Applicability of Saccharomyces cerevisiae Strains for the Production of Fruit Wines Using Cocoa Honey Complemented with Cocoa Pulp.

Research background: Cocoa honey and cocoa pulp are both highly appreciated fruit pulp, but until now, cocoa honey has been less processed than cocoa pulp. In this work, we investigate the applicability of Saccharomyces cerevisiae strains to ferment cocoa honey complemented with cocoa pulp to obtain fruit wines and improve cocoa honey commercialization. Experimental approach: The strain, previously isolated from cachaçaria distilleries in Brazil, was selected based on its fermentation performance. The following conditions for fermentation with S. cerevisiae L63 were then studied: volume fraction of cocoa honey (φ CH) complemented with cocoa pulp, sucrose addition (γ suc), temperature (t) and inoculum size (N o). The best conditions were applied in order to obtain fermentation profiles. Results and conclusions: S. cerevisiae L63 (N o=107-108 cell/mL) is capable of fermenting φ CH=90 and 80% for 24 or 48 h with γ suc=50 and 100 g/L at t=28-30 °C resulting in wines with ethanol volume fractions from 8 to 14%. Additionally, the wine produced from φ CH=90% had lower residual sugar concentration (<35 g/L) than the wine produced from φ CH=80% (~79 g/L) which could be classified as a sweet wine. In general, S. cerevisiae L63 resulted in a similar fermentation performance as a commercial strain tested, indicating its potential for fruit pulp fermentation. Novelty and scientific contribution: Saccharomyces cerevisiae L63 can ferment cocoa honey complemented with cocoa pulp to produce fruit wines with good commercial potential, which may also benefit small cocoa producers by presenting a product with greater added value.

Integrating microbial metagenomics and physicochemical parameters and a new perspective on starter culture for fine cocoa fermentation.

Cocoa beans used for chocolate production are fermented seeds of Theobroma cacao obtained by a natural fermentation process. The flavors and chemical compounds produced during the fermentation process make this step one of the most important in fine chocolate production. Herein, an integrative analysis of the variation of microbial community structure, using a shotgun metagenomics approach and associated physicochemical features, was performed during fermentation of fine cocoa beans. Samples of Forastero variety (FOR) and a mixture of two hybrids (PS1319 and CCN51) (MIX) from Bahia, Brazil, were analyzed at 7 different times. In the beginning (0 h), the structures of microbial communities were very different between FOR and MIX, reflecting the original plant-associated microbiomes. The highest change in microbial community structures occurred at the first 24 h of fermentation, with a marked increase in temperature and acetic acid concentration, and pH decrease. At 24-48 h both microbial community structures were quite homogenous regarding temperature, acetic acid, succinic acid, pH, soluble proteins and total phenols. During 72-96 h, the community structure resembles an acidic and warmer environment, prevailing few acetic acid bacteria. Taxonomic richness and abundance at 72-144 h exhibited significant correlation with temperature, reducing sugars, succinic, and acetic acids. Finally, we recommend that dominant microbial species of spontaneous fine cocoa fermentations should be considered as inoculum in accordance with the farm/region and GMP to maintain a differential organoleptic feature for production of fine chocolate. In our study, a starter inoculum composed of Acetobacter pausterianus and Hanseniaspora opuntiae strains is indicated.