Abstract: The objective of this study was to investigate the effects of natural fermentation and inoculated fermentations with Pichia pastoris and active dry wine yeast BV818 (Saccharomyces cerevisiae) on the flavor of yellow peach wine. Simultaneous inoculation, sequential inoculation of P. pastoris and BV818 with a time interval of one and three days, and inoculation of BV818 alone were used. Gas chromatography-mass spectrometry (GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS) and quantitative descriptive sensory analysis were used to study the effects of different fermentation methods on volatile flavor substances in yellow peach wine. The results showed that for all groups, ethanol fermentation was completed within 15 days, and 31 and 22 compounds were detected by GC-MS and GC-IMS, respectively. In the sequential fermentation groups, the content of alcohols increased, the contents of acids and esters decreased, and the numbers of terpenes, alcohols and acids increased. In the sensory evaluation, the sequential fermentation groups had higher aroma richness and aroma balance than the other groups. The simultaneous fermentation group scored higher in sensory score for nutty and sweet aroma. The naturally fermented wine had the strongest sour aroma. In summary, mixed fermentation with P. pastoris and S. cerevisiae can improve the aroma of yellow peach wine, and the sensory score of the wine produced by sequential inoculation with a three-day interval was highest.

Key words: yellow peach wine; gas chromatography-mass spectrometry; gas chromatography-ion mobility spectrometry; volatile organic compounds; Pichia pastoris; sensory evaluation; partial least squares regression