Theobroma cacao L.
Chocolate, Cacao, Cocoa
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
- Chemical Analysis of Biomass Fuels
Cacao seeds are the source of commercial cocoa, chocolate, and cocoa butter.
Fermented seeds are roasted, cracked and ground to give a powdery mass from
which fat is expressed. This is the cocoa from which a popular beverage is
prepared. In the preparation of chocolate, this mass is mixed with sugar,
flavoring, and extra cocoa fat. Milk chocolate incorporates milk as well.
Cocoa butter is used in confections and in manufacture of tobacco, soap, and
cosmetics. Cocoa butter has been described as the world's most expensive fat,
used rather extensively in the emollient "bullets" used for hemorrhoids.
Reported to be antiseptic, diuretic, ecbolic, emmenagogue, and parasiticide,
cacao is a folk remedy for alopecia, burns, cough, dry lips, eyes, fever,
listlessness, malaria, nephrosis, parturition, pregnancy, rheumatism,
snakebite, and wounds (Duke and Wain, 1981). Cocoa butter is applied to
wrinkles in the hope of correcting them (Leung, 1980).
Per 100 g, the seed is reported to contain 456 calories, 3.6 g H2O, 12.0 g
protein, 46.3 g fat, 34.7 g total carbohydrate, 8.6 g fiber, 3.4 g ash, 106 mg
Ca, 537 mg P, 3.6 mg Fe, 30 mg b-carotene equivalent, 0.17 mg thiamine, 0.14
mg riboflavin, 1.7 mg niacin, and 3 mg ascorbic acid. According to the Wealth
of India, the edible pulp of the fruit contains 79.788.5% water, 0.50.7%
albuminoids, astringents, etc.; 8.313.1% glucose, 0.40.9% sucrose, a trace of
starch, 0.20.4% non-volatile acids (as tartaric), 0.03% Fe2O3 and 0.4% mineral
salts (K, Na, Ca, Mg). The shell contains 11.0% moisture, 3.0% fat, 13.5%
protein, 16.5% crude fiber, 9.0% tannins, 6.0% pentosans, 6.5% ash, and 0.75
theobromine. Raw seeds contain 0.24 mg/100 g thiamine, 0.41 riboflavin, 0.09
pyridoxine, 2.1 nicotinamide, and 1.35 pantothenic acid. The component fatty
acids of cocoa butter are 26.2% palmitic and lower acids, 34.4 stearic and
higher acids, 37.3% oleic acid, 2.1% linoleic and traces of isoleic. In g/100g
the individual amino acids in the water soluble fractions of unfermented and
fermented beans are lysine 0.08, 0.56; histidine 0.08, 0.04; arginine 0.08,
0.03; threonine 0.14, 0.84; serine 0.88, 1.99; glutamic acid 1.02, 1.77;
proline 0.72, 1.97; glycine 0.09, 0.35; alanine 1.04, 3.61; valine 0.57, 2.60;
isoleucine 0.56, 1.68; leucine 0.45, 4.75; tyrosine 0.57, 1.27; and
phenylalanine 0.563.36 g/100g. Unfermented and fermented beans contain
p-hydroxybenzoic acid, vanillic acid, p-coumaric acid, ferulic acid, and
syringic acid, while the fermented beans also contain protocatechuic,
phenylacetic, phloretic acid and the lactone esculetin and o- and
p-hydroxyphenyl acids. Caffeic acid occurs in the unfermented beans (C.S.I.R.,
19481976). According to an article in the Chicago Sun Times, people who
suffer extreme depression as victims of unrequited love have an irregular
production of phenylethylamine. Such individuals often go on chocolate binge
during periods of depression. Chocolate is particularly high in
phenylethylamine, perhaps serving as medication. Theophylline is a potent CNS
and cardiovascular stimulant with diuretic and bronchial smooth muscle relaxant
properties. Recently this drug was proven effective in preventing and treating
apnea in premature infancy. Cocoa contains over 300 volatile compounds,
including esters, hydrocarbonslactones, monocarbonyls, pyrazines, pyrroles, and
others. The important flavor components are said to be aliphatic esters,
polyphenols, unsaturated aromatic carbonyls, pyrazines, diketopiperazines, and
theobromine. Cocoa also contains about 18% proteins (ca 8% digestible); fats
(cocoa butter); amines and alkaloids, including theobromine (0.5 to 2.7%),
caffeine (ca 0.25% in cocoa; 0.7 to 1.70 in fat-free beans, with forasteros
containing less than 0.1% and criollos containing 1.43 to 1.70%), tyramine,
dopamine, salsolinol, trigonelline, nicotinic acid, and free amino acids;
tannins; phospholipids; etc. Cocoa butter contains mainly triglycerides of
