Optimization of mixed-strain fermentation process of purple yam wine and its quality analysis

In order to improve the flavor of purple yam wine, the mixed-strain fermentation of Saccharomyces cerevisiae and Terbospora delbuispora was used to produce purple yam wine. The fermentation process of purple yam wine was optimized by single factor and orthogonal experiments with sensory score and alcohol content as evaluation indexes. Meanwhile, the effects of T. delbuispora addition on antioxidant properties, organic acids and volatile flavor components of purple yam wine were analyzed. The results showed that the optimal fermentation process of purple yam wine was as follows: S. cerevisiae inoculum 8%, T. delbuensis inoculum 4.8%, sucrose addition 20%, fermentation temperature 23 ℃, time 10 d. Under the optimized conditions, the sensory score of purple yam wine reached 92 points, the alcohol content was 10.3%vol, the total polyphenol content was 508 mg/L, and the anthocyanin content was 185 mg/L. The addition of T. delbuispora significantly increased the antioxidant capacity, organic acid content and volatile aroma components of purple yam wine. Compared with single S. cerevisiae fermentation wine, the scavenging rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion and hydroxyl free radical increased by 11.2%, 4.9% and 2.8%, respectively. The total organic acids increased by 0.52 g/L, the number of aroma components increased from 11 to 28, and the types and contents of esters and aldehydes increased. On the whole, the T. delbuispora endowed purple yam wine with more flavor substances, and improved the quality of purple yam wine to some extent.