrus are, however, influenced by agro-climatic conditions and cultural practices from region to region. Oranges and mandarins have a typical flavour and taste. The flavour is determined largely by sugar and acid content

12

35

of the fruits. The preferred sugar:acid ratio in sweet oranges is 8.5 to 8.9 and in mandarins between 10.5 to 13.0. For Kinnow mandarin, this ratio should be between 12.1 to 14.1. In Kinnow, colour break occurs much before the maturity, the TSS/acid ratio (12:1 to 14:1) should therefore, be taken as index of maturity. Grape: Since grapes ripen only on tree, so ripening standard is practically applicable for harvesting. Grapes are considered ripe when the fruits have reached the condition of accumulation of sugar and acid contents, which are the best suited for intended use. At harvest, the berries should have attained attractive appearance, good eating and keeping quality and TSS/acid ratio. Heat units are other useful criteria for predicting maturity in grapes. Papaya: One of the major problems facing papaya fruit marketing is the identification of optimum harvesting maturity to ensure adequate fruit ripening and good eating quality. For local markets, half-yellow fruits should be harvested. However, the fruits can also be harvested at the appearance of yellow streaks on the dark green surface. Softness to touch, seed colour, jellyness of seed and the change in latex colour (from white to watery) are other indices of papaya maturity. Pineapple: Fruit maturity is evaluated on the extent of ‘eye’ flatness, peel yellowing and fruit flavour. Harvesting for local markets should be done when the colour of bracts start changing and the eyes get flattened in the center and buldge on the sides, the bracts become loose and turn brown in colour. However, the fruit is usually harvested when the surface colour is between colour break and quarter yellow for shipment by sea and half to three quarter yellow colour for transportation by air. Sugar:acid ratio (0.9 to 1.3) and TSS (12%) are other indices of maturity. Litchi: Since litchi fruit maturity does not change after harvest, the fruit must be picked at optimal maturity indicated by visual appearance and good eating quality. The maturity of fruit is determined by the flatness of tubercles and comparative smoothness of epicarp but change in pericarp colour is the most commonly used as harvesting index. however, oBrix : acid ratio (70:1 ) is adopted internationally as the commercial maturity standard for litchi. Guava: Guava fruits generally take 17 to 20 weeks to reach maturity after fruit set. Guava, which is a climacteric fruit, is consumed at different stages of fruit growth and development. The recommended optimum stage for harvesting is about 2-3 weeks before attaining full growth. Besides, fruit age, detachment force, peel and pulp texture, peel colour, sugar and tannin contents, TSS and titratable acidity, may also be adopted as maturity indices. Avocado: Avocado fruit grows continuously on the tree but would ripen only after harvest and thus identification of horticultural maturity is difficult in avocado. Hence, the finding out of the proper stage of maturity in avocado is of great significance. Based on fruit size, shape and colour, avocado of different races are harvested between 150-180 days after flowering. In addition, oil contents (8 to 15%) can also be used as harvesting index. Coconut: Coconut usually matures in about 12 to 13 months after the opening of the inflorescence. In order to get the maximum yield of copra and oil, only fully matured nuts should be harvested. As fully matured nuts contain small amount of water inside, it can be recognized by shaking of the nuts. The coconuts should be harvested in green immature stage if these are to be sold for coconut water.

36

Cashewnut: Usually the nuts are picked after falling from the tree. The best quality nuts are obtained where freshly fallen nuts are collected, the apples are removed and the nuts are sun dried for 2-3 days to reduce the moisture to 9 per cent. If cashew apples are to be used for processing, it is better to harvest them from the tree without damaging the apples. Sapota: Sapota is a climacteric fruit, which improves in quality after harvesting at proper maturity. The time taken from fruit set to maturity is an indicator of maturity, which is attained 120 to 245 days after anthesis, depending on cultivar and agroclimatic conditions. Maturity can be judged by the following external symptoms :

i Fruits dull orange or potato in colour. ii Fruit show light yellow streak after scratching instead of a green streak, which is a

sign of immature condition. iii Disappearance of brown scaly material from the fruit surface. iv Dropping the milky latex content almost to zero. v Falling of the dried spine like stigma at the tip of the fruit automatically or by touch.

Ber: Ber fruits ripen either on the tree or after harvest, provided that picking is done at proper stage of maturity. Fruits harvested at correct stage of maturity ripen properly, giving characteristic colour, flavour and taste. Change in fruit colour from green to pale, titratable acidity, total soluble solids and specific gravity of the fruit are the maturity indices for ber. Annonaceous fruits: Fruits are plucked from the tree while these are still firm and plumpy. If left on the tree, the fruits get damaged due to splitting instead of ripening properly. Likewise, immature fruits after harvest become soft and rot, though the skin remains intact. It is, therefore, essential to harvest the fruits at the proper stage of maturity. The following three maturity indices are usually adopted for annonaceous fruit crops:

i Development of light green colour in fruit. ii Development of white colour between the carpels. iii Initiation of cracking of peel between the carpels.

For these observations, the fruits should be examined individually every alternate day to determine the right stage of maturity for harvesting. Pomegranate: The fruits are ready for harvesting between 135 to 170 days after anthesis. Fruits are harvested when their peel turns slightly yellow and the fruits give a metallic sound when tapped. At maturity, the fruit colour changes to dark yellow in summer and dark red in winter. The buds at the anterior end of the fruit curve inwards and become hard and dry at maturity. Similarly, the properly mature fruits are easily scratched with a finger nail. The TSS:acid ratio (70:1) has also been considered to be the best chemical criterion of maturity for harvesting. Figs: The criterion for establishing the optimum time for picking figs are based primarily on colour and firmness of fruit. Black peeled figs could be harvested before the peel turns really dark and light peeled should be picked when the colour is yellowish white to light yellow. For the best flavour, the fruits should not be picked until they are soft and wilt at the neck, hanging down from their own weight. They are then fully mature, ripe and ready to be eaten. Milky latex exuding from the stem when the fruit is pulled off indicates that the fruit is still immature. As the figs are extremely perishable, fully ripe fruits cannot be transported to

37

distant markets, for that purpose, it is better to harvest the crop before the onset of full maturity. Dates: The dates are eaten at different stages of maturity, depending upon the variety. Thus, the time of harvesting also varies according to local demand. However, in general, dates are harvested at dang stage of maturity, when the fruits start softening. In India, dang stage is never reached due to pre-monsoon showers and hence these are harvested at doka stage, when the colour of fruit starts changing to pink and the astringency decreases significantly. Loquat: The colour of fruits (golden yellow) is the most reliable maturity index in loquat. Aonla: The colour of the fruit is the most reliable harvesting index in aonla. The fruits are normally light green but on maturity and ripening, the colour becomes dull, greenish yellow or rarely brick red. Vitamin C content can also be taken as a reliable maturity index. Jamun: The ripe fruits of jamun should be picked up immediately because those cannot be retained on the tree in ripe stage. The fruit ripens in June-July. The ripe fruits develop full size and deep purple or black colour, which is the reliable maturity index for harvesting jamun. Bael: Bael is a climacteric fruit and must be harvested at full maturity. At the time of maturity, the trees generally get defoliated and fruits are completely exposed. If left on tree for longer time, they are liable to cracking/splitting. Apple: Apple is a climacteric fruit and thus maturity of fruit does not coincide with the ripening. The fruits usually do not attain full ripe edible quality on the tree while harvesting. Therefore, the fruits should be harvested at proper picking maturity. Picking of immature fruits results in poor quality, lacking in flavour and taste, which shrivel during storage. Over mature fruits develop soft scald and internal breakdown with poor shelf life. There are several maturity indices, which can be adopted for harvesting at right time. The TSS content of the pulp, ease in separation of fruit from the spur, change in ground surface colour from green to pale or red, change in seed colour to light brown, fruit firmness and days from full bloom to harvest are some reliable maturity indices for apple, which can be considered singly or in combination. Peach: To get premium price and reduce the losses during packaging and transportation, peaches should be harvested at optimum stage of maturity. A large number of maturity indices like days to maturity, calendar date, fruit size, firmness, sense of touch, pit discolouration, taste, ground colour, sugars, acidity, sugar:acid ratio etc. been assessed, which singly or in combination can be used as maturity index for harvesting peaches.

38

Effect of Ethylene on Ripening and Chemicals Used for Hastening and Delaying Ripening of Fruits

Vijay Rakesh Reddy, S.

