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Category: Applied and Industrial Microbiology; Food Microbiology
Cocoa and Coffee, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555815912/9781555814076_Chap39-1.gif /docserver/preview/fulltext/10.1128/9781555815912/9781555814076_Chap39-2.gifAbstract:
The majority of the world's cocoa is fermented on drying platforms, in heaps covered with banana leaves, in baskets, or in an assortment of wooden boxes. Wet cocoa beans are spread directly onto drying platforms where they ferment and dry during the day and are heaped into piles each night to conserve heat and retard the growth of surface molds. The initial microbial population is variable in number and type; however, the key groups active during fermentation are yeasts, lactic acid bacteria, and acetic acid bacteria. Significant changes in pH, temperature, and moisture occur during cocoa fermentation and drying processes that influence the type and quantity of flavor precursor compounds produced by enzymatic action. A summary of cocoa bean enzymes and their substrates and optimum pHs is provided in this chapter. The ultimate goal of biochemical changes during fermentation is to produce cocoa beans with desirable flavor and color characteristics. Unlike that in cocoa fermentation, there is no defined microbial succession that occurs with coffee maturation and fermentation. Although serving somewhat different purposes, microbial fermentation plays a critical role in the production of both cocoa and coffee. Coffee and cocoa are no exceptions, and it is the proper control of the fermentation process that largely determines the color and flavor qualities of the final products. Consequently, understanding the microbiology and biochemistry of cocoa and coffee production, as well as the factors that influence them, is critical to quality control.
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Physical (A) and chemical (B) changes in cocoa beans during fermentation and drying in Belize. Fermentation was conducted with 2,000 lb of wet cocoa beans from ripe pods in wooden boxes that were turned daily. Drying was conducted in flat-bed dryers indirectly heated with hot air. Data represent results from an average of 11 fermentation trials using composite samples collected daily. (A) Temperature was measured in the whole bean mass. Moisture (%) and pH analyses are based on shell-free cotyledons. (B) Sucrose, glucose (Glc), fructose (Fruc), total amino acid, acetic acid, and ethanol contents (%) were determined by analysis of water extracts from shell-free cotyledon samples. Data are taken from Lehrian ( 33 ).
Microorganisms isolated from fermenting cocoa beans
Characteristics of the principal enzymes active during the curing of the cocoa bean a