Coinoculation of Saccharomyces cerevisiae and Bacillus amyloliquefaciens in solid-state and submerged coffee fermentation: Influences on chemical and sensory compositions

Abstract

This study aimed to evaluate the influence coffee fermentation with yeast and bacillus as starter cultures in SIAF method applied in solid-state and submerged process. Saccharomyces cerevisiae and Bacillus amyloliquefaciens were separately and coinoculated into natural coffee in buckets with or without water adding. The fermentations were performed for until 96 h, and the effects on physicochemical composition including the concentrations of organic acids (citric, lactic, acetic, malic), sugars (glucose, fructose, sucrose), ethanol, and glycerol as well as the sensory profiles of the resulting coffee beverages, were evaluated. All coffees produced were classified in specialty coffee with final score above 84. The coinoculated coffees obtained the highest sensory scores in submerged process (>86). Due to the results found, the type of process, submerged and solid-state, showed more influence in chemical and sensory analyses than type of inoculation. Submerged process showed major concentration of lactic acid, while solid-state process promotes major concentrations of ethanol, glycerol and acetic acid. Different sensory descriptions were observed in each treatment. Coffees from the submerged process showed nutty, cocoa, and sweet sensory descriptions, while solid-state process produced coffees with sour and acidic attributes.