- Most important crops
CHAPTER 13 IN THE TEXT
Many plant materials are used for beverages. For example, the juices of many fruits are drunk. Tea
and coffee are consumed daily by at least 1/3 of the world's population.
Table of beverages and the compounds they contain p. 314. Also see table on page 317.
Many of the beverages we drink contain caffeine. These give the consumer a general feeling of well
being. This series of beverages is consumed by most people in the world on a daily basis.
Flor Jamaica, hibiscus or roselle
The dried, fermented fruits of Coffea arabicaor C. canephora(Rubiaceae) are second only
to petroleum in the value of the material traded annually on the international market. See coffee
diagram on page 317.
Coffee has up to 3% caffein by weight. Coffee probably originated in Ethiopia. The leaves, which
also contain caffeine, were originally chewed. At some point, however, people started using the
fruits. The plant was taken to the Arabian peninsula in about the 6th century. The Arabs were the
first to "brew coffee".
Coffee drinking didn't spread to Europe until about the 1600's. This beverage became an important
aspect of social and political development in England about 1650. There were 3000 coffee houses in
1675; these institutions served as forums for political and religious debate. The king tried to have
them closed, but didn't get very far.
The Arabs monopolized the coffee trade. They killed the seeds before marketing them. Eventually,
however, the Dutch acquired live seeds from Mocha, the traditional source of Arabic coffee. The
Dutch started plantations in Sri Lanka and the East Indies and broke the Arab monopoly.
Coffee was taken to the West Indies in about 1723. From a tree taken from Paris to Martinique in
1723, coffee spread through the western hemisphere. Now Brazil leads the world in coffee
Coffea arabicaaccounts for about 90% of world's trade in coffee. Coffea canephora
accounts for about another 9%. C. libericaaccounts for about 1%. Both are more productive
and more disease resistant. C. arabicais a self-compatible polyploid. The other two are
self-incompatible diploids. More importantly, the coffee from Coffea arabicahas better
C. canephorais used often to make instant coffee although it is preferred in some parts of
The fruit of coffee is a type of berry (inferior fruited). The seeds are removed from the fruits
and are the part used to prepare the beverage. Coffee fruits are often called "beans". Coffee
is usually cultivated in tropical and subtropical latitudes. It prefers rich soils and high
rainfall, with a seasonally dry period. A plant produces fruit after 3 years and until the plant
is about 40 years old.
The plants are often shaded in plantations, but open orchards are used as well. Many of the shade
trees are legumes and fix nitrogen. The best coffee usually comes from areas with cool nights.
Coffee is seldom harvested mechanically. The best coffee comes from berries picked just when
The seeds are separated from the outer portion of the fruit by either a wet or dry process. In
the dry process, the fruits are dried and the outer portion abraded away. In the wet process
(see the diagrams on page 319 and 321), the fruits are depulped by a machine and the seeds washed.
The wet seeds are allowed to ferment for 12-24 hours. After fermentation, the seeds are dried for
about a week. The remaining endocarp and the seed coats are removed mechanically. Roasting is
also essential to development of flavor of the final product. The temperature and time of roasting
In recent years instant and freeze dried coffee have become extremely popular and account for a large
part of the market. Much instant coffee is made by flash drying. "Aroma components"
are added to give the product enhanced flavor and odor.
Decaffeinated coffee is also important. In 1981, this form of the beverage accounted for about 17%
of the coffee drunk in the U.S. The caffeine is removed from green coffee beans by
solvent extraction, water extraction, or steam extraction. Methylene chloride is often used as the
There are many serious disease problems with coffee. These have made it difficult to grow Coffea
arabicain many parts of Africa and these diseases now have been introduced into Brazil.
Cacao is native to the Americas. Although considered as a berverage in this lecture, eating chocolate
is more important than the beverage today. The plant, Theobroma cacao(Sterculiaceae) is a
small tree. Cacao was a quite different beverage to the Indians of Central America than it is to
us today. See the diagram on page 325.
When Columbus and his men landed in Nicaragua, they reported seeing the Indians drinking a strange
beverage. Cortez reported on the importance of cacao in the Aztec court. Quetzlcoatl gave cacao
to the Indians.
The beans were roasted and mixed with ground achiote, Bixa orellana(Bixaceae). Red pepper
was also added. The whole thing was cooked into a paste and made into tablets. The drink was made
by putting these tablets into water. The drink was often thickened by adding atole.
