Investigation of metabolite differences in green coffee beans fermented with various microbes

Abstract

In this study, green coffee beans were fermented using three yeast and three lactic acid bacteria (LAB) starters. The effects of each starter on the metabolite profiles of green coffee beans were comparatively analyzed. The principal component analysis (PCA) biplot showed a clear separation between the groups fermented with LAB (Leuconostoc mesenteroides, Lactobacillus plantarum, and Pediococcus pentosaceus) and the groups fermented with yeast (Saccharomyces cerevisiae, Candida parapsilosis, and Pichia guilliermondii). Various metabolites, including palmitic acid, stearic acid, and piperidine, were associated with the LAB strains. 2-Palmitoylglycerol, ribonic acid, and arabitol were related to C. parapsilosis and P. guilliermondii. Phenylethyl alcohol, succinic acid, shikimic acid, and methylamine contributed greatly to the separation of S. cerevisiae from the other strains in the PCA biplot. In addition, chlorogenic acid levels were higher in the LAB strains than in the yeast strains after fermentation. In particular, C. parapsilosis and P. guilliermondii showed much lower levels. The level of caffeine was highest in P. pentosaceus and lowest in C. parapsilosis after fermentation. This study provides comprehensive information on the metabolic changes after green coffee bean fermentation according to the type of microbes used.