Influence of alcohol level and temperature on rice wine metabolite changes during 200-day storage

초록

Rice wine is typically freshly consumed, but its quality during long-term storage depends on storage conditions. The relative impacts of alcohol concentration and storage temperature on the long-term quality of rice wine have not been quantitatively evaluated. In this study, rice wine adjusted to 6 %, 9 %, or 12 % alcohol was stored at 4 degrees C or -2 degrees C for 200 days, and its physicochemical, microbial, and metabolite profiles were examined. Yeast viability decreased over time but was better maintained at higher alcohol levels and under sub-zero storage, while lactic acid bacteria showed greater cold sensitivity. Principal component analysis (PCA) indicated that alcohol concentration primarily determined compositional differences, whereas temperature governed the magnitude of temporal change; the rate of metabolic change, defined as accumulated Euclidean distance divided by elapsed days, was up to threefold higher at 4 degrees C. Higher alcohol levels retained more organic acids and polyols, whereas lower alcohol favored gamma-aminobutyric acid (GABA) accumulation. Three metabolites-GABA, malic acid, and sorbitol-were identified as condition-specific markers based on fold change (>= 2) and statistical significance (q < 0.05). These findings demonstrate that alcohol content and storage temperature exert complementary influences on microbial survival and metabolic dynamics, providing insights for optimizing rice wine storage.

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