AGRO- PROCESSING OF PATCHOULI (Pogostemon cablin Benth.) FOR EFFICIENT ESSENTIAL OIL

EXTRACTION

ANITHA, M.

DEPARTMENT OF AGRICULTURAL ENGINEERING

UNIVERSITY OF AGRICULTURAL SCIENCES BANGALORE

2008

ii

AGRO- PROCESSING OF PATCHOULI (Pogostemon

cablin Benth.) FOR EFFICIENT ESSENTIAL OIL EXTRACTION

ANITHA, M.

THESIS SUBMITTED TO THE

UNIVERSITY OF AGRICULTURAL SCIENCES, BANGALORE

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE

AWARD OF THE DEGREE OF

MASTER OF TECHNOLOGY (AGRICULTURAL ENGINEERING)

IN

POST HARVEST PROCESS AND FOOD ENGINEERING BANGALORE

JULY, 2008

iv

Affectionately Dedicated to My Beloved Parents

& Sisters

iii

C e r t i f i c a t e

This is to certify that the thesis entitled Agro-Processing of Patchouli (Pogostemon cablin Benth.) for Efficient Essential Oil

Extraction submitted in partial fulfillment of the requirements for the

award of degree of Master of Technology (Agricultural Engineering) in

Post Harvest Process and Food Engineering to the University of

Agricultural Sciences, Bangalore, is a bona fide record of research work carried out by Ms. Anitha, M. under my guidance and supervision and that

no part of the thesis has been submitted for the award of any other degree,

diploma, associateship, fellowship or any other similar titles.

Bangalore Dr. V. PALANIMUTHU July 2008 Major Advisor

APPROVED BY:

Chairman : ______________________________

(V. PALANIMUTHU)

Members: ______________________________

1. (B. RANGANNA)

______________________________

2. (H. ESHWARAPPA)

______________________________

3. (K.B. MUNISHAMMANA)

______________________________

4. (M. HANUMANTHAPPA)

v

Acknowledgment

I am extremely grateful and indebted to my chairperson Dr. V. Palanimuthu, Assistant research Engineer, PHT Scheme, UAS, Bangalore for his inspiring, untiring, valuable guidance, constructive criticism, constant encouragement and above all the love and affection offered to me during the course of my study and research. Without his constant support and guidance, preparation of this manuscript wouldn’t have been possible. I consider myself lucky to have worked under the guidance of the knowledge hungry, excellence pursuing and ever helpful personality.

My heartfelt thanks are due to Dr. B. Ranganna, Professor and Research Engineer, PHT Scheme, UAS, Bangalore, for his constant encouragement, sense of responsibility and help as a human being, advice and for his valuable suggestions during the course of my investigation.

I place to record my profound indebtedness and gratitude to Mr. R. Chandru, Associate Professor of Biochemistry, PHT Scheme, for his encouragement, valuable suggestions, sustained interest on the selected problem and the help during the course of my investigation.

I owe an intellectual debt to, Mr.H. Eshwarappa Professor and Head, Department of Agricultural Engineering, for all his help during my research and stay at UAS, Bangalore.

My heartfelt thanks are also due to Mr. Munishyamanna, Associate Professor, PHT Scheme, UAS, Bangalore, who served as one of my Members of Advisory Committee.

I thank Central Institute of Medicinal and Aromatic Plants for providing patchouli fresh herbage for drying purpose and for quality analysis of patchouli oil performed in their laboratory.

I thank to IISC,for providing Astra dryer for patchouli drying.

I take this opportunity to thank the staff of PHT scheme, Mr. Mohan, Mrs. Channamma and the workers Narayanappa and Hanumakka, workshop staff Mr. Bhaskar, Anand, , Kumar and Changappa sir, Dept of Horticulture who have helped me during my research work and also were a great company in Scheme.

My vocabulary fails to get words to convey my wholehearted thanks to my lifetime friends pex, jay, and Sum and my room mates Lacchi, Jo, Prathi, Chethu for their

vi

natured and selfless help during my research. Their constant companionship, love and moral support always give me strength in odd times.

I would also like to thank my PG friends Anupama, Jyothi, Shwetha, Ravi, Raghu, and Shivbasappa for their kind help and company during my studies.

Words sometimes fail to express when the occasion really demands it. However, with all the limitations of words, I offer my floral salutations laden with pure love that contain only my feelings towards my parents (Muniramaiah& susheela), elder sister (vanaja) younger sister (sunitha) and to my whole family members. It is my sinscere duty to acknowledge their undemanding, steadfast support and love during my entire career that stands immaculately in my memory.

I would like to express my sincere thanks to my cousins, aunty, uncle and for their constant inspiration, encouragement and blessings.

I sincerely thank all those who directly or indirectly helped me during the course of this investigation.

I’m grateful to University of Agricultural Sciences, Bangalore for providing me the opportunity and facilities to prosecute my Post-graduation Degree.

Bangalore July 2008 (Anitha.M)

Agro-Processing o f Patchouli (P(>gostemon cablin Benth.J fo r EfficientEssential o / / Extraction

A n itha M.

Thesis Abstract

A g ro -p ro c e s s in g o f p a tc h o u l i , (cv. j 0 }X 0 r e } a n im p o r ta n t a ro m a tic he rb v a lu e d for i ts e s s e n t i a l oil, w a s a t te m p te d . The d ry ing c h a ra c te r is t ic s of h e r b a g e w e re s t u d i e d u n d e r v a r io u s m e th o d s n am ely , in sh a d e , in tray d r y e r a n d in ASTRA C ro p W a s te g aseci Dryer. T he in itial d ry ing bed t h i c k n e s s w a s u n i fo r m ly m a in t a in e d a t 100 m m in all m e th o d s a n d the h e r b a g e w a s d r ie d f ro m 80% (w b) initial m o is tu re to 11-12% final m o is tu r e . U n d e r B a n g a lo re c l im a tic cond itions (21 .0-24 .4°C ; 40 -81% RH), p a t c h o u l i r e q u i r e d 5 4 h o f d ry in g tim e in s h a d e w hile in ASTRA d ry e r , i t w a s j u s t 14 h . In c o n v e c t i0 n a i tray d ryer (electrical), th e d iy ing t im e a t 3 0 , 4 0 , 5 0 , 6 0 a n d 70°C w a s 13, 12, 11, 7 a n d 6 h, respectively.

C le v e n g e r ’s E s s e n t i a l Oil D is til la tion U nit w as u s e d to e s t im a te the e s s e n t i a l oil y ie ld fro m d r ie d p a tc h o u l i an d the oil q u a li ty w as analyzed u s i n g G a s C h r o m a to g r a p h . T h e m e a n e ssen tia l oil y ie lds w ere 2 .41 , 2 .24 a n d 2 .2 5 - 2 .4 0 % re s p e c t iv e ly in s a m p le s dried in sh ad e , ASTRA d ry e r an d t r a y d ry e r . T h e r e w a s a c o n s id e r a b le varia tion in th e q ua li ty of ex trac ted p a tc h o u l i e s s e n t i a l oil in t e r m s p a tc h o u l i alcohol, a -g u a ien e , ct-bulnesene a n d (3 -p a tc h o u le n e c o n t e n t s , from h e rb ag e dried u n d e r different m e th o d s . P a tc h o u l i a lc o h o l c o n t e n t w as 64 .6 5 , 4 2 .2 7 a n d 5 7 .15 -66 .26% in th e d is t i l le d o i ls f ro m h e r b a g e dried in sh ad e , ASTRA d ry e r a n d tray d ry e r , re sp ec t iv e ly . T h e a - g u a ie n e a n d a -b u ln e se n e c o n te n t s were h igher in e s s e n t i a l o i ls d is t i l le d fro m h e rb ag e dried in ASTRA dryer, p- p a t c h o u l e n e c o n t e n t w a s h ig h e r in th e oil distilled from h e rb ag e dried a t 70°C in t r a y d iy e r .

E s s e n t i a l oil y ie ld a n d i ts q u a li ty by s te a m distilla tion techn ique w e re s tu d i e d in a P ilo t S c a le S te a m Distillation U nit a t d ifferent pack ing b e d d e n s i t i e s a n d d is t i l la t io n p e rio d s u s in g sh a d e d r ied patchouli h e r b a g e . F o r d i f f e r e n t p a c k in g d e n s i t ie s , th e p a tch o u l i e ssen tia l oil yields w ere : a t 4 k g / 0 . 5 m 3 - 2 .7 8 , 3 .0 6 , 3 .2 6 a n d 3 .42% ; a t 5 k g /0 .5 m 3 - 2 .46 , 2 .7 4 , 2 .9 5 a n d 3 .1 0 % ; a n d a t 6 k g /0 .5 m 3 - 2 .25 , 2 .54 , 2 .7 9 a n d 2 .97% re sp ec t iv e ly fo r 3, 4 , 5 a n d 6 h d is t i l la t ion . F rom s te a m distilled e ssen tia l o ils , p a t c h o u l i a lc o h o l w a s 3 4 .7 4 , 34 .92 a n d 27 .78% ; a -b u ln e se n e c o n t e n t w a s 2 0 .0 4 , 1 9 .7 5 a n d 19 .38% ; a -g u a ien e c o n te n t w as 12.75, 12 .71 a n d 1 9 .3 8 % ; a n d p - p a tc h o u le n e c o n te n t w as 0 .0 1 8 7 , 0 .0 1 6 5 a n d 0 .0 0 0 % re s p e c t iv e ly a t b e d d e n s i t i e s 4, 5 a n d 6 k g /0 .5 m 3.

C o s t e c o n o m ic a n a ly s i s o f p a tch o u l i e s se n t ia l oil d is tilla tion u s in g P ilo t S c a le S t e a m D is t i l la t io n U n it in d ica ted th a t the ex trac tion is viable w i th C o s t : B e n e f i t R a t io o f 1 :1 .26 .

D a te : 0 1 / 1 0 / 2 0 0 8 P lace : B a n g a lo re

(V. PALANIMUTHU)M ajor Advisor

Contents

Sl. No.

TITLE

Page No.

I

INTRODUCTION

1-5

II REVIEW OF LITERATURE

6-21

III MATERIALS AND METHODS

22-41

IV RESULTS

42-64

V DISCUSSION

65-72

VI SUMMARY

73-76

VII REFERENCES

77-85

APPENDICES

86-89

ii

List of Tables

Table No. TITLE Page

No.

4.1 Effect of drying of patchouli herbage on the refractive index of extracted essential oil 56

4.2 The influence of packing density and distillation time on patchouli essential oil quality 58

4.3 Effect of bed packing density and distillation

time on refractive index of patchouli essential oil 60

4.4 Effect of type of distillation on the yield and quality of essential oil 61

iii

List of Figures Fig. No. TITLE

Page No.

4.1 Drying characteristics of patchouli herbage in tray dryer 43

4.2 Drying behaviour of patchouli herbage under shade 43

4.3 Drying behaviour of patchouli herbage in ASTRA Model Waste Based Crop Dryer 44

4.4 Drying air temperature variation at different levels inside ASTRA Model Dryer during Patchouli drying 44

4.5 Essential oil recovery from Patchouli herbage dried under Shade, in tray dryer at different drying temperature and in ASTRA Dryer

47

4.6 Gas chromatographic profile of patchouli oil 48

4.7 Effect of drying of patchouli herbage on patchouli alcohol content of extracted patchouli oil 49

4.8 Effect of drying of patchouli herbage on β- patchoulene content of extracted patchouli oil 49

4.9 Effect of drying of patchouli herbage on -Guaiene content of extracted patchouli oil 51

4.10 Effect of drying of patchouli herbage on -Bulnesene content of extracted patchouli oil 51

4.11 Effect of steam distillation time on patchouli essential oil recovery at packing bed density of 4 kg/0.5m³ 53

4.12 Effect of steam distillation time on patchouli essential oil recovery at packing bed density of 5 kg/0.5m³ 53

4.13 Effect of steam distillation time on patchouli essential oil recovery at packing bed density of 6 kg/0.5m³ 54

4.14 Essential oil recovery from shade dried patchouli herbage at various distillation time intervals (packing bed density of 4 kg/0.5m³)

54

4.15 Variation in patchouli oil quality at different distillation time intervals for packing bed density 4 kg/0.5m³ 55

4.16 Variation in patchouli oil quality at different distillation time intervals for packing bed density 5 kg/0.5m³ 55

4.17 Variation in patchouli oil quality at different distillation time intervals for packing bed density 6 kg/0.5m³ 63

iv

List of Plates

Plate No.

TITLE

Page No.

3.1 A view of shade drying of patchouli 24

3.2 Convective tray dryer 24

3.3 ASTRA dryer 27

3.4 Tray of ASTRA Dryer 27

3.5 Fuel Briquettes 29

3.6 Dial Thermometer 29

3.7 Moisture Determination Apparatus 31

3.8 Clevenger’s Essential Oil Distillation Unit 33

3.9 Pilot Scale Steam Distillation Unit 36

3.10 Essential oil separating funnel 36

3.11

Patchouli essential oil 36

3.12 Gas chromatograph 40

3.13 Polarimeter 40

3.14 Refractometer 40

INTRODUCTION

1

I INTRODUCTION

Patchouli, a small bushy perennial herb with fragrant leaves, is an

important aromatic plant. It is botanically known as Pogostemon cablin

Benth. and belongs to the family Labiatae. The patchouli plant was first

described by botanists Pelletier-sautelet in Philippines in 1845 and was

named Pogostemon Patchouli. It is believed to be a native of the

Philippines. It grows wild in Malaysia, Indonesia and Singapore. It is

often confused with Pogostemon heyneaxhus Benth., which is indigenous

to India and is grown in gardens, but has no commercial importance.

Patchouli oil is a key constituent in exotic perfumes to which it gives a

rich, spicy fragrance. It can also be used as a perfume in its own right. It

has also good fixative properties, especially in soap perfumes (Farooqui

and Sreeramu, 2001).

Patchouli was introduced to India during the year 1941 in Madhya

Pradesh, Tamilnadu, Kerela and Karnataka. Experiments have revealed

that good quality patchouli oil can be produced from patchouli grown

under Bangalore weather conditions (Sarwar et al., 1982).

Patchouli is grown for its essential oil which is found mainly in the

leaves and a small quantity of oil is also present in the tender parts of

the stem. The dry leaves of patchouli on steam distillation yield an

essential oil called ‘oil of patchouli’. The leaves harvested and dried in

shade have an oil content in the range of 2.5-3.5%.

Most of the patchouli oil of the world is produced by Indonesia,

Malaysia and Singapore. Indonesia supplies most of the world’s

requirement of around 1500 tonnes per year. India produces about 1

tonne of patchouli oil (Rao, 2004) and the demand borders around 220

2

tonnes annually (Vijyakumar, 2004). Commercial cultivation of the crop

in India was first attempted by Tata Oil Mills in 1942 (Anup Kumar et al.,

1986). After the initial stray attempts to grow the crop, its systematic

cultivation started in 1962 by CIMAP (Anup Kumar et al., 1986).

