Influence of S. cerevisiae and P. kluyveri as starters on chocolate flavour

Abstract

BACKGROUND: Fermented cocoa beans (Theobroma cacao L.) are a pivotal raw material for chocolate production. A cocktail yeast applied in the cocoa fermentation process can promote the formation of pleasant metabolites. Saccharomyces, Pichia and Hanseniaspora have been widely used in fermentation to improve the final product organoleptic profile, highlighting that fermentation is a critical point for chocolate flavour precursor production. This study aims to evaluate the impact of Pichia kluyveri and Saccharomyces cerevisiae strains as starter cultures on the fermentation for two cocoa hybrids, FA13 and CEPEC2002. RESULTS: During fermentation processes, volatile organic compounds (VOCs) and protein profiles were assessed. Chocolates produced were also assessed regarding the presence of VOCs. Eighty VOCs were identified using gas chromatography coupled to mass spectrometry analysis. Mass spectrometry provided the protein profile evolution during fermentation and showed that the profiles changed with inoculation type (spontaneous versus inoculated fermentation). Chocolate obtained from FA13 inoculated with S. cerevisiae strain contained a greater amount of organics acids, being categorised as sourer than chocolate produced by spontaneous fermentation of FA13. CEPEC2002 inoculated with S. cerevisiae strain in co-culture with P. kluyveri strain generated less sour and sweeter chocolate than spontaneous fermentation only.CONCLUSIONS: Chocolates from inoculated assays with starter cultures were more accepted by evaluators, highlighting that P. kluyveri and S. cerevisiae influence the composition of VOCs. Besides, protein profiles also changed throughout fermentation. Further investigation should be conducted to clarify protein degradation dynamics during inoculated fermentations to define which of the microbial cultures positively affect the chocolate sensory characteristics.

Phylogenomics of a Saccharomyces cerevisiae cocoa strain reveals adaptation to a West African fermented food population

“…Overall, these findings suggested that the production of VOCs in the cocoa pulp-bean mass will not primarily depend on the presence of different S. cerevisiae strains but rather on the biochemical composition of the cocoa pulp (providing flavor precursors) or gene expression levels. Still, genomic comparison between strains of species of different yeast genera naturally occurring during cocoa fermentation processes, such as Hanseniaspora and Pichia , should be performed, as previous studies have demonstrated differential VOC productions according to the yeast species inoculated ( Díaz-Muñoz et al., 2021 ; Moreira et al., 2021 ). However, the single amino acid changes found in the acetyltransferases ATF1 and IMO32P, affecting strains from the West African fermented food cluster and West African cocoa cluster, respectively, may result in a different activity of those ester-synthesizing enzymes and, thus, may have an impact on the VOC production by S. cerevisiae cocoa strains.…”

Innovation in Cocoa Fermentation: Evidence from Patent Documents and Scientific Articles

“…Using starter cultures [9,37,[58][59][60][62][63][64][65][66][67][68][69][70][71][72][73][74][75] Using enzymes [76- Given the important role of microorganisms in cocoa fermentation, several studies propose the use of starter cultures as a strategy to improve cocoa quality and maintain reproducibility among fermentation batches [8,[58][59][60]. Potential starter cultures have also been studied to elucidate microbial diversity, structure, and functional and metabolic pathways.…”

Selección de levaduras promisorias para el desarrollo de un iniciador microbiológico promotor de la fermentación del cacao

“…The production of aromas during cacao fermentation has been mainly associated with the microbiological consortium of yeasts in the process (10,25,28,29). It is subjected to factors such as the nutrient concentration of the substrate, biochemical conditions of the process, and yeast genetics that, in turn, intervene in the production of enzymes and generation of metabolites of interest, as expressed by Kongor et al ( 30) and Moreira et al (31). The aroma production test in the cacao pulp substrate of the yeasts under study is shown in Figure 6 through the aroma profile of the musts.…”