ICAR-Central Institute for Arid Horticulture, Bikaner

Ethylene is one of the most important plant hormones affecting various plant biological processes. Numerous biological roles of ethylene have been discovered and the most studied effect of ethylene is the promotion of fruit ripening. The climacteric fruits are more responsive to ethylene and they undergo a significant increase in respiration and ethylene production during ripening. The discovery of the biosynthetic pathway of ethylene and elucidation of the important elements involved in its perception and downstream signal transduction have been achieved for better understanding the role of ethylene and its mode of action. Genes encoding 1-aminocyclopropane-carboxylase (ACC) synthase (ACS) and ACC oxidase (ACO), the two key enzymes catalyzing the last steps of the ethylene biosynthetic pathway, were early targets of fruit ripening studies and manipulation in tomato and other species. Suppression of ethylene production by knocking out the expression of ACO and ACS has resulted in a strong inhibition of the ripening, which proved the vital role of ethylene in the regulation of ripening process in climacteric fruits.

Role in climacteric fruits The climacteric fruits are characterized by sudden upsurge in ethylene production

during ripening. Most of the climacteric fruits are susceptible to severe postharvest losses due to rapid ripening, triggered by ethylene. Many complex changes occur in the climacteric fruits with the onset of ripening and these changes are occurring mostly independent of one another. Some of the important changes that occur during ripening are seed maturation, color change, abscission, change in respiration rate, change in ethylene production rate, changes in tissue permeability and cellular compartmentation, softening, reduction of organic acids, development of flavor volatiles and wax on the fruit skin. Due to high perishable nature, less than one per cent of the fresh fruits get exported and 30- 40 per cent of the produce goes waste annually due to faulty or improper handling during transportation and storage. Reduction in such losses can improve farmers’ income and per capita consumption. The objective of successful storage is to delay the ripening process, retard the bio-chemical changes, reduce the microbial growth and finally enhance the shelf life of these perishables. However, in crops like mango, banana, sapota, papaya etc. the ethylene can be used to ripe them artificially at the will of the traders/ consumers. For this the fruits (climacteric) are harvested at full mature (physiological) stage, transported to the targeted location and then ripening artificially in the ripening chambers.

Ethrel as a ripening accelerator

Ethrel/ Ethephon is a versatile plant growth regulator which improves colouration and accelerates uniform ripening of fruits like pineapple, mango, tomato, etc. It can be deployed in specific uses like defoliation in pomegranate and breaking alternate bearing in mango. It is used in various ways. Major practice is through dipping treatments where in farmers dip

13

39

unripe mature fruits in 0.1 per cent ethrel solution (1 ml of ethrel solution in 1 litre of water) and wipe it dry. The fruits are then spread over a newspaper without touching each other and a thin cotton cloth is covered over this. In this method, the fruits will ripen within twodays.

Recently, a simple and harmless technique is being developed by ICAR-IIHR, Bangalore wherein, 10 ml of ethrel and 2 gm of sodium hydroxide pellets are mixed in five litres of water taken in a wide mouthed vessel. This vessel is placed inside the ripening chamber near the fruits and the room is sealed air tight. About a third of the room is filled with fruits leaving the remaining area for air circulation. Ripening of fruits takes place in about 12 to 24hours. In order to reduce the cost of chemical, some ethylene releasing fruits such as papaya and banana can also kept in the same room. The same can be done using make shift detachable ripening units formed using PVC pipes and covering the structure with HDPE sheet.

Fig 1: Sophisticated ripening chamber; Low cost (makeshift) ripening chamber

Ethylene being a natural hormone does not pose any health hazard forconsumers of the fruits. It is a de-greening agent, which can turn the peel from green toperfect yellow (in the case of bananas) and maintain the sweetness and aroma of the fruit,thus value addition in the fruit is possible as it looks more appealing. It has been known for a long time that treatment of unripe fruits with ethylene would merely stimulatenatural ripening until the fruit itself starts producing ethylene in large quantities.

Methods of applying ethrel

Method selected for applying ethylene depends on cost, convenience and safety factors. Use of diluted ethylene gas mixtures is safer than using pure ethylene, which is explosive and flammable at concentrations of 3% or higher. Fruit to be ripened ideally isplaced in an airtight ripening room maintained at a constant temperature (18-21oC for most fruits, but 29-31oC in mango). Optimum storage and ripening temperatures for a few fruits are given below.

40

Commodity Ethylene Conc.(ppm)

Ethylene exposure time (hr)

Ripening Temp (ºC)

Storage Temp (ºC)

Avocado 10-100 12-48 15-18 4.4-13 Banana 100-150 24 15-18 13-14 Honey dew melon 100-150 18-24 20-25 7-10 Kiwifruit 10-100 12-24 0-20 0.5-0 Mango 100-150 12-24 20-22 13-14 Orange degreening 1-10 24-72 20-22 5-9

There are two methods of exposing fruit to ethylene. Trickle method in volve strickling ethylene gas into room so as to maintain a concentration of 10 ul per litre, usually for a period of 24 hours. During this time, relative single initial charge of ethylene at a concentration of 20 to 200 ul /litre. Room is then ventilated after 24 hours to prevent carbon dioxide exceeding 1% concentration, which would retard ripening. Rooms that are poorly sealed are packed in vented cartons stacked on pallets, and fruit temperature is controlled by forced air circulation as in a cooling facility. A small fan can be used to ensure a uniform continuous flow of ethylene into and through the room. Forced-air ripening provides more uniform temperature and ethylene concentration throughout ripening room.

Ripening can also be initiated using ethylene generated by passing ethanol over abed of activated alumina. This method is safer than using pure ethylene gas. Ethylene releasing compounds such as ethephon (2-chloroethy1 phosphonic acid) are sometimesused to ripen tomatoes destined for processing. When using ethephon as spray, amount of ethylene released will increase as pH and/or relative humidity increase.

Degreening

Controlled degreening sometimes is carried out on citrus grown in tropics. Many citrus cultivars mature before green colour disappears from peel. Breakdown of chlorophyll and production of a rich orange colour require exposure to low temperatureduring maturation, and this explains why mature citrus frequently is sold green on markets in humid tropics, where even night temperatures may not drop much below25oC. The ceiling of room is relatively high, allowing boxes to be stacked at least four boxes high. A false ceiling is added to provide for adequate air.

Degreening is carried out in ripening rooms, with same ethylene concentrations as above. This process takes 2 to 3 days, and it is again necessary to ventilate daily to ensurethat carbon dioxide levels do not exceed 1%. The most rapid degreening occurs at temperatures of 25 to 30oC but the best colour (concentration of peel carotenoids) occursat 15 to 25oC.

41

Fig 2. Use of ethylene for degreening of citrus fruits

Ethylene management for reducing postharvest losses

Alternatively, manipulating the ripening process is very important in extending the shelf life and ensuring appropriate quality of fruit to the consumer. Ethylene is known to trigger ripening in climacteric fruit and senescence in non-climacteric fruits. Ripening inhibitors viz., ethylene synthesis inhibitors, ethylene action inhibitors and ethylene absorbents can be used to delay ripening of several climacteric fruits.

Ethylene is synthesized from S-adenosylmethionine (SAM) by way of the intermediate 1- aminocyclopropane-1- carboxylic acid (ACC). Ethylene synthesis inhibitors affects the ACC synthase (ACS), ACC oxidase (ACO) activity or ACC production itself (Fig.3). Whereas ethylene action inhibitors interact with ethylene receptors and thereby prevents ethylene dependent responses in many horticultural commodities. On the other hand, ethylene absorbents reduce the further autocatalytic production of ethylene by absorbing the initial ethylene produced by the fruits.

A few ethylene synthesis inhibitors include Aminooxyaceticacid (AOA), Aminoethoxyvinylglycine (AVG), Salicylic acid (SA), Brasinosteroids (BR), Nitric oxide (NO) and 1-MCP (1-Methylcyclopropene) is a known example for ethylene action inhibitor. Potassium permanganate (KMO4) is the widely used ethylene absorbent. Of these several treatments, postharvest application of ethylene synthesis inhibitors such as salicylic acid (SA), Sodium nitroprusside (SNP as NO donor) and 1-MCP as an effective ethylene action inhibitor has emerged as one of the promising technologies in some fruits.

