Essential oil crops

613 Pages·1997·34.57 MB·English

by  Weiss

ESSENTIAL OIL CROPS

Essential Oil Crops
E.A. Weiss
Agricultural Adviser
Eaglemont
Victoria
Australia
CAB INTERNATIONAL
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OCAB International 1997. All rights reserved. No part of this publication may be
reproduced in any form or by any means, electronically, mechanically, by
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A catalogue record for this book is available from the British Library, London, UK
A catalogue record for this book is available from the Library of Congress, Washington
DC, USA
First published 1997
Transferred to print on demand 2002
ISBN 0 85199 137 8
Printcd and bound by Antony Rowe, Eastbourne
Contents
Introduction vii
Acknowledgements xi
1. World Trade in Essential Oils 1
2. Annonaceae 10
Cananga 10
3. Geraniaceae 24
Pelargonium 24
Geranium 50
4. Gramineae 59
Citronella 67
Lemongrass 86
Palmarosa and Gingergrass 103
Vetiver 117
5. Lamiaceae 138
Patchouli 138
6. Lauraceae 155
Camphor 156
Cassia 168
Cinnamon 180
Sassafras 195
Ocotea 198
Laurel 200
Litsea cubeba 207
7. Myristicaceae 214
Nutmeg 215
V
Vi Contents
8. Myrtaceae 235
Clove 235
Euclayptus 259
Melaleuca 302
Leptospermum 319
Pimenta 322
Myrtle 333
9. Oleaceae 342
Jasmine 342
Osmanthus 359
10. Piperaceae 362
Pepper 363
Cubeb Pepper 384
Betel Pepper 386
11. Rosaceae 393
Rose 394
12. Rutaceae 417
Lime 435
Bitter Orange 444
Bergamot Orange 459
Lemon 464
Grapefruit 475
Mandarin 482
Sweet Orange 49 1
Boronia 501
West Indian Sandalwood 504
13. Santalaceae 516
Sandalwood 516
14. Zingiberaceae 539
Ginger 539
15. Distilling and Extracting Essential Oils 568
Glossary 579
Index 585
Introduction
Plants producing an aromatic oil, fruit, or seed were used in religious
ceremonies or for personal use and adornment long before recorded history,
and remain popular for similar reasons. Words derived from their use,
including perfume from the Latinperfumum and alembic from the Arabic al-
inbic, are in common use.
The Vedic literature written in India around 2000 BC lists hundreds of
aromatic substances including cinnamon, ginger and sandalwood, and the
Rig Veda describes their use for religious and medical purposes. Aromatics
were considered more than perfumes, as in languages of the region atar
means smoke, wind, odour and essence. Probably the most well documented
and certainly the best known ancient use of a wide range of aromatic materials
was in dynastic Egypt. The gums and oils employed in embalming are
detectable today, together with the remains of scented unguents contained in
ornate funerary jars and cosmetic pots found in the Pharoah’s tombs.
The Greeks profited from Egyptian knowledge and experience in the use
of aromatics, but the Romans exceeded the Greeks in their extravagant use
of these materials especially oils. Romans recognized three basic perfumery
types: solid unguents ladysmata, scented oils stymmata, and perfumed pow-
ders diapasmata. Herodotus, around 425 BC, was the first to record the
distillation of turpentine, and his books provide information about perfumes
and aromatics then used in the Middle East. A detailed study of the source
and use of some six hundred plants and aromatics used by the Greeks and
Romans in the 1s t century AD was compiled by Pedanius Dioscorides in his
De materia medica. Hippocrates, born about 460 BC, prescribed perfumed
fumigations and fomentations; one of the most famous compounded from
myrrh, cinnamon and cassia was named megaleion for its original maker
Megallus, and like a similar Egyptian remedy, the kyphi, was used as
perfume, to alleviate skin inflammations, and pain of battle wounds.
There is also an ancient link between perfume and sensuality; in Persia,
Greece and Rome, youths and girls wearing only fragrant flowers and
vii
viii introduction
anointed with aromatic oils danced for the erotic pleasure of guests at ruler’s
feasts. Solomon, King of Israel, in his oft-quoted Song described the
exquisitely smelling ointments that stirred young maidens to love, and who
perfumed his bed with essences of myrrh, aloes and cinnamon; a common
contemporary practice by women wishing to attract a lover. It is recorded
that the great general Hannibal had good reason to regret the relationship;
after crossing the Alps and defeating the Romans he quartered his army in
Capua, capital of Campania. Defeated Romans corrupted his idle troops
and quickly made the town a trading centre for perfumes, aromatic oils and
associated sexual excess practices which spread rapidly throughout the
-
Empire.
Today the association between perfumes and sexual attractiveness con-
tinues to be exploited in the electronic and print media and names of major
perfumes; while insects and some animals disperse a pheromone to attract a
mate.
The author has long been interested in aromatic plants, and wherever
possible introduced them into research programmes or integrated their