Not surprisingly, Europeans didn't like this drink too much. They added sugar and left out the chili
peppers. In the middle 1600's, chocolate drinks were extremely popular in Europe. The Spanish had
a monopoly on the chocolate trade. The Dutch broke the Spanish monopoly by establishing plantations
in southeast Asia in 1670. Cacao was introduced into Africa in 1878 and now most cacao is
produced in Africa. Cacao was cultivated in Mexico by about the 7th century.
The pods are harvested, opened, and the seeds and pulp removed. The seeds are allowed to ferment for
4 to 7 days. Water loss causes them to shrink from the seed coats. See the diagram on page 325.
The pulp is liquified by microbes, and the seeds inside are then dried and then polished. The seeds
are then shipped.
As is true for coffee, roasting is an important part of development of cacao flavor. The chocolate
flavor only develops during this part of the processing. The seed coats are removed. The seed
coats and seeds can be extracted to produce a lipid known as cocoa butter (about 30% of the
cotyledons). This is used in other food products and in pharmaceuticals. The seeds contain
theobromine, a compound with similar properties to caffeine.
Chocolate is made by making the nibs or cotyledons into a paste. In the Dutch process, the cocoa
butter is separated and dry cocoa powder produced. The acids are neutralized with
alkalai. About 90% of all cocoa is produced this way. The English devised adding milk to cocoa
as a beverage. The Swiss started adding milk to the cocoa to make milk chocolate. Cocoa butter
is re-added to make the product more creamy.
Tea is drunk by a larger number of people than coffee, but does not have as high dollar value. Most
tea is consumed locally and comparatively small quantities enter international trade.
The exact origin of tea, Camellia sinensis(Theaceae), is obscure, but the plant appears to have
arisen in China. The first book on tea was written in 780 B.C. Tea came to Japan in
593 B.C. The Mongols got tea from the Chinese and traded it across Asia.
The Russians got tea in this way. Europeans first got into tea when the Portugese brought it back
from China. In the 1700's tea had become an important item of trade. Both the British and Dutch
bought tea in the Orient and sold it in Europe. People drank tea predominately in the U.S. until
the Boston Tea Party; then coffee became a more popular beverage. Tea is of course still very
popular in England.
The British started planting tea in India in about 1818. Sri Lanka has been the second most important
tea producer, but tea production there only started after the coffee rust wiped out coffee in
Because of the hand labor, tea is not grown extensively in the U.S. or most other countries in the
Western Hemisphere (some is grown in Argentina).
The plants are evergreen; they require lots of rainfall and a constant cool temperature. Only the
two or three youngest leaves are used for good quality tea. For green tea the leaves are dried
fairly quickly to stop most enzyme activity. For black teas, the leaves are allowed to wither, and
rolled or twisted (the leaves are broken) and then allowed to ferment for several hours. This
modifies the tannins and polyphenols in the leaves. The tea is then fired or heated to stop
further enzyme action. Oolong teas are semifermented. See the outline of tea manufacture on
Yerba maté (Ilex paraguayensis, Aquifoliaceae) is a common beverage of southern South
America. The Indians of much of South America used maté at one time. As it true for tea, the
leaves of yerba maté are used. The leaves and small twigs are heated over a fire and then
allowed to stand for a period of time. The leaves, small twigs, and stems are crushed and used to
make a tea like beverage.
Maté is traditionally drunk from a gourd, or maté, filled with plant material. Hot water
is added. The "straw" is called a bombilla.
The seeds of Paullinia cupana(Sapindaceae) are used to make a beverage called guaraná.
This was originally from the Amazonian region of Brazil. This preparation is rich in caffeine.
The ground seeds are made into a paste that sets up like a brick. A small amount of this material
is rasped off and mixed with hot water to make the beverage guaraná. Guaraná is
second only to coffee as the most popular drink in Brazil. A soft drink prepared with this material
is similar to cola flavors.
Paullinia cupana fruits
A relative of cacao ( Cola nitida, Sterculiaceae) is used to prepare the flavor of cola
beverages. The seeds of the plant are also fermented in the manufacture of the flavoring. Cola
is native to West Africa where it has been used for a long time.
The pulp of the fruits is also eaten in many African countries. The seeds are dried and ground
to make a beverage in West Africa. This plant also contains caffeine.
Kava kava (from Piper methysticum, Piperaceae) is an important beverage plant in the South
Pacific. It as an integral part of social and religious life there.
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Revised April 2005
© David S. Seigler, Integrative Biology 363, Plants and Their Uses,
Department of Plant Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois, Urbana,
Illinois 61801, USA. 217-333-7577. email@example.com.