Ethylene synthesis inhibitors are present in plants itself but in very small amounts and their levels decrease with maturation and ripening. Hence, there is an opportunity for modulating their levels with exogenous application of these inhibitors for not only delaying ripening but also alleviate the chilling injury, reduce the disease incidence and maintain the fruit quality.

a.) Aminoethoxyinylglycine (AVG) and Aminooxyacetic acid (AOA)

Aminoethoxyvinylglycine (AVG) and Aminooxyacetic acid (AOA) are well known as a strong inhibitor of ACC synthase. AVG is commercially registered for use on apple crop in USA and many other developed countries. In market, it is commercially available with the trade name ReTainR (ValentBioSciences Corp., Libertyville, Illinois, USA), and it contains 15 per cent w/w AVG as active ingredient. Pre-storage treatment of AVG/AOA was found to

42

delay fruit softening, starch degradation, accumulation of soluble sugars, decrease in acidity, and generation of ester volatiles related to flavor during storage. The AVG/AOA inhibits the ethylene biosynthesis by acting on the key enzyme ACS which catalyzes the reaction for formation of ACC. AOA treatment of light-yellow stagebanana fruits decreases the ethylene evolution and prevents their preliminary over ripening, which is important for preserving bananas before selling. Thus, their application as either pre- or post-harvest treatment could effectively extend the shelf life of climacteric fruits.

b.) Acetaldehyde and ethanol These two compounds act by inhibition of the key enzyme ACC Oxidase (ACO) and

there by inhibiting the synthesis of the ripening hormone ethylene. Since the acetaldehydes were found to be carcinogenic recently, their use for commercial post-harvest applications is limited. Hence, as an alternative, more research is being carried out with ethanol (a GRAS compound). Currently formulations based on alcohol powers that gradually release ethanol vapors are being tested. It was found to have the ability to inhibit the superficial scald on apple, a maturity related disorder. However, it couldn’t delay the ripening in banana as it couldn’t penetrate through the thick peel of it. Thus, no general conclusion can be drawn from the ethanol treatments, since the fruit response is dependent on a wide number of variables (species, cultivar, maturity, concentration, treatment period etc.) and would limit its commercial use.

c.) Salicylic Acid (SA) and Nitric oxide (NO) Salicylic acid as a natural and safe phenolic compound that exhibits high potential in

controlling post-harvest losses in horticultural crops. SA delays respiration, softening of fruits, and prevents the fruits from diseases. Application of SA as pre- harvest and post- harvest application of fruits reduces respiration rates, suppress the ethylene production/ delay in appearance of climacteric peak and delay the fruit ripening and softening.

Nitric oxide (NO) is recognized as a biological messenger in plants and optimum NO levels could delay the climacteric phase of many tropical fruits and prolong the post-harvest shelf life of a wide range of horticultural crops by preventing ripening and senescence. Nitric oxide fumigated fruits reduced ethylene production due to binding of NO with ACC and ACC oxidase to form a stable ternary complex, thus limiting ethylene production.

d.) Polyamines Polymaines are the naturally occurring compounds found in most of the living

organisms i.e. both plants and animals where they play a wide range of physiological roles. They too have the S-adenosylmethionine (SAM) as their precursor compound and thus they compete with the ethylene biosynthesis. Thus, an appropriate balance between these two opposite growth regulators is crucial in retarding or accelerating the ripening process. Some of the most commonly used polyamines for exogenous postharvest treatment include putrescine (Put), spermidine (Spd), and spermine (Spm). Spermine (1.5 mM) and spermidine (2.0 mM) were found to extend the shelf life of kiwi fruits during storage at ambient conditions.

Fig 3. inhibito

e.) 1-M which baction. receptorstandardpowdereffectivfruit increstricteinducedin reduc

f.) PotaPotassiuethylenlimited dissolveoxidatioatmosph

(A) Ethylors; (B) Mo

CP Treatm1-Methylcybinds with Its affinity rs with timd temperatur that releaseve even at vclude the ined skin colod postharvescing chilling

assium permum permane scrubber. extent in so

es in water on by potashere. This

lene biosynode of actio

ment yclopropene

ethylene rto receptor

me, thus fruure and prees its activevery low conhibition oor changes, st physiologg injury sym

manganatenganate, an

Scrubbing ome commto give int

ssium permawas made

nthesis (Yaon of ethyle

e (1-MCP receptors irrs is tenfolduit ripeningessure, thise ingredientoncentrationf respiratioprolonged

gical disordmptomsin tr

e (KMnO4)n effective

units basedercial storatensely pinkanganate is possible w

43

ang) cycleene action i

or C4H6) rreversibly d greater thag is not coms 1-MCP is when mixens of ppb leon and ethy

cold storagders. 1-MCPropical fruit

) oxidizer of

d on the catge facilitiesk or purplehighly dep

with the ab

showing inhibitor i.e

is known so that ethan ethylenempletely ins a gas thaed with watevels.The b

ylene produge life and aP treatment t during cold

f ethylene, talytic oxidas. It is a sta solutions.

pendent on ibsorption o

action of e. 1-MCP

as ethylenhylene canne. Plant tissunhibited butat has been er. This non

beneficial efction, delayalleviation ohas also be

d storage.

is commeation of eth

able purple The effectiits surface aof KMnO4

various sy

ne action innot bind anue synthesit only delaformulated

ntoxic compffects of 1-yed fruit soof certain eeen found e

ercially usehylene are usolid whichiveness of earea expose

onto poro

ynthesis

nhibitor, nd elicit zes new

ayed. At d into a pound is MCP in

oftening, thylene-effective

d as an used to a h readily ethylene ed to the ous inert

44

materials such as celite, vermiculite, alumina, zeolite, and clay etc. Some of the commercially available carriers of potassium permanganate using alumina beads are Purafil (Purafil, Doraville Ga), Circul-Aire (Circul-Aire, Montreal), Ethysorb (Molecular products, Thaxted, Essex) and Bloomfresh (Ausdel, Cheltenham, Victoria) etc.

Conclusion:

From the very time of harvest, all fruits begin to lose their quality and eventually decay. Ethylene is the natural plant hormone generated internally, which governs the speed at which quality and freshness are lost. The ethylene management decisions are usually dependent on the type and value of the produce, handling and storage conditions, destination market etc. the return on investment guides the adoption of any of the available postharvest technologies for ethylene management. Maintaining very low ethylene level is very important especially during storage and transport because ethylene-rich environments can trigger the ripening process too quickly, which results in spoilage, loss and waste. The efficacy of the postharvest treatments can be enhanced manifold by following hybrid approaches through combination of technologies aimed at regulation of vital physiological processes viz., respiration transpiration and ethylene production. The best fit approach for each and every commodity needs to be worked out in consultation with all major stakeholders in the fresh fruit handling.

45

Different Packaging Material for Some Major Fruits

R. R. Sharma

Division of Food Science and Postharvest Technology ICAR- Indian Agricultural Research Institute, New Delhi, 110012

Introduction

Nowadays packaging has become an integral part of fresh and processed fruits. Almost all the fresh products are packaged and shipped to the consumers. Hence, this document has been compiled to describe the different aspects of containers used for packaging of fresh fruits. Packaging should be designed to prevent premature deterioration in product quality, in addition to serving as a handling unit. Packages should prevent or reduce physical injury during transit and handling, provide ventilation to hasten cooling and escape of heat caused by respiration, and reduce water loss from the produce. Some packages promote sale of the produce.

Roles of Packaging

The prime goal of packaging is to contain the food in a cost-effective way that satisfies industry requirements and consumer desires, maintains food safety and minimizes environmental impact. The specific roles of packaging can be enlisted as:

Packaging materials used to serve the following purposes: Besides providing a uniform-size package to protect the produce, there are other requirements for a container

o It should be easily transported when empty and occupy less space than when full, e.g. plastic boxes which nest in each other when empty, collapsible cardboard boxes, fibre or paper or plastic sacks

o It must be easy to assemble, fill and close either by hand or by use of a simple machine

o It must provide adequate ventilation for contents during transport and storage

o Its capacity should be suited to market demands

o Its dimensions and design must be suited to the available transport in order to load neatly and firmly

o It must be cost-effective in relation to the market value of the commodity for which used

o It must be readily available, preferably from more than one supplier

Packaging materials for fresh produce

1. Basket made of woven strips of leaves, bamboo, plastic etc.

2. Sacks: flexible, made of plastic or jute.

i) Bags: small size sack

ii) Nets: sacks made of open mesh

iii) Net bags

3. Wooden crates

14

46

4. Fibreboard boxes

i) Solid fibreboard boxes

ii) Corrugated fibreboard boxes

5. Plastic crates

6. Biodegradable plastic material

7. New innovations in packaging of fruits, vegetables and root crops such as blister packaging, punnets for strawberry, flow pack wrappers, wrapping films etc.

8. Pallet boxes and shipping containers

Precautions during packing

o Containers should not be filled either too loosely or too tightly for best results

o Loose products may vibrate against each other and cause bruising

o Over-packing results in compression bruising

o Proper filling along with cushioning can minimize rubbing damage

Packaging of some common fruits

1. Raw fruits: Raw fruits may be packed loose in bulk or packed in containers for trading and transport. Fruits should be packed in new loosely woven gunny bags or wooden/plastic crates or in lined or unlined corrugated fibreboard boxes.

2. Guava, Lime and mandarin: They should be packed in wooden boxes or lined or unlined corrugated fibreboard boxes. The boxes should be made in such a manner as to allow for proper aeration of the fruits. Sufficient quantity of straw should be put in the container to prevent fruits from rubbing against each other. Super grade fruit should be wrapped individually either in tissue paper or in any other suitable material before being packed into the container.

