Abstract:

With alcohol degree, reducing sugar, total acid and liquor yield as indexes, the effects of rate of material to water, inoculation amount, wheat koji amount and initial pH value on high temperature gelatinization rice wine were investigated. The fermentation condition was as following: material-water ratio 2.5:1, inoculation amount 10%, wheat koji amount 10% and initial pH 4.5. Under this condition, the alcohol degree reaches 17.1%, and reducing sugar and total acid are 23 g/L and 4.42 g/L, respectively. In order to decrease the total acid and wheat koji amount, a fed-batch feeding process was adopted. Results showed that the total acid and wheat koji amount decrease to 3.56 g/L and 7.5% respectively by using a two-stage supplement strategy, with the first supplement at 24 h and the second supplement at 36h after preliminary feeding. Regardless the different pretreated process, the results of alcohol degree, reducing sugar, total acid and yeast amount in optimized high temperature gelatinization two-stage feeding fermentation are similar to those of traditional steaming rice process. Therefore, the process for fed-batch fermentation of high temperatureα-gelatinized rice is available to be applied extensively in rice wine production.

Key words: high temperature α-gelatinization, rice wine, fermentation