Camellia sinensis (L.) Kuntze
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Dried and cured leaves widely used for a beverage, which has a stimulant effect
due to caffeine. Used for this purpose in China for nearly 3,000 years.
Chasei is a tea extract; powdered tea (Teu-cha) a ceremonial tea. Green tea is
made from leaves steamed and dried, while black tea leaves are withered,
rolled, fermented and dried. Steam distillation of black tea yields an
essential oil. Tea extract is used as a flavor in alcoholic beverages, frozen
dairy desserts, candy, baked goods, gelatins, and puddings (Leung, 1980).
Air-dry tea seed yields a clear golden-yellow oil resembling sasanqua oil, but
the seed cake, containing saponin, is not suitable for fodder. Refined teaseed
oil, made by removing the free fatty acids with caustic soda, then bleaching
the oil with Fuller's earth and a sprinkling of bone black, makes an oil
suitable for use in manufacture of sanctuary or signal oil for burning
purposes, and in all respects is considered a favorable substitute for
rapeseed, olive, or lard oils. The oil is different from cottonseed, corn, or
sesame oils in that it is a non-drying oil and is not subject to oxidation
changes, thus making it very suitable for use in the textile industry; it
remains liquid below -18deg.C. Tea is a potential source of food colors
(black, green, orange, yellow, etc.).
The infusion, once recommended in China as a cancer cure, contains some tannin,
suspected of being carcinogenic. Chinese regard tea as antitoxic, diuretic,
expectorant, stimulant, and stomachic (Leung, 1980). Tea, considered
astringent, stimulant, and acts as a nervine or nerve sedative, frequently
relieving headaches. It may also cause unpleasant nerve and digestive
disturbances. The infusion is also recommended for neuralgic headaches.
According to Leung, tea is reportedly effective in clinical treatment of amebic
dysentery, bacterial dysentery, gastroenteritis, and hepatitis. It has also
been reported to have antiatherosclerotic effects and vitamin P activity
(Leung, 1980). Teabags have been poulticed onto baggy or tired eyes,
compressed onto headache, or used to bathe sunburn. Duke and Wain (1981)
report that the plant has a folk reputation as analgesic, antidotal,
astringent, cardiotonic, carminative, CNS-stimulant, demulcent, deobstruent,
digestive, diuretic, expectorant, lactagogue, narcotic, nervine, refrigerant,
stimulant, and stomachic; used for bruises, burns, cancer, cold, dogbite,
dropsy, dysentery, epilepsy, eruptions, fever, headache, hemoptysis,
hemorrhage, malaria, ophthalmia, smallpox, sores, toxemia, tumors, and wounds (Duke and Wain, 1981).
Fresh leaves from Assam contain 22.2% polyphenols, 17.2% protein, 4.3%
caffeine, 27.0% crude fiber, 0.5% starch, 3.5% reducing sugars, 6.5% pectins,
2.0% ether extract and 5.6% ash. Per 100 g, the leaf is reported to contain
293 calories, 8.0 g H2O, 24.5 g protein, 2.8 g fat, 58.8 g total carbohydrate,
8.7 g fiber, 5.9 g ash, 327 mg Ca, 313 mg P, 24.3 mg Fe, 50 mg Na, 2700 ug
beta-carotene equivalent, 0.07 mg thiamine, 0.8 mg riboflavin, 7.6 mg niacin,
and 9 mg ascorbic acid. Another report tallies 300 calories, 8.0 g H2O, 28.3 g
protein, 4.8 g fat, 53.6 g total carbohydrate, 9.6 g fiber, 5.6 g ash, 245 mg
Ca, 415 mg P, 18.9 mg Fe, 60 mg Na, 8400 ug beta-carotene equivalent, 0.38 mg
thiamine, 1.24 mg riboflavin, 4.6 mg niacin, and 230 mg ascorbic acid. Yet
another gives 299 calories, 8.1 g H2O, 24.1 g protein, 3.5 g fat, 59.0 g total
carbohydrate, 9.7 g fiber, 5.3 g ash, 320 mg Ca, 185 mg P, 31.6 mg Fe, 8400 ug
beta-carotene equivalent, 0.07 mg thiamine, 0.79 mg riboflavin, 7.3 mg niacin,
and 85 mg ascorbic acid (Duke and Atchley, 1984). Leaves also contain
carotene, riboflavin, nicotinic acid, pantothenic acid and ascorbic acid.
