Abstract: An aroma-producing yeast strain was isolated from bittern and identified as Saccharomycopsis fibuligera CAU752. The effect of fermentation by this strain on the flavor quality of Yunnan arabica coffee was investigated using the one-factor-at-a-time method and gas chromatography-quadrupole time-of-flight mass spectrometry (GC-QTOF-MS). The results showed that after 48 h of fermentation at 30 ℃ with an inoculum size of 0.1% (V/V), the contents of caffeine, trigonelline, and chlorogenic acid in the coffee significantly decreased by 53.8%, 33.6%, and 6.8% (P < 0.05), respectively, effectively reducing the bitterness and astringency. Newly formed volatile compounds, including diethyl succinate and linalool, were detected in the fermented coffee. Furthermore, the odor activity value (OAV) of methyl salicylate and phenethyl alcohol increased by 80.4% and 392.7%, respectively, imparting fruity, floral, and sweet flavor characteristics to the coffee. These results indicate that S. fibuligera CAU752 can serve as an excellent starter culture for the processing of coffee with high sensory quality.

Key words: arabica coffee beans; Saccharomycopsis fibuligera; fermentation; flavor