3. Grape: Grapes are highly perishable in nature and after harvest needs treatments to prolong the shelf life. The grapes harvested at optimum maturity packed in ventilated CFB boxes of 4 kg capacity lined with polythene film containing one sheet of grape guard (protect against decay) can be stored for 45-50 days (Flame Seedless) and for 30 days (Perlette) at 0-2°C temperature and 90-95% RH. The 3 ply CFB boxes which can hold 2 to 4 kg of grapes are generally used for domestic purpose. The boxes are perforated and line with newspapers. Plastic crates are also used for local market. For export purposes: The grapes are placed in polyethylene pouches with vents and then arranged in trays and finally trays are made into a pallet then cooled and kept in cool storage for export. 4. Kinnow: Harvest the fruits at proper maturity, packed in ventilated corrugated fibre board boxes can be stored for 45 days at 5-6°C with 90-95% RH. Waxing of the fruits also enhance the shelf life of Kinnow. After harvesting, clean the fruits with 0.01% chlorinated water, dry under shade and then apply Citrashine wax. After waxing, dry the fruits under shade and then pack in CFB boxes. These can be stored for two weeks at ambient temperature. Another wax NIPRO Fresh SS-40T or SS-50 can also be successfully applied on Kinnow fruits which can be cold stored for 45 days in cold rooms and 10 days at room temperature.

Shrink Wrap Packaging (SWP) SWP is a packaging technology that helps in extending the shelf-life of fresh fruits

products, reduces shrinkage, weight loss, occurrence of various blemishes and refrigerated

cost. Thneeds aSWP cashrink wanotherbarrier commo the packlife of th

Advant1) Main2) As th3) Prev4) Redu5) Leas6) Dela7) Mini8) EnhaExamp1. Kinnwrappepacked room te

he techniquattention in dan be done wrapping, thr protective

between thodity from d

Tray wrap kage therebhe commod

tages of shrntains freshnhe fruit is vients seconduced chillingt contamina

ay ripening aimize the usanced aestheples of somenow: Marked. After pain 10 micr

emperature.

e is well esdeveloping either indivhe fruit is player after

he fruit andeterioration

packaging by helping idity.

Flow Char

rink wrap pness due to isible, consu

dary infectiog injury ation possiband undesirse of chemicetic value the fruits cometability of

acking themron thick hi

tablished incountries li

vidually or acked indivnaturally p

nd external n and thus hon the othen retardatio

rt for carry

packaging reduced weumer can exon which is

ble due to exrable colourcals. hus fetches

mmonly shrthe fruits c

m in mouldegh density

47

n developedike India whas tray over

vidually as apresent cutic

atmospherhelps in exteer hand helpon of senesc

ying out sh

eight loss xamine the pimportant f

xternal cover developme

higher pricerink wrappcan be enhaed trays, Kipolyethylen

d countries shere postharr wrap packa single unitcle or bloome. This pro

ending its shps in creatincence and w

rink-wrap

produce beffor long term

ering ent

e in the marped anced for 2 nnow fruitsne bags and

such as Israrvest loses akaging. In ct with the wm thereby aocess helpshelf life. ng a micro which result

packaging

fore purcham storage

rket

weeks, if ths can also bd can be sto

ael, USA, Sare more thcase of indi

wrap aroundacting as a ps in protec

environments in enhanc

g

asing

he fruits arbe individuaored for 8 w

pain but an 30%. vidually

d making physical ting the

nt inside ced shelf

re shrink ally seal weeks at

48

2. Peach: This is highly perishable fruit and has very short shelf life of 1-2 days at ambient conditions. To improve the shelf life of peach fruits, these should be packed in heat shrinkable films or cling film. The shrink film prolonging the shelf life for 9 days at 18-20°C temperature and 4 days at 28-30°C temperature. 3. Pomegranate: Individual pomegranate fruit shrink wrapped in flexible film extended the shelf life of fruits for 3-4 weeks at ambient conditions and 10-12 weeks at 8°C temperature. Modified Atmosphere packaging (MAP)

MAP is very effective in retaining freshness, and for extending the shelf life of fresh fruit. MAP is also ideal for the marketing of minimally processed produce, such as mixed salads, fruit salads and fresh cut produce. This type of package is designed to exactly match the handling conditions and respiration rates of specifically packaged produce, by manipulating O2 and CO2 levels in the packages, so as to:

• Reduce loss due to the production of respiratory heat by produce;

• Maintain the natural fresh taste of produce;

• Extend the shelf life;

• Delay ripening.

In some instances, MAP films are impregnated with minerals, in order to absorb and remove ethylene produced in the storage environment around the bagged produce. Impregnated MAP films are particularly suitable for transporting bulk fresh fruit to distant markets or between farmers and consumers at supermarkets and retail outlets. The produce must, however, be properly handled and packaged prior to transport. Recent successes in the use of MAP for reducing postharvest losses in fresh fruits are as follows:

Advantages of MAP

• Extends shelf life

• Prevents dehydration

• Retains green color and prevents yellowing

• Preserves fresh taste and aroma

• Delays ripening

• Prevents fungal and bacterial growth

• Increases the sale of fresh produce

Conclusion:

Food packaging is a system by which the fresh or processed produce will reach the consumer from the production centre in a safe and sound condition at an affordable cost. It serves two basic objectives, i.e., marketing and logistics. Adopting improved packaging, handling and transportation methods during distribution and marketing can successfully avert huge post-harvest losses.

49

Packaging of Fresh Fruits

R. A. Kaushik

Department of Horticulture, Rajasthan College of Agriculture MPUAT, Udaipur

Packaging is defined as a mean or system by which a fresh produce or processed product will reach from the production centre to the ultimate consumer in safe and sound condition at an affordable price. Packaging is the backbone in taking the fresh fruits from grower to consumer in the right condition.

Packaging is required to keep fruits in good condition until it is soled and consumed

Packaging serves as an efficient handling unit to carry produce from field to consumer

The package should also protect the produce against rotting

Packages must protect against possible damage

The product requirements, the marketing system and the personnel preference will determine the type of packaging to use

There is an urgent need to adopt proper post harvest management practices by adopting improved packaging, handling and efficient transportation methods

Packaging materials are used to serve the following purposes

Serves as an efficient handling unit

Protects from mechanical damage

Protects against moisture loss

Provides clean and sanitary storage

To prevent pilferage

Provides sales and service motivation

Reduces cost of transport and marketing Functions of Packaging Material Two main functions of packaging are

To assemble the produce into convenient units for handling

To protect the produce during distribution, storage and marketing Cushioning material

Dry grass, paddy straw, leaves, saw dust, paper shreds etc. can be used as cushioning material for packaging fruits

It should dissipate the heat of respiration of the produce

It should be free from infection and should be physiologically inactive

Moulded pulp tray, honeycomb portion, cell pack are used

One of the newest trends in produce packaging is the shrink-wrapping of individual produce items. Shrink-wrapping with an engineered plastic wrap can reduce

Shrinkage,

Protect the produce from disease,

Reduce mechanical damage and

Provide a good surface for stick-on labels

15

50

Care during filling of container/package Containers should not be filled either too loosely or too tightly for best results

Loose products may vibrate against each other and cause bruising

While over-packing results in compression bruising

Proper filling along with cushioning can minimize rubbing damage Packaging Requirements

Different horticultural products need different types of packages depending on their physical, anatomical and physiology (mainly transpiration, respiration and ethylene production rate) nature and susceptibility to microbial decay. Temperature, relative humidity and ventilation also play a very important role in determining the post-harvest life of the fresh produce. Thus, the packaging requirements for fresh produce are • Protection against bruising and physical injury • Protection against microbial contamination and deterioration • Provide ventilation for respiration and exchange of gases • Protect against moisture / weight loss • Slow down respiration rate, delay ripening and increase storage life • Control ethylene concentrations in the package.

Types of packages for fruits

1. Consumer / Retail packs Consumer Packs Consumer packages are small in size and designed to hold ½ dozen

– 1 dozen fruits or ½ kg to 2 kg of fruits. Many types of packages in terms of forms and materials are used as consumer packs. The selection criterion for the type of consumer pack depends on marketing characteristics of the product. The most commonly used packages are Flexible Plastic Films: Different types of flexible plastic films like LDPE (Polyethylene),

PVC (Poly Vinyl Chloride), PP (Polypropylene) and cellulose acetate films are used for packaging of horticultural produce. These films are mostly used as pouches with holes punched at regular intervals to allow respiration. They are available in a wide range of thicknesses and grades and can be engineered to control the environmental gases inside the pouch. LDPE is the most widely used material.