production into agricultural projects under his control. The crops selected
are those the author believes should be encouraged in countries where cash
crops are limited, or outside inputs to raise rural incomes difficult to obtain.
For this reason the important pine oils have not been included, since these
are frequently produced in more developed countries. It is emphasized that
this book is basically concerned with growing essential oil plants to obtain an
aromatic derivative, and not with essential oils per se.
Oil is contained in specialized structures in all or some plant parts: cavities
or ducts in the epidermis as in eucalyptus leaves or citrus fruit peel; glands or
hairs originating from epidermal cells as in the modified leaf hairs on
geranium. Why plants secrete oils or waxes has yet to be fully explained,
although certain activities can reasonably be attributed to their presence; to
deter browsing animals, as an insect repellent or to increase disease resist-
ance, while terpenes leached from eucalyptus leaves contribute to allelo-
pathic effects on the forest floor thus inhibiting germination and growth of
competitors. Highly scented oil contained in flowers is the exception, and
generally accepted as an aid to reproduction by attracting pollinators. Hence
the recommendation to integrate bee-keeping into commercial production
of essential oil crops whenever possible, as the author demonstrated most
profitably with certain oilseeds, and why honey production has been men-
tioned where applicable.
While the advantage to plants of their oil remains unclear, so also is the
mode of action of essential oils in phytotherapy. It would appear the
lipophilic character of compounds in oils could be responsible for the broad
spectrum of biological activities; however, to massage oils into the human
skin as in aromatherapy is of little therapeutic value, although it may induce
a feeling of sensual well-being!
lntroduction ix
The plant metabolic processes involved in oil secretion, the rate it occurs,
the biosynthetic pathways determining its composition and evolution of
various components, require further investigation. The detailed composi-
tion of many essential oils, however, has been published in the literature, and
reviews such as those of Dr Brian Lawrence are a valuable reference
source.
Oil composition, especially the terpene components, is now important in
plant classification as chemotaxonomy, since physical characters may be
virtually impossible to differentiate. The increasing precision of analytical
techniques, including enantioselective gas chromatography, allows very
accurate determination of oil composition. How this is linked to odour is
debatable, and assessing oil odour remains highly subjective. However,
determining a specific constituent or formulation is possible using an elec-
tronic nose, which is an array of chemical sensors linked to a neural network
(see Chapter 15).
Biotechnology can influence the breeding or development of essential oil
plants, and could theoretically produce plants containing oil of a required
composition or odour. It is also possible agronomically to modify a partic-
ular oil by varying the time of harvest, and thus regulating the abundance of
a specific constituent. Genetic manipulation can be commercially successful
as demonstrated on a fatty oil by scientists at CSIRO in Australia, who
successfully modified linseed to produce an edible oil, linola (Weiss, 1993).
French plant breeders have also used these techniques to alter the natural
scent of jasmine and rose flowers to produce novel odours aimed directly at
the fragrance industry.
Certain components of essential oils can be replaced by relatively cheap
synthetics, and although such compounds are useful in what are virtually
industrial products such as soft drinks, few are able fully to duplicate the
natural essence. Additionally, there is considerable worldwide pressure by
consumers on manufacturers to use what are perceived to be natural
compounds in edible and personal products. To take advantage of this and
similar trends, growers in all countries must upgrade agricultural methods
and improve management techniques to either increase yield or raise profita-
bility. A range of suitable agricultural equipment is now available, including
a variety of small manually-operated machines, computer-controlled seed-
ers and transplanters, and integrated harvestingidistilling combinations.
Semi-automatic fruit pickers are available, and citrus-picking robots in-
dicate future trends.
Weed control should incorporate rotations and efficient use of herbicides,
which remain important and economical, while application machinery is
continually improving including weed-detecting sprayers. Integrated pest
management can reduce the amount of chemicals applied, since some
adversely affect oil characteristics or odour. Improvements in soil manage-
ment, especially irrigation techniques, could be more widely applied. Water