Currently, India producing a very meager quantity of patchouli oil and

thus is annually importing about 20 tonnes of pure patchouli oil and 100

tonnes of formulated oils.

The first harvest of patchouli crop is obtained after 5-6 months of

transplanting. It is harvested when the foliage becomes pale green to

light brown and when the stand emits the characteristic patchouli odour

that can be smelt by a passer-by, especially in the morning hours.

Subsequent harvests can be done after every 3-4 months interval. The

crop can be maintained for three years. The harvested material is

generally dried under shade in thin layers and for proper drying, the

material has to be periodically turned. Drying normally takes about three

days (Farooqui and Sreeramu, 2001) and the shade dried material is

stored for ageing even for months before distillation to improve the

characteristic aroma. The duration of distillation is about 6-8 hours for

complete recovery of oil (Anon., 2004a).

The patchouli crop yields about 1750-2500 kg dried leaves

(includes twigs also), 45-65 kg of patchouli oil and a net profit of Rs

40,000-60,000 per hectare per annum can be realized (Anon., 2004a).

Only matured patchouli leaves are harvested, shade dried and steam

distilled (Jain, 1978) and an average essential oil yield of 2.5% may be

considered satisfactory in commercial distillation (Farooqui et al., 2001).

Dry patchouli leaves are used for scenting wardrobes. The leaves

and tops are added in bath for their anti rheumatic action. In Chinese

medicine, decoction from the leaves is used with other drugs to treat

3

nausea, vomiting, diarrhea, cold and headaches (Leung, 1980). A related

species P. heyneanus is reported to contain principles possessing

anticancer activity (Purushothaman et al., 1985).

The chemical constituents that are most odour-intensive in the

patchouli oil are patchouli alcohol and nor patchoulenol. Other

components include Alpha Bulnesene, Alpha, Beta and Delta

Patchoulene, Alpha and Delta Guaiene, Beta Elemene and Seychellene

(Shankaranrayan, 2002).

In aromatherapy, patchouli is often used as a relaxant. It can ease

and diminish anxiety and depression. In high dose, it can stimulate and

in lower dose, it is a sedative. It is used to sharpen intelligence and

improve concentration (Shankaranrayan, 2002).

Patchouli oil is thick, viscous, sticky and very slow to volatilize.

High quality oils possess an elusive, wine-like, floral, sweet top-note. This

top-note commands more of a presence as the oil ages (approximately

one year from distillation). The body note is incredibly rich, intensely

sweet, woody, balsamic and earthy (Anon., 2005a). It is found that 92%

of the patchouli oil consists of compounds which have very little

influence upon its odour. Sesquiterpenes constitute 40 to 45% of the oil,

out of which patchouli camphor or patchouli alcohol or patchoulol

represents 35 to 40% of the oil. Patchouli alcohol is also odourless.

However, it is found that one or more satellite compounds of patchoulol

may be responsible for the characteristics odour. In addition, a

crystalline fraction of norsesquiterpenic alcohol called nor patchoulenol

is isolated which is found to be the true odour carrier of the patchouli oil

(Sarwar et al., 1982).

4

Patchouli oil is used so extensively that is very difficult to specify

its field of application. It is one of the most important essential oils in

perfume industry. It blends well with other essential oils such as, vetiver,

sandalwood, geranium, lavender, caedarwood derivatives and clove oil.

The oil is extensively used as a flavor ingredient in major food products

including alcoholic and non alcoholic beverages, frozen dry desserts,

candy, baked goods, gelatin, and meat and meat products. Blended with

sandalwood oil, it gives one of the finest attars, widely used in soaps,

cosmetics, tobacco and incense sticks. Hence, it is regarded as the best

fixative for heavy perfumes which imparts strength, character, alluring

notes and lasting qualities. There is no synthetic chemical to replace the

oil of patchouli, which further enhances its value and unique position in

the perfumery market. There is a great demand for it in soaps, scents,

body lotions, detergents, tobacco and incense manufacturing factories.

The oil of patchouli is used also as an ingredient in insect repellent

preparations and is said to have anti-bacterial properties as well

(Farooqui and Sreeramu, 2001).

Only few works are reported on the processing aspects of patchouli

though considerable progress has been made in the cultivation front. It is

reported that in the commercial extraction facilities, the oil yield is only

about 1-2.5 % or even less, either due to poor distillation technique/

equipment or due to improper handing of raw material before distillation

(Anon., 2004b).

Pallavi et al. (2006) studied the drying characteristics of patchouli

herbage in a convectional tray dryer and reported that the drying

temperatures of 30-50°C did not influence the essential oil yield and the

oil yield was similar to that of shade dried sample. Tandon et al. (2002)

reported that there was no significant increase in the oil recovery rather

5

there was a loss of the oil occurring at high steam pressures during

distillation of Menthe herb.

Patchouli is a farmer friendly crop and it is not so delicate to

handle like many other aromatic plants. The leaves once dried and

properly preserved can be used for distillation leisurely. Since the

present extraction efficiency of this high valued oil is poor due to many

hurdles, the development of a good distillation equipment and proper

process technique will definitely enhance the oil extraction efficiency. The

process technique will be highly beneficial to the farming community and

it will increase their net returns considerably.

With the above points in view, the present investigation was

undertaken with the following objectives:

Objectives

1) Standardization of drying practices of patchouli for distillation.

2) Optimization of distillation parameters for maximum oil recovery from patchouli using a Pilot Scale Steam Distillation Unit.

3) Quality analysis of steam distilled patchouli essential oils.

4) Cost-economic analysis of patchouli distillation process.

REVIEW OF LITERATURE

6

II. REVIEW OF LITERATURE

Patchouli is an important aromatic crop yielding an invaluable

essential oil. The review of literature indicates that there is not much

published research work on processing aspects of this plant like initial

raw material handling, drying practices and distillation.

In the following sections of this chapter, valuable information

regarding patchouli, its drying, development/testing of a small pilot scale

distillation unit, extraction and quality analysis of patchouli essential oil

and other informations relevant to this investigation have been briefly

reviewed.

2.1 Drying Studies of Aromatic Crops

The fermentation of patchouli leaves and its effect on yields of oil

has been a matter of debate. Subba Rao and Nagesa Rao (1945) reported

that fermentation of leaves improved the oil quality.

Nirody et al. (1961) have shown that though it is said that the

fermentation helps to increase the breakdown of cells and thereby

promotes the oil yield, there is little experimental evidence, if any, to

show additional oil generation by fermentation. Improper fermentation

may cause moldy odour of the oil, while some experts believe that unless

the leaves are fermented, oil of the best odour quality cannot be

obtained.

Nair et al. (1980) studied the factors influencing the yield of

essential oils during distillation. In case of lemongrass and Palma Rosa,

7

field drying and storing of the cut crop in open air reduced the oil yield

as well as the active chemical content in the oil.

A pilot plant scale experiment conducted by Hazra et al. (1990) to

study the effect of drying mint herb in shade and direct sunlight in two

different seasons indicated that in field drying, the oil yield progressively

reduced with time. However, in shade drying, the oil yield increased up to

two days of drying, and then gradually decreased.

Deans and Svoboda (1992) conducted experiments on drying of

seven herb spices. The herbs were dried at temperatures between 40°C

and 100°C for 24 h and the dried material was then steam distilled. They

reported that the volatile compounds decreased with increase in drying

temperature and there was a significant change in oil composition of all

the seven herb spices studied. The composition of marjoram and basil

oils changed significantly, those of tarragon, sage and savery oils

changed at 50-60°C, while those of thyme and rosemary oils did not

change significantly.

Raghavan et al. (1995) subjected fresh Indian thyme to different

drying treatments. Shade drying was found to be time consuming

process (124h) during which most of the monoterpenes were lost due to

volatilization. Thymol was retained in all dried samples. Considering the

time of drying and the flavour quality of the herb, through-flow drying

(40°C, 8 h) was found to be a method of choice. However shade drying

resulted in a product with a good green colour and minimum loss of

volatile oil compared to other drying methods.

Upon subjecting Artemisia annua to six drying techniques (sun, air

dried inside or outside and forced air heat at 30, 50, 80°C) and five

durations (0, 12, 24, 36 and 48 h), artemisinin content was best retained

8

when leaves were dried under ambient conditions, compared with forced

air (Charles et al. 1995).

Chiumenti et al. (1996) studied the effect of drying temperature on

Salvia officinals and reported that as the temperature increased, the

process duration decreased from 56.8 to 13 h. The total drying energy

required for heating air increased with temperature up to 75°C and then

decreased. Essential oil composition was found to vary slightly depending

on temperature.

Drying of patchouli normally takes three days under shade,

yielding an average of 2.5% essential oil up on distillation (Farooqui et al.

2001).

Pallavi et al. (2006) studied the drying characteristics of patchouli

herbage in a conventional tray dryer and reported that the drying

temperatures of 30-50°C did not influence the essential oil yield and the

oil yield was similar to that of the shade dried sample.

Though drying is one of important the unit operations before

essential oil extraction, very little information is available in the literature

on drying studies of patchouli herbage.

2.2 Extraction of Essential Oil from Aromatic Plant

The basic criteria for essential oils conforming to EOBBD

(Essential Oils Botanically and Biochemically Defined) quality standards

are the exact botanical identification of the aromatic plant, its

geographical origin, stage of development at the time of harvest, the

distilled organ and the most important and critical factor, the process of

9

steam distillation. Each essential oil is identified by its GC-MS profile

besides other physical properties. The quality of essential oil is

established by the presence of specific biochemical constituents at

defined levels for effective human application (Manivannan and

Suvarnalatha, 1988).

Among the various production methodologies of essential oil,

distillation methods are good for grassy and leafy materials where as,

extraction is suitable for highly priced, delicate and thermally sensitive

perfumery materials like jasmine, tuberose, violet, etc.Super-critical fluid

extraction is the most recent and promising method of production of

essential oil from natural products (Singh, 1990).

During the early history of man, distilled waters of herbs were

produced and used as remedy for many illnesses. In the fourth century,

stills were constructed with a gorge weir situated at the bottom portion of

the head. The weir allowed some separation of the condensates. In the

twelfth century, the distillation still was practically of same shape as it is

now and the head gorge weir had been replaced by a worm placed in a

cold water vat in which vapors were condensed and cooled (Vacchiano,

1992).

Until year 1955, separation techniques were essentially based on

chemical composition, fractional distillation and crystallization. Complete

separation of all the components is not readily achieved since, many

terpenoids and other classes of compounds have a small range of boiling

points, even the most efficient fractionating procedures do not always

produce pure compounds. Some polymerization occurs during distillation

and resolutions are only mediocre (Singh et al. 1995).

10

2.3 Extraction Methods

A new extraction process for isolation of essential oil/extractives

from natural substances using liquid and dense carbon dioxide has been

described. Cardamom (fruits), cumin (seeds), clove (buds), ginger

(rhizomes), parsley (seeds), mace (arils), sandalwood (stems) and vetiver

(roots) are used as extraction materials in a specially designed high

pressure soxhlet apparatus for preliminary studies of liquid carbon

dioxide extraction. The essential oils/extractives obtained by this method

are found superior in quality and flavour compared with the conventional

steam distilled essential oils. The process conditions for extraction of

clove, parsley and vetiver with liquid and dense carbon dioxide studied at

different pressure and temperatures in a high pressure gas extraction are

found at sub critical state (Naik et al., 1988).

The different methods presently available for extracting aroma of

floral materials are:

a) Distillation with water or wet steam

b) Extraction with hexane, concentrate of the extract with low

temperature, removal of plant waxes by precipitation with an

odourless alcohol and removal of alcoholic solvent at low

temperature

c) Super critical carbon dioxide extraction (Geunther, 1948).

d) Liquid carbon dioxide for extraction (Naik et al. 1988).

Steam distillation of air dried leaves yield oil of patchouli. Different

methods of distillation are employed by distillers. Experienced distillers

prepare oils of special quality by varying the conditions of distillation.

Distillation is the main method used for extracting essentials oils.

Distillation is based on the principal that when plant material is placed

11

in boiling water, the essential oil in it will evaporate and rise up along

with the steam. Once the steam and oil have been condensed, the oil

separate from the water, and it can be collected. Plants are crushed to

encourage them to release their oils. The collected essential oils are

poured in to Florentine flasks for separation. Five to six tonnes of roses

are needed to obtain one kilogram of essential oil. Current methods also

involve placing the plants on a screen and steam is passed through them

(Anon., 2005b).

There are several techniques that allow the extraction of

compounds responsible for the aroma of plants. The composition of the

aromatic material obtained is strongly dependent on the method of

isolation. The techniques used at industrial scale are cold pressing,

hydro distillation, extraction with organic solvents and extraction with

compressed CO2. Both cold pressing and hydro distillation enable the

isolation of the essential oil borne in the plant; however both approaches

have their disadvantages. Hydro distillation can thermally degrade and

hydrolyse some of the oil components, which in some cases can lead to

significant distortion of the composition of oils found in the natural herb.

Cold pressing is insufficient and the oil obtained requires refining to

concentrate the oil produced (Anon., 2005c).

i) Hydro-distillation

There exits three types of hydro distillations in essential oil

industry:

1. Water distillation

2. Water and steam distillation

3. Direct steam distillation

12

All the three types are basically similar in principle of two phase

system of distillation with only difference in handling the plant material.

The term hydro-distillation was coined by Von Rechenberg, referring to

the distillation with water vapors that isolated a majority of essential oils.

(Prasad et al. 1988).

Hydro distillation is a process where botanicals are fully

submerged in water, and heated up. The steam produced that contains

the aromatic plant molecules is condensed and separated to obtain

essential oils. This is the most ancient method of distillation and the

most versatile. The risk, of course, is that the still can run dry, or be

overheated, burning the aromatics and resulting in an essential oil with a

burnt smell. Hydro distillation seems to work best for powders (i.e. spice

powder, ground wood etc) and very tough materials like roots, wood or

nuts (Anon., 2005d).

ii) Steam distillation

Steam distillation is the common method used for the extraction of

essential oils from plants. The plant material is placed in a still (very

similar to pressure cooker) where pressurized seam passes through the

plant material. The heat from the steam causes the globules of oil in the

plant to burst and the oil then evaporates. The essential oil vapour and

the steam then passes out the top of the still in to a water cooled pipe

where the vapors are condensed back to liquids. At this point the

essential oil separates from the water floats to the top (Anon., 2005e).

Although there are other techniques, steam distillation remains the

preferred process for the extraction of essential oils from plant material

from the consumer point of view. From a commercial point of view, the

ability to process large quantities of material with a technique that

13

requires relatively modest investment and skill levels is attractive (Anon.,

2005f).