Trays with Overwrap: The trays used are usually made of moulded pulp tray or plastic material like EPS, PVC and PP. The produce is placed in individual cavities so that abrasion and bruising is avoided during transportation. The trays also provide cushioning effect to the produce. The overwrap film is a transparent see through food-grade, odourless plastic film with the property of clinging to the product packed when stretch wrapped. This film can be applied without the application of heat. It is usually made of LDPE, LLDPE or PVC. The films are semi-permeable and allow exchange of gases for respiration of the product.

Plastic Punnets: These are strong, versatile, clear, bright containers, which offer product visibility and are provided with holes for ventilation, which keeps the produce fresh. These containers are food-grade, odourless, light weight, stackable and recyclable and give good presentation. They are either made of PET, PVC or PP

51

Plastic Net bags (Extruded & Woven): The plastic net bags have the feature to stretch and accommodate all sizes and shapes of produce. These bags are available in roll form or in precut lengths with stretch width of 200 mm – 400 mm. By allowing air to circulate in and around the produce, these net bags prolong the freshness and shelf-life of the fresh produce. They also eliminate pack condensation thereby preventing spoilage and wastage. They make a colourful point of sale display by allowing clear visibility of the contents, enhancing the natural colours of fresh produce. These are generally made of HDPE (High Density Polyethylene) or PA (Polyamide).

Foam Sleeve: This is a plastic tubular film made of polyethylene foam available in different colours, diameters and lengths. It can be easily slipped over the individual fruits in a snug fit form. It provides a cushioning effect and protects the fresh produce against abrasion and scratches during transit. It is hygienic, nontoxic and odourless.

Light Weight Plastic Crates: These are lightweight crates, which need not be put into an outer pack for transportation. The perforations provide ventilation and keep the produce fresh. The crates are stackable and have high compression strength and therefore provide adequate protection to the fresh produce packed inside. These crates are hygienic, clean, reusable and can be recycled. They can be made of HDPE or PP.

Shrink Wrap: One of the newest trends in fresh produce packaging is the shrink wrapping of individual produce. The greatest advantage of individual shrink wrapping is its ability to control moisture loss. By reducing the transpiration rate and maintaining the fruit firmness the film forms a barrier which increases the resistance to water vapour. The transpiration rate can be reduced 5 to 20 times using selective permeable plastic films. The individual fruit is loosely sealed in a flexible film. The film is then shrunk tightly around the produce by passing these packs through a heat shrunk tunnel where they are exposed to hot blown air for a very short period (few seconds). The fresh produce is then cooled by rapid ventilation. The films most commonly used are LDPE or LLDPE.

Corrugated Boxes/Cartons: Many fruits like mangoes, apples, grapes, etc. are packed in small packs of 2-4 kgs, either in corrugated boxes made of paper board or polymers like polypropylene. These boxes/cartons are light-weight with good compression strength. They can be printed to have a good shelf appeal.

Trays with Overwrap Plastic Punnets

Pla

Light We

Corruga

W

astic Net ba

eight Plasti

ated Boxes/

ooden Box

ags

ic Crates

Cartons

es

52

Corrugate

Foam Sl

Shrink W

Bamboo B

d Fibre Bo

leeve

Wrap

Baskets

oard/Plasticc Boxes

53

17

Sacks Cushioning material 2.Transport / Bulk packs

Transport packages are designed for long distance transportation in capacities ranging from 4 – 5 kgs to 20 – 25 kgs. These packs must withstand impacts, compression and vibration during transport. The transport packages can be broadly categorized as rigid containers made of wood, corrugated fibre board or plastics and flexible containers such as sacks made of plastic. Along with these materials some traditional materials used are jute (jute sacks), wooden boxes and bamboo baskets. The variety of packaging materials used for transport packaging of fresh fruits are Bamboo Baskets: Bamboo baskets are widely used even today as transport packs in domestic market. They are available in various shapes, sizes and designs but they do not have rigidity and stackability during long distance transport. Today plastic baskets or Kilta’s have also been developed and used for storage & transportation of fruits. Wooden Boxes: The conventional baskets have been replaced by wooden boxes as they give better protection to the fresh produce against transportation hazards. They have high puncture resistance, good tensile strength as well as compression strength; but they occupy more space and add on to the tare weight. Also, the nails cause injuries to the produce during long transportation. However, the use of wooden boxes is discouraged now-a-days as it directly promotes deforestation. Corrugated Fibre Board/Plastic Boxes: Corrugated fibreboard boxes are widely used as transport/ shipping containers for fresh produce because of the following advantages : Low cost to strength and weight ratio Good cushioning properties Smooth and non-abrasive surface Good printability on the outer surface of the board Easy to set up and collapsible for storage Reusability and recyclable They can be manufactured in high volumes They can be provided with ventilation by punching holes.

Since the CFB boxes have poor wet strength, now-a-days they are laminated with plastic film like LDPE, PP or PVC. Plastic corrugated boxes made of PP and HDPE are partly replacing CFB boxes because of their low weight to strength ratio, high degree of water resistance and re-usability. However, its cushioning properties are not comparable to CFB • Plastic Crates: These are usually made of HDPE or PP by injection moulding. Polyethylene has higher impact strength and a low degradation by ultra-violet radiation while

54

polypropylene has a better scratch resistance. The performance of both materials can be improved by adding antioxidants and UV protectants (for sunlight protection). These crates are either of stackable, stack-nest or collapsible in design. Collapsible plastic crates are the most expensive crates followed by stack-nest and then the stacking crates. The collapsible crates reduce the storage space requirement and transport cost of empty containers. The normal capacity varies between 20 – 40 kg. Sacks: These are generally used to bring the raw materials from the field. The commonly used materials are cotton, jute, plastic (HDPE, PP). They are very useful because of low cost, high strength, re-usability and require less space for empties. However, they have low protection against puncture, compression, vibration and impact injuries. They are poor in stackability. These sacks are usually combined with bamboo baskets and wooden boxes to improve cushioning and reduce bruise injuries and losses during transportation.

55

Determination of Physiological Loss in Weight,

Total Soluble Solids and Total Sugars in Fresh Fruits

Vijay Rakesh Reddy, S. ICAR-Central Institute for Arid Horticulture, Bikaner

Physiological Loss in Weight (PLW): Water is the major component of majority of the fresh fruits. It is stored in the

vacuoles of plant cells and thus maintains the cell turgidity. Generally, freshly harvested fruits are more turgid and with the passage of time, they lose some water through transpiration and get shrivelled gradually. Thus, loss of water is the major factor rendering the fresh produce unattractive to consumers. In general, it is said that any fresh fruit losing more than 10 per cent moisture from it could render them unfit for consumption. However, few fruits such as apple appear quite attractive even after loss of 10 per cent moisture. Hence, determination of moisture loss from freshly harvested fruit is very important. Physiological loss in weight of the fresh produce is mainly due to

Water loss from the commodities

Metabolic activity due to utilisation of respiratory substrates Water loss is water vapor movement from product to the environment. Water loss from the commodities occurs in the form of transpiration through the stem ends, epidermis and stomata. In certain fruits, through the peel, lenticels and from the damaged surfaces. Water loss is affected mainly by packaging, temperature, relative humidity and airflow as well as product characteristics. Water loss is cumulative and it predominantly affects the quality, loss of salable weight, freshly appearance, texture, turgidity due to altered physiology of the produce since harvest. Material required: Fruits, weighing balance, thermometer, hygrometer, trays Procedure: Take the sample of fruit divide them in to two batches, mark them and note down

their initial weights Keep them in the trays and keep the two batches of fruits at two different storage

conditions i.e. one batch under ambient conditions and the other under refrigerated conditions.

Record the temperature and humidity of the chambers where the produce have been placed using the thermometer and hygrometer

Keep a record on loss of physiological weight everyday Calculate PLW (%) as per the following formulae record it in your practical records. ( ) = ( − )

Compare the data of the produce stored under ambient conditions and refrigerated conditions to know the effects of temperature and humidity in controlling PLW.

Compare the PLW data of fruits to know which kind of produce losses more water with storage.

Also, note if any fruit remain attractive and edible even after loss of 10 per cent PLW.

16

56

Total Soluble Solids (TSS): Total Soluble Solid represent the amount of water soluble solids present in the unit

volume of solution extracted from fruits. It primarily includes sugars, very less quantity of organic acids and other water soluble polysaccharides. Generally, high TSS represent more sweetness and vice-versa. Traditionally, TSS is measured in percentage using Abbe’s Refractometer or Hand refractometer. It is also represented by degree brix (ºB) at 20ºC. Now a-days digital refractometers are available for the measurement of TSS. The Brix is usually considered equivalent to the percentage of sucrose (sugar) in the solutioni.e. (60° Brix is equivalent to a sugar content of 60%). Principle:

The main principle behind the measurement of TSS using refractometer is based on the measurement of critical angle which is defined as the angle of refraction when the incident radiation passes through a medium at an angle of 90 degrees i.e. grazing angle. The medium when viewed from the other end, the critical rays appears as the boundary between a dark and a light field. Thus, the refractometer measures the ability of any solution to bend or refract a light beam, which in-turn is proportional to the solution’s concentration. The degree of refraction depends on the density of the medium through which the light passes. Whenever the solution changes its concentration, there would be change in the refraction and it could be easily measured with refractometer. Total soluble solids (ºB) is also temperature dependent.

