在单因素实验的基础上结合Plackett-Burman设计法和响应面分析法对格瓦斯发酵条件进行优化。利用Plackett-Burman设计法从原料汁比例、菌种比(酵母菌∶乳酸菌)、接种量、发酵时间、发酵温度中筛选出对格瓦斯品质影响最重要的因素。研究结果表明,原料汁比例、接种量、菌种比是影响格瓦斯品质最重要的3个因素;再利用最陡爬坡实验及Box-behnken设计进一步优化发酵条件,优化后的发酵工艺参数为:玉米汁含量24.5%、安琪酵母与瑞士乳杆菌比例2.5∶1、接种量5.0%、发酵时间22 h。发酵温度37℃。采用优化发酵条件制得的格瓦斯饮料的滴定酸度为28.5°T、乙醇体积分数为1.6%。

The method of Plackett-Burman design and response surface analysis based on the results of one-factor experiments was used to optimize the Kvass fermentation conditions. First,three factors that have an important impact on the Kvass quality were selected from material ratio,proportion of yeast and lactic acid bacteria,inoculum size,fermentation time and fermentation temperature with the Plackett-Burman design. The results showed that material ratio, proportion of yeast and lactic acid bacteria,inoculum concentration were the factors that had important impact on the Kvass quality. Then,the steepest climbing test and Box-behnken design were used to further optimize the conditions. The finial determined conditions were as follows: maize content of 24. 5%,strain ratio of Lactobacillus helveticus and Anqi yeast 2. 5∶ 1,inoculum concentration 5. 0%,fermentation time 22h,fermentation temperature at 37℃. The titritable acidity and concentration of alcohol of the kvass sample under optimized fermentation conditions were 28. 5°T and 1. 6%,respectively.