Caffeine and tannin are among the more active constituents (C.S.I.R.,
1948-1976). Ascorbic acid, present in the fresh leaf, is destroyed in making
black tea. Malic and oxatic acids occur, along with kaempferol, quercitrin,
theophylline, theobromine, xanthine, hypoxanthine, adenine, gums, dextrins, and
inositol. Chief components of the volatile oil (0.007-0.014% fresh weight of
leaves) is hexenal, hexenol, and lower aldehydes, butyraldehyde,
isobuteraldehyde, isovaleraldehyde, as well as n-hexyl, benzyl and phenylethyl
alcohols, phenols, cresol, hexoic acid, n-octyl alcohol, geraniol, linalool,
acetophenone, benzyl alcohol, and citral. Does this mean that the leaves
contain more dangerous substances than herb tea? More properly it only
indicates that Camellia has been more intensively studied than most herb teas.
Certain constituents, especially catechin, epigallocatechin, and
epigallocatechin gallate are said to have antitoxidative properties (Leung,
1980). October 1, 1979, caffeine was trading at ca $9 per kilo, theobromine at
about $10 and theophylline at about $12.
According to Tyler, there is evidence indicating that the condensed catechin
tannin of tea is linked to high rates of esophageal cancer in some areas where
tea is heavily consumed. This effect apparently may be overcome by adding milk
which binds the tannin preventing its deleterious effects. GRAS
([[section]]182.20). Tyler (1982) produces a chart comparing various caffeine
sources to which I have added rounded figures from Palotti (Industric
Alimentaire 16:) (1977).
Cup (6 oz.) expresso coffee: 310mg
Cup (6 oz.) boiled coffee: 100mg
Cup (6 oz.) instant-coffee: 65mg
Cup (6 oz.) tea: 10-50mg
Cup (6 oz.) cocoa: 13mg
Can (6 oz.) cola: 25mg
Can (6 oz.) coca cola: 20mg
Cup (6 oz.) mate: 25-50mg
Can (6 oz.) pepsi cola: 10mg
Tablet Caffeine: 100-200mg
Table (800 mg) Zoom (Paullinia cupana): 60mg
In humans, caffeine, 1,3,7-trimethylxanthine, is demethylated into three
primary metabolites: theophylline, theobromine, and paraxanthine. Since the
early part of the 20th century, theophylline has been used in therapeutics for
bronchodilation, for acute ventricular failure, and for long-term control of
bronchial asthma. At 100 mg/kg theophylline is fetotoxic to rats, but no
teratogenic abnormalities were noted. In therapeutics, theobromine has been
used as a diuretic, as cardiac stimulant, and for dilation of arteries. But at
100 mg, theobromine is fetotoxic and teratogen (Collins, FDA By-lines No. 2,
April 1981). Leung reports a fatal dose in man at 10,000 mg, with 1,000 mg or
more capable of inducing headache, nausea, insomnia, restlessness, excitement,
mild delirium, muscle tremor, tachycardia, and extrasystoles. Leung also adds
"caffeine has been reported to have many other activities including mutagenic,
teratogenic, and carcinogenic activities; ...to cause temporary increase in
intraocular pressure, to have calming effects on hyperkinetic children ...to
cause chronic recurring headache...
