Dissecting fine-flavor cocoa bean fermentation through metabolomics analysis to break down the current metabolic paradigm

Cocoa fermentation plays a crucial role in producing flavor and bioactive compounds of high demand for food and nutraceutical industries. Such fermentations are frequently described as a succession of three main groups of microorganisms (i.e., yeast, lactic acid, and acetic acid bacteria), each producing a relevant metabolite (i.e., ethanol, lactic acid, and acetic acid). Nevertheless, this view of fermentation overlooks two critical observations: the role of minor groups of microorganisms to produce valuable compounds and the influence of environmental factors (other than oxygen availability) on their biosynthesis. Dissecting the metabolome during spontaneous cocoa fermentation is a current challenge for the rational design of controlled fermentations. This study evaluates variations in the metabolic fingerprint during spontaneous fermentation of fine flavor cocoa through a multiplatform metabolomics approach. Our data suggested the presence of two phases of differential metabolic activity that correlate with the observed variations on temperature over fermentations: an exothermic and an isothermic phase. We observed a continuous increase in temperature from day 0 to day 4 of fermentation and a significant variation in flavonoids and peptides between phases. While the second phase, from day four on, was characterized for lower metabolic activity, concomitant with small upward and downward fluctuations in temperature. Our work is the first to reveal two phases of metabolic activity concomitant with two temperature phases during spontaneous cocoa fermentation. Here, we proposed a new paradigm of cocoa fermentation that considers the changes in the global metabolic activity over fermentation, thus changing the current paradigm based only on three main groups of microorganism and their primary metabolic products.

Fermentation of Cocoa Beans

Cocoa bean fermentation is a spontaneous process driven by an ordered microbial succession of a wide range of yeasts, lactic acid and acetic acid bacteria, some aerobic sporeforming bacteria and various species of filamentous fungi. The process of cocoa fermentation is a very important step for developing chocolate flavor precursors which are attributable to the metabolism of succession microbial. The microbial ecology of cocoa has been studied in much of the world. In Venezuela, studies have been carried out with Criollo, Forastero, and Trinitario cocoa, fermented under various conditions, the results obtained coinciding with the reported scientific information. Fermentation must be associated with the type of cocoa available, carried out knowing the final processing and derivative (paste, butter, powder). The results shown in this chapter correspond to investigations carried out with cocoa from three locations in Venezuela. The quantification, identification, isolation, functionality of the most representative microbiota involved in the fermentation of these grains was sought. This to give possible answers to the fermentation times and improvement of the commercial quality. Likewise, generate greater interest on the part of the producers in carrying out the fermentation.

Changes in Physico-Chemical and Microbiological Properties in Thai Cocoa Bean Fermentation

The purpose of this research is to investigate the quality-related physical, chemical, and microbiological changes in Thai cocoa beans during fermentation in 2 types of wooden containers. The results will compose a book of guidelines for good Thai cocoa fermentation in order to educate Thai farmers. Fresh Thai cocoa beans have a low pH value (5.0 - 5.5) compared to those from other countries in general (6.0 - 7.0). However, fermented temperature is able to reach 40 - 45 °C in 6 days, which is a main criteria for finishing cocoa fermentation. The color of fresh cocoa beans changes from white to brown within 2 days; after that, cocoa beans are mixed from the top to the bottom of the containers. Three groups of microorganism are evaluated with 3 different sampling points in wooden containers. The results reveal that yeast is grown quickly in 2 days on the top of containers, and then acetic acid bacteria and lactic acid bacteria are grown by the utilized yeast’s metabolites. These behaviors were found in both of the 2 wooden containers; however, a heap of cocoa beans (200 - 250 kgs) in a wooden box showed better quality of cocoa fermentation than a small volume (40 - 50 kgs) in a wooden tray. HIGHLIGHTS Understanding changes in Thai cocoa beans fermentation based on traditional method Two type of wooden containers applied for comparing all quality-related cocoa fermentation Proper cocoa beans fermentation process composed to a book of guideline for Thai Farmers GRAPHICAL ABSTRACT

Biotechnological starter potential for cocoa fermentation from cabruca systems / Potencial biotecnológico de leveduras starter na fermentação do cacau de sistema cabruca

Cocoa is a fruit of great economic importance, being the main raw material in the manufacture of chocolate. Among the stages of pre-processing, the main and most important is the spontaneous fermentation of the cocoa pulp by microorganisms, especially the yeasts, which initiate the process and contribute to the death of the germ of the seed, releasing compounds that directly influence the quality of the final product (flavor and aroma). Poorly fermented almonds confer bitter and astringent taste on chocolate, so it is advantageous to select autochthonous yeasts with better performance in the fermentation (producing enzymes of interest in the process) to be used as inoculum starter when added in the spontaneous fermentation, where they can accelerate the fermentation and contribute to raising the quality of the product. Therefore, the objective of this work was to qualitatively determine the production of enzymes of biotechnological interest by yeasts for the fermentation of cocoa through the cup plate method, in order to select a candidate yeast inoculum and use molecular typing technique to evaluate the diversity. Many promising yeasts were identified for use as inoculum among the diverse yeast groups found.