Hand Refractometer and its components

Procedure: 1. Checking/ calibration of the refractometer: this is to be done with distilled water. Add

two drops of distilled water on the prism of refractometer. Cover the lid and view the

57

reading through the eye piece. If the demarcation line between dark and light coincides to 0 of the scale, then the instrument needs no calibration.

2. Extract the juice and filter it through muslin cloth in a clean and dry beaker 3. Note the temperature of the sample 4. Take a drop of the representative sample on the prism of the refractometer and read

the value in similar way as mentioned in first step. 5. If the determinations are made at temperatures other than 20ºC, correct the reading at

20ºC with the help of temperature correction chart given below

Precautions:

1. Wash the prism with distilled water and wipe it carefully using soft tissue paper in order to avoid scratches

2. Set zero on the prism using distilled water 3. Temperature corrections should be done to get exact values of TSS

Reducing and Total Sugars: Sugars are basically polyhydroxy aldehydes/ketones. Fruits contains majorly two types of sugars; i.e. fructose and glucose. The proportions of each vary, but most fruits are about half glucose and half fructose. Glucose raises blood sugar, so the body must use insulin to metabolize it. Fructose does not raise blood sugar. Reducing sugars are the sugars that are capable of acting as a reducing agent because they have a free aldehyde group or a free ketone group. All monosaccharides (galactose, glucose, glyceraldehyde, fructose, ribose, and xylose) are reducing sugars, along with some

58

disaccharides (cellobiose, lactose, and maltose), some oligosaccharides, and some polysaccharides. Sugars are estimated using Lane and Eynon method, wherein the Invert sugar reduces the copper in Fehling’s solution to red, insoluble cuprous oxide. The sugar content in the food sample is estimated by determining the volume of the unknown solution required to completely reduce a measured volume of Fehling’s solution. Principle: Lane and Eynon method is based on the principle of reduction of Fehling’s solution by reducing sugars. Fehling’s solution is a mixture of copper sulphateand alkaline Rochelle salt (sodium potassium tartarate). Rochelle salt complexes with the cupric hydroxide formed in alkaline solution and prevent itfrom precipitation. Reducing sugars reduces the complexed cupric hydroxideto red, insoluble cuprous oxide under the experimental conditions. Anoxidation-reduction indicator, usually methylene blue, detects the end point ofthe reaction. The first step in the estimation of reducing sugars by Lane and Eynon method is the determination of Factor for Fehling’s solution. Fehling factor is thequantity of invert sugar in grams required to completely reduce the Fehling’s solution (usually 5 ml each of Fehling’s A and B solutions). Total sugars include reducing sugars and non-reducing di - and oligosaccharides like sucrose, which on mild acid hydrolysis are converted intoreducing sugars. Starch is hydrolysed by strong acids into glucose. Materials required: Chemical balance, 1mg sensitivity; Hot plate; Burette (50 ml cap.) with an off-set tip, Volumetric flask, 250 ml; Pipette, 5 ml and 25 ml; Conical flask, 250 ml; Weighing bottle; Funnel (small); Whatman No. 1 filter circles Chemicals/ Reagents Fehling’s solution A: Dissolve 69.28 g copper sulphate (CuSO4.5H2O) indistilled water and dilute to 1000 ml. Filter and store in amber colour bottle. Fehling’s solution B: Dissolve 346 g Rochelle salt (Potassium sodium tartrate: KNa C4H4O6.

4H2 O) and 100 g NaOH in distilled water. Dilute to 1000 ml.Filter and store in amber colour bottle. Neutral lead acetate solution: Prepare 20% neutral lead acetate solution. Potassium oxalate solution: Prepare 10% potassium oxalate (K2C2O4. H2O) solution. Methylene blue indicator: Prepare 1% methylene blue solution in distilledwater. Procedure: Standardization of the Fehling’s Solution for Invert Sugar: Accurately weigh 4.75g of AR grade sucrose. Transfer to 500 mlvolumetric flask with 50 ml distilled water. Add 5 ml conc. HCl and allow to stand for 24 hr. Neutralise the solution with NaOH

using phenolphthalein as end point indicator and make up to volume. Mix well and transfer 25 ml to a 100 ml volumetric flask and make up to volume (1

ml = 2.5 mg of invert sugar). Transfer to a burette having an off-set tipand titrate against Fehling’s solution (5 ml of

A and 5 ml of B) as described below for sample.

59

Observations: Titre = V1 ( ml) Calculations: ′ ( ) = .

= 0.0025 × V1 (grams)

Determination of Reducing sugars: Preparation of sample: Weigh accurately 10-50 g sample as such (juices, beverages etc.) or homogenized sample (jams, preserves etc.) and transfer to 500 ml volumetric flask. Add about 100 ml water and neutralize with NaOH solution to phenolphthalein end point. Add 10 ml neutral lead acetate solution, shake and let stand for 10 min. Add potassium oxalate solution in small amounts until there is no further precipitation. Make up to volume, mix the solution well and filter through Whatman No. 1 filter circle. Transfer the filtrate to a 50 ml burette having an off-set tip. Preliminary titration: Pipette out 5 ml each of Fehling A and B solutions in to 250 ml conical flask. Mix and add about 10 ml water and a few pumice stone or glass beads. Dispense the sugar solution from the burette. Heat the solution to boiling. Add 3 drops of methylene blue indicator. Continue the addition of the sugar solution drop wise until the blue colour disappears to a brick-red end point. (The concentration of the sample solution should be such that the titre value is between 15 to 50 ml). Maintain a total boiling period of 3 min. Note down the titre value. Final titration: Pipette out 5 ml each of Fehling A and B solutions into a 250 ml conical flask. Add sample solution about 0.05 to 1.0 ml less than titre value of the preliminary titration. Heat the flask to boiling. Add 3 drops of methylene blue indicator. Complete the titration within 1 min by adding 2 to 3 drops of sugar solution at a time, until the indicator is decolourized. At the end point, the boiling liquid assumes the brick redcolour. Note down the titre value. Perform the titration in duplicate andtake the average. Note: i) Preliminary titration must be finished within 3 min. ii) Conical flask should not be disturbed or removed from the burner before the titration is finished. Observations: Weight of the sample = W (g) Dilution volume for the sample = V2 (ml) Volume of clarified sample solution required for Fehling’s reaction(titre) = V3(ml) Calculations: Based on the factor for Fehling’s solution, V3 ml sample solution contains: 0.0025 V1 g reducing sugar (as invert sugar) 0.0025 × V1 × V2 × 100 Therefore, % = . = . = %

Results: Reducing sugars (as invert sugar) = % by wt.

60

Determination of Total sugars Principle: Total reducing sugars represent reducing sugars and non-reducing di and oligosaccharides, which can be hydrolysed into reducing sugars with dilute acids. Procedure: Pipette an aliquot of 50 ml of the clarified, de-leaded filtrate to a 100 ml volumetric

flask. Add 5 ml of conc. HCl and allow to stand at room temperature for 24 hours. Neutralise with conc. NaOH solution followed by 0.1N NaOH using phenolphthalein

as end point indicator. Make up to volume and transfer to 50 ml burette having an off-set tip. Perform the titration against Fehling's solution similar to the procedure described for

reducing sugars, and determine the total sugars as invert sugars. Observations:

Volume of the acid hydrolysed sample solution required for Fehling solution (titre) = V4 (ml) Calculations:

Based on the factor for Fehling’s solution, total reducing sugars in V4 (ml) = 0.0025 × V1 g

As 50 ml of the clarified and de-leaded solution is diluted twice (50 ml to100 ml) after hydrolysis, dilution volume of the sample = (2 × V2). Therefore, % = . = . = %

Total reducing sugars comprises of reducing sugars and non-reducing sugars, which can be hydrolysed into reducing sugars under the experimental conditions. This non-reducing sugar is usually expressed in terms of sucrose.

