antioxidants presentation

Presented by

EZHIL . C

ANTIOXIDANTSIN

FOOD INDUSTRY

4/27/2010Antioxidants in Food Industry

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WHAT IS ANTIOXIDANT ?

Antioxidant is a substance which act against oxidation ( anti +oxidant )

It is defined as any substance which prevent ,retard or inhibit oxidation.

Oxidation –combination of oxygen which other elements 0r removal of hydrogen ion or removal of electron from an element.

Reduction –it is process of removal of oxygen or addition of hydrogen ion or addition of electron to an element


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Antioxidant is a reducing agent (donates electron, thereby causes another reactant to be reduced ).

How does it act against oxidation? -Hence it is a reducing agent ,it donates electron to the oxidizing agent. -it get oxidized itself and prevent other element from been oxidized.

Note :All antioxidants are reducing agent but all reducing agents are not antioxidants.


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Need for Antioxidants in food industry

Success of food product depends on consumer acceptability

Taste,Flavor and odour are important factors for a consumer –judge the product

Causes of deterioration -microbial destruction - Rancidity of fats and oils

Microbial destruction can be prevented by preservation and processing


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Rancidity can be prevented by freezing ,packaging under vacuum

These method are expensive and not completely satisfactory

There comes a need for alternative cost effective method – usage of antioxidants

First used during World War II for food preservation


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Definition

In food industry,

“ Antioxidants are defined as any substance which is capable of delaying ,retarding or preventing the development of rancidity or other flavour deterioration due to oxidation”


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Types based on Functionality

Two types -primary ( scavenging free radicals) -secondary ( inhibit the pro-oxidant which produce free radicals)

Primary Antioxidant

Free radicals - they are highly reactive particle - produced by auto oxidation of lipids - occurs at excited state by metal catalysis or by light


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Working mechanism

O2 Lipid Free radical Antioxidant electron 4/27/2010Antioxidants in Food Industry

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Secondary antioxidant

Pro oxidant – substance which can oxidize any element and in turn produce free radicals

Antioxidants combine with pro oxidant and form stable compounds

Thus no free radicals are produced


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Types based on production

General classification - Natural - ArtificalNatural Extract from natural raw materialsVariable compositionEx - Citric acid,Vitamin E ,tocopherol

Note :Nowadays most of natural antioxidant are also synthesized with same molecular structure for uniform composition


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ArtificalProduced by chemical reactionPure and of constant compositionEx-butylated hydroxyanisole (BHA) , butylated hydroxytoluene (BHT).

Note: Even though many natural and synthetic compounds have antioxidant properties, only a few of them have been accepted as ‘generally recognised as safe (GRAS)’.


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Mechanism

Antioxidants inhibit the oxidation by four mechanism

Hydrogen donation by the antioxidant

Electron donation by the antioxidant

Addition of the component(oxidizing element) within the aromatic ring of the antioxidant

Formation of complex between the oxidizing compound with the antioxidant


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Usage in food Products

Ascorbic acid and citric acids – prevention of oxidative discoloration of meats ,fruits.

They are also used against discoloration due to enzymatic oxidation

Water soluble Rosemary extracts are used in sauces, marinades and salad dressings (Giese,1996)

Oil soluble Rosemary extracts used in lipid based foods.

This is stable at higher temperature and very active even at a concentration of 0.02%


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Rice bran oil proposed as antioxidant spray for snacks. It removes objectionable colour and flavours.(Taylor et al.,1996)

It contains several antioxidants such as tocopherol, tocotrienols, oryzanol and triterpene alcohols

It is also used to preserve edible oils containing high linolenic acids such as soyabean ,wheat grem oil ,rapeseed oil and canola

The green tea catechins solution is used in products such as pie crusts, dressings, meats,snacks and pastries


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Wood smoke containing 2,6-dimethyoxyphenol, 2,6-dimethylphenol and 2,6-dimethyloxy -4- ethylphenol are used as

antioxidant.

Phenolic compounds such as BHA (butylated hydroxyanisole), BHT (butylated hydroxytoluene) are used in vegetable oils.

TBHQ (Tertiary butylated hydro –quinone) has an excellent ability to retard oxygen absorption in french fries ,potato chips

Combination gives more antioxidant property than used separately –synergism .Buck (1981),coulter (1988)


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Case study –Paprika(Ricardo Gomez et al)

Paprika is a natural colourant extracted from pepper

There was a serious outbreak of food poisoning by microorganism (Sjoberg et al,1991)

To reduce the microbial load heat treatment was employed to attain commerical sterility.

Super heated water vapour of 150-160 N C was used,followed by rapid cooling


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…….

Microbial stability was attained but there was loss of colour

Natural antioxidant – extract of rosemary was mixed with final proportion in 1% level.

