凝结芽孢杆菌发酵枸杞汁的工艺优化及主要成分变化

以宁夏枸杞干果为原料，进行凝结芽孢杆菌（Bacillus coagulans）发酵枸杞汁工艺条件优化并分析发酵期间枸杞汁主要成分的变化。以乳酸含量和感官评分为考察指标，在单因素试验的基础上进行响应面优化试验，研究不同的接种量、白砂糖添加量、发酵温度等对发酵的影响，并在最佳条件下对发酵过程中枸杞汁中总糖、黄酮类化合物、蛋白质、活菌数等成分的变化进行分析。结果表明，凝结芽孢杆菌发酵枸杞汁的优化工艺条件为接种量8%、白砂糖添加量5%、发酵温度36 ℃、转速50 r/min、发酵时间10 h。在此最佳工艺条件下，得到的发酵枸杞汁的活菌数为2.1×108 CFU/mL，感官评分为91分。枸杞汁经发酵后，赋予了产品较高的活菌数，总糖含量95.6 μg/mL，蛋白质含量0.2 μg/mL，总黄酮含量0.31 mg/mL，口感与风味得到较大提升。

Fermentation technology of goji juice by Bacillus coagulans and its major nutrients components changes

Using Ningxia dried goji fruits as raw materials, the fermentation technology of goji juice by Bacillus coagulans was optimized and changes of the major nutritional components during fermentation were analyzed. Using B. coagulans as starter, lactic acid content and sensory evaluation as the main indexes, based on the single factor experiments, the fermentation technology was optimized by response surface methodology. The effects of inoculum, sugar content and fermentation temperature were studied, under the optimal conditions, the changes of total sugar, flavonoids, protein, viable count and other components in the fermented goji juice were analyzed during fermentation. The results showed that the optimum conditions for B. coagulans fermentation were inoculum 8%, sugar 5%, fermentation temperature 36 ℃, rotation speed 50 r/min, fermentation time 10 h. Under these conditions, the viable count was 2.1×108 CFU/ml and sensory score was 91. After fermentation of goji juice, the product had higher viable count, the total sugar content decreased to 95.6 μg/ml, the protein content decreased to 0.2 μg/ml, the total flavonoids content remained 0.31 mg/ml, and the taste and flavor were greatly improved.