As 0.95 g sucrose on hydrolysis yields 1 g invert sugar (glucose + fructose): % Sucrose in the sample = (Total reducing sugars − % Reducing sugars originally present) × 0.95 = (Y – X) × 0.95 [% Total sugars = (% Reducing sugars + % Sucrose)]

61

Causes of Post Harvest Losses in Fresh Fruits and

Their Control Measures

Ram Asrey Division of Post Harvest Technology, Indian Agricultural Research Institute, New Delhi

Estimates of the post-harvest losses of food grains in the developing world from mishandling, spoilage and pest infestation are put at 25 per cent; this means that one-quarter of what is produced never reaches the consumer for whom it was grown, and the effort and money required to produce it are lost-forever. Fruit crops are much less hardy and are mostly quickly perishable, and if care is not taken in their harvesting, handling and transport, they will soon decay and become unfit for human consumption. Causes of Losses

All fruits crops are living plant parts containing 65 to 95 percent water, and they continue their living processes after harvest. Their post-harvest life depends on the rate at which they use up their stored food reserves and their rate of water loss. When food and water reserves are exhausted, the produce dies and decays. Anything that increases the rate of this process may make the produce inedible before it can be used. The principal causes of loss are discussed below. Physiological deterioration

An increase in the rate of loss because of normal physiological changes is caused by conditions that increase the rate of natural deterioration, such as high temperature, low atmospheric humidity and physical injury. Abnormal physiological deterioration occurs when fresh produce is subjected to extremes of temperature, of atmospheric modification or of contamination. This may cause unpalatable flavours, failure to ripen or other changes in the living processes of the produce, making it unfit for use. Mechanical damage (physical injury) The high moisture content and soft texture of fruit crops make them susceptible to mechanical injury, which can occur at any stage from production to retail marketing because of: Poor harvesting practices. Unsuitable field or marketing containers and crates, which may have splintered wood,

sharp edges, poor nailing or stapling. Over packing or under packing of field or marketing containers. Careless handling, such as dropping or throwing or walking on produce and packed

containers during the process of grading, transport or marketing. Injuries caused can take many forms: Splitting of fruits from the impact when they are dropped. Internal bruising, not visible externally, caused by impact; Superficial grazing or scratches affecting the skins and outer layer of cells. Crushing of leafy vegetables and other soft produce.

Injuries cutting through or scraping away the outer skin of produce will. Provide entry points for moulds and bacteria causing decay. Increase water loss from the damaged area. Cause an increase in respiration rate and thus heat production.

Bruising injuries, which leave the skin intact and may not be visible externally causes: Increased respiration rate and heat production.

17

62

Internal discoloration because of damaged tissues. Off-flavours because of abnormal physiological reactions in damaged parts

Diseases and pests All living material is subject to attack by parasites. Fresh produce can become infected before or after harvest by disease causing agents widespread in the air, soil and water. Some diseases are able to penetrate the unbroken skin of produce; others require an injury in order to cause infection. Damage so produced is probably the major cause of loss of fresh produce.

Control Measures Harvesting at right maturity

A critical time for growers of fruit is the period of decision on when to harvest a crop. Normally any type of fresh produce is ready for harvest when it has developed to the ideal condition for consumption. This condition is usually referred to as harvest maturity. Confusion may arise because of the word maturity since, in the botanical sense, this refers to the time when the plant has completed its active growth (vegetative growth) and arrived at the stage of flowering and seed production (physiological maturity. Harvest maturity thus refers to the time when the "fruit" is ready to harvest and must take into account the time required to reach market and how it will be managed en route. This time lag usually means that it is harvested earlier than its ideal maturity. How is harvest maturity identified? Most growers decide when to harvest by looking and sampling. Judgments are based

on: Sight-colour, size and shape. Touch-texture, hardness or softness. Smell-odour or aroma. Taste-sweetness, sourness, bitterness. Resonance-sound when tapped. Experience is the best guide for this kind of assessment. Newcomers to fresh produce-

growing may find that learning takes time. Harvest maturity can readily be observed in some crops: bulb onions when their green tops collapse and potatoes when the green tops die off. Other crops can be more difficult: avocados remain unripe off the tree after maturity. When are conditions right for harvesting a crop? The basic rules to observe are: Harvest during the coolest part of the day: early morning or late afternoon. Do not harvest produce when it is wet from dew or rain. Wet produce will overheat if

not well ventilated, and it will be more likely to decay. Some produce may be more subject to damage when wet, e.g. oil spotting and rind breakdown in some citrus fruits.

Protect harvested produce in the field by putting it under open-sided shade when transport is not immediately available. Produce left exposed to direct sunlight will get very hot.

Harvesting technique In most circumstances, harvesting by hand, if done properly, will result in less

damage to produce than will machine-harvesting. Hand-harvesting is usual where fruit or other produce is at various stages of maturity within the crop, that is, where there is need for repeated visits to harvest the crop over a period of time. Machine-harvesting is usually viable only when an entire crop is harvested at one time.

63

Harvesting and field containers The packing of produce directly into marketing packages in the field at harvest

reduces the damage caused by multiple handling and is used increasingly by commercial growers. At all stages of harvesting and handling, methods should aim at avoiding damage to produce and providing ventilation to prevent temperature rises. Sorting

A preliminary sorting of produce should remove unmarketable pieces and foreign matter (plant debris, soil or stones) before the produce passes on to further operations. All discarded material should be quickly hauled away from the packing house or placed in closeable bins for later removal. This is because accumulations of decaying or infested waste in or near the packing house will contaminate produce destined for market. Cleaning and washing The removal of soil and stones mentioned above can be done by hand-picking or by sieving. Some types of produce can be washed, brushed, or cleaned with a soft cloth. Cleaning produce by hand-polishing or machine-brushing can remove light soil contamination or dust from produce, especially fruit. This should be done with care since damage to the skin of fresh produce will promote early decay. Washing is also required to clean produce which has acquired latex stains from injuries caused during harvesting, notably in mangoes, sapota and bananas. It is important to note that washing should be carried out only when absolutely essential. If it is necessary to wash produce, a fungicide should normally be applied immediately afterwards. Use only clean, running water for washing. The washing of produce in recirculated or stagnant water should be avoided because it can quickly become heavily contaminated with decay organisms, leading to heavy rotting of the washed produce.

Washed produce which is to be treated with fungicide should first be drained after washing in order to reduce the danger that residual wash water will dilute the fungicide below its effective concentration. When washing is not to be followed by fungicide treatment, the washed produce should be spread out in a single layer on raised racks of mesh or slats, in the shade but exposed to good ventilation to aid rapid drying. Fungicide treatment Most fungicides used for post-harvest decay control are in the form of wettable powders or emulsifiable concentrations. They form suspensions in water, not solutions; this means that they settle out of suspension if the mixture is not constantly agitated during its application. Thus the concentration of fungicide applied to the crop will fall below the effective level if the suspension is not continuously stirred. In small-scale packing operations, fungicide can be applied by: Dipping- Treatment is carried out by hand, using a suspension of fungicide agitated by hand; wire-mesh baskets can be used to dip several small pieces at one time; after dipping, produce should be drained and dried in a shaded, airy place. Spraying -This can be accomplished with a hand-operated knapsack sprayer while produce is still in trays or racks after washing and drying produce should be sprayed completely and to the point of runoff. Larger spraying operations may require a simple mechanized spray or drenching arrangement with a mechanical mixer for the fungicide. Produce passes through the spray or drenching in perforated trays perhaps while moving on a belt or roller conveyor. Other methods of application, such as smokes, dusts or vapour, are used only by large-scale operations where produce is to be stored.

64

Quality selection and size grading Although produce will have been sorted on the farm or on its arrival at the packing

house, there may be a further selection for quality and size immediately before it is packed. The scope of these operations depends on the market: will buyers be prepared to pay premium prices for quality-graded produce? Many urban customers are more demanding of quality than are rural customers. Selection and grading in a small packing house are best done by human eye and by hand. Waxing The application of wax or similar coating to enhance appearance and limit water loss from produce requires specialized equipment and has little relevance to small-scale packing. Packaging Packaging in small-scale operations means the filling of marketing containers by hand. Machines are used to pack durable produce like apples in big packing houses, but they are expensive and not suitable for small volumes of different products. There are various methods of packing: Loose-fill jumble pack is used where there is no advantage to size-grading; weighing

is necessary. Multilayer pattern pack has size-graded produce sold by count of the produce: citrus,

apples, etc. Multilayer size-graded pack used in mechanical packing has separator trays between

layers; sold on per-box basis. Single-layer packs for high-value produce may have each piece wrapped in tissue or

placed in a divider holding it alone; sold on per-box basis. Transportation and storage

In India and other developing countries, fruits are generally transported loose in tractor trollies and carts from field to local markets. The big traders get it grade and packed for different destinations. From local assembly markets, produce is transported by trucks and rail wagons. Un-vented rail wagons are not suitable for transport of fresh produce as the losses are very high during transit. Wooden and CFB boxes should be used for packing and transportation as these have high staking strength and suitable for truck transportation. Long period storage is generally advised cold storage meant for specific commodities. Low cost storage structure (zero energy cool chamber) having hollow cavity walls filled with fine riverbed sand with drip system of watering device from the top periphery for bring down temperature by evaporative cooling, have been found ideal for small scale on farm storage of fruits. In this chamber, storage life of the produce can be extended up to 15 days in summer months. The cost of 2 tonnes storage capacity chamber comes about Rs. 5000 to 6000. Controlled atmosphere (CA) and modified atmosphere (MA) techniques are also available, but these are commercially used for the storage of the high value crops.

