Profile of Volatile Compounds of On-Farm Fermented and Dried Cocoa Beans Inoculated with Saccharomyces cerevisiae KY794742 and Pichia kudriavzevii KY794725

Abstract

This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high fermentative capacity: Saccharomyces cerevisiae, Pichia kudriavzevii, the mixture in equal proportions 1:1 of both species, and a control fermentation (with no inoculum application). Three starter cultures of yeasts, previously isolated and identified in cocoa fermentation in the municipality of Tomé-Açu, Pará state, Brazil. The seeds with pulp were removed manually and placed in wooden boxes for the fermentation process that lasted from 6 to 7 days. On the last day of fermentation, the almonds were packaged properly and placed to dry (36 °C), followed by preparation for the analysis of volatile compounds by GC-MS technique. In addition to the control fermentation, a high capacity for the formation of desirable compounds in chocolate by the inoculants with P. kudriavzevii was observed, which was confirmed through multivariate analyses, classifying these almonds with the highest content of aldehydes, esters, ketones and alcohols and low concentration of off-flavours. We conclude that the addition of mixed culture starter can be an excellent alternative for cocoa producers, suggesting obtaining cocoa beans with desirable characteristics for chocolate production, as well as creating a product identity for the producing region.

How Climatic Seasons of the Amazon Biome Affect the Aromatic and Bioactive Profiles of Fermented and Dried Cocoa Beans?

“…In this study, no pyrazines compounds were identified, which are highly desirable (in ideal quantities) for promoting the characteristic chocolate flavor [9]. However, this finding can mean a positive differential in the aromatic quality of the chocolate produced with these almonds since several compounds with fruity, floral, and sweet attributes have been identified.…”

“…During the fermentation of cocoa, several biochemical transformations essential for the formation of precursors of chocolate aromas occur [5][6][7]. In this sense, aldehydes, esters, ketones, and alcohols are the results of the metabolism of certain yeast species that act spontaneously in the first days of fermentation, such as those of the genus Saccharomyces, Pichia, and others [8][9][10][11]. Once formed, some compounds are degraded, volatilized, or participate in chemical and biochemical reactions in later stages, such as drying and roasting [9,12].…”

“…In this sense, aldehydes, esters, ketones, and alcohols are the results of the metabolism of certain yeast species that act spontaneously in the first days of fermentation, such as those of the genus Saccharomyces, Pichia, and others [8][9][10][11]. Once formed, some compounds are degraded, volatilized, or participate in chemical and biochemical reactions in later stages, such as drying and roasting [9,12]. These aromatic compounds are responsible for imparting fruity, sweet, and floral notes typical of good quality chocolates, thus being well-received in the market.…”

“…These aromatic compounds are responsible for imparting fruity, sweet, and floral notes typical of good quality chocolates, thus being well-received in the market. Several important sensory molecules come from the metabolism of the microbial population that participates in the fermentation process, mainly due to the participation of yeast species [5,9].…”

“…The first study on volatile compounds in fermented cocoa seeds in the Brazilian Amazon [9] reported a considerable diversity of aromatic compounds from different classes (alcohols, aldehydes, ketones, and ethers) after the fermentation process started with applying starter cultures of S. cerevisiae and P. kudriavzevii: 2-Nonanol, Phenylacetaldehyde, Benzaldehyde, 2-Nonanone, 2-Phenethyl acetate, and Isoamyl benzoate. All of them are the result of the metabolism of the microbial population that includes several species and yeasts, and lactic and acetic bacteria [5,9].…”