It prevents carotenoids in paprika from losing the colour

The extract’s antioxidant activity is from a series of phenolic compounds such as carnosic acid ,carnosol ,rosmarinol and rosmarin (Escalante et al,2001)


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Antioxidants on heating

In foods antioxidants can be lost during food processsing such as sterilisation, pasteurization, dehydration and cooking

During thermal treatment, beside nutritent loss ,chemical reaction such maillard reaction takes place.

The non nutrient component such as maillard reaction components (MRPs) are formed.

MRP act as antioxidants (i.e as chain breaker & oxygen scavengers) (Maria cristina et al,1997)


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Case study –MRPs(Tuaro et al,1996)

A 6 N Brix tomato puree was tested

Aliquots of tomato + virgin olive oil mixture were introduced into 100ml screw capped bottles and heated at 95 N C upto 6 hrs. Ascorbic acid was taken as standard.

Antioxidant activity was determined .(The ability of a compound or a mixture of compounds to quench peroxyl radical produced by 2,2’azo-bis(2 amidinopropane)dihydrochloride is measured spectophotometrically at 443 nm)

Antioxidant activity for every 2hrs is measured for every 1 hr.4/27/2010Antioxidants in Food Industry

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Relationship between Antioxidant activity and heating time


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Result –from the study

Although natural antioxidants are lost during heating , overall antioxidant property has increased.

Due to the development of new antioxidant components MRPs.

MRPs play an important role in food stability and hence gaining importance

Note: To prevent natural antioxidants from destruction due to heat, encapsulation with suitable binding materials are done.


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Role of antioxidants in Human health

They are the soldiers or missile defense system of your body, preventing damage from molecular bombs called free radicals.

Oxygen reacts with food to give energy

This reaction releases harmful byproduct called free radicals

They are highly reactive forms of oxygen that have a missing electron


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To get the missing electron, they damage the healthy cell and its DNA

Free radicals are capable of causing heart disease, cancer ,aging etc

Anti-oxidants combine with free radicals to form more stable compounds

Thus damage to the body can be prevented


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Mechanism of aging

Oxidative stress

Free radical , healthly cellsAntioxidants combine with free radicals and stop this

chain reaction of damaging healthy cells


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Methods to determine antioxidants

FRAP (Ferric reducing/antioxidant power),first test used to determine antioxidants.

This assay depends on the reduction of ferric tripyridyltriazine (Fe3+ -TPTZ) complex to ferrous tripyridyltriazine (Fe2+ -TPTZ)

Fe2+ -TPTZ has an intensive blue colour and can be measured by 593 nm spectrometrically.

Here the ability of the compound Fe3+ to produce Fe2+ is measured.


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Fe2+ is a pro oxidant ,it can react with H2O2 to produce free radicals (OH N )

Why the ability to reduce Fe3+ is defined “total antioxidant power”?

Since almost all antioxidants such as ascorbic acid,uric acid can reduce Fe3+

This test is misleading ,since all the reductants that are able to reduce Fe3+ are considered antioxidants


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TRAP Assay

The Total Radical Trapping assay of Wayner et al was the most widely used method of the last decade.

This method uses 2,2’ azobis (2-amidinopropane)dihydrochloride (AAPH) as peroxy radical producer

Plasma is used as oxidizable material, oxidation is inhibited by the internal antioxidant Trolox

(6-hydroxyl-2,5,7,8 –tetramethylchroman -2-carboxylic acid).

This value is measured and kept as standard and other antioxidants ability is measured and compared with the standard


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ORAC Method

Oxygen Radical Absorbance Capacity (ORAC) is an exciting and revolutionary new test tube analysis for antioxidant (Glazer’s

laboratory)

It is an improved form of TRAP assay

This analytical procedure measures the ability of a food, vitamin, nutritional supplement, or other chemicals to protect against the attack by free radicals, or to act as an Antioxidant


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This assay is based on generation of free radical using AAPH (2,2-azobis 2-amido propane dihydrochloride)

b-phycoerythrin (b-PE) was used as target oxidizable material.

It is fluorescent material,it losses its fluorescence on oxidation. Addition of antioxidant prevent oxidation of b-PE

Measurement of decrease in fluorescence in presence of free radical scavengers was noted.( Hong et.al., 1996)


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Trolox Equivalent (TE) was determined using Trolox as standard

The ORAC value is then calculated from the Trolox Equivalent and expressed as ORAC units or value

The higher the ORAC value, the greater the “Antioxidant Power”


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Regulations for antioxidants in food

The Codex Alimentarius is a collection of internationally adopted food standards .

