title: The impact of yeast starter cultures on the microbial communities and volatile compounds in cocoa fermentation and the resulting sensory attributes of chocolate.
abstract: Theobroma cacao seeds are the main raw material for chocolate production. During their fermentation, a succession of microorganisms are responsible for the physicochemical changes occurring in the pulp and inside the beans. The aim of this study was to investigate the effects of yeast inoculation (Saccharomyces cerevisiae UFLA CA11, Pichia kluivery CCMA0237, and Hanseniaspora uvarum CCMA0236) on the profile of the volatile compounds and microbial communities in cocoa fermentation. The resulting chocolate was also evaluated by temporal dominance of sensations (TDS) analyses. The dominant microorganisms during spontaneous fermentation were S. cerevisiae, H. uvarum, H. guilliermondii, Lactobacillus fermentum, Pediococcus sp., and Acetobacter pasteurianus. Similarly, S. cerevisiae, P. kluyveri, Candida sp., Pediococcus sp., and A. pasteurianus were the predominant microorganisms assessed by Denaturing Gradient Gel Electrophoresis (DGGE) in inoculated fermentation. Sixty-seven volatile compounds were detected and quantified by gas chromatography/mass spectrometry (GC/MS) at the end of fermentation and chocolates. The main group of volatile compound found after the inoculated and spontaneous fermentations was esters (41 and 39 %, respectively). In the chocolates, the main group was acids (73 and 44 % from the inoculated and spontaneous fermentations, respectively). The TDS analyses showed a dominance of bitter and cocoa attributes in both chocolates. However, in the inoculated chocolate, lingering fruity notes were more intense, while the chocolate produced by spontaneous fermentation was more astringent. Thus, the inoculation of yeast influenced the microbial profile, which likely affected the volatile compounds that affect sensory characteristics, resulting in chocolate with dominant bitter, cocoa, and fruity attributes.
authors.affiliation: Department of Food Science, Federal University of Lavras, Lavras, MG 37.200-000 Brazil.
authors.forename: Nádia Nara
authors.initials: NN
authors.lastname: Batista
authors.affiliation: Department of Biology, Federal University of Lavras, Campus Universitário, 3037, Lavras, MG 37.200-000 Brazil.
authors.forename: Cíntia Lacerda
authors.initials: CL
authors.lastname: Ramos
authors.affiliation: Department of Food Science, Federal University of Lavras, Lavras, MG 37.200-000 Brazil.
authors.forename: Disney Ribeiro
authors.initials: DR
authors.lastname: Dias
authors.affiliation: Department of Food Science, Federal University of Lavras, Lavras, MG 37.200-000 Brazil.
authors.forename: Ana Carla Marques
authors.initials: AC
authors.lastname: Pinheiro
authors.affiliation: Department of Biology, Federal University of Lavras, Campus Universitário, 3037, Lavras, MG 37.200-000 Brazil.
authors.forename: Rosane Freitas
authors.initials: RF
authors.lastname: Schwan
keywords: Chocolate; Cocoa fermentation; GC/MS; PCR-DGGE; Temporal dominance of sensations