Food Chemistry

21 Coffee, Tea, Cocoa

21.1 Coffee and Coffee Substitutes

21.1.1 Foreword

Coffee (coffee beans) includes the seeds of crim-
son fruits from which the outer pericarp is com-
pletely removed and the silverskin (spermoderm)
is occasionally removed. The seeds may be raw or
roasted, whole or ground, and should be from the
botanical genusCoffea. The drink prepared from
such seeds is also called coffee.
Coffee is native to Africa (Ethiopia). From there it
reached Arabia, then Constantinople and Venice.
Regardless of the prohibition of use and medical
warnings, coffee had spread all over Europe by
the middle of the 17th century. The coffee tree
or shrub belongs to the familyRubiaceae.De-
pending on the species, it can grow from 3–12 m
in height. The shrubs are pruned to keep them at
2–2.5 m height and thus facilitate harvesting. The
evergreen shrubs have leathery short-stemmed
leaves and white, jasmin-like fragrant flowers
from which the stone fruit, cherry-like berries,
develop with a diameter of about 1.5cm. The
fruit or berry (Fig. 21.1) has a green outer

Fig. 21.1.Longitudinal section of a coffee fruit (accord-
ing toVitzthum, 1976)

skin which, when ripe, turns red-violet or

deep red and encloses the sweet mesocarp or

the pulp and the stone-fruit bean. The latter

consists of two elliptical hemispheres with

flattened adjacent sides. A yellowish transparent

spermoderm, or silverskin, covers each hemi-

sphere. Covering both hemispheres and sepa-

rating them from each other is the strong fibrous

endocarp, called the “parchment”. Occasionally,

10–15% of the fruit berries consist of only one

spherical bean (“peaberry” or “caracol”), which

often brings a premium price.

The coffee shrub thrives in high tropical al-

titudes (600–1200 m) with an annual average

temperature of 15–25◦C and moderate moisture

and cloudiness. The shrubs start to bloom 3–4

years after planting and after six years of growth

they provide a full harvest. The shrubs can bear

fruit for 40 years, but the maximum yield is

attained after 10–15 years. Fruit ripening occurs

within 8–12 months after flowering. Only 3 of

the 70 species of coffee are cultivated:Coffea

arabica, which provides 75% of the world’s pro-

duction;C. canephora, about 25%; andC. liber-

icaand others, less than 1%. The quantity (in

Table 21.1.Production of coffee beans in 2006 (1000 t)

Continent Raw Country Raw

coffee coffee

World 7843 Brazil 2593

Viet Nam 854

Africa 922 Colombia 696

America, Central 1020 Indonesia 653

America, North 3 Mexico 288

America, South India 274

and Caribbean 4782 Ethiopia 260

Asia 2069 Guatemala 257

Europe – Honduras 191

Oceania 68 Peru 175

∑(%)a 75

aWorld production = 100%.

H.-D. Belitz · W. Grosch · P. Schieberle,Food Chemistry 938
© Springer 2009