Optimization of fermentation process and volatile flavor compounds of selenium-rich black glutinous rice wine

The selenium-rich black glutinous rice wine was made using selenium-rich black glutinous rice as raw material. Using selenium content as main evaluation indicator, supplemented by total phenols, alcohol content and sensory scores, the fermentation process of selenium-rich black glutinous rice wine was optimized using single-factor experiments and response surface methodology. The quality of the wine was detected using conventional methods, and key aroma components were analyzed using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS- SPME-GC-MS), combined with relative odor activity value (ROAV). The results showed that the optimal fermentation conditions for the wine were fermentation time 110 h, saccharified koji addition 6‰, material-to-liquid ratio 1.0:1.1 (g:ml), and fermentation temperature 30 ℃. Under these conditions, the alcohol content, reducing sugar, protein, total acid, selenium and total phenol content of the selenium-rich black glutinous rice wine were 9.90%vol, 2.14 g/100 g, 3.02 g/100 g, 0.91 g/100 g, 0.19 mg/L, and 963.20 mg/L, respectively. The total number of colonies was 8 CFU/g, and no coliform bacteria were detected. The sensory score was 95.06, with all indicators met the relevant standard requirements. A total of 22 volatile flavor compounds were detected in the selenium-rich black glutinous rice wine, including 4 alcohols, 8 esters, 7 acids, and 3 phenols. The key aroma compounds (ROAV>1) included isoamyl alcohol, phenylethanol, 4-ethylphenol, butyric acid, ethyl palmitate, ethyl phenylacetate and ethyl decanoate.