It permits only those antioxidants which have been evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA)

The primary objective of establishing permitted levels of use of antioxidants in various food groups is to ensure that the intake does not exceed the acceptable daily intake (ADI).


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Acceptable daily intake (ADI) of various antioxidants

ANTIOXIDANT ADI (mg/kgbw)BHA 0–0.5TBHQ 0–0.2gum guaiac 0–2.5Tocopherols 0.15–2.0Ethoxyquin 0–0.06EDTA 2.5citric acid not limitedascorbic acid not limitedascorbyl palmitate 0–1.25

propyl gallate 0–2.5BHT 0–0.125Phosphates 0–70.0tartaric acid 0–30.0Lecithin not limitedSulphites 0–0.7

bw –body wt


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Regulation of European Union

E U regulation of antioxidants is stipulated by European Parliament under Directive No. 95/2/EC of 20 February 1995 on food additives other than colours and sweeteners

There is a special position for sulphur dioxide and sulphites

They are classified as preservatives but may be used as antioxidants when the risk of oxidation is greater than risk of microbial spoilage


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Antioxidants used in various foodsE number Name Foodstuff Maximum level

E 330 citric acid weaning foods quantum satisE 300 l-ascorbic acid fruit- and vegetable-

baseddrinks, juices 0.3 g/kg0.3 g/kgE 301 Sodium l-ascorbate

E 302 calcium l-ascorbate Fat containing cereal-based foods including biscuits

0.2 g/kg

E 304 l-ascorbyl palmitate fat-containing cerealbiscuits, rusks

100mg/ kg individually or with combinationE 306 Tocopherol

E 307 α-tocopherolE 308 Y-tocopherolE 309 β-tocopherolE 322 Lecithins biscuits and rusks, cereal

based foods10 g/kg

E 330 E 334

citric acidtartaric acid

Cocoa and chocolate products

0.5%

E 322 lecithins Non-emulsified oils and fats of animal or vegetable origin

30 g /kg


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Rules to be followed by Producer

Only food grade antioxidants according to FAO/WHO limits can be used

The food producer has full responsibility for the choice of suitable antioxidant

They should obtain all information about the antioxidant and declares its safety.

In most countries the antioxidants used in the product must be labelled on the package.


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Benefits for Consumer

Antioxidants can play a significant role towards reducing the health hazards and decrease the deterioration of oils,fats and foodstuffs made from them

Extra expenditure which is about 0.04% is significantly less when compared to the value of the products and benefits derived out of them( Sumit Arora et al,2004)


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Conclusion

Recent investigations have been targeted towards identification of novel antioxidants from natural sources because of adverse toxicological reports on many synthetic antioxidants

There is an urgent need for standardization of evaluation methods in order to obtain meaningful information

These are the big task for the food technologists to find ways in discovering new natural antioxidants and determination its activity

It is also necessary to make the consumers to know why and how the antioxidant are useful for the welfare of the society


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Antioxidants rich Fresh fruits and vegetables readily available in our local market and their antioxidant content (ORAC METHOD)

ORAC CONTENT

5570

207210 100750

1450


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References

Maria Christina Nicoli, Monica Anese,1997.Loss and /or formation of antioxidants during food processing and storage . Elsevier Science Ireland Ltd ,pp 71-74

Shama Rao P,J.Jaganathan,2004.Role of Antioxidants in food industries . Beverage & Food World , June 2004,71-72

Ronald L.Prior ,Guohua Cao,1999.In vivo total antioxidant capacity and comparation of different analytical methods. Free radical Biology & Medicine, Vol 27,pp 1173-1181

Ahmed Liyaqati S,2004.Role of antioxidants in improving the

quality and shelf life of food and food products. Beverage & Food World , July 2004,52-54


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Charles R. Caldwell,2000.A device for the semiautomatic determination of Oxygen Radical Absorbance Capacity . Analytical Biochemistry 287,226-233

Singh.V.P,Neelam,2006.Natural antioxidants and their Health Aspects. Processed Food Industry ,Vol-3,21-23

Joseph A. Price, Charles G. Sanny , Dennis Shevlin,2006,

Application of manual assessment of oxygen radical absorbent capacity (ORAC) for use in high throughput assay of ‘‘total’’ antioxidant activity of drugs and natural products. Journal of Pharmacological and Toxicological Methods 54 (2006) 56 – 61

Codex Alimentarius General Requirements, 1995 Vol. 1A.


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Official Journal of the European Communities, 1995 38 L 61. Jan Pokorny , Nedyalka Yanishlieva , Michael Gordon, 2001,

Antioxidants in food .Woodhead Publishing Ltd


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Consume antioxidant rich foods…..Stay young…stay fit…..

THANK U

4/27/2010Antioxidants in Food Industry 42

antioxidants presentation

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