Small evergreen tree to 16 m tall, usually pruned back to shrubs in
cultivation, with strong taproot giving rise to a surface mat of feeders with
endotrophic mycorrhizae; leaves alternate, exstipulate, lanceolate to obovate,
up to 30 (usually 4-15) cm long, 2-5 (7-12) cm broad, pubescent, sometimes
becoming glabrous, serrate, acute or acuminate; flowers 1-3, in axillary or
subterminal cymes, deflexed, 2-5 cm broad, aromatic, white or pinkish,
actinomorphic, sepals and petals 5-7, pedicels 5-15 mm long; stamens numerous;
ovary 3-5-carpellate, each carpel 4-6-ovulate; capsules depressed-globose,
brownish, lobate, to 2 cm broad, valvate, with 1-3 subglobose seeds in each
lobe; approximately 500 seeds per kg. Fl. Oct.-Dec. in Japan.
Reported from the China-Japan, Hindustani Centers of Diversity, tea or cvs
thereof is reported to tolerate drought, frost, low pH, peat, shade, and slope.
Because of the long cultivation of tea, many cultivars have been developed,
based on flavor of the tea-producing substances, size, of leaves and
adaptability to climatic conditions. Named teas often depend on where they
originate, the color as tea or the combinations of tea so blended. Pekoe,
Orange Pekoe and Flowery Pekoe indicate partly the fineness of leaf in each.
Black teas which have undergone fermentation or a chemical process, include
Hyson, Young Hyson, Gunpowder and Imperial. Oolong Tea, a favorite in North
America, comes from Taiwan. Green teas come mainly from China, India and Sri
Lanka. Sri Lanka and Indian teas include: Quality Djarling, Golden Djarling,
Assam Tea and Ceylon Flowery. Sri Lanka teas are usually blacker than Indian
teas. Chinense teas are grouped as red, green, yellow, red brick and green
brick; each group is subdivided into 4 grades: rough, tender, old and new.
Yellow tea is Mandarin Tea, a very fine tea. Surplus tea is finely powdered,
steamed and pressed into hard bricks, tablets or balls for easier
transportation, known as Compressed Tea, and may be either green or black.
Black Brick is usually 20 x 30 cm; Green Brick, 15 x 30 cm. Tablets of
Compressed Tea are employed in Manchuria, Mongolia and Siberia as money. Some
of the Chinese Tea is shipped to Tibet and contains prunings and lower leaves;
Tibet Bricks together with four dumplings and butter are used as soup.
Botanical variations include: forma rosea with pink flowers and forma
macrophylla with larger leaves and is usually the cultivated form.
(2n = 30, 45, 60)
Native to Southeast Asia, from Sri Lanka and India to Assam and China, tea has
been planted widely in tropical and subtropical areas. Near the Equator, it
ranges up to nearly 2,000 m elevation.
Ranging from Warm Temperate Dry to Wet through Tropical Very Dry to Moist
Forest Life Zones, tea is reported to tolerate annual precipitation of 7
to 31 dm, annual temperature of 14 to 27°C, and pH of 4.5 to 7.3. Although
evergreen, tea is intolerant of frost, and requires equable, humid, warm
situations; some Chinese tea varieties can tolerate cooler climes. Thrives on
tropical red earths and deep, well-drained, acid (pH 4.5-6.0) soils. Mean
minimum temperatures should not fall below 13°C, nor maximum go above
30°C. An annual rainfall of 120 cm or more is desirable. Several months
With less than 5 cm rainfall each are intolerable. Successful plantations have
been established in southeast United States.
Tea is propagated either from seeds or by vegetative means. Seedbearing trees,
selected for yield and quality, are cross-fertilized, and the progeny of seed
sown in new seed orchards, spaced 300-350 trees/ha. Under better conditions,
selected clones are propagated vegetatively. It requires 4-12 years to bear
seed. Better seeds from seed orchards are planted in nursery or at stake,
protected from sun and wind. At first, seedlings should be shaded. Seedlings
6-12 months old may be outplanted with a ball of earth, while much older
seedlings can be planted bare-rooted, cutting the stem 10 cm from the ground
mark. Single-internode cuttings, cut just above a node with an axillary bud,
inserted in the soil at an angle so that the subtending leaf rests on the
medium, take well. Hedge plantings in rows about 1.5 m apart spaced 60 cm
apart in the row give better initial yields and may facilitate mechanical
harvesting. Interplantings with shade trees is no longer recommended. In
Assam, the 'bushes' are let grow for 3 years and pruned across the leaders and
laterals at about 45 cm. Subquently they are top-pruned each year; or the
entire plant is trimmed back to 15 cm when bush is 1-1.5 m tall. Assam teas
give a linear response to nitrogen up to 140 kg/ha.
