BSCI 124 Lecture Notes
Undergraduate Program in Plant Biology, University of Maryland
LECTURE 28 - STIMULATING BEVERAGES
Importance of trade in stimulating beverages, spices: Greater in age
of discovery than now; fortunes made were comparable to today's fortunes
in defense, computers, software, or cocaine.
Rationale for stimulating beverages: flavor, feeling of alertness.
Caffeine is active ingredient
in the most popular stimulating beverages. Caffeine is chemically related
to purine bases in DNA.
Desirable effects: Stimulation of central nervous system,. faster heartbeat,.
constriction of blood vessels,. increased respiration rate, suppression of
appetite (reason caffeine is in diet pills), diuresis.
Undesirable effects: headaches on withdrawal, infertility, birth defects,
insomnia: see coffee/caffeine
See what caffeine does to and
Coffee (Coffea arabica):
Terminology about coffee
A brief review of origin and
history of coffee use.
Native of eastern Africa; fruits and leaves eaten for stimulation.
Grown in Yemen;
domesticated, roasting of beans invented, 13th century.
Coffee brewing spread to
Arabian world in the 16th
spreads to Europe in the 17th century. Coffeehouses popular throughout
Europe by 1700.
Center of trade: Mocha, Arabia, in 17th century; Dutch East Indies and Ceylon
in 18th; spread to
in 18th, Brazil
in 19th, where it had a profound
impact; now most produced in Brazil,
Additional minor species
Growing and harvesting
coffee beans: see some
images of coffee
is a small tree, grows in cool subtropical mountain habitats.
ii. Small fruit is called cherry, contains two seeds called beans; harvested
ripe, by hand.
Hull removed, seeds fermented (non-alcoholic) 12-24 hrs, dried 1 week.
Coffee beans are
roasted; produces flavor, dark brown color.
Coffee may be
decaffeinated before roasting; caffeine sold for use in medicines, soft
Coffee brewed with hot water or steam.
Blends & Roasts and
kinds of espresso
Importance: More people drink tea than any other stimulating beverage, but
international trade is less than for coffee.
Origin and history of use
[REQUIRED READING]: China, about 2700 BC, according to legend. Our word China
derived from chai, Russian word for tea. Early to Japan; Portuguese and Dutch
introduced to Europe late 1600s, after coffee. To American colonies; Boston
Tea Party 1773, protest of tea tax.
Cultivation and growth: Tea is a small tree, but is pruned to a bush.
leaves and stem stips are
Green tea: leaves
are steamed, rolled to break cells and release aroma, dried.
Black tea: leaves are
withered, rolled, fermented (non-alcoholic), dried.
Aroma and flavor from essential oils, additional taste from tannins; stimulating
effect from caffeine and theophylline.
Caffeine levels vary with the type of tea, black most, oolong intermediate,
green tea least; also length of brewing will determine
the amount of caffeine
in a cup of tea.
[REQUIRED READING] or
cacao) -- See archeological data here!
Importance: source of cocoa for beverage and chocolate for confectionery
and even known for its
Origin and history of use:
used by Aztecs, who made drink of chocolate, vanilla, and chili pepper.
Introduced to Spain by Cortes 1520s; Spanish added sugar. Later to rest of
Europe, but not as popular as coffee or tea; greasy drink due to cocoa butter.
Cocoa butter processed out 19th century, made modern cocoa.
bars also 19th century. Now grown in plantations, leading producers
Singapore, Ivory Coast, Brazil.
Cultivation and growth: cacao is a
native to South and Central American tropical forests. Fruit is size and
shape of a small football, borne on trunk.
Fruit harvested by hand, cut open, pulpy seeds.
review; go down the page for cultivation, processing and chemistry
Processing: Seeds fermented (non-alcoholic) 4-7 days, develops flavor and
dark brown color. Seeds then are dried, polished, roasted, cracked and dehulled
to release nibs (= cotyledons). Nibs are ground to paste, = chocolate liquor;
molded directly for baking chocolate. Remove cocoa butter, get cocoa powder.
Stimulating effect from theobromine, chemically related to caffeine.
Cola drinks: from
of kola tree
acuminata) from West Africa. Seeds fermented (non-alcoholic), dried,
ground. Contains caffeine.
Coca Cola: Invented 1886, extract of coca leaves and cola seeds; coca extract
contained cocaine, later removed, but Coca Cola still contains rest of coca
Other Sites of Interest:
Seeds of Change Garden
and Agriculture in the Americas
The world of tea
History of the teapot
A tour of tea
chocolate: The original stuff
"Where chocolate grows on
trees" by Carby Kummer; from The Atlantic Monthly
assignment" by Kate: A good review!
The following treatments were prepared by James A. Duke