Natural microbial inocula for efficient cacao fermentation in Colombia

Abstract

The microbiological diversity that colonizes fermentation is a resource that could be used to develop natural microbiological starters that promote fermentation. The study involved the application of a natural microbial inoculate derived from 48-hour pre-fermented cacao pulp and beans under controlled laboratory conditions, aiming to evaluate its potential in improving the efficiency and quality of cacao bean fermentation. Pre-fermented pulp (liquid inoculum) and a mixture of the pre-fermented pulp and grains (semisolid inoculum) were used at four levels: 0 %, 1 %, 2 %, and 3 %, concerning the total cacao mass to be fermented. The variables soluble solids, pH, total anthocyanins, and fermentation percentage were recorded during fermentation. At the end of the fermentation process, the total content of polyphenols, theobromine, caffeine, volatile compound profile, and sensory evaluation were determined. The results showed higher soluble solids consumption in inoculated fermentations. The partial least squares regression performed at the end of the fermentation related the sensory evaluation with the biochemical characteristics of the cocoa liquor, finding a high correlation between total anthocyanins, the percentage of well-fermented beans, and the cocoa, nutty, fresh fruit, and floral attributes with better overall quality for the treatments added with liquid inoculum at 2 % (LPF 2 %), 3 % (LPF 3 %), and semisolid inoculum at 3 % (SPF 3 %). Therefore, it can be concluded that pre-fermentation achieves a substantial improvement in the biochemical dynamics of fermentation and enhances the sensory attributes of the grain. It is a promising alternative for reducing defects related to poor post-harvest handling of cocoa. According to data from the FAO in 2023, Colombia ranks second in cocoa bean production in South America, surpassed only by Ecuador.