关键词: 复合发酵, 糯米, 红提葡萄酒, 工艺优化, 香气活性值

Abstract: Objective: This study aimed to improve the quality of wine made from table grapes by addition of natural exogenous sugars for the fermentation process. Methods: Wine was prepared from red globe grapes with added saccharified glutinous rice. The fermentation process was optimized using one-factor-at-a-time method and response surface methodology based on a three-variable, three-level Box-Behnken design. The independent variables considered were fermentation temperature, substrate ratio, yeast inoculum size and SO2 addition. The responses were ethanol and anthocyanin concentration. Results: Using one-factor-at-a-time method, addition of 80 mg/L SO2, a fermentation temperature of 20 ℃, an inoculum size of 1 g/L and a saccharified glutinous rice/red globe grape ratio of 1:4 (V/V) were determined to be the optimal conditions. Using response surface methodology, the fermentation conditions were further optimized as follows: temperature 21 ℃, inoculum size 1.2 g/L, SO2 concentration 84 mg/L, and substrate ratio 1:4. After 7 d fermentation under these conditions, the alcohol concentration was 12.7%. A total of 39 volatile compounds were identified in the wine by gas chromatography-mass spectrometry (GC-MS), including 15 alcohols, 15 esters, 5 acids and 2 terpenes. Based on their odor activity value (OAV), 12 volatile compounds were identified as the major characteristic aromas including β-damascenone, ethyl caproate, ethyl caprylate, isoamyl acetate, ethyl caprate. Conclusion: Saccharified glutinous rice juice can be used as an exogenous sugar source to improve the alcohol concentration of red globe wine, and the wine has a good taste and typical wine flavor.

Key words: co-fermentation, glutinous rice, red globe wine, process optimization, odor activity value