fatty acids that consist primarily of oleic, stearic, and palmitic acids. Over
73% of the glycerides are present as monounsaturated forms (oleopalmitostearin
and oleodistearin), the remaining being mostly diunsaturated glycerides
(palmitodiolein and stearodiolein), with lesser amounts of fully saturated and
triunsaturated (triolein glycerides). Linoleic acid levels have been reported
to be up to 4.1%. Also present in cocoa butter are small amounts of sterols
and methylsterols; sterols consist mainly of b-sitosterol, stigmasterol, and
campesterol, with a small quantity of cholesterol. In addition to alkaloids
(mainly theobromine), tannins, and other constituents, cocoa husk contains a
pigment that is a polyflavone glucoside with a molecular weight of over 1500,
this pigment is claimed to be heat and light resistant, highly stable at pH 3
to 11, and useful as a food colorant; it was isolated at a 7.9% yield (Leung,
Reviewing the work on safrole, Buchanan (J. Food Safety 1:275.1978) concluded
that it is the most thoroughly investigated methylenedioxybenzene derivative.
The major flavoring constituent in sassafras root bark, safrole also occurs in
basil (Perdue and Hartwell, eds., 1976), black pepper, cinnamon leaf oil,
cocoa, mace, nutmeg, parsley, and star anise oil. When safrole was identified
as a "low grade hepatocarcinogen, it was banned in root beer, and the FDA in
1976 banned interstate marketing of sassafras for sassafras tea. The oral LD50
for safrole in rats is 1950 mg/kg body weight, with major symptoms including
ataxia, depression, and diarrhea, death occurring in 45 days. Ingestion of
relatively large amounts of sassafras oil produced psychoactive and
hallucinogenic effects persisting several days in humans. With rats, dietary
safrole at levels of 0.25%, 0.5% and 1% produced growth retardation, stomach
and testicular atrophy, liver necrosis, and biliary proliferation and primary
hepatomas. Sutton (1981) reports the collapse and death of a 3-year old bitch
that had eaten a 250 g package of cocoa. Postmortem examination revealed
congestion of lungs, liver, kidney, and pancreas, and petechial and ecchymotic
hemorrhage of the thymus, all compatible with acute circulatory failure. The
stomach contained high concentrations of theobromine and/or caffeine. Though
used cosmetically, cocoa butter has been reported to have allergenic and
comedogenic properties in animals. Tyler (1982) produces a chart comparing
various caffeine sources to which I have added rounded figures from Palotti
Cup (6 oz.) expresso coffee: 310 mg
Small tree usually 48 m tall, rarely up to 20 m; at 11.5 m the terminal bud
breaks into 35 meristems to give several lateral upright shoots; primary
branching by successive whorls of normally spreading branches; young branchlets
terete, grayish green or brownish, densely or sparsely pubescent, with simple
or furcate hairs 0.10.3 mm long, later glabrate, more or less striate;
stipules subulate, very acute, 514 mm long, 0.51.5 mm broad at base,
pubescent, deciduous; leaves large, coriaceous or chartaceous, alternate,
distichous on normal branches, green; petiole pubescent or tomentose, with
simple, rather dense, spreading hairs, thickened pulvinate at ends; blades
1260 cm long, 420 cm broad, elliptic to obovate-oblong, entire, glabrous;
inflorescence on trunk and branches, usually borne on small tubercles in short
cymose branchlets, peduncles 13 mm long, stellate-pubescent; bracts ovate or
ovate-oblong, pubescent; bracteoles ovate-oblong, acute or subacute, 0.51.2 mm
long, pubescent, deciduous; pedicels capillary, rigid, pale green, whitish or
reddish, 515 mm long, with stellate or furcate hairs and sparce many-celled,
glandular, capitate trichomes; sepals lanceolate or oblong-lanceolate, acute,
white, greenish-white, pale violaceous or reddish, faintly 3-veined, united at
base, 58 mm long, 1.52 mm broad, with hairs and trichomes; petals contorted
in aestivation, thick-membranous, hood 34 mm long, 0.52 mm wide, obovate,
rounded at apex, white, 3-veined, lamina pale yellowish, 1.52.5 mm long, 1.52
mm broad, obovate, attenuate at apex; staminodes 46 mm long, narrowly
