Microbiological diversity associated with the spontaneous wet method of coffee fermentation

Abstract

The evaluation of the microbiota present during coffee wet fermentation was done in two distinct regions of Minas Gerais, Brazil: one farm in the South of Minas Gerais (Lavras = L) and another farm in the savannah region (Monte Carmelo = MC). The yeast population ranged from 2.48 to 4.92 log CFU/g and from 2 to 4.81 log CFU/g, the mesophilic bacteria population ranged from 3.83 to 8.47 log CFU/g and from 5.37 to 7.36 log CFU/g, and the LAB population ranged from 2.57 to 5.66 log CFU/g and from 3.40 to 4.49 log CFU/g in the L and MC farms, respectively. Meyerozyma caribbica and Hanseniaspora uvarum were the dominant yeasts in coffee wet fermentation at L farm, and Torulaspora delbrueckii was the dominant yeast at MC farm. The species Staphylococcus warneri and Erwinia persicina were the predominant bacteria at L farm, and Enterobacter asburiae and Leuconostoc mesenteroides were the dominant species at MC farm. Lactic acid was the principal acid detected, reaching 2.33 g/kg at L farm and 1.40 g/kg at MC farm by the end of the process. The volatiles composition was similar for roasted coffee from the two different regions and furans, acids, and alcohol were the main groups detected. Temporal Dominance Sensation (TDS) analyses showed that the coffee beverage from L farm was dominated by citrus and herbaceous sensory characteristics, while the coffee from MC farm was dominated by citrus, herbaceous, and nuts sensory characteristics. Evaluating the microbiota in these two regions was important in improving the knowledge of the microbial species present during coffee wet fermentation in Brazil.