Optimization of Bottling Fermentation Process of Draft Huangjiu by Response Surface Methodology

In order to increase the sensory evaluation score of bottling fermentation draft Huangjiu indicated by the national judges and young students, six factors of the fermentation (initial brix, water bath sterilization time, liquid filling amount, fermentation temperature, fermentation time, inoculation amount) were analyzed by Plackett-Burman tests in which three significant factors were screened as initial brix, fermentation temperature and time. Then the reasonable range of factors was determined by the steepest ascent method, and optimized by central composite design response surface test. The model was significant and therefore provided a good fit to the actual data and predicted responses. The results showed that the optimal initial brix, fermentation time, temperature, filling volume, 95 ℃ water bath and inoculum volume were 126 g/L, 20.5 ℃, 69.2 h , 195 mL, 2.5 h, 10 mL, respectively. Under the optimal conditions, the sensory evaluation score of bottling fermentation draft Huangjiu reached 96.6, which was better than that before tests.