Steam distillation results in two separate by products: (1) The

liquid distillate itself which contains the volatile, water soluble parts of

the plant materials is known as “hydrosol” and (2) The volatile non water

soluble material which possesses the greater of the plant constituents

and is known as the “essential oil”. Additionally, the process of

distillation inherently produces new chemical compound that would not

be found naturally or in the same form in the plant itself as we find it in

its natural state (Anon., 2005g).

iii) Super critical fluid extraction

Super critical fluid extraction (SFE) with respect to the extraction

of essential oils involves the use of carbon dioxide as the solvent. SFE is

a relatively new process, which uses carbon dioxide in the supercritical

state to dissolve soluble material out of the plant matrix. This process

gives a better quality extract but the capital costs are slightly higher.

Carbon dioxide is cheap, inflammable, and leaves no detectable residue.

A typical SFE process consists of two major segments, the extractor and

the separator. The material to be extracted is packed in to the extractor

and supercritical carbon dioxide enters the extractor where it dissolves

the volatile compounds in the plant material. The carbon dioxide and the

extract then goes to the separator where the pressure is below critical

thereby allowing the carbon dioxide to revert to the gas phase and

deposit the extract. The CO2 can then be recycled to the extractor vessel.

In order for the CO2 to be in the super critical state, the pressure and the

temperature must be above the critical point of CO2, i.e. 74 bars and

31°C (Anon., 2005 h).

14

iv) Liquid carbon dioxide for extraction

The use of liquid carbon dioxide as a solvent for fruit juice

concentrate extraction was reported earlier by Horvath (1939).

Subsequently, Francis (1954) presented an extensive experimental data

on solubility studies of different organic compounds like aliphatics,

aromatics, hetercylics, alcohols, esters, amines, nitriles and phenols with

liquid carbon dioxide and this work is the mile stone for carbon dioxide

extraction. Then the same technique was applied for extraction of aroma

and specially chemicals. It has been found that liquid carbon dioxide is

completely miscible in essential oils and the components like aldehyde,

ketones, esters and alcohols of essential oils have got good solubility in

liquid carbon dioxide while protein, starch, mineral salts and water are

insoluble in liquid carbon dioxide. The essential oils obtained by liquid

carbon dioxide extraction are superior in comparison to steam distillation

and solvent extraction. Recently, number of experimental results has

been reported on natural product extraction such as phyrithrins from

pyrethrum flower, essential oils from anise, carway, clove, staranise and

cinnamon and ginger (Naik et al., 1988).

2.4 Equipment for Distillation

Distillation tests conducted by the method based on the

determination of two parameters, the “increment parameter” and the

“basic time parameter” after dimensioning of a still suitable for the

processing of the plant could be made (Denny, 1991).

A portable distillation unit working on fuel wood was designed and

fabricated for field distillation of eucalyptus hybrid foliage. Under

optimum conditions, 1-1.8% (average-1.43%) of oil was distilled with this

15

unit, which is higher than that obtained with stationary stills of larger

dimensions. More than 95% of oil could be distilled out in the first two

hours of distillation, of which the first hour collection (about 75%) was

found to be more of cineole than the second hour collection. This unit

could be used with advantage for distilling oils from other plant materials

(Theagarajan et al., 1993).

Rao et al. (1999) reported about field distillation, using a 1000 kg

capacity distillation vessel using steam at about 2 bar pressure. It took

120 min to what was considered a full extraction and about 60 min to

obtain 90% of the total oil extracted.

2.4.1 Certain Conditions that affect the distillation

During distillation, a number of parameters that influence the

distillation of essential oils from plant materials such as : Storage,

Charge, Period of collection, Conditions of herb, Comminution

/disintegration process, Distillation period, Temperature, Other

constituents present, Condensation of the constituents and pH of

distillation water (Rajendra Prasad et al., 1987).

2. 5 Essential Oil Recovery

Patchouli yielded 3.27 % of the volatile oil on steam distillation and

only 2.98% on water distillation. The steam distillation in certain plant

materials has been found to increase the total yield of oil (Guenther,

1948).

Denys et al. (1990) compared different extraction methods for

rapid determination of essential oil content and composition of basil. It

16

was noticed that the yield of essential oil was consistently higher from

steam distillation than hydro distillation.

Singh and Maheshwari (1997) compared the yield of essential oil

by hydro distillation against CO2 extraction from callistemon, Murraya,

Lantana, Tagestes and Ocimum plants and reported that there was

increase in yield with supercritical CO2 extraction when compared to

hydro distillation process. Extraction using liquid CO2 was convenient

and superior in terms of both quantity as well as quality of the extracts

as compared to hydro distillation process. It was reported that the

terpene compounds of the essential oil got oxygenated resulting in

constant deterioration with time in the quality of oils obtained by hydro

distillation process.

2.6 Effect of Variety on Oil Content and Oil Yield

Buitkhi et al. (1975) observed that the essential oil of mint species

varied from 1.5% in Menthe silvestris to 2.5% in Menthe lavanduliodora.

Radhakrishnan et al. (1991) reported that shaded environment

yielded higher herb and oil of patchouli. This study was conducted in

Kerala where higher temperatures prevail (max. temp. often>35°C)

compared to the present site (max. temp. -26 to 33°C) during crop growth

period. Therefore, under mild temperature conditions, shading may not

create significant differences in patchouli yield. However, more

investigations are required to study the influence of shade under

different temperature regimes.

Vasundhara et al. (1992) reported that the application of GA3 at

200 PPM increased the fresh herb yield which resulted also in the

maximum recovery in majoram.

17

Maheshwari et al. (1993) reported that the essential oil content in

patchouli was maximum in Indonesia cultivars (2.71%) followed by

Singapore (2.5%) and Malaysian cultivars (2.4%) ; while essential oil yield

per maximum in Singapore cultivar (7.9 ml), followed by Indonesia (6.36

ml) and Malaysian cultivars (4.66 ml).

A field experiment was conducted in a red loam soil under semi-

arid tropical conditions to investigate the influence of partial shade(50%)

on the yield and quality of patchouli oil. Patchouli (Pogostemon cablin)

leaves contained 67% more chlorophyll under shaded environment

(Prakasa Rao et al., 1997).

Ramachandra et al. (2003) studied the effect of varieties and

spacing on growth, yield and quality of patchouli (Pogostemon patchouli

Pellet). They reported that cv. Java was more robust and recorded higher

dry herbage yield compare to cv. Johore had higher essential oil content

(2.7%) and the patchouli oil content in the oil was also high (44.7%)

when compared to cv. Java.

Oil recovery studies conducted on patchouli (Pogostemon cablin)

indicated that almost 100% oil was recovered with in 3 h in case of fresh

leaf (80-87% moisture). Semi-dried leaf (30-40% moisture) took about 5-6

h for recovery of 80-90% oil, while more than 90% oil was recovered with

in 9 h of distillation in case of dried leaf (10-20% moisture). Shade drying

of leaf and storage up to 150 days seemed to be congenial condition for

maximum recovery of oil. Ageing period exceeding 150 days for both

shade and sun drying of leaf had negative effect on oil recovery. Patchouli

alcohol was found to be maximum (42.37%) when dried leaves were

distilled for 11 h (Sarma and Sarma, 2003).

18

2.7 Distillation Process Variables

Nair et al. (1980) conducted an experiment at lemongrass research

station to study the effect of oil of different steam pressures on the yield

and quality of oil of lemongrass during steam distillation. They reported

that the yield of its oil and its critical content increased when steam

pressure was increased from 5 to 20 lb/inch² though it was not

statistically significant.

Prasad et al. (1987) reported that during distillation of almost all

medicinal and aromatic herbs, greater part of the constituents distilled

out with in the first two hours of distillation. Relatively long action of

steam or boiling water on plant material affects some of the more delicate

constituents of the oil deleteriously and hydrolysis, polymerization and

resinification may take place. Higher boiling constituents, if partly

soluble in water, are not carried by steam and hence, cannot be isolated

even after prolonged distillation. As a result of this, the distilled oil does

not always represent the natural oil as it originally occurred in the plant.

A portable distillation unit working on fuel wood was designed and

fabricated for field distillation of eucalyptus hybrid foliage by

Theagarajan et al. (1993). Under optimum conditions, 1-1.8% (average

1.43%) of oil could be distilled with that unit which was higher than that

obtained with satisfactory stills of larger dimensions. They also reported

that more than 95% of the oil distilled out in the first two hours of

distillation.

The herbs which contain high boiling oils that are chemically

stable at higher temperature (associated with high pressure distillation)

are best distilled under pressure (Varshney, 1993).

19

Waikhom et al. (1995) studied the essential oil yield in relation to

duration of distillation and stages of bud of clove. They reported that the

soaked cloves released the oil more rapidly (compared to the dry ones)

both in whole and powdered buds.

The study on comparative oil yield at different biomass to water

ratio carried out for eucalyptus leaves by Rath et al. (1997) showed that

the ratio of 1:7 was optimum and gives the highest oil yield. Also the

quality of the oil was transparent and excellent.

Tandon et al. (2002) conducted a study on the effect of steam

injection rate and steam inlet pressure on the distillation of the essential

oil of Menthe arvensis. It was reported that the steam pressure of the

order of 10 psig and injection rate in the range of 5-10 kg/h were optimal

for obtaining better yield of the essential oil.

2.8 Essential Oil Quality

The oil of patchouli is said to contain about 97% of compounds

which have almost no influence on its aroma. Of these, 40-45% belongs

to sesquiterpene group and the balance seems to consist of patchouli

alcohol. The oil contains small amount of benzaldehyde, eugenol,

cinnamic aldehyde, an alcohol with a rose like fragrance, a ketone with

orris like odour, another ketone, two bases possessing a strong

benumbing odour, azulene and a sesquiterpene alcohol – Patchoulene, γ-

guaiene,α-bulnesene,α-terpene cadinene,benzaldehyde and patchouli

alcohol have been identified chromatograghically (Guenther, 1952; Bates

and Slagel, 1962).

20

In patchouli, Haripraksha Rao and Vasantha Kumar (1983)

observed leaf reddening and attributed it to iron toxicity and in balance

in nutrient concentration also resulted in low amount of essential oil

production in affected plants compared to healthy plants. Hence, the

production of high quality oil in patchouli plants mainly depends on

balanced nutrition.

Leaves of patchouli (Pogostemon cablin) from various geographical

locations were extracted and the distilled oil subjected to analysis by gas

chromatography, gas chromatography – mass spectrometry and nuclear

magnetic resonance. More than 16 compounds were dectected, of which

11 were identified as alpha/beta/and delta-patchoulene, beta-elemene,

beta- caryophyllene, alpha/ and delta- guaiene, seychellene, alpha-

bulenese, delta-cardinene, pogostol (tentative identification) and

patchouli alcohol. Patchouli oil content was 32-37% and found to be the

most odour-intensive constituent of the oil (Dung et al., 1990).

The testing and analysis of the essential oils extracted for refractive

index, relative density, acid value and the geraniol content was carried

out as per standards (Datta and Malik, 1993). The chemical composition

of any essential oil also reveals its quality (Lawrance, 1989). For

comparing the quality of the oil with any other oil extracted by the

conventional steam distillation process, a few samples of the oils

commercially being produced by a local company M/s Konark Paper

Industries Limited (KPIL) by steam distillation were collected and tested

under similar conditions (Rath et al., 1997).

The essential oil from Indonesian patchouli (P. cablin) was analyzed

qualitatively and quantitatively by gas chromatography (FID) and gas

chromatography/mass spectrophotometery. Using different ionization

techniques in mass spectrometry (EI, NCI and PCI with ammonia and

21

deuterated ammonia as reagent gases), 41 compounds were separated,

and 28 of which (92% of the total oil) were identified. Four new

compounds were found in the oil; γ-gurjunene (2.2%), germacrene D

(0.2%), aciphyllene (3.4%) and 7-epi-α-selinene (0.2%) (Bure and Sellier,

2004).

Narayanan (2004) observed that Indian patchouli oils were light

yellow in colour when compared to darker oils from Indonesia due to

better distillation practices followed in India especially the use of

stainless stills. The use of mild stills in Indonesia for patchouli oil

distillation resulted in picking up of colour by the essential oil.

The essential oil from leaves of Cinnamomum tamala L. (Lauraceae)

was obtained by hydro distillation and the yield was 2.42% on dry weight

basis. The oil was analyzed by gas chromatography-mass spectrometry.

51 compounds accounting for 93.03% of the oil were identified. Eugenol

(81.69%) was the most abundant with the appreciable amounts of α –

phellandrene (4.08%) and cymol (1.37%) (Rana and Blazquez, 2005).

MATERIAL AND METHODS

22

III MATERIALS AND METHODS

This chapter deals with the materials used and various

procedures/methods followed during the course of research study titled

“Agro-Processing of Patchouli (Pogostemon cablin Benth.) for Efficient Oil

Extraction”. It gives details of various unit operations carried out on

patchouli like drying, extraction of essential oil, quality analysis of the

essential oil extracted and development/testing of a small pilot scale

distillation unit for patchouli oil extraction.

The experiments were mostly carried out in the Post Harvest

Technology Scheme, Department of Horticulture, University of

Agricultural Sciences, Gandhi Krishi Vignan Kendra, Bangalore, and in

Indian Institute of Science, Bangalore. The quality analysis of patchouli

oil samples was however, done at Central Institute of Medicinal and

Aromatics Plants (CIMAP), Bangalore.

3.1 Raw Materials

For drying studies, the fresh patchouli (cv. Johore) was obtained

from Department of Horticulture, UAS, Bangalore, and also from CIMAP,

Bangalore. The herbage was harvested at right stage and both leaves and

twigs in the ratio of 80:20 were taken for various drying experiments like

tray drying, shade drying and drying in ASTRA, (Waste Based Dryer). The

shade dried patchouli used for pilot scale steam distillation is, however,

obtained directly from the local farmer through the contact of M/s Flower

Valley Bio-tech Pvt, Ltd, Bangalore.

23

3.2 Drying Studies of Patchouli Herbage

Freshly, harvested patchouli crop was dried by three different

methods: i) Shade drying ii) Convective tray drying and iii) Drying using

ASTRA Model Waste Based Dryer. In tray drying, five different drying

temperatures namely, 30, 40, 50, 60 and 70°C were attempted and the

initial drying bed thickness (depth) of fresh herbage was kept uniformly

at 100 mm.

3.2.1 Shade drying

During shade drying, the fresh patchouli herbage was spread on a

stainless steel tray and was allowed to dry in a well ventilated room (Plate

3.1). The initial drying bed thickness was 100 mm and the herbage was

turned frequently. Though slight variation in initial moisture content of

herbage was noticed, the moisture content was normalized at the

beginning of the experimentation to around 80% (wb). The average

ambient temperature and relative humidity of the room was recorded

using a Digital Thermo-Hygrometer. During shade drying, the ambient

temperature varied from 21.0-24.4°C and the relative humidity varied

from 40-81%. The periodic weight loss of the samples was recorded at

every one hour interval using a sensitive electronic balance (make:

Essae-DIGI, model: DS-450) and the moisture content at a given time

was estimated accurately by Toluene Distillation Method (AOAC, 1995).