subulate, red or purplish, minutely papillose-pilose, ciliate, with slender,
simple hairs; stamens diantheriferous, with anthers about 0.4 mm long; ovary
oblong-ovoid, superior, with 5 carpels; fruits usually considered drupes but
referred to as pods, indehiscent, variable in size and shape, 1032 cm long,
spherical to cylindrical, pointed or blunt, smooth or warty, with or without 5
or 10 furrows; pods white, green or red, ripening to green, yellow, red or
purple; seeds 2060 per pod, arranged in 5 rows, variable in size, 24 cm long,
1.22 cm broad, ovoid or elliptic; cotyledons white to deep purple, convoluted,
large. Seeds/kg 6251125. Roots mostly a mass of surface-feeding roots, with
taproot penetrating to 2 m in friable soil, less deeply where compacted (Reed,
Reported from the South and Middle American Centers of Diversity, cocoa, or cvs
thereof, is reported to tolerate some diseases, heavy soils, laterite, low pH,
photoperiod, shade, slope, and waterlogging (Duke, 1978). Several subspecies
and forms of cacao have been recognized, from which a great number of cvs have
been developed. Some cvs are named according to the place where they were
found or developed. Others are classified as 'Criollo' types which have
elongated, ridged, pointed fruits and white cotyledons and 'Forastero', with
short, roundish, almost smooth fruits and purplish cotyledons. Hybrids have
been obtained with other species, e.g. Th. grandiflora, mainly to
incorporate disease-resistance. (2n = 20)
Native to South America, probably on the equatorial slopes of the Andes; now
cultivated pantropically, especially in West Africa.
Ranging from Subtropical Dry to Wet through Tropical Very Dry to Wet Forest
Life Zones, cacao is reported to tolerate annual precipitation of 4.8 to 42.9
dm (mean of 109 cases = 16.3), annual temperature of 18.0 to 28.5°C (mean of
108 cases = 25.3), and pH of 4.3 to 8.7 (mean of 43 cases = 6.4) (Duke, 1978).
Grown from 20°N to 20°S with the bulk between 10°N and 10°S,
usually below 300 m, but in sheltered valleys of Colombia at 900 m. Requires
uniformly high temperatures with recommended mean of 26.6°C. Trees are
wind-intolerant and therefore are often planted on hillsides for wind
protection and good drainage. Being drought-intolerant, cacao thrives in
climates with high humidity and rainfall. Plants are shade-tolerant, and
thrive in rich, organic, well-drained, moist, deep soils. Shallow laterite
soils are said not to be suitable. Maximum temperature of 33.5°C and
minimum 13°C, with diurnal temperature variation between 33.5 and 18°C
are suggested (Reed, 1976).
Propagation may be by cuttings, buddings or graftings, but seeding is cheaper.
Seeds germinate at maturity, and are viable only a short time. They may be
stored 1013 weeks if moisture content is kept at 50%. Soon after picking,
pulp is removed from seed which are planted in shaded nursery beds or baskets.
Transplant in few months (when ca 0.6 m tall) into shaded fields at 2.4 m x 2.4
m or 3.6 m x 3.6 m. Spacing is closer if soils are poor and elevations above
300 m. Fields should remain shaded for 3 years. Remove floral buds until
trees are 5 years old. Cacao is of ten intercropped with other trees of
economic value, as bananas, rubber, oil palm, or coconut. Weeding is by hand
or herbicides. Irrigation may be practiced, but drain ditches should always be
provided to prevent excess water. Responds to fertilizers, mostly in the
absence of shade; recommended is 5 cwt urea, 2.5 cwt triple superphosphate, 10
cwt potassium sulfate per hectare. Windbreaks are usually provided.
Although fruits mature throughout the year, usually only two harvests are made.
In West Africa, the main harvest begins in September, extends to February, with
a second smaller harvest in MayJune. From fertilization to harvesting the
fruit requires 56 months. Harvest season lasts about 5 months. Pods are cut
from trees and allowed to mellow on the ground. Then pods are cracked and the
beans removed, the husks are burned. Beans are fermented in leaf-lined kegs
28 days before drying in sun, at which time they change from purple to brown.