Terminal sprouts with 2-3 leaves are usually hand-plucked, 10 kg of green
shoots (75-80% water) produce about 2.5 kg dried tea. Bushes are plucked every
7-15 days, depending on the development of the tender shoots. Leaves that are
slow in development always make a better flavored product. Various techniques
are used to produce black teas, usually during July and August when solar heat
is most intense. Freshly picked leaves are spread very thinly and evenly on
trays and placed in the sun until the leaves become very flaccid, requiring 13
hours or more, depending on heat and humidity. Other types of black teas are
made by withering the leaves, rolling them into a ball and allowing to ferment
in a damp place for 3-6 hours, at which time the ball turns a yellowish copper
color, with an agreeable fruity one. If this stage goes too far, the leaves
become sour and unfit for tea. After fermenting, the ball is broken up and the
leaves spread out on trays and dried in oven until leaves are brittle and have
slight odor of tea. Tea is then stored in air-tight tin boxes or cans. As
soon as harvested, leaves are steamed or heated to dry the natural sap and
prevent oxidation to produce green tea. Still soft and pliable after the
initial treatment, the leaves are then rolled and subjected to further firing.
Thus dried, the leaves are sorted into various grades of green tea.
In Assam yields range from 1,200-2,250 kg/ha, but clonal tea yields in Sri
Lanka have attained 6,700 kg/ha. World tea production, excluding Mainland
China, for 1971 was approximately 1,092,000 metric tons. Some of the major
producing countries include Pakistan, India, Kenya, Uganda and Argentina.
World tea exports, including estimates for Mainland China, in 1970 were 635,000
tons, a 10% gain over the previous year's level of 574,000; South African
exports totaled 101,000 tons, South American, 23,000 tons; Asian, 511,000 tons.
London auction prices in 1970 for all teas averaged 49.7cents/lb, as compared
to 44.1cents/lb in 1969; with an average price of $1.25/kg. Largest importers
of tea are United Kingdom, totaling 254,564 tons in 1970, and the United
States, approximately 150 million pounds in 1970. Sri Lanka remains the
largest source of U.S. imports with 46.1 million pounds, followed by Indonesia,
India, and Kenya.
There was a world low production yield figure of 300 kg/ha in South Korea, an
international production yield of 861 kg/ha, and a world high production yield
of 2,586 kg/ha in Bolivia (FAO, 1980a). Clonal tea yields as high as 6,700
have been reported (Sri Lanka), but this represents many pluckings. Only 25%
of the harvest remains in dried tea, the 75% moisture having evaporated.
Annual productivities in species of Camellia range from 6-16 MT/ha.
Much of this would be pruned back annually to keep the shrubs at good plucking
height. Tea yields of 1-4 MT/ha/yr of dry shoot tips are much less than those
of other vegetative crops like grasslands or forests growing in similar
conditions, partly because plucking restricts tea biomass production, but
mainly because the harvest index of tea is small. In Kenya, plucked tea
produced 36% less biomass/ha per year than unplucked tea and 64% less wood.
Only 8.3% of the total annual biomass increment was harvested. This proportion
might be increased by plucking older leaves, increasing the shoot:root ratio,
and by lowering the plucking table so that less wood was produced. (Magambo
and Cannell, 1981) Near Kericho, Kenya, tea yields only 1.0-2.5 MT/ha/yr at
elevations over 2,000 m, rarely more than 4 MT at lower elevations. Still
these are high. Tea's poor biomass productivity is due to plucking, which
decreased annual production by 36%. Unplucked tea produced 26.3 MT/ha/yr which
at 2,178 m altitude near the equator, may be as much as is produced by C3
grasslands, forests, or root crops. Of the 9.4 MT ."extra" dry matter produced
by unplucked bushes, 64% (6 MT/ha) went to stems, 16% (1.5 MT) went to roots,
and 20% (1.9 MT) went to leaves (Magambo and Cannell, 1981).