Shade drying was continued until there was no more weight loss by the

sample as indicated by constant consecutive weight readings. At this

point, the herbage was assumed to be dried to its stable equilibrium

moisture content of around 11-12 % (wb). At the end of drying, in the

dried samples were stored in sealed LDPE (200g) bags until the oil

extraction was carried out by hydro distillation technique.

24

Plate 3.1 Shade drying

Plate 3.2 Convective Tray Dryer

25

3.2.2 Tray drying

3.2.2.1 Convective tray dryer

The experimental Tray Dryer (Plate 3.2) consisted of an insulated

cabinet of 18”x18”x24” (internal dimensions) with a door. Inside the

cabinet, 4 stainless steel trays could be placed one over the other with

some gap in between them. There was a heating unit situated at the

bottom of the cabinet consisting of three resistive type electrical heaters

of 1 Kw capacity each that actually heated up the drying air. The heating

unit was insulated using asbestos sheet and glass wool. The heated air

was circulated inside the cabinet using a fan operated by a 1/13 hp

electric motor. Two ventilation vents are provided on the side walls of the

cabinet to partially exhaust the wet air out of the dryer. The temperature

of the hot air was controlled with the help of a digital temperature

controller situated at the top of the cabinet and the temperature could be

maintained from ambient temperature to 175°C ±2°C using a thermostat

control.

3.2.2.2 Drying of samples

The tray dryer was put on for about 10-15 min before the start of

the experiment for initial warming up of the system. When the desired

drying air temperature was attained, the patchouli samples in sample

trays were placed inside the drying chamber and were dried at selected

temperatures. Tray drying experiments were conducted with samples of

400g fresh herbage. Small sample trays of 100 mm depths were

separately fabricated with stainless steel wire mesh and were used as

sample holders. The herbage was spread evenly to 100 mm initial bed

depth and the sample trays were placed inside the tray dryer (Plate 3.2).

26

The drying experiments were conducted at five different temperatures of

30, 40, 50, 60 and 70°C. The trials were replicated thrice for each drying

temperature selected. During drying, periodic weight loss (at hourly

intervals) of the samples were recorded using a sensitive electronic

balance and the moisture contents at a given time were estimated

accurately by Toluene Distillation Method (AOAC, 1995). Tray drying was

continued until there was no more weight loss by the sample as

indicated by constant consecutive weight readings. At this point, the

herbage dried was assumed to be dried to its stable moisture content of

(around 11-12 % (wb)). At the end of the drying, the extraction of

essential oil from dried samples was carried out by hydro distillation

technique.

3.2.3 Tray drying using ASTRA Model Agricultural Waste Based Crop

Dryer

3.2.3.1 ASTRA Model Agricultural Waste Based Crop Dryer

Center for Sustainable Technologies, Indian Institute of Science,

Bangalore has developed a simple batch type tray drier popularly known

as ASTRA Model Agricultural Waste Based Crop Dryer based on the

principle of a fuel efficient wood stove (Plate 3.3). In this dryer, hot flue

gases is conveyed through a duct that constantly heated the sucked

drying air. The heated drying air is made to pass over the material kept

in stainless steel trays in an orderly fashion due to natural convection.

The drying air removes the moisture from the material to be dried before

being vented off separately at the top. The design of dryer is such that

the cycle of heating, cooling, humidifying and reheating of drying air

takes place throughout its passage i.e., from bottom to the top of the

drier. The large area of flue duct contacting drying air (due to the internal

design for ordered flow of air) results in high heat transfer efficiency and

thus over 90% of heat generated by combustion is transferred to drying

27

Plate 3.3 ASTRA Dryer

Plate 3.4 Tray of ASTRA Dryer

28

air. The bottom flue duct ensures safe hot air while reheating of the

cooled and humidified drying air with in the dryer enables better drying

of product. Temperature of drying air could be controlled reasonably by

adjusting the burning rate of the fuel.Though the dryers of different

capacities are available, the one used in this study had a 7.8 sq.m

stainless steel tray area for drying the product. The cost of the equipment

is Rs 40,000 which works out to Rs 5200 per sq.m of stainless steel tray

area.

3.2.3.2 Drying of samples

The dryer was fired by using agricultural waste like wood

briquettes (Plate 3.5) for about 30-45 minutes before the start of the

experiment for initial warming up of the system. The temperature of

drying air at different levels could be maintained between 45-95°C by

controlling the rate of burning of fuel. When the desired drying air

temperature was attained, the fresh patchouli samples (in sample trays)

were dried at required temperature. Tray drying experiments were

conducted with samples of 3 kg fresh herbage. Sample trays of 100 mm

depth were used as sample holders (Plate 3.4) and the herbage was

spread evenly on trays to the required depth of 100 mm (initial bed

depth). The drying experiment was replicated thrice. During drying,

periodic weight loss of the samples (at hourly intervals) was recorded

using a sensitive electronic balance and the drying air temperature was

recorded at every one hour interval using a dial type thermometer (Plate

3.6) .The moisture content of patchouli sample at a given time was

estimated by toluene distillation method (AOAC, 1995). Drying was

continued until there was no more weight loss by the sample as

indicated by constant consecutive weight readings. At this point, the

herbage dried was assumed to be dried to its stable equilibrium moisture

29

Plate 3.5 Fuel Briquettes

Plate 3.6 Dial Thermometer

30

content of around 11-12 % (wb). After drying, the extraction of essential

oil from dried patchouli was carried out by hydro distillation technique.

3.3 Determination of Moisture Content of Patchouli Herbage

Moisture content of patchouli herbage samples was determined by

Toluene Distillation Method (Plate 3.7) as described in AOAC (1995).

Materials: 1000 ml short neck round bottom flask, 10 ml capacity

moisture receiver, 400 mm condenser and heating unit.

Reagents required: Toluene

Procedure: 10 g of patchouli herbage (8 g leaves and 2 g tender stem)

was placed in a 1000 ml distillation flask. Toluene was added to cover

the sample completely (never more than 250 ml). The receiving tube was

filled with toluene by pouring it through top of the condenser. A loose

cotton plug was inserted on top of condenser to prevent condensation of

atmospheric moisture into the tube. Using an electrically controlled

heating mantle, the toluene in the flask was brought to its boiling point

so that the moisture present in the sample also distilled at the rate of 2

drops per second. Gradually heating was intensified so as to distill at

about 4 drops per second and the distillation was continued till no more

moisture was collected in the condenser. It took about 3 hours to collect

all the moisture available in the sample. The amount of water collected in

the graduated receiver was directly proportional to the moisture present

in the sample.

3.4 Essential Oil Extraction by Hydro Distillation

The extraction of patchouli essential oil from the experimental samples of

dried patchouli herbage (by convective tray drying, shade drying, drying

in ASTRA model dryer) was done in the laboratory by hydro-distillation

technique (AOAC, 1995) using a Clevenger’s Apparatus (Plate 3.8).

31

Plate 3.7 Moisture Determination Apparatus

32

Apparatus: a) Volatile oil trap: Clevenger type with standard taper joints

for oils having densities near or less than that of water.

b) Flask 2000 ml round bottom, short neck with standard 29/42 taper

joint.

Procedure: A known quantity of dried patchouli herb (50 g) in the ratio

of 80:20 (leaves: tender sticks) was transferred in to the round bottom

flask and distilled water was added until the whole material was

immersed in the water (1000 ml). Well cleaned (with chromic acid)

Clevenger’s oil trap was fitted in the flask and the trap was filled with

distilled water. The flask was placed on an electrically heated mantle and

the contents were allowed to boil slowly. The steam passing out of the

flask along with the volatile oil was cooled in the water cooled condenser

and was collected in the oil trap. The distillation was carried out for

about 6 h (i.e., until there was no further oil collection). The patchouli oil

being lighter than water and immiscible formed a separate layer over the

water column in the Clevenger’s trap. The amount of patchouli oil

collected could be directly read from the graduated oil trap and thus oil

extraction in percentage (ml/100 g sample) was worked out.

3.5 Steam Distillation of Patchouli Essential Oil in Pilot Scale Unit

3.5.1 Pilot Scale Steam Distillation Unit

In the present study, though there was a mandate to develop a

pilot scale distillation unit, it could not be taken up due to exorbitant

cost involved for the fabrication of stainless steel unit. Therefore, an

available laboratory model pilot scale steam distillation unit in the

Department of Horticulture was made use of in the present study. The

pilot scale steam distillation unit used for the extraction of essential oil

33

Plate 3.8 Clevenger’s Essential Oil Distillation Unit

34

from shade dried patchouli herbage is given in Plate 3.9. The unit

consisted of: a) Steam generator, b) Distillation still, c) Condenser and

d) Essential oil receiver

The steam generator was an electrically heated boiler that

generated live steam at about 1 kg/cm2 pressure for distillation. During

operation, the water level inside the boiler was maintained manually so

that the boiler was not dried out. The distillation still was basically a

double walled vertical drum (inside wall made up of stainless steel) with

a tight lid on the top. The inside diameter of the still was 0.54 m and the

height of the still was 0.6m (sample holding height), thus having a

volumetric capacity of 0.5 m3. Inside the still, there was a perforated

false floor on which the dried patchouli herbage to be extracted (charge)

is placed. The steam entered the still at the bottom, rose through the

charge extracting volatiles and came out of the still at the top to enter

into the condenser. The condenser was a double pipe heat exchanger

where in the steam coming along with the essential oil vapour from

distillation still was condensed by cooling water circulated in the outer

tube. The condensate that contained water and essential oil was collected

in a receiver tank and the condensate was allowed to settle overnight for

rough separation of essential oil from water layer.

3.5.2 Extraction of Patchouli Oil in Pilot Scale Steam

Distillation Unit

During pilot scale distillation study, the patchouli bed packing

density inside the still and distillation time were varied to study the

quantity and quality of oil distilled as given below:

Independent variables:

Packing bed density (kg/0.5 m³): 4, 5 and 6

Distillation time (h) : 3, 4 and 5

35

Dependent variables:

Essential oil recovery

Quality of distilled essential oil

Total Treatments: 3 x 3 = 9

Replications : 3

Design : Factorial CRD

A known quantity of shade dried patchouli herbage directly

obtained from farm was packed uniformly in the distillation still and the

lid of the still was closed air-tight. The leaf to stick ratio of the herbage

was found to be about 60:40. The electrically heated boiler was switched

on and the water level in the boiler was manually maintained to a

required level. It took about 15 min for the boiler to issue steady steam

at a pressure of about 1 kg/cm². The distillation time was counted only

after the steam at steady pressure entered the distillation still. Thus the

steam while passing through the charge heated up the herbage. The

essential oil present in the cells of the patchouli herbage came out of the

cellular material due to vaporization and it rised along with steam. The

essential oil vapour and steam that came out of the distillation still were

condensed back to liquid phase in the water cooled condenser and the

condensate was collected in the receiver tank. The condensate was

basically a two-phase system with top layer of patchouli oil floating over

the heavier bottom layer of water. The condensate in the receiver tank

was allowed to stand for sufficient time (over night) so that the patchouli

oil separated out as far as possible from the water layer. After reasonable

separation in the receiver tank, the essential oil was further separated

from the water phase using a Separating Funnel (Plate 3.10). The oil was

still turbid due to the presence of some small tiny water droplets and

therefore, the oil was further dried using sodium sulphate. Then it was

36

Plate 3.9 Pilot Scale Patchouli Steam Distillation Unit

Plate 3.10 Essential oil separating funnel Plate 3.11 Patchouli essential oil

37

filtered through a Whatman filter paper to get clear essential oil (Plate

3.11). The clear essential oil thus obtained was stored in coloured glass

bottles till further analysis.

Quality Analysis of Essential Oil

The patchouli essential oil samples collected from different

experiments of the present study were subjected to quality analysis. The

composition of the oil was determined by the method of Gas-Liquid

Chromatograpy. The optical rotation and refractive index of essential oil

samples were determined using a Polarimeter and Abbey Refractometer,

respectively.

3.6.1 Gas Chromatographic analysis

Gas Chromatography (GC), a method for measuring the volatile

chemical constituents, is used to determine the composition of the

patchouli essential oil. It is one of the four objective tests done to

determine the quality, identity and purity of every essential oil. GC

analysis produces a “finger print” of the oil by showing the quantitative

presence of each chemical compound. In the present study, Gas–Liquid

Chromatography analysis of the patchouli essential oil samples were

conduced in Central Institute for Medicinal and Aromatic Plants,

Bangalore. The tests were conducted for four major components: β-

patchoulene, -guaiene, -bulnesene and patchouli alcohol. The results

were obtained in percent composition.

In the present study, the gas chromatographic analysis (IS 326:

Part 19) of patchouli essential oil was carried out using a Gas

Chromatograph having capillary column (Plate 3.12). The duration of test

in the GC with capillary column was 60 minutes. The computerized data

38

acquisition system collected the real time GC data that was analyzed

with the help of dedicated software supplied with GC.

Procedure (IS: 3398 - 2003): A small amount of essential oil was

introduced into a gas liquid partition column. The various components

that were volatile under the conditions of test were vaporized and were

transported through the test column by a carrier gas. The separated

components were measured in the effluent by a Flame Ionization

Detector and recorded as a chromatogram. The chromatogram was

interpreted by applying component attenuation and detector response

factors to the peaks, areas and the relative concentrations of various

constituents were determined by relating the individual peak responses

to the total peak responses. The following are the test conditions during

GC analysis:

Gas chromatographic conditions

Polar

Column Capillary, silica, length 30m, internal diameter 0.25mm

Stationary Phase

Polyethylene glycol 20M, film thickness 0.255 micrometer

Oven temperature programming

100 to 220°C at the rate of 2°C / min and isothermal for 30 min at 220°C

Injector temperature

250°C

Flame ionization detector temperature

250°C

Carrier gas

Nitrogen, 1 ml/min

Split ratio

1:100

Volume Injected

0.2 µl

39

3.6.2 Determination of Optical Rotation of Patchouli Essential Oil

Principle: When a beam of plane polarized light is passed through a

solution of compound such as (S)-alanine, the plane of polarization of the

light that emerges is rotated relative to the original plane. This

phenomenon is known as optical activity, and the compounds that rotate

the plane of polarized light are said to be optically active. The rotation of

polarized light through a liquid establishes its optical activity whether

dextrorotatory (bends light to the right) or laevorotatory (bends light to

the left). The reading is compared to the established standards;

significant deviation from the standard may indicate impurities and give

cause for further investigation.

Apparatus: Polarimeter (Plate 3.13), source of light- sodium vapour

lamp, distilled water, filtering device.

