The Ecuadorian Nacional cocoa variety may outshine the use of starter cultures
Nacional cocoa is an established fine cocoa variety from Ecuador, known for its qualitative flavour characteristics. However, non-standardized farm practices mask the full potential of cured Nacional cocoa beans. An in-depth investigation of the effect of a starter culture to perform Nacional cocoa fermentation processes (CFPs) was lacking and may bring a solution. Therefore, the present study aimed to assess the influence of the addition of starter culture mixtures composed of yeast and bacterial strains on the microbial community and metabolite dynamics during fermentation of the cocoa pulp-bean mass and drying of the resulting cocoa beans. Two spontaneous and four starter culture-initiated (SCI) CFPs were performed in large, four-stage wooden boxes that were sampled at top, middle, and bottom locations. The yeast strains Saccharomyces cerevisiae IMDO 050523 and/or Pichia kudriavzevii IMDO 060005 were combined with the lactic acid bacterium strain Limosilactobacillus fermentum IMDO 0611222 and the acetic acid bacterium strain Acetobacter pasteurianus IMDO 0506386. An amplicon sequence variant approach based on sequencing of the full-length 16S rRNA gene allowed to confirm the successful inoculation of the bacterial strains. Similarly, sequencing of the internal transcribed spacer (ITS1) region confirmed the successful inoculation of the yeast strains.