Beans are then bagged and shipped. Further processing includes roasting,
crushing, and separating out the kernel, grinding the nibs and extraction of
about half of the fat.
The world low production yield is 29 kg/ha in American Samoa, an international
production yield of 346 kg/ha, and a world high production yield of 2,000 kg/ha
in Haiti. Yields of 3,375 kg/ha of dry beans are possible on good plantations.
The oil content (3550%) suggests potential oil yields of more than 1750 kg/ha.
Average yields range from 0.510 kg/tree; 2.25 MT beans/ha. Over 3375 kg/ha of
dry cacao beans have been produced on plantations well-manured, well-shaded,
and with excellent control of weeds, pests and diseases. In 1980, the US is
estimated to have consumed more than 75,000 MT of cocoa butter, in a business
amounting to nearly $600 million. Chocolate manufacturers consumed nearly
half. One ton went into suppositories, 10 to 20% of which are made with a
cocoa butter base. In 1981, there was a world surplus of ca 700,000 tons,
close to 6 months production, and price down to ca $1.30/kg. In July 1965, a
record cocoa crop in Ghana sent cocoa bean prices to below $0.20/kg, an
all-time low. A dozen years later, the beans spiralled to more than $5.00/kg.
Normally cocoa butter runs 25 times as high as the bean (Anon., 1981b).
Two-thirds of the world's production presently comes from Ghana, Nigeria, and
Ivory Coast in West Africa, and one-third from Brazil and Dominican Republic.
In 1971, the US imported from Africa about 200,908 MT of cocoa beans, valued at
$120 millions, and from Latin America, 107,841 MT valued at $54 millions.
World production of beans in 1971 was 1.59 million MT. Major consumers are
United States, West Germany, Netherlands, and United Kingdom. New York prices
on 'Accra' beans in 1971 was $0.68/kg. Cocoa is produced in tropical
countries, but is processed and consumed in temperate countries.
For every kilogram of dry beans, there can be 2 kg of pod meal; indicating a
1:2 seed:pod ratio. To convert production figures into pod waste figures, this
suggests we multiply by two. Pod meal contains ca 12.6% moisture, 7.6% ash,
8.1% protein, 34.8% crude fiber, 3.3% fat, and 33.6% N-free extract. One
hundred kg cacao pod meal has the same feeding value as 9697 kg chopped corn
(including husks). Prunings could amount to 18 MT/ha/yr, depending on
biological and environmental variables. During the third year, main branches
may be reduced to 3 or 4, and thenceforth, excess limbs and diseases tissues
should be removed. For each MT of production, it seems safe to conclude there
will be 2 MT of pods and 2 MT of prunings as residue, perhaps more in unshaded
cacao. Shade trees might best be selected on basis of (1) nitrogen fixed, (2)
fuelwood produced, (3) nonantagonism or amelioration of cacao. Seedling cacao
does best with only 25% full sunlight, saplings with closer to 50%. Species of
energy-fixing species of Albizia, Erythrina, Gliricida, Inga, Leucaena,
Musanga, Peltophorum, and Terminalia have been recommended as shade
trees or "Madre de Cacao". (Purseglove, 1968)
Midges are thought to be the pollinators of cacao, but aphids, ants, thrips,
wild bees, or a combination of these are also suspect. Cacao grows in areas
with high humidity; several hundred fungi have been reported as attacking this
tree. However, the most important fungi that cause diseases which must be
controlled include the following: Armillaria mella (Collar crack),
Botryodiplodia theobromae (Pod rot), Botryobasidium salmonicolor
(Pink disease), Calonectria rigidiuscula (Green point cusion-gall),
Cephaleuros virescens (Algal spot), Ceratobasidium stevensii
(Thread blight), Ceratocystis fimbriata (Canker), Corticium
incisum (Thread blight), Fomes lamaensis (Brown rot), F.
lignosus (White rot), F. noxius (Brown crust), Marasmius
byssicola (Brown thread), M. perniciosus (South American witches
broom), M. scandens (White thread), M. trichorrhizus (Brown
thread), Monilia roreri (Gray pod rot), Nectria cacaoicola (Pod
rot), Phytophthora palmivora (Black pod), Rosellinia bunodes
(Root rot), R. pepo (Root rot), Septobasidium tanakae (Felty
fungus), Sphaerostilbe repens (Violet root rot), Taphrina bussei
(Witches broom), Thielaviopsis paradoxa (pod rot), Trachysphaera
fructigena (Mealy pod), Ustilina zonata (Collar rot), and
Verticillium dahliae (Sudden death). Bacteria known to cause disease in
cacao include: Agrobacterium tumefasciens, Bacillus megatherium, B.
