chapter  13
24 Pages

Tea, Coffee, and Cacao

ByUlrich Schillinger, Louis Ban-Kof, Charles M. A. P. Franz

Tea, coffee, and cacao are popular beverages consumed all over the world. They are all cultivated exclusively in tropical and subtropical climates. Tea, coffee, and cacao originate from three different continents. The tea plant is an evergreen of the Camellia family that is native to China, Tibet, and northern India; coffee originates from the subtropical forest ecosystems of the Ethiopian highlands, and cacao is native to Central America where it was ™rst domesticated by the Aztecs. Tea, coffee, and cacao have in common relatively high concentrations of alkaloids that are stimulatory for humans. Two structurally related compounds, theobromine and caffeine, are especially important. Theobromine is a bitter alkaloid from the cacao plant and is also present in the leaves of the tea plant. It is a cyclic adenosine monophosphate (cAMP)

13.1 Introduction .................................................................................................... 353 13.2Tea .................................................................................................................. 354

13.2.1Green, White, Oolong, and Black Teas ............................................. 354 13.2.1.1Antibacterial and Antifungal Activities of Tea ................. 355 13.2.1.2Functional Properties of Tea .............................................. 355

13.2.2Microbial Fermented Teas and Tea Products: Puer Tea, Fuzhuan Brick Tea, Kombucha, Miang ............................................ 355 13.2.2.1Puer Tea ............................................................................. 355 13.2.2.2Fuzhuan Brick Tea ............................................................. 356 13.2.2.3Miang ................................................................................. 356 13.2.2.4Kombucha .......................................................................... 357

13.3Coffee ............................................................................................................. 358 13.3.1Coffee Processing .............................................................................. 359 13.3.2Microbiology of Coffee Fermentation ...............................................360 13.3.3Mycotoxin Production ....................................................................... 362

13.4Cacao .............................................................................................................. 362 13.4.1Fermentation of Cacao Beans............................................................364 13.4.2Microbiology of Cacao Fermentation ............................................... 367 13.4.3Biochemical Changes during Processing .......................................... 369

13.5Conclusion ...................................................................................................... 370 References ................................................................................................................ 370

phosphodiesterase inhibitor. Caffeine is known to be the main stimulatory compound in coffee (0.9%–2.6%) and tea (black tea leaves contain 3%–3.5% caffeine). In addition to the aroma of these beverages, the high concentration of these psychostimulants has contributed to the popularity of drinking coffee and tea. Coffee, tea, and cacao develop their distinctive color, •avor, and aroma during a fermentation process involving various microorganisms. Most of the teas are produced by a natural oxidation process without microorganisms; however, there are also microbial fermented teas like kombucha or puer tea. The fermentation process is of crucial importance for the quality of all products. Cacao and coffee require a roasting process before they acquire their full •avors.