Procedure: The polarizer was directed towards monochromatic source of

light. The polarimeter tube (200 mm) was completely filled with distilled

water and its lid was closed tightly taking care to see that no air bubble

was formed. This tube was placed in the sample holder between the

polarizer and the analyser of the polarimeter. The analyser was rotated

till the tint of passage i.e., the two halves of the field of view was of

uniform intensity and colour. The angular reading (Ro) of the analyser

was noted in the main and the vernier scales. The essential oil was then

filled in the polarimeter tube as explained before and the tube was

mounted again between the polarizing and analyzing nicol prisms in the

sample holder. The analyser was rotated clockwise or anticlockwise until

the field of view was of uniform intensity and colour. The angle of

rotation (R) was again noted. Then the optical rotation was calculated as:

Optical Rotation = (R - Ro)

40

Plate 3.12 Gas Chromatograph

Plate 3.13 Polarimeter Plate 3.14 Refractometer

41

3.6.3 Determination of Refractive Index of Patchouli Essential Oil

The index of refraction is related to the physical structure of the

medium through which light is passing. Refractive index is defined as the

ratio of the velocity of light in a vacuum to its velocity in a specimen

(transparent). Higher the refractive index, greater the amount of

dispersion, which increases the brilliance of the material. The refractive

index values for the patchouli essential oil samples were determined

using Abbey Refractometer (Plate 3.14).

Procedure: A drop of the patchouli essential oil sample was paced on

the cleaned fixed prism and slowly the two prisms of the refractometer

were brought together and clamped. The refractometer was aligned to the

light source for proper illumination. The border line was brought into

field of view using coarse adjustment (lower right hand side). The border

line was dark blue on the other side. The cross wires were observed

through the eye piece and the border line was brought up to the

intersection of cross wires by means of the coarse or fine hand controls.

The refractive index reading of the patchouli essential oil was read

directly on the side scale of the refractometer through the magnifier.

After taking the reading, the prisms were opened and carefully cleaned

with a piece of lens paper.

3.7 Statistical Analysis

The statistical analysis of data in the present study was done using

the AIRS Computer Facility of University of Agriculture Sciences,

Bangalore, as per the statistical design employed. The computer

programme was developed in-house by Department of Agricultural

Statistics in FORTRAN language specifically for the VAX Platform.

EXPERIMENTAL RESULTS

42

IV. EXPERIMENTAL RESULTS The results of the experiments conducted during the course of

research study titled “Agro-Processing of Patchouli (Pogostemon cablin

Benth.) for Efficient Oil Extraction” are presented in this chapter.

4.1 Drying Studies of Patchouli Herbage

The drying characteristics of fresh patchouli herbage dried at

different temperatures in a convective tray dryer are depicted in Fig. 4.1

while the shade drying characteristics are given in Fig. 4.2. The drying

behaviour of fresh patchouli in ASTRA Model Agricultural Waste Based

Dryer is presented in Fig. 4.3.

4.1.1 Drying characteristics of patchouli in Tray Dryer

The drying behaviour of freshly harvested patchouli at different

temperatures in a convectional tray dryer is given in Fig. 4.1. The

moisture loss was relatively high during the initial phase of drying, say

up to 65-70 % moisture content and the patchouli lost its moisture more

rapidly at all drying temperatures .However, when drying continued the

rate of moisture reduction slowed down and when the herbage almost

reached its equilibrium moisture content the loss of moisture from the

sample is very slow. It could be observed that the drying time required to

dry the herbage from a moisture content of about 80 % (wb) to around 11

% (wb) varied considerably depending upon the temperature of drying.

For 100 mm initial drying bed depth, the drying time required at 30, 40,

50, 60 and 700C temperatures were 13, 12, 11, 7 and 6 h, respectively.

The influence of drying temperature on tray drying time of patchouli was

clearly discernible. As the drying temperature increased, the rate of

drying generally increased resulting in lesser time. For e.g., at 300C, it

43

0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10 12 14Drying time (h)

Moi

stur

e co

nten

t (%

wb)

70°C

60°C

50°C

40°C

30°C

╚

Fig 4.1 Drying characteristics of patchouli herbage in tray dryer

0

20

40

60

80

100

0 10 20 30 40 50 60

Drying time (h)

Moi

stur

e co

nten

t (%

wb)

R1

R2

R3

Fig 4.2 Drying behaviour of patchouli herbage under shade

R1, R2 and R3 – Trial runs

44

0102030405060708090

0 2 4 6 8 10 12 14 16

Drying time(h)

Moi

stur

econ

tent

(%w

b) R1

R2

R3

` Fig 4.3 Drying behaviour of patchouli herbage in ASTRA Model

Waste Based Crop Dryer

R1, R2 and R3 – Trial runs

0102030405060708090

100

0 2 4 6 8 10 12 14 16

Drying time (h)

Dry

ing

tem

pera

ture

(°C

) T1T2T3T4T5T6T7

Fig 4.4 Drying air temperature variation at different levels inside ASTRA Model Dryer during patchouli drying

T1, T2, T3, T4, T5, T6 and T7 – Temperature of drying air

measured at different levels from bottom to top inside

ASTRA Dryer

45

required about 13 h of drying time where as at 400C, it required only

about 12 h of drying time (for the same 100 mm of initial bed thickness).

Similar trend in reduction of drying times were observed at 50, 60 and

700C temperatures also.

4.1.2 Shade drying characteristics of patchouli

Shade drying behaviour of freshly harvested patchouli dried at an

initial drying bed thickness of 100 mm are depicted in Fig. 4.2. Under

the moderate ambient conditions of temperature (21–24.4°C) and relative

humidity (40-81%) that prevailed at Bangalore during shade drying, the

fresh patchouli herbage required about 54 h of drying time to dry the

fresh patchouli herbage at an initial moisture content of 80 %(wb) to a

final moisture content of 11-12 %(wb). The reduction in moisture content

with time was almost uniform but very slow. For the same 100 mm initial

drying bed depth, the tray drying time required were much lower than

the shade drying time at drying temperatures of 30, 40, 50, 60 and 700C

drying temperatures.

4.1.3 Drying characteristics of patchouli in ASTRA Model Agricultural Waste Based Crop Dryer

The drying behaviour of freshly harvested patchouli in ASTRA

Model Agricultural Waste Based Crop Dryer is depicted in Fig 4.3. It was

observed that the drying air temperature inside this ASTRA model Dryer

varied from 45 to 95°C during drying experiments and the drying air

temperature distribution at various levels inside the dryer is presented in

Fig.4.4. For 100 mm of initial drying bed thickness, the fresh patchouli

herbage required about 14 h of drying time to dry from an initial

moisture content of 80% (wb) to a final moisture content of 11-12 % (wb)

in ASTRA Dryer. The reduction in moisture content with time was almost

uniform but still very slow as compared to convective tray drying.

46

4.2 Effect of Drying Techniques on Essential Oil Yield

The quantities of essential oil extracted by hydro-distillation using

Clevenger’s apparatus from samples of patchouli dried under shade and

in the laboratory convectional tray dryer and in ASTRA Dryer are

presented in Fig. 4.5. It could be observed that the mean essential oil

yields were about 2.41% in shade dried sample, 2.25 – 2.40% in tray

dried samples and 2.24% in samples dried in ASTRA Dryer (Appendix –

A). Statistical analysis of data indicated that there was no significant

difference between various drying techniques with respect to essential oil

yield.

4.3 Effect of Drying Methods on Quality of Essential Oil The patchouli essential oil distilled from the patchouli herbage

dried in tray dryer, ASTRA dryer and by shade were analyzed for quality.

Gas chromatographic analysis of patchouli oils was done to determine

the various constituents of patchouli oil and a sample graph obtained

during the analysis is shown in Fig. 4.6. Refractive index was also

determined for various oil samples using Abbey Refractometer.

Considerable variation was observed in the composition of four major

patchouli oil constituents namely, β-patchoulene, -guaiene, -bulnesene

and patchouli alcohol.

4.3.1 Patchouli alcohol

The effect of drying methods of patchouli herbage on the patchouli

alcohol content of the extracted patchouli essential oil (from it) is

presented in Fig. 4.7. It could be observed that the patchouli alcohol

content was highest (66.26%) in the patchouli essential oil sample

extracted from the herbage dried at 70°C in convective tray dryer. And it

was observed to be 64.54, 64.19, 63.87 and 57.15% in the other

47

2.15

2.2

2.25

2.3

2.35

2.4

2.45

30 40 50 60 70 Shadedrying

ASTRAdrying

Drying Temperature (°C)

Esse

ntia

l Oil

Rec

over

y (%

)

Fig 4.5 Essential oil recovery from patchouli herbage dried under shade, in tray dryer at different drying temperatures and in ASTRA dryer

48

Fig 4.6 Gas chromatographic profile of patchouli oil

49

0

20

40

60

80

30 40 50 60 70 Shadedrying

ASTRAdrying

Drying temperature(°C)

Patc

houl

i Alc

ohol

Con

tent

(%)

Fig 4.7 Effect of drying of patchouli herbage on patchouli alcohol

content of extracted patchouli oil

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

30 40 50 60 70 Shadedrying

ASTRAdryer

Drying temperature(°C)

Bet

a Pa

tcho

ulen

e C

onte

nt (%

)

Fig 4.8 Effect of drying of patchouli herbage on β- patchoulene content of extracted patchouli oil

50

patchouli oil samples distilled from the herbage dried respectively at 50,

40, 60 and 30°C in convectional tray dryer. Similarly, the patchouli

alcohol content of essential oil from shade dried herbage was found to be

64.65 % while the sample dried in ASTRA Dryer had only 42.27%, much

less when compared to the patchouli alcohol contents of oils extracted

from the herbage dried in the tray dryer and by shade drying.

4.3.2 β-Patchoulene

The effect of drying methods of patchouli herbage on the β-

patchoulene content of the extracted patchouli oil (from it) is depicted in

Fig. 4.8. The β-patchoulene content was considerably higher in the

essential oil distilled from the tray dried patchouli herbage at 70°C

temperature (0.0302 %) when compared to the values of 0.0277 , 0.0249

, 0.0206 and 0.0103 %, respectively in the essential oils distilled from the

patchouli herbage tray dried at 60, 50, 40 and 30°C temperatures. The β-

patchoulene content of sample from the shade dried patchouli herbage is

comparable as tray dried sample (0.0249 %) and the least β-patchoulene

content of 0.0076% was noticed in samples from ASTRA Dryer.

4.3.3 α-Guaiene

From Fig. 4.9, it could be observed that the essential oil distilled

from patchouli herbage dried in ASTRA Dryer contained a -guaiene

content of 0.0991%. The essential oil distilled from the patchouli herbage

dried at 30, 40, 50, 60 and 70°C in tray dryer was 0.2352, 0.1452,

0.1629, 0.2397 and 0.0824 %, respectively. It could be observed that the

-guaiene content was 0.0401% in the essential oil distilled from the

shade dried herbage, which of course was less when compared to the -

guaiene content of oils extracted from the herbage dried in the tray dryer

and ASTRA Dryer.

51

0

0.05

0.1

0.15

0.2

0.25

0.3

30 40 50 60 70 Shadedrying

ASTRAdryerDrying Temperature(°C)

α- G

uaie

ne C

onte

nt (%

)

Fig 4.9 Effect of drying of patchouli herbage on α-Guaiene content of extracted patchouli oil

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

30 40 50 60 70 Shadedrying

ASTRAdryer

Drying temperature (°C)

Alph

a Bu

lnes

ene

Con

tent

(%)

Fig 4.10 Effect of drying of patchouli herbage on α-Bulnesene

content of extracted patchouli oil

52

4.3.4 α-Bulnesene

The effect of drying of patchouli herbage on the α-bulnesene

content of the patchouli oil extracted from it is depicted in Fig. 4.10. The

α-bulnesene composition was found to be 0.12904% in the essential oil

distilled from the herbage dried in ASTRA Dryer. The α-bulnesene

contents was 0.1278, 0.0571, 0.0512, 0.0407 and 0.0512 % respectively

in the essential oils obtained from the herbage dried in tray dryer at

temperatures of 60, 50, 40, 70 and 30°C while the above value was

0.1278 % in the oil distilled from the shade dried herbage.

4.3.5 Refractive index

The refractive index of patchouli oil samples distilled from

patchouli herbage dried under shade, in ASTRA Dryer, as well as in tray

dryer at different drying temperatures varied from 1.501 to 1.505 (Table

4.1). The refractive index values of patchouli oils obtained from different

samples of dried patchouli herbage did not show much variation and

neither the method of drying nor the experimental range of drying air

temperatures studied (30, 40, 50, 60 and 70°C) had any significant

influence on refractive index of oils extracted.

4.4 Pilot Scale Steam Distillation of Patchouli Essential Oil

Pilot scale steam distillation of shade dried patchouli herbage was

carried out at 3 different packing bed density levels of 4, 5 and 6

kg/0.5m3 and distillation time of 3, 4, 5 and 6 h to find out the essential

oil yields and quality.

53

00.5

11.5

22.5

33.5

4

0 1 2 3 4 5 6 7Distillation time (h)

Esse

ntia

l oil

yiel

d (%

)

Fig 4.11 Effect of steam distillation time on patchouli essential oil recovery at packing bed density of 4 kg/0.5m³

0

0.5

1

1.5

2

2.5

3

3.5

0 1 2 3 4 5 6 7

Distillation time (h)

Esse

ntia

l oil

yiel

d (%

)

Fig 4.12 Effect of steam distillation time on patchouli essential oil recovery at packing bed density of 5 kg/0.5m³

54

00.5

11.5

22.5

33.5

0 1 2 3 4 5 6 7

Distillation time (h)

Esse

ntia

l oil

yiel

d (%

)

Fig 4.13 Effect of steam distillation time on patchouli essential oil recovery at packing bed density of 6 kg/0.5m³

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1 2 3 4 5 6 7

Distillation time (h)

Esse

ntia

l oil

yiel

d (%

)

Fig 4.14 Essential oil recovery from shade dried patchouli herbage

at various distillation time intervals (packing bed density of 4 kg/0.5m³)

55

0

5

10

15

20

25

30

35

40

45C

onte

nts

(%)

(1-3) h (3-4) h (4-5) hDistillation Period

Patchouli AlcoholAlpha-BulneseneAlpha-GuaieneBeta-Patchoulene

Fig 4.15 Variation in patchouli oil quality at different distillation

time intervals for packing bed density 4 kg/0.5m³

0

5

10

15

20

25

30

35

40

45

Con

tent

s (%

)

(1-3) h (3-4) h (4-5) hDistillation Period

Patchouli AlcoholAlpha-BulneseneAlpha-GuaieneBeta-Patchoulene

Fig 4.16 Variation in patchouli oil quality at different distillation time intervals for packing bed density 5 kg/0.5m³

56

Table 4.1 Effect of drying of patchouli herbage on the refractive

index of extracted essential oil

Temperature (°C)

R1 R2

Refractive Index Mean

30

1.502

1.504

1.5030

40

1.502

1.502

1.5020

50

1.502

1.503

1.5025

60

1.503

1.502

1.5025

70

1.504

1.503

1.5035

Shade

1.505

1.503

1.5040

Astra 1.501 1.501 1.5010

F- Test

NS

NS

NS

CD

-

-

-

NS - Not Significant

57

4.4.1 Influence of packing bed density and distillation time on patchouli essential oil yield

The effect of packing bed density and distillation time on patchouli

essential oil yield is presented in Fig.4.11 to 4.13. It could be observed

that the variation in packing bed density and distillation time had

significant influence on the essential oil yield.