subtilis, B. undulatus, Bacterium accendens, B. aceti, B. orleanense, B.
xylineum, B. xylmoides, and B. xylum. Golden (p.c. 1984) lists the
following nematodes: Aphasmatylenchus nigeriensis, Criconemella goodeyi,
Helcotylenchus cavenessi, H. concavus, H. microcephalus, H. multicinctus,
Hoplolaimus seinhorst, Meloidogyne incognita, M. incognita acrita., M.
javanica, M. sp., Paratylenchus arculatus, Pratylenchus brachyurus, P.
coffeae, P. sp., Rotylenchulus reniformis, Scutellonema clathricaudatum,
Tylenchorhynchus annulatus, T. nudus, Xiphinema ebriense, X. elongatum, X.
ifacolum, X. nigeriense, and X. setariae. Viruses isolated from
cacao include: Akaran, Apoplectic disease, Asalu, Ilesha, Konongo, Kpeve cacao,
Mottle leaf, Necrosis, New Juaben (B.C.), New Juaben cacao, Offa Igbo (Nigeria)
cacao, Offa Igbo 1 and 2, Olanla 1 and 2, Red mottle, Swollen-shoot, Trinidad
cacao, Vein clearing, and Viruses 1A, 1B, 1C, and 1M. Cacao trees may be
parasitized by Cuscuta campestris, C. cublinclusa, and Phthirusa
Analysing 62 kinds of biomass for heating value, Jenkins and Ebeling (1985)
reported a spread of 19.04 to 17.97 MJ/kg, compared to 13.76 for weathered rice
straw to 23.28 MJ/kg for prune pits. On a % DM basis, the hulls contained
67.95% volatiles, 8.25% ash, 23.80% fixed carbon, 48.23% C, 5.23% H, 33.19% O,
2.98% N, 0.12% S, and undetermined residue.
Cup (6 oz.) boiled coffee: 100 mg
Cup (6 oz.) instant coffee: 65mg
Cup (6 oz.) tea: 1050 mg
Cup (6 oz.) cocoa: 13 mg
Can (6 oz.) cola: 25 mg
Can (6 oz.) coca cola: 20 mg
Cup (6 oz.) mate: 2550 mg
Can (6 oz.) pepsi cola: 10 mg
Tablet Caffeine: 100200 mg
Tablet (800 mg) Zoom (Paullinia cupana): 60 mg
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 diuretic, as a 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 (1980) 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..."
Complete list of references for Duke, Handbook of Energy Crops
- Buchanan, R.L. 1979. Toxicity of spices containing methylenedioxybenzene
derivatives: A review. J. Food Safety 1:275.
- C.S.I.R. (Council of Scientific and Industrial Research). 19481976. The wealth
of India. 11 vols. New Delhi.
- Duke, J.A. 1978. The quest for tolerant germplasm. p. 161. In: ASA Special
Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.
- Duke, J.A. and Wain, K.K. 1981. Medicinal plants of the world. Computer index
with more than 85,000 entries. 3 vols.
- Jenkins, B.M. and Ebeling, J.M. 1985. Thermochemical properties of biomass
fuels. Calif. Agric. 39(5/6):1416.
- Leung, A.Y. 1980. Encyclopedia of common natural ingredients used in food,
drugs, and cosmetics. John Wiley & Sons. New York.
- Palotti, G. 1977. The 'time for a Coca Cola' may not be right. Industrie
- Perdue, R.E., Jr. and Hartwell, J.L. (eds.). 1976. Plants and cancer. Proc.
16th Annual Meeting Soc. Econ. Bot. Cancer Treatment Reports 60(8):9731215.
- Purseglove, J.W. 19681972. Tropical crops. 4 vols. Longman Group Ltd.,
- Reed, C.F. 1976. Information summaries on 1000 economic plants. Typescripts
submitted to the USDA.
- Sutton, R.H. 1981. Cocoa poisoning in a dog. Veterinary Record
- Tyler, V.E. 1982. The honest herbal. George F. Stickley Co., Philadelphia,
Last update Friday, January 9, 1998 by aw