65

Post-Harvest Treatments for Shelf Life Extension of

Horticultural Crops

Ram Asrey Division of Post Harvest Technology

Indian Agricultural Research Institute, New Delhi

Fresh fruits are living tissues subject to continuous change after harvest. Some changes are desirable from consumer point of view but most are not. Post-harvest changes in fresh fruits cannot be stopped, but these can be slowed down within certain limits to enhance the shelf life of fruits. The post-harvest treatments play an important role in extending the storage and marketable life of horticultural perishables. Some of such treatments are discussed briefly hereunder. Cleaning or washing

For some commodities such as Kiwi fruits and avocadoes, dry brushing may be sufficient to clean the produce. Other commodities, such as bananas require washing. The choice of brushing or washing will depend on the type of commodity and type of contamination. Certain produce should not be washed because washing will remove the natural waxes that protect the produce from water loss and the incidence of diseases.

Wash before cooling and packing: tomatoes.

Wash to remove latex, reduce staining: mangoes, bananas.

Wash after storage:

Dry brush after curing or storage: kiwifruit.

Chemical treatments

Washing with chlorine solution

Chlorine treatment (100-150 ppm available chlorine) can be used in washing water to help control inoculums build up during packing operations. Maintain pH of wash water between 6.5 and 7.5 for best results.

Use of growth regulator/ fungicides

The growth regulators (GA3) or fungicidal (Carbendazim) application can be effectively used to extend/ enhance the shelf life of fruits. In mandarins, such as kinnow, the application of Carbendazim/ thiabendazol increased the shelf life of fruits. Likewise, the application of cytokinins or GA3 (20 ppm) is helpful to extend the shelf life of citrus fruits particularly Baramasi lime. To control the mango anthracnose, the post-harvest dips of fungicides in cold water rarely reduced level of infections, but when fungicides was applied in hot water, complete control could be achieved. Treatment of litchi fruit with 0.25% SOPP (Sodium-ortho-ohenyl-phenate) in 6% wax emulsion provides protection against a number of fungal diseases.

Calcium application

The post-harvest application of CaCl2 or Ca (NO3)2 play an important role in enhancing the storage and marketable life of fruits by maintaining their firmness and quality.

18

66

The post-harvest application of CaCl2 (2-4%) for 5-10 minutes dip, extends the storage life of pear upto 2 months and apple upto 7 months and plum upto 4 weeks at 0-2OC with excellent colour and quality. Treatment of mangoes with 2-8% CaCl2 solution resulted in delayed softening of fruit during storage at 20OC by 8-12 days compared to untreated fruits.

Thermal treatments

Hot water treatment

Fruits may be dipped in hot water before marketing or storage to control various post-harvest diseases and improving peel colour of the fruit. In mangoes, the hot water treatment is recommended at 50-52OC for 5 minutes to reduce the fungal infection during ripening or storage. This treatment helps in attaining uniform ripening within 5-7 days. Fruits should not be handled immediately after heat treatment. Cool water showers or forced air should be provided to help return the fruit to their optimum temperature as soon as possible after completion of the treatment. Hot water treatment has been very useful in several other fruits (Table 1).

Table 1.Recommended hot water treatments for controlling different pathogens in fruits

Commodity Pathogens Temp. (°C) Time (min) Possible injuries

Apple Gloeosporium sp. Penicillium expansum

45 10 Reduced storage life

Grapefruit Phytophthora citrophthora 48 3 Lemon Penicillium digitatum

Phytophthora sp. 52 5-10

Mango Collectotrichum gloeosporioides

52 5 No stem rot control

Orange Diplodia sp. Phomopsis sp. Phytophthora sp.

53 5 Poor degreening

Papaya Fungi 48 20 Peach Monolinia fructicola

Rhizopus stolonifer 52 2.5 Motile skin

Vapour heat treatment (VHT) This treatment proved very effective in controlling infection of fruit flies in fruits after

harvest. For this treatment, the boxes containing fruits are stacked in a room, which are heated and humidified by injection of steam. The temperature and exposure time are adjusted to kill all stages of insects (egg, larva, pupa and adult), but fruit should not be damaged. A recommended treatment for citrus, mangoes, papaya and pineapple is 43OC in saturated air for 8 hours and then holding the temperature for further 6 hours. VHT is mandatory for export of mangoes.

67

Fumigation The fumigation with SO2 in successfully used for controlling post-harvest diseases of

grapes. This is achieved by placing the boxes of fruits in a gas tight room and introducing the gas from a cylinder to the appropriate concentration. Special sodium metabisulphite pads are available, which can be packed into individual boxes of grapes to release SO2 slowly. The primary function of treatment is to control the Botrytis cinerea. The SO2 fumigation is also used to prevent discolouration of peel of litchis. The fumigation of litchi fruits with sulfur dioxide (600 g/tonne of fruits), followed by dipping of fruits in 1M HCl for two minutes help in retaining the red colour of litchi fruits and maintaining the market quality for 3 weeks at 2°C and 90-95% RH. Paper pads or wraps impregnated with biphenyl fungicides are commonly applied to citrus fruits. The chemical vaporizes slowly thus protect the fruits from fungal infection. Irradiation Ionizing radiation can be applied to fresh fruits to control micro-organisms and inhibit or prevent cell reproduction and some chemical changes. It can be applied by exposing the crop to radiations from radioisotopes (normally in the form of gamma-rays but X-rays can also be used) and from machines, which produce a high-energy electron beam. Radiation doses are measured in Grays (Gy). In older literature, they were quoted in rads, where 1 Gray = 100 rads. Irradiation doses for different fruits are given in Table 2.

A combination of hot water treatment (55°C for 5 minutes) followed by 30 Gy irradiation was found to be the best treatment for shelf life extension and quality maintenance of mangoes. After this treatment, mangoes had a storage life of 38 days (at 15°C), 28% rotting and no irradiation injury. Irradiation can also be used to control postharvest diseases of other fresh fruits. Irradiation can be used as a postharvest treatment to disinfest fruit of insects. 300 Gy has shown to control mango stone weevil, 150 Gy prevents the adults emerging from the fruit. Doses of irradiation in excess of 600 Gy caused lenticel spotting, surface discoloration and retardation of ripening of Kensington Pride mangoes, but irradiation at this level contributed only minor improvement in disease control. However, irradiation followed immediately by hot benomyl treatment controlled anthracnose and stem-end rot during storage at 20°C for 15 days. In Hawaii, irradiation at a minimum of 250 Gy was recommended for the commercial control of fruit fly in papaya, preferably combined with hot water treatment. It has been reported that dosages of 100 Gy gave 100% prevention of the most resistant stage (third in star larva) from developing into adults in papayas. A dose of 25 to 50 Krad has been recommended for delaying the ripening of mango and banana fruits.

Table 2. Doses of irradiation for different fruits for postharvest disease control

Fruit crop Minimum dose required (Gy)

Maximum dose tolerated (Gy)

Apple 150 100-150 Apricot, peach, nectarine 200 50-100 Avocado -- 15 Lemon 150-200 25 Orange 200 200 Strawberry 200 200 Grapes -- 25-50

68

Waxing Waxing of fruits is a common post-harvest practice. Food grade waxes are used to

replace some of the natural waxes removed during harvesting and sorting operations and can help for reducing water loss during handling and marketing. It also helps in sealing tiny injuries and scratches on surface of fruits. It improves cosmetic appearance and prolongs the storage life of fruits.

The commercial available waxes are citrashine, Stayfresh, Sta-fresh 451, Semper fresh, Carnauba wax, bees wax etc. Coatings may be applied by either by dipping, brushing/ sprouting, spraying etc. The wax coating must be allowed to dry thoroughly before packing. Different types of coatings used in different fruits are given in Table 3.

Table 3. Specific coating applications for different fruits

Coating material Fruit Prolong Banana Semperfresh Banana Semperfresh with organic acid Banana Ban-seel Banana & plantains Tal prolong, Semperfresh and applewax Apple Nutri-save Golden delicious apple Semperfresh Granny smith apple Brilloshine Apple, avocado & citrus fruits Nu-coatflo, Brilloshine and Citrashine Citrus fruits Semperfresh Guava Palm oil Guava Vapor gard Mango Chitosan strawberry & raspberry N,O-Carboxymethyl chitosan Fruits Zein Tomato Trehalose Biological molecules & foods

final manual coa 24-06-2020

Documents