At 4 kg/0.5m3 packing bed density, the patchouli essential oil

yields were 2.78, 3.06, 3.26 and 3.42 % respectively for 3, 4, 5 and 6 h

distillation time. At 5 kg/0.5m3 packing bed density, the patchouli

essential oil yields were 2.46, 2.74, 2.95 and 3.10 % respectively for 3, 4,

5 and 6 h distillation time. Similarly, at 6 kg/0.5m3 packing bed density,

the patchouli essential oil yields were 2.25, 2.54, 2.79 and 2.97%

respectively for 3, 4, 5 and 6 h distillation time. It was interesting to note

that the statistical analysis of essential oil yield data from pilot scale

distillation (Appendix-B) showed significant difference with respect to

both packing bed density and distillation time.

Further, from Fig. 4.14, it could be seen that the essential oil

recovery was faster at the beginning of steam distillation i.e., up to first 3

h and later on the oil yield was decreasing with time. Beyond 5 h of

steam distillation in the Pilot Scale Unit, very little oil was collected (at

packing bed density of 4 kg/0.5m3).

4.4.2 Influence of packing bed density and distillation time on patchouli essential oil quality

The compositions of patchouli essential oils extracted from shade

dried patchouli herbage using Pilot Scale Steam Distillation Unit at

different packing densities and distillation times were analyzed in a Gas

Chromatograph and the results are presented in Table 4.2. It could be

observed that the patchouli alcohol content varied from 34.74% in 4

kg/0.5m³, 34.92% in 5 kg/0.5m³, and 27.78% in 6 kg/0.5m³,

58

Table 4.2 Influence of packing density and distillation time on patchouli essential oil quality

NS – Not significant

Distill-ation Time (hr)

Packaging Bed Density

4 kg/ 0.5 m3

5 kg/ 0.5 m3

6 kg/ 0.5 m3

Patchouli alcohol

(%)

α- Bulnesene

(%)

α- Guaiene

(%)

β- Patchoulene

(%)

Patchouli alcohol

(%)

α- Bulnesene

(%)

α- Guaiene

(%)

β- Patchoulen

e (%)

Patchouli alcohol

(%)

α- Bulnesene

(%)

α- Guaiene

(%)

β- Patchou-lene (%)

3 4 5

25.15

36.18

42.89

21.95

19.94

18.21

16.14

12.33

9.77

0.0195

0.0171

0.0195

25.46

35.43

43.86

22.40

19.40

17.44

16.48

12.44

9.21

0.0100

0.0219

0.0177

23.33

29.58

30.42

22.74

20.52

14.89

16.68

13.74

8.56

0.0000

0.0000

0.0000

Mean 34.74 20.04 12.75 0.0187 34.92 19.75 12.71 0.0165 27.78 19.38 19.38 0.0000

F-test NS NS NS NS NS NS NS NS NS NS NS NS

59

α-Bulnesene content varied from 20.04% in 4 kg/0.5m³, 19.75% in 5

kg/0.5m³, and 19.38% in 6 kg/0.5m³, α- Guaiene content varied from

12.75% in 4 kg/0.5m³, 12.71% in 5 kg/0.5m³, and 19.38% in 6

kg/0.5m³, and β- Patchoulene varied from 0.0187% in 4 kg/0.5m³,

0.0165% in 5 kg/0.5m³, and 0.000% in 6 kg/0.5m³ for different samples

of essential oils. The statistical analysis indicated that there was no

significant difference between the treatments with respect to quality.

4.4.3 Refractive index

The refractive index of patchouli essential oil samples steam

distilled from shade dried herbage in the Pilot Scale Unit at different

packing bed densities and distillation times were between 1.5030 and

1.5055 (Table 4.3) which was similar to the BIS standard value specified

for patchouli oil (IS 3398 : 2003). There was no significant difference

between various treatments as far as the refractive index values of

essential oils distilled from them is concerned.

4.5 Comparison of Hydro and Steam Distillation Methods for Patchouli Essential Oil Yield and Quality

4.5.1 Essential oil yield

The yields of patchouli oil extracted from shade dried herbage by

two distillation techniques namely, hydro and steam distillation are

presented in Table 4.4. The shade dried patchouli herbage distilled in a

Pilot Scale Steam Distillation Unit (4 kg/0.5m3 packing bed density)

yielded 3.26% essential oil which was higher than the yield of essential

oil obtained in the laboratory (2.41%) by hydro-distillation technique

using Clevenger’s apparatus.

60

Table 4.3 Effect of bed packing density and distillation time on

refractive index of patchouli essential oil

NS - Not Significant

Bed packing density

(kg)

Refractive Index

Time of Distillation (h) Mean

3 4 5 6 4 1.5040 1.5035 1.5032 1.5035 1.5040

5 1.5030 1.5030 1.5040 1.5040 1.5039

6 1.5055 1.5045 1.5050 1.5050 1.5040

Mean 1.5033 1.5032 1.5045 1.5048

-

Distillation time

Bed packing

density

Interaction

SEM± CD @ 5% F value

0.0007 0.0020 NS

0.0006 0.0017 NS

0.0011 0.0035 NS

61

Table 4.4 Effect of type of distillation on the yield and quality of

essential oil

Parameter

BIS Standard

Values (IS 3398 : 2003)

Hydro Distillation

Steam Distillation

Oil Yield (%) - 2.41 3.26

Patchouli Alcohol Content (%) 27 - 35 64.65 42.89

Refractive Index 1.502 - 1.512 1.504 1.506

Optical Rotation ( ° ) -66 to -40 -47.1° -54.1°

62

4.5.2 Essential oil quality

The quality of patchouli essential oil extracted varied considerably

(Table 4.4) with the type of distillation technique employed. The BIS

standard for patchouli oil specifies that the patchouli alcohol content

should be in the range of 27-35% of the total composition. In the present

study, the patchouli alcohol content was 64.65% and 42.89%, the

refractive index of essential oils were 1.504 & 1.506 and optical rotation

of oils were -47.1° & -54.1° respectively in the essential oils distilled from

hydro-distillation technique (using Clevenger’s apparatus) and steam

distillation technique. Except for patchouli alcohol content, these values

were well within the range specified in BIS Code for patchouli oil for

patchouli oil. Higher patchouli alcohol content observed in the present

study is, however, a desirable trait for trade.

4.6 Cost Economics of Patchouli Oil Distillation

The cost economic analysis for extraction of essential oil from shade

dried patchouli herbage in the Pilot Scale Steam Distillation Plant is

presented in Appendix C. The total cost of distillation per batch (5 kg of

shade dried patchouli herbage) was worked out to be Rs. 429/- and the

net profit was calculated to be Rs. 144/- (26.5%). The cost: benefit ratio

of patchouli oil distillation was found to be 1: 1.26.

4.7 Variation in Major Constituents in the Patchouli Essential Oil

Distilled at Different Steam Distillation

The proportion of major constituents of patchouli essential oil

namely, patchouli alcohol, -guaiene, -bulnesene and β -patchoulene

were found to vary in the patchouli collected at different period of steam

distillation (1-3h, 3-4h, 4-5h) and the results are presented in Fig. 4.15,

4.16 and 4.17 for various packing bed densities of distillation.

63

0

5

10

15

20

25

30

35

(1-3) h (3-4) h (4-5) hDistillation Period

Con

tent

s (%

)

Patchouli Alcohol

Alpha-BulneseneAlpha-Guaiene

Beta-Patchoulene

Fig 4.17 Variation in patchouli oil quality at different distillation time intervals for packing bed density 6 kg/0.5m³

64

For 4kg/0.5m3 packaging bed density and at (1-3h), (3-4h) and (4-5h)

distillation periods the patchouli alcohol contents were – 25.15%, 36.18%

and 42.89%; -bulnesene contents were – 21.95%, 19.94% and 18.21%;

-guaiene content were – 16.14%, 12.33% and 9.77%; and β -

patchoulene content were - 0.0195%, 0.0171% and 0.0195%,

respectively.

It is clear from the data that the proportions of major constituents

varied significantly with the distillation period. It was interesting to note

that -guaiene distilled out faster at the beginning of distillation cycle

whereas the patchouli alcohol came out in higher quantities later. This

indicated that if distillation is for shorter period of time the resultant

patchouli essential oil will contain lesser amount of patchouli alcohol.

Similar, results were observed at 5kg/0.5m3 and 6kg/0.5m3 packaging

bed densities.

DISCUSSION

65

V DISCUSSION

The results of the experiments conducted during the course of

research study titled “Agro-Processing of Patchouli (Pogostemon cablin

Benth.) for Efficient Oil Extraction” are analyzed and discussed in this

chapter.

5.1 Drying Studies of Patchouli Herbage

The drying characteristics of fresh patchouli herbage dried at

different drying temperatures in a convective tray dryer are depicted in

Fig. 4.1 where as, the shade drying characteristics are given in Fig. 4.2

and drying characteristics in ASTRA Dryer are given in Fig.4.3.

5.1.1 Tray Drying Characteristics

In a tray dryer, the total drying time required to dry the freshly

harvested patchouli herbage from a moisture content of about 80% (wb)

to 10 – 11% (wb) was found to vary considerably depending upon the

temperature of drying. For 100 mm initial drying bed thickness, the

drying period required at 30, 40, 50, 60 and 70°C drying temperatures

were 13, 12, 11, 7 and 6 h, respectively which were much lower than the

shade drying time of 54 h. The influence of drying temperature on tray

drying time of patchouli was clearly discernible. Similar results were

reported by Raghavan et al. (1995) in drying fresh Indian thyme and

Chiumenti et al. (1996) in drying Salvia offinalis. The drying time reduced

considerably as drying temperature increased. For e.g., for 30°C, the

drying time was 13 h and for 70°C the drying time was 6 h only. Since,

the drying phenomena is a simultaneous heat and mass transfer

process, increase in drying temperature increased the drying potential

(i.e., temperature differential between product and drying air) which

helped faster drying of patchouli. Further, in a convective tray dryer, the

66

movement of relatively hotter drying air that carried the evaporated

moisture from th material also helped in improving the drying rate. The

moving drying air also aided the heat transfer process from the medium

to the drying material which is necessary for the vaporization of moisture

in the material. This is exactly the reason why the material dries faster in

a convective tray dryer than in an oven.

5.1.2 Shade Drying Characteristics

Under the moderate ambient conditions that prevailed in

Bangalore during shade drying, the fresh patchouli herbage required 54

h of drying time at 100 mm of initial drying bed thickness. Relatively

moderate ambient temperatures (21.0–24.4°C) and high relative humidity

(40-81%) that prevailed during shade drying prolonged the duration of

shade drying. Though this was similar to the duration of shade drying (2-

4 days) reported by Farooqui et al. (2001), the ambient conditions at the

time of their study and the final moisture content attained were not

reported for reasonable comparison.

5.1.3 Drying Characteristics in ASTRA Dryer

In ASTRA dryer, the total drying time required to dry the freshly

harvested patchouli herbage from a moisture content of about 80 to 10-

11% (wb) was found to be 14 h for 100 mm initial drying bed thickness.

Though the drying period required was only about 14 h as compared to

54 h of shade drying, it was higher than the drying times observed in

convective tray dryer. Since, the air movement inside this dryer must be

laminar (at low velocity) due to natural convection drying rate was

relatively slow. Further, inside the ASTRA dryer, the temperature varied

from 45-95°C at different levels that necessitated the shifting of trays

periodically from top to bottom position and vice versa. Further, the

drying air temperature control in this dryer was difficult and required lot

67

of skill since, it was done only by adjusting the rate of burning of fuel

(wood/briquettes). The dip in drying temperatures at the middle of

drying period in Fig. 4.4 was due to stoppage of dryer on the first day.

The drying was started when the dryer warmed up to 450C in the

following day. In the present study, the wood and briquettes are used as

fuel and the calorific value of wood and briquettes was 3500 kcal/kg.

Another disadvantage was elevated drying temperature of 95°C at the

bottom level may lead to the loss of volatile compounds present in the

patchouli oil in spite of this still the dryer is considered to be efficient for

drying patchouli herbage.

5.2 Effect of Drying of Herbage on Patchouli Essential Oil Yield

The quantities of essential oil extracted by hydro-distillation using

Clevenger’s apparatus from samples of patchouli dried under shade and

in the laboratory convectional tray dryer and in ASTRA Dryer are

presented in Fig. 4.5. It could be observed that the mean essential oil

yields were about 2.41% in shade dried sample, 2.25 – 2.40% in tray

dried samples and 2.24% in samples dried in ASTRA Dryer (Appendix –

A). Statistical analysis of data indicated that there was no significant

difference between various drying techniques with respect to essential oil

yield.

This study indicated that the fresh patchouli herbage can be dried

mechanically in a tray dryer without a loss in essential oil recovery. The

finding is really a boon for the farmers of some areas where the climatic

conditions are unfavorable for shade drying. This study also indicated

that the control of temperature was difficult in ASTRA dryer and heat

sensitive crops have to be carefully handled if this dryer has to be used

for them.

68

In the present drying study, the yields of patchouli essential oil, in

general, were comparable (2.25-2.41%) to the yield of around 2.5-2.98%

reported in the literature by Guenther (1948) and Farooqui et al. (2001).

Since, the leaves contain more patchouli oil of about 2.5 to 2.8%

compared to tender sticks (0.5%) (Farooqui and Sreeramu, 2001). The

ratio of dried patchouli leaves to tender sticks in this study was all along

maintained at 80:20 and therefore, the oil recovery was slightly less

compared to the reported results.

5.3 Effect of Drying of Herbage on Quality of Extracted Patchouli

Essential Oil

The patchouli alcohol content is the most important quality

attribute of the patchouli essential oil that is valued in commerce. The

patchouli alcohol contents of patchouli essential oils distilled from the

herbage dried under shade (64.65%) as well as in tray dryer at different

temperatures (57.15 to 66.26%) and in ASTRA dryer (42.27%) were

much higher than the value of 32-37% reported by Dung et al. (1990)

and the BIS specification for standard patchouli oil (27-35%). The

patchouli alcohol content, however, was slightly lower in the essential oil

distilled from dried herbage of ASTRA Dryer when compared to that from

the herbage dried in shade and tray dryer. Exact reason could not be

established in the present study. One possible reason might be that the

high temperatures of 90°C encountered at some levels of the ASTRA

Dryer during drying leads to the loss of patchouli alcohol content.

