Cocoa Fermentations Conducted with a Defined Microbial Cocktail Inoculum

Abstract

Cocoa fermentations were performed in wooden boxes under the following four experimental regimens: beans naturally fermented with wild microflora; aseptically prepared beans with no inoculum; and beans inoculated with a defined cocktail containing microorganisms at a suitable concentration either at zero time or by using phased additions at appropriate times. The cocktail used consisted of a yeast,Saccharomyces cerevisiae var. chevalieri, two lactic acid bacterial species, Lactobacillus lactis andLactobacillus plantarum, and two acetic acid bacterial species, Acetobacter aceti and Gluconobacter oxydans subsp. suboxydans. The parameters measured were cell counts (for yeasts, filamentous fungi, lactic acid bacteria, acetic acid bacteria, and spore formers, including reisolation and identification of all residual cell types), sugar, ethanol, acetic acid, and lactic acid contents (and contents of other organic acids), pH, and temperature. A cut test for bean quality and a sensorial analysis of chocolate made from the beans were also performed. The natural fermentation mimicked exactly the conditions in 800-kg boxes on farms. The aseptic box remained largely free of microflora throughout the study, and no significant biochemical changes occurred. With the zero-time inoculum the fermentation was almost identical to the natural fermentation. The fermentation with the phased-addition inoculum was similar, but many changes in parameters were slower and less pronounced, which led to a slightly poorer end product. The data show that the nearly 50 common species of microorganisms found in natural fermentations can be replaced by a judicious selection and concentration of members of each physiological group. This is the first report of successful use of a defined, mixed starter culture in such a complex fermentation, and it should lead to chocolate of more reliable and better quality.

Occurrence and diversity of yeasts involved in fermentation of West African cocoa beans

“…Even though citrate often has been mentioned as an important carbon source during cocoa fermentation [11], except for a minor part of the C. krusei isolates none of the isolates within the dominant yeast species were able to assimilate citrate, which indicates that citrate assimilation is not an important selective parameter among yeast strains during cocoa fermentation in West Africa.…”

Elaboration of a fruit wine from cocoa (Theobroma cacao L.) pulp

“…The three S. cerevisiae strains have previously been isolated from natural cocoa and sugar cane fermentations and selected because of their differences in fermentative behaviour in synthetic fermentation medium (Schwan, 1988;Schwan et al, 2001). The strains belong to the Microbial Physiology laboratory at DBI/ UFLA and are codified as CA116, CA1162 and CA1183.…”

Fermentation of cacao (Theobroma cacaoL.) seeds with a hybridKluyveromyces marxianusstrain improved product quality attributes

“…Traditionally, cacao seed fermentation is a noncontrolled process initiated by microorganisms naturally occurring at fermentation sites, including yeasts, lactic and acetic bacteria, Bacilli, and filamentous fungi (Roelofsen, 1958;Ostovar & Keeney, 1973;Schwan, 1998). These fermenting organisms utilize the seed pulp as a carbon and nitrogen source.…”