Enhancement of the fruity flavor in coffee beverages by solid-state fermentation in green coffee: a multi-block...

Seeking to develop specialty coffee profiles from regular coffee and knowing fruity is desirable, this study evaluated solid-state fermentation (SSF) of green coffee. The samples were analyzed in three blocks: physicochemical analysis; volatile compound analysis using headspace solid-phase microextraction (HS-SPME), gas chromatography coupled to an olfactometer (GC-O), and the same equipped with a Time of Flight mass detector (GC-QTOF-MS); and non-volatile compound analysis through untargeted metabolomics using both liquid and gas chromatography with high-resolution mass spectrometry (RP-LC-QTOF-MS/GC-QTOF-MS). The fermentation of the green coffee beans increased fructose from 0.01 % to over 1 %, while glucose levels increased by 80 % in the same samples. The metabolomics revealed changes across carbohydrates, cinnamic acids, glycerophospholipids, organic acids and flavonoids due to the fermentation. Despite a slight decay in aroma and fragrance, high-fruity samples were preferred overall and exhibited a more complex profile. The effect of the bioprocess also resulted in three specialty coffee samples, with a 10-point increase in one of the samples being the most relevant. Consequently, the process was demonstrated to be effective in modulating the fruity flavor attribute, and the multi-block approach leaves a solid framework that allows the study of the metabolic pathways occurring during the fermentation. ________________________________________________________________________.