Further, the patchouli alcohol content of the oils obtained from the

herbage dried at drying temperatures of 30°C was slightly less when

compared to 40, 50, 60 and 70°C.

The effect of drying of patchouli herbage on the β-patchoulene

content of the extracted patchouli oil (from it) is depicted in Fig. 4.8. The

69

β-patchoulene content was considerably higher in the essential oil

distilled from the tray dried patchouli herbage at 70°C temperature

(0.0302 %) when compared to the values of 0.0277 , 0.0249 , 0.0206 and

0.0103 % respectively in the essential oils distilled from the patchouli

herbage tray dried at 60, 50, 40 and 30°C temperatures. The β-

patchoulene content of sample from the shade dried patchouli herbage is

comparable at 0.0249% and the least β-patchoulene content of 0.0076%

was noticed in samples from ASTRA Dryer. As it is known that these

aromatic compounds are sensitive to temperature, higher drying

temperatures might have resulted in degradation of β-patchoulene, -

guaiene and -bulnesene compounds. Chiumenti et al. (1996) observed

that the essential oil composition of Salvia officinalis was found to vary

slightly depending on drying temperature and the content of sensitive

compounds decreased with increased temperature, although the

contents of other compounds remained relatively constant.

Recent studies by Bure et al. (2004) have shown that patchouli

essential oil contains many more compounds, of which 41 of them were

separated and 28 of them (92.9% of total oil) were actually identified

using advance analysis techniques. The gas chromatographic analysis

(GC-FID) technique employed in the present study probably could not

explain the variation in quality aspects of patchouli oil exactly. Many

peaks that were detected in the chromatograph could not be associated

with known compounds. Therefore, it could be concluded that the oil

quality vis-à-vis the drying effect were only suggestive in nature

(probably sufficient for commerce) and further research may be

necessary in this area.

The refractive index values of the essential oil samples extracted

from different drying treatments did not vary significantly. The refractive

70

index values ranged between 1.501-1.505, which falls within the BIS

specifications (IS 3398:2003) for patchouli oil (1.502-1.512).

5.4 Pilot Scale Steam Distillation of Patchouli Essential Oil Pilot scale steam distillation of shade dried patchouli

herbage was carried out at 3 different packing bed density levels of 4, 5

and 6 kg/0.5m3 and the distillation times were also varied at 3, 4, 5 and

6 h to find out the essential oil yields and quality.

The effect of packing bed density and distillation time on patchouli

essential oil yield is presented in Fig.4.11 to 4.13. It could be observed

that the variation in packing bed density and distillation time had

significant influence on the essential oil yield.

At 4 kg/0.5m3 packing bed density, the patchouli essential oil

yields were 2.78, 3.06, 3.26 and 3.42 % respectively for 3, 4, 5 and 6 h

distillation time. At 5 kg/0.5m3 packing bed density, the patchouli

essential oil yields were 2.46, 2.74, 2.95 and 3.10% respectively for 3, 4,

5 and 6 h distillation time. Similarly, at 6 kg/0.5m3 packing bed density,

the patchouli essential oil yields were 2.25, 2.54, 2.79 and 2.97%

respectively for 3, 4, 5 and 6 h distillation time.

Further, from Fig. 4.14, it could be seen that the essential oil yield

was faster at the beginning of steam distillation i.e., up to first 3 h and

later on the oil yield was decreasing with time. Beyond 5 h of steam

distillation in the Pilot Scale Unit, very little oil was collected (at packing

bed density of 4 kg/0.5m3). Rao et al. (1999) reported field distillation

using steam at about 2 bar pressure in a 1000 kg capacity distillation

vessel. It took 120 min to what was considered a full extraction and

about 60 min to obtain 90% of the total oil extracted. Distillation tests

conducted by the method based on the determination of two parameters,

the “increment parameter” and the “basic time parameter” after

71

dimensioning of a still suitable for the processing of the plant could be

made (Denny, 1991).

5.5 Comparison of Steam and Hydro Distillation Methods

The yields of patchouli oil extracted from shade dried herbage by

two distillation techniques namely, hydro and steam distillation are

presented in Table 4.4. The shade dried patchouli herbage distilled in a

Pilot Scale Steam Distillation Unit (4 kg/0.5m3 packing bed density)

yielded 3.26% essential oil which was higher than the yield of essential

oil obtained in the laboratory (2.41%) by hydro-distillation technique

using Clevenger’s apparatus.

Similar results were obtained by Guenther (1948) for patchouli and

Denys et al. (1990) for Basil. Guenther (1948) reported that patchouli

yielded 3.27 % essential oil on steam distillation and only 2.98 % on

hydro-distillation. It was also reported that steam distillation in certain

plant materials has been found to increase the total yield of essential oil.

Denys et al. (1990) noticed that the yield of essential oil of Basil was

consistently higher from steam distillation than hydro-distillation. The

essential oil yield in hydro-distillation was generally less due to the fact

that some of the high boiling constituents of patchouli essential oil that

are partly soluble in water might not distill out completely as vapours

(Prasad et al. 1987). Where as in steam distillation, the temperature of

distillation was slightly higher than hydro-distillation and that helped

better extraction of available oil in the material.

5.6 Cost Economics of Patchouli Oil Distillation

The cost economic analysis worked out for the pilot scale steam

distillation of shade dried patchouli herbage showed that the net profit

for patchouli steam distillation was 26.50%. This works out to be

72

economical (cost : benefit ratio – 1:1.26) for the farmers who grow

patchouli and wish to distill the essential oil.

5.7 Variation in Major Constituents in the Patchouli Essential Oil Distilled at Different Steam Distillation

The proportion of major constituents of patchouli essential oil

namely, patchouli alcohol, -guaiene, -bulnesene and β-patchoulene

were found to vary in the patchouli collected at different period of steam

distillation (1-3h, 3-4h, 4-5h) and the results are presented in Fig. 4.15,

4.16 and 4.17 for various packaging bed densities of distillation.

For 4kg/0.5m3 packaging bed density and at (1-3h), (3-4h) and (4-

5h) distillation periods the patchouli alcohol contents were – 25.15,

36.18and 42.89%; -bulnesene contents were – 21.95, 19.94 and

18.21%; -guaiene content were – 16.14, 12.33 and 9.77%; and β-

patchoulene content were - 0.0195, 0.0171 and 0.0195%, respectively.

It is clear from the data that the proportions of major constituents

varied significantly with the distillation period. It was interesting to note

that -guaiene distilled out faster at the beginning of distillation cycle

whereas the patchouli alcohol came out in higher quantities later. This

indicated that if distillation is for shorter period of time the resultant

patchouli essential oil will contain lesser amount of patchouli alcohol.

Similar, results were observed at 5kg/0.5m3 and 6kg/0.5m3 packaging

bed densities.

SUMMARY

73

VI SUMMARY

Patchouli is an important aromatic herb grown for its essential oil.

Patchouli oil is found mainly in the dried leaves and a small quantity of

oil is also present in the tender parts of the stem. Due to its good fixative

properties, patchouli oil is a key constituent in exotic perfumes especially

in soap perfumes. Post harvest handling of the patchouli herbage play an

important role in obtaining the patchouli essential oil both in terms of oil

yield and quality. The present extraction efficiency of this high valued oil

is only about 2 – 2.8% (available 3 – 3.5%) probably due to improper post

harvest handling practices at various stages like herbage drying,

distillation, etc. Therefore, this study on “Agro-Processing of Patchouli

(Pogostemon cablin Benth.) for Efficient Oil Extraction” was undertaken to

study and standardize the initial raw material handling and drying

practices of patchouli for improved distillation efficiency and also to

study essential oil yield and quality.

To study the drying characteristics of patchouli, fresh herbage (cv.

Johore) was dried under shade, in ASTRA dryer as well as in a

convectional Tray Dryer at 30, 40, 50, 60 and 70°C temperatures and the

initial drying bed thickness was uniformly maintained at 100 mm. The

effects of drying methods on the patchouli essential oil yield and its

quality were studied using Clevenger’s Essential Oil Distillation Unit and

Gas Chromatograph. Patchouli oil was also extracted from shade dried

patchouli herbage using a Pilot Scale Steam Distillation Unit at different

packing bed densities and distillation times. Further, a comparative

study was made between hydro distillation of patchouli using

Clevenger’s Unit and steam distillation using Pilot Scale Steam

Distillation Unit in terms of essential oil yield and quality.

74

From the results obtained from the above studies, the following

important conclusions could be drawn:

1. Under the moderate ambient conditions of temperature (21.0–

24.4°C) and relative humidity (40-81%) that prevailed at Bangalore

during shade drying, the fresh patchouli herbage required about 54 h

of drying time (for 100 mm of initial drying bed thicknesses) to dry it

from an initial moisture content of 80 % (wb) to a final moisture

content of 11-12% (wb).

2. For drying patchouli herbage, in a tray dryer, the drying period

required at 30, 40, 50, 60 and 700C drying temperatures were 13, 12,

11, 7 and 6 h, respectively for 100 mm initial drying bed depth.

3. The fresh patchouli herbage required about 14 h to dry from an

initial moisture content of 80 %(wb) to a final moisture content of 11-

12 %(wb)in ASTRA Dryer.

4. The mean essential oil yields were about 2.41% in shade dried

sample, 2.25 – 2.40% in tray dried samples and 2.24% in samples

dried in ASTRA Dryer. Statistical analysis of data indicated that there

was no significant difference between various drying techniques with

respect to essential oil yield.

5. There was a considerable variation in the quality of patchouli oil

extracted from herbage dried at different drying temperatures.

Patchouli alcohol content in the essential oil was highest (66.26%) in

the oil distilled from the herbage dried at 70°C in a tray dryer and it

was least (42.27%) in the oil distilled from the herbage dried ASTRA

Dryer. The sample from shade dried herbage was found to contain

64.65% patchouli alcohol content and it was observed to be 64.54%,

75

64.19%, 63.87% and 57.15% in the other patchouli oil samples

distilled from the herbage dried respectively at 50, 40, 60 and 30°C in

convectional tray dryer. The composition of -guaiene and -

bulnesene in the patchouli essential oil were higher in the oil distilled

from Astra dried herbage. The compositions of β-patchoulene in the

patchouli essential oil were higher in the oil distilled from the herbage

dried at 70°C in a tray dryer.

6. The refractive index of patchouli oil samples distilled from patchouli

herbage dried under shade, ASTRA dryer as well as in tray dryer at

different drying temperatures varied from 1.504 to 1.506.

7. The notion that shade drying will yield better oil with better quality

has been disproved. The patchouli herbage dried mechanically yielded

the same quantity of oil with premium quality attributes as that of

shade dried herbage.

8. Patchouli essential oil yields from steam distillation of shade dried

patchouli herbage in a Pilot Scale Steam Distillation Plant at different

bed densities and at different distillation times were as follows : At 4

kg/0.5m3 packing bed density, the patchouli essential oil yields were

2.78, 3.06, 3.26 and 3.42 % respectively for 3, 4, 5 and 6 h distillation

time; At 5 kg/0.5m3 packing bed density, the patchouli essential oil

yields were 2.46, 2.74, 2.95 and 3.10% respectively for 3, 4, 5 and 6 h

distillation time; and at 6 kg/0.5m3 packing bed density, the

patchouli essential oil yields were 2.25, 2.54, 2.79 and 2.97%

respectively for 3, 4, 5 and 6 h distillation time.

9. Patchouli essential oil quality from steam distillation of shade dried

patchouli herbage in a Pilot Scale Steam Distillation Plant at different

bed densities and at different distillation times were as follows:

Patchouli alcohol content varied from 34.74% in 4 kg/0.5m³, 34.92%

76

in 5 kg/0.5m³, and 27.78% in 6 kg/0.5m³; α-Bulnesene content

varied from 20.04% in 4 kg/0.5m³, 19.75% in 5 kg/0.5m³, and

19.38% in 6 kg/0.5m³; α- Guaiene content varied from 12.75% in 4

kg/0.5m³, 12.71% in 5 kg/0.5m³, and 19.38% in 6 kg/0.5m³; and β-

Patchoulene varied from 0.0187% in 4 kg/0.5m³, 0.0165% in 5

kg/0.5m³, and 0.000% in 6 kg/0.5m³ for different samples of

essential oils.

10. The shade dried patchouli herbage distilled in a Pilot Scale Steam

Distillation Unit (4 kg/0.5m3 packing bed density) yielded 3.26%

essential oil which was higher than the yield of essential oil obtained

in the laboratory (2.41%) by hydro distillation technique using

Clevenger’s apparatus.

11. The patchouli alcohol content was 64.65% and 42.89%, the

refractive index of essential oils were 1.504 & 1.506 and optical

rotation of oils were -47.1° & -54.1° respectively in the essential oils

distilled from hydro-distillation technique (using Clevenger’s

apparatus) and steam distillation technique. Expect for patchouli

alcohol content, these values were well within the range specified in

BIS Code for patchouli oil. Higher patchouli alcohol content observed

in the present study is, however, a desirable trait for trade.

12. Cost economic analysis of patchouli essential oil using Pilot Scale

Steam Distillation Unit indicated that the extraction is viable and the

cost: benefit ratio of patchouli oil distillation was found to be 1: 1.26.

REFERENCES

77

VII REFERENCES

ANONYMOUS, 2004a, Patchouli Essential Oil Information – 2004.

(http://esssentialoils.co.za/essential_oils/patchouli.html) 24th

Sept., 2004.

ANONYMOUS, 2004b, Annual Report - 2003. Report No. UAS/ PHT/

2002/37, PHT Scheme, University of Agril. Sciences, Bangalore,

India, pp: 84-89.

ANONYMOUS, 2005a, Patchouli Oil - 2004.

(http://Frontiercoop.com/info/index.html) 14th Jan. 2005.

ANONYMOUS, 2005b, Extraction of Essential Oils for Perfumes – 2005.

(http://geocities.com / model career/ extraction_of_essential _oils.)

5th Aug. 2005.

ANOMYMOUS, 2005c, CO2 Extracts -2005. (http://doteasy.com) 9th

June 2005.

ANONYMOUS, 2005e, Extraction Methods of Essential Oils and Resins-

2005. (http: /Plantresins.Com / splash.html) 9th June 2005.

ANONYMOUS, 2005f, Distillation of Essential Oils – 2005.

(http://distillation.co.uk/distillation.html) 5th Aug 2005.

ANONYMOUS, 2005g, Producing Pure Essential Oils, Ottos, Attars, Ruhs

and Absolutes Oils – 2005. (http:/erzulies.com/rareprecious-

essential oils.php) 12th June 2005.

78

ANONYMOUS, 2005h, Chemicals from Crops for St. Kitties-Nevis 2005.

(http://uwichill.edu.bb/bnccde/sk&n?conference/paperdex.html)

13th May 2005.

