Abstract:In order to select a more suitable sterilization method and maintain the original flavor of purple rice sweet wine as much as possible, this article used electronic nose, headspace gas chromatography-ion mobility spectroscopy (HS-GC-IMS) to analyze and compare the volatile components of four groups of samples of heat sterilization, irradiation sterilization, ultra-high pressure sterilization and unsterilized control. The results of electronic nose test showed that the discrimination between the samples was good, and the differences of volatile components were mainly caused by nitrogen oxides, alcohols and aldehydes and ketones, methyls, sulfides. HS-GC-IMS detection and identification found that the 4 groups of samples shared 42 substances in 7 categories of alcohols, esters, aldehydes, ketones, acids, olefins and alkanes. The relative content of alcohols was the highest (62.03%~65.73%), followed by esters (12.70%~13.93%) and ketones (9.36%~11.59%), the sterilization method had a great influence on the relative content of each component. The relative odor activity value (ROAV) showed that there were 11 key flavor compounds in the samples, mainly including ethyl 2-methylbutyrate (69.39~100), acetaldehyde (38.61~42.05), ethyl isovalerate (18.16~27.23), isoamyl alcohol (9.91~18.08), butyraldehyde (14.13~18.06), ethyl isobutyrate (8.22~12.18). Both linear discriminant analysis and nearest neighbor algorithm analysis showed that the volatile components of ultra-high pressure and unsterilized samples were the most similar, followed by irradiation and heat sterilization samples, indicating that ultra-high pressure sterilization had the least effect on the aroma of samples, which was the best sterilization method for purple rice wine. The results of this study provide reference value for the selection of sterilization methods for sweet fermented rice.