Tea flowers are largely, if not completely, self-sterile and require
cross-pollination by insects to produce seed. Numerous fungi attack the tea
plant, including the following: Aglaospora aculeata, Amphitiarospora
neothiosporoides, Armillaria mellea, Asterina camelliae, Auricularia
polytricha, Beltrania indica, Botryodiplodia theobromae, Botryosphaeria
microspora, B. ribis, B. theicola, Calonectria theae, Cephaleuros virescens, C.
mycoidea, Cercospora theae, Colletotrichum camelliae, Corticium salmonicolor,
C. solani, Cylindrocladium camelliae, C. parvum, Diatrype conferta,
Didymosphaeria theae, Discosiella longiciliata, Elsinoe theae, Exobasidium
vexans, Fomes lignosus, F. noxius, Fusarium oxysporum, Glomerella cingulata,
Guignardia camelliae, Helicobasidium compactum, Hypocrella scutata, Hypoxylon
michelianum, H. vestitum, Irpex destruens, Leptoporum lignosus, Leptosphaeria
depressa, L. tornatospora, Macrophoma theae, M. theicola, Macrophomina
phaseoli, Marasmius equicrinus, M. pulcher, M. scandens, Massaria theicola,
Melanoconiella stellata, Mycosphaerella camelliae, M. ikedai, M. theae, Nectria
lucida, Penicillium caryophilum, Pestalotia theae, P. guepini, Pestalotiopsis
gigas, P. nattrassii, P. theae, Phaeosphaerella theae, Phoma camelliae,
Phyllosticta erratica, Ph. theae, Pythium complectens, P. vexans, Rhizoctonia
bataticola, Rosellina arcuata, R. bunodes, Sclerotium rolfsii, S. zeylanicum,
Sphaerostilbe repens, Sporidesmium deightonii, S. tropicale, Stachylidium
bicolor, Stilbella theae, Thyronectria pseudotrichia, Trichoderma viridi,
Ustulina deusta and U. zonata. Bacteria known to attack tea
include: Agrobacterium tumefaciens, Erwinia theae and Pseudomonas
theae. The cause of oil-spot is undetermined. Many nematodes are known to
infest tea also, including: Anguillulina pratensis, Basirotyleptus archius,
B. basiri, B. eximius, Criconema octangulare, Criconemella. rustica,
Helicotylenchus erythrinae, Hemicriconemoides brachyurus, H. gaddi, H.
kanayaensis, Hemicycliophora longicaudata, Longidorus utriculoides, Meloidogyne
arenaria, M. brevicauda, M. camelliae, M. hapla, M. incognita, M. incognita
acrita, M. javanica, Paratylenchus curvitatus, Pratylenchus coffeae, P. loosi,
P. pratensis, Radopholus similes, Trichodorus monohystera, Xiphanema
campinense, X. radicicola.
Complete list of references for Duke, Handbook of Energy Crops
C.S.I.R. (Council of Scientific and Industrial Research). 1948-1976. The wealth
of India. 11 vols. New Delhi.
Duke, J.A. and Atchley, A.A. 1984. Proximate analysis. In: Christie, B.R.
(ed.), The handbook of plant science in agriculture. CRC Press, Inc., Boca
Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index
with more than 85,000 entries. 3 vols.
Leung, A.Y. 1980. Encyclopedia of common natural ingredients used in food,
drugs, and cosmetics. John Wiley & Sons. New York.
Magambo, M.J.S. and Cannell, M.G.R. 1981. Dry matter production and partition
in relation to yield of tea Camellia sinensis. Tea Res. Inst. E. Afr.
P.O. Box 91, Kericho, Kenya. Exp. Agr. 17(1).EN 33-38.
Palotti, G. 1977. The 'time for a Coca Cola' may not be right. Industrie
Tyler, V.E. 1982. The honest herbal. George F. Stickley Co., Philadelphia,
Last update July 3, 1996