Abstract: Objective: To make good use of onion and prepare palatable and healthy onion wine. Methods: Onion was used as the raw material and three pre-treatment methods were applied to treat onion. Response surface methodology was used to optimize fermentation parameters for the production of onion wine. Results: Onion wine was palatable when onion was subjected to microwave treatment at 539 W power for 20 min. The optimal fermentation parameters were fermentation temperature of 25.3 ℃, yeast bacillus inoculation amount of 0.84% and fermentation time of 48.36 h. Under the optimal conditions, the alcohol content of onion wine was 9.7% and the extraction rate of flavonoids from onion wine was 65.12%. Multivariate regression analysis showed that established regression models for alcohol content or extraction rate of flavonoids  as a function of fermentation temperature, yeast bacillus inoculation amount and fermentation time were both remarkable, which could be used for practical prediction. Conclusion: Microwave pre-treatment can effectively remove the unpleasant aroma in onion and the optimized fermentation conditions for producing onion wine are reliable.

Key words: onion wine, pretreatment, alcohol content, extraction rate of flavonoids, response surface methodology