AOAC, 1995, AOAC Official Methods of Analysis. 16th ed., Vol. I & II,

Association of Official Analytical Chemists, USA.

ANUP KUMAR, GAUNIYAL, A.K. AND VIRMANI, O.P., 1986, Cultivation of

Pogostemon patchouli for its oil. CROMAP, 8(2): 79-86.

BATES, R.B. AND SLAGEL, R.C., 1962, β-bulnesene, γ-guaiene, β-

Patchoulene and guaioxide in essential oils. Chem. Ind., 39: 1715-

16.

BIS, 2003, IS 3398 :2003 Oil of Patchouli – Specification. Bureau of

Indian Standards, New Delhi.

BUITKHI, BANG, NIKOLAEV, A.G., 1975, Mint spices as the source of

linalol. Rastitelyne Resury., 11: 104-109.

BURE, C.M. AND SELLIER, N.M., 2004, Analysis of the essential oil of

Indonesian Patchouli (Pogostemon cablin Benth.) using GC/MS

(EI/CI). Journal of Essential Oil Research, 16(1): 17-19.

CHANDRAVADANA, M.V. AND KUMAR, V.T., 1989, The yield and oil

quality of scented geranium as affected by biomass duration and

different temperatures. Indian Perfumer, 33(4): 246-248.

CHARLES, O.J., SIMON, J.E., C.C., FEIBERL, E.B.G., SIMTH, R.M. AND

JANICK, J., 1995, Effect of water stress and post harvest handling

79

on artemisinin content in the leaves of Artemisis annua L. Indiana

polis, Indiana, 6(9): 640-643.

CHIUMENTI, R., BORRO-F-DA AND DA-BOROSO-F., 1996, Artificial

drying of Salvia officinalis L. Atti Convegno Internationals, pp. 381-

390.

DATTA, D.K. AND BORAH, U.C., 1986, Essential oil distillation. Indian

Perfumer, 30(2-3): 345-354.

DATTA, D.K., AND MALIK, V., 1993, Standardization in the field of

essential oil. Indian Perfumer, 37(1): 11-12.

DEANS, S.G. AND SVOBODA, K.P., 1992, Effect of drying regime on

volatile oil and microflora of aromatic plants. Acta-Hort., 306: 450-

452.

DENYS, J., CHARLES, JAMES, E. AND SIMON, 1990, Comparision of

extraction methods for the rapid determination of essential oil

content and composition of Basil. J. Amer. Soc. Hort. Sci., 115:

458-462.

DENNY, E.F.K., 1991, Field Distillation for Herbaceous Oils. 2nd ed.,

Lilydale, Tasmania, Australia.

DUNG, N.X., LECLERCQ, P.A., THAI, T, H. AND MOI, L.D., 1990,

Chemical composition of essential oil of Vietnam. Proceedings of

the 11th International Congress of Essential Oils, Fragrances and

Flavours, New Delhi, India, 12-16th November, pp. 99-102.

80

FAROOQUI, A.A. AND SREERAMU, B.S., 2001, Cultivation of Medicinal

and Aromatic Crops. Universities Press (India) Ltd., Hyderabad,

424 p.

FAROOQUI, A.A., VASUNDHARA, M. AND SRINIVASAPPA, K.N., 2001, A

Guide to Cultivation of Commercially Important Aromatic Crops.

Div. Hort., Univ. Agric. Sci., Bangalore, India, pp. 13-22.

FRANCIS, A.W., 1954, J. Phys. Chem., 58: 1099-1114.

GUENTHER, E., 1948, The Essential Oils, Vol. I, D. Van Nontrand & Co,

New Jersey, pp. 87-180, 189-200, 208-212.

GUENTHER, E., 1952, Recent developments in essential oil production -

Patchouli oil. Econ. Bot., 6(4): 355.

HARIPRAKASHA RAO, M. AND VASANTHA KUMAR, T., 1983, Reddening

and defoliation of patchouli (Pogostemon patchouli Pellet.) due to

imbalanced nutrition. International Congress of Essential Oils,

Singapore, Technical Book No.2., pp., 75-77.

HAZRA, P., KAHOL, A.P. AND AHMED, J., 1990, Study of the effect of

mode of drying on the yield, quality and steam consumption in

distillation of Menthe arvensis. Indian Perfumer, 34(1): 47-55.

HORVATH, F.J., 1939, U.S. Patent Specification 2: 145,395.

JAIN, P.C., 1978, Potentialities of growing patchouli (Pogostemon

patchouli). Indian Perfumer, 22(1): 47-55.

81

LAWRANCE, B.M., 1989, Progress in essential oils. Perfumer and

Flavourist, 18(2): 43-58.

LEUNG, A.Y., 1980, Encyclopedia of Common Natural Ingredients Used in

Food, Drugs and Cosmetics. John Wiley and Sons, Inc., pp. 261.

MAHESHWARI, M.L., VASANTHA KUMAR, T., SHARMA, N. AND

CHANDEL, K.P.S., 1993, Patchouli- an Indian perspective. Indian

Perfumer, 37(1): 9-11.

MANIVANNAN, D. AND SUVARNALATH, G., 1988, Quality of essential

oils for aromatherapy, Indian Perfumer, 44(3): 167-170.

NARYANAN, P., 2004, Quality control of essential oils. Proceedings of

National Seminar on “Prospects & Potentials of Medicinal &

Aromatic Crops”, University of Agril. Sciences, Bangalore, India,

June, pp. 82-87.

NAIK, S.N., MAHESHWARI, R.C. AND MAHESHWARI, M.L., 1988,

Extraction of essential oils in liquid and dense carbondioxide.

Indian Perfumer, 32(1): 74- 84.

NAIR, E.V.G., CHINNAMMA, N.P. AND NAIR, C.K., 1980, Optimization

studies on the factors of processing of essential oils. Indian

Perfumer, 24(2): 110-114.

NIRODY, B.S., CHACKO, M.C. AND BHATI, A. 1961, Cultural

experiments on patchouli. Indian Perfumer, 5(2): 75-84.

PALLAVI, G.S, PALANIMUTHU, V. CHANDRU, R. AND RANGANNA, B.,

2006, Study of tray drying behaviour of aromatic patchouli

82

herbage and its effect on essential oil recovery. Paper presented in

National Seminar on “40th Annual Convention & Symposium of

ISAE” organized by TNAU, Coimbatore, India, Jan 19-21.

PRAKASA RAO, E.V.S., GANESHA RAO, R.S., NARAYAN, M.R. AND

PAMESH, S., 1997, Influence of shade on yield and quality of

patchouli oil. Indian Perfumer, 41(4): 164-166.

PRASAD, R.Y., ALANKARARAO, G.S.J.G. AND BABY, P., 1987,

Distillation of essential oils -certain inadequacies. Indian Perfumer,

31(1): 1-6.

PRASAD, R.Y., ALANKARARAO, G.S.J.G. AND BABY, P., 1988,

production of essential oil. Indian Perfumer, 32(1): 5-6.

PURUSHOTHAMAN, K.K., SARADA, A.,MATHURAM,V., BRINDHA,P.,

SASIKALA, E. AND RUKMANI, S., 1985, Pharmacognostic and

chaemotaxonomic studies of some Indian medicinal plants. Acta

Hort., 188A: 165-67.

RADHAKRISHNAN, V.V., VISWANATHAN, T.V., CHERIAN, S. AND

REGHUNATH, B.R., 1991, Shade tolerance studies on patchouli

(Pogostemon patchouli). South Ind. Hort., 39(6), 388-89.

RAGHAVAN, B., ABRAHAM, K.O. AND KOLLER, W.D., 1995, Flavour

quality of fresh and dried Indian thyme (Thymus vulgaris L.). Pafai

Journal, Oct-Dec: 9-14.

RAMACHANDRA, K.N., VASUNDHARA, M., FAROOQI, A.A., AND

SRINIVASAPPA, K.N., 2003, Effect of varieties and spacing on the

83

growth, yield and quality of patchouli (Pogostemon patchouli Pellet.)

Journal of Spices and Aromatic Crops, 12(1): 43-46.

RANA, V.S. AND BLAZQUEZ, M.A., 2005, GC-MS analysis of the

essential oil of Cinnamomum tamala L. leaves. Indian perfumer,

49(4): 475-478.

RAO, Y.R., DASH, P.K., MISRA, R. AND BEHERA, S., 1999, Present

practice of Kewda (Pandanus odoritissimus L.) flower distillation

and scope for improvement in distillation technique. Indian

Perfumer, 43(2): 70-73.

RAO, P.E.V.S., 2004, Potential of aromatic crops in South India. Indian

Perfumer, 48(3): 266-272.

RAJENDRA PRASAD, Y., ALANKARARAO, G.S.J.G. AND BABY, P., 1987,

Distillation of essential oils - Certain inadequacies. Indian

Perfumer, 31(1): 1-6.

RATH, T., ROHELLA, R.S., PAUL, S.C., MISHRA, B.C. AND MURMU, S.,

1997, Distillation of essential oils - A Kinetic study. Indian

Perfumer, 41(2):62-68.

SARMA, A. AND SARMA, T.C., 2003, Patchouli oil recovery and effect of

leaf ageing. Indian Perfumer, 47(2): 151-154.

SHANKARANARAYAN, V., 2002, Patchouli constituents and its usage in

perfumery. Indian Perfumer, 46(4): 313-314.

84

SARWAR, M., NARAYANA, M.R. AND VIRMANI, O.P., 1982, Patchouli and

its cultivation in India. Farm Bulletin No. 17, Central Institute of

Medicinal and Aromatic Plants, Lucknow, India.

SINGH, G., SINGH, K.I.P. AND MUDI MANNAN, S., 1995, Studies on

essential oils - Part 2. Uses and abuses of modern analytical

techniques. Indian Perfumer, 39(4): 149-153.

SINGH, K.R., 1990, Recent trends in production methods of essential

oils. Indian Perfumer, 34(1): 64-70.

SINGH, R. AND MAHESHWARI, R.C., 1997, Essential oil constituents:

Hydro distillation Vs CO2 extraction. Indian Perfumer, 40(1): 26-29.

SUBBA RAO, M.N. AND NAGESA RAO, N., 1945, Oil of Patchouli - A

Monograph. Board of Scientific and Industrial Research, Govt. of

Mysore, India

TANDON, S., KAHOL, A.P. AND AHMED, J., 2002, Study on the effect of

steam injection rate and steam inlet pressure in the distillation of

essential oil of Mentha arvensis. J. Medicinal and Aromatic Plant

Sci., 24: 36-38.

THEAGARAJAN, K.S. AND PRABHU, V.V. AND RAVI KUMAR, G.R., 1993,

Distillation of eucalyptus hybrid oil using portable distillation unit

in the field. Indian Perfumer, 37(2): 181-187.

VACCCHIANO, 1992, Distillation and extraction: Evolution of Biolandees

process. Indian Perfumer, 36(2): 129-133.

85

VARSHNEY, S.C., 1993, Efficiency of stem distillation system for herbs.

Indian Perfumer, 37(1): 63-67.

VASUNDHARA, M., FAROOQI, A.A., DEVAIAH, K.A. AND

SHRIDHARAYYA, M., 1992, Influence of some growth regulators on

the growth, herbage and oil yield in marjoram (Majorana hortensis

Moench.). Indian Perfumer, 36(2): 171-174.

VIJYAKUMAR, K., 2004, Patchouli and India – a great leap forward.

Proceedings of National Seminar on “Prospects & Potentials of

Medicinal and Aromatic Crops”, Univ. Agric. Sci., Bangalore, India,

June, pp. 106-107.

WAIKHOM, D., SINGH, K.S. AND SINGH, R.S., 1995, Essential oil yield

in relation to duration of distillation and storage of bud of clove.

Indian Perfumer, 39(2): 97-98.

APPENDIX

86

Appendix - A

Effect of drying temperature of patchouli herbage on patchouli

essential oil yield under different drying methods

Temperature

(°C) R1 R2

R3

Mean essential oil yield (%)

30

2.39 2.40 2.41 2.40

40 2.28 2.29 2.33 2.30

50 2.31 2.31 2.34 2.32

60 2.27 2.31 2.29 2.29

70 2.27 2.23 2.25 2.25

Shade

2.37 2.43 2.43 2.41

Astra 2.21 2.25 2.26 2.24

F- Test NS NS NS NS

CD - - - -

NS – Not Significant

87

Appendix –B

Effect of bed packing density and distillation time on patchouli

essential oil yield

*- Significant at 5%

Packing bed density (kg)

Essential Oil Yield (%)

Distillation Time (h) Mean

3 4 5 6

4 2.78 3.06 3.26 3.42 2.92

5 2.46 2.74 2.95 3.10 2.85

6 2.25 2.54 2.79 2.9 7 2.80

Distillation Time Mean 3.03 2.87 2.77 2.77

-

1) Packing bed density 2)Distillation time 3)Interaction

SEM± CD @ F value 5% 0.0214 0.0625 * 0.0247 0.0722 * 0.0428 0.125 *

88

Appendix - C

Cost Economics of Pilot Scale Steam Distillation of Patchouli Oil

1. Fixed cost:

Capital cost of distillation unit = Rs. 55,000/-

Expected life = 10 years

Expected operational hours of

distillation unit / year = 300 distillations x 6 h

= 1800 h

a) Depreciation = 55,000 - 5500 1800 X 10 = Rs. 2.75/h

b) Interest on capital

investment @ 12% = (55000 + 5500)/2 X

(12/100) X (1/1800)

= Rs. 2.02/h

c) Insurance and maintenance cost

at 5% of machinery cost per year = (5/100) X 55000 X 1/1800

= Rs. 1.52/h

Total Fixed Cost = Rs. 2.75 + 2.016 + 1.527

= Rs. 6.30/h

2. Variable cost:

a) Power consumption = 1 Unit/h

Energy cost @ Rs. 3.20/unit = Rs. 3.20/h

b) Labour cost @ Rs. 60/day of 6 h work = 1 X Rs. 60 X 1/6

= Rs. 10/h

c) Herbage required = 5 kg dry herbage

89

Herbage cost @ Rs. 52/kg dry herbage = Rs. 52/h

Total Variable Cost = Rs. 3.20 + 10 + 52

= Rs. 65.20/h

Total cost of distillation = Fixed cost + Variable cost

= Rs. 6.30+ Rs.65.20

= Rs. 71.5/h

Total cost of distillation/batch = Rs. 71.5 X 6

= Rs. 429/batch

Essential oil yield per distillation at 3.10% yield = 155 ml

Market price of patchouli oil per liter = Rs. 3500/-

Revenue = 155/1000 X 3500

= Rs. 543/- per batch

Net return per batch = Revenue – Total Cost

= Rs. 543 – Rs. 429

= Rs. 114/-

Net annual returns = Rs. 144 X 300

= Rs. 34,200/-

Profit (%) = (114/429) X 100

= 26.5%

Cost Benefit Ratio = 429: 543

= 1: 1.26