短乳杆菌发酵苹果汁工艺优化及有机酸变化

Optimization of fermentation process of apple juice by Lactobacillus brevis and its organic acids changes

该研究利用短乳杆菌发酵苹果汁,生产能够调节人体肠道功能的乳酸菌苹果汁。通过单因素实验确定最适碳源、氮源以及缓冲因子;并以总酸、还原糖的变化为依据,进行响应面优化,确定最适发酵工艺条件,采用高效液相色谱法测定苹果汁发酵过程中有机酸组成及含量变化。结果表明,优化后发酵苹果汁的最佳培养基条件为:葡萄糖质量浓度50 g/L,蛋白胨质量浓度9 g/L,K 2HPO 4质量浓度4 g/L;菌种接种量为8%,发酵温度为36℃,发酵时间为6 d。在该条件下测得苹果汁的总酸为2.61 g/100 g、还原糖为5.027 g/100 g;经短乳杆菌发酵后苹果汁的品质明显优于发酵前。发酵后乳酸、富马酸、乙酸、奎宁酸含量显著增多;苹果酸、琥珀酸含量均持续减少,酒石酸含量无明显变化。

In this study,Lactobacillus brevis was used to produce novel apple juice product.The optimized carbon source,nitrogen source and buffer factor were determined by single factor experiment.Based on the change of total acid and reducing sugar,the response surface methodology was used to optimize fermentation conditions.High performance liquid chromatography was used to determine the composition and content of organic acids in apple juice product.The results showed that the optimal medium for Lactobacillus brevis fermented apple juice were:50 g/L of glucose,9 g/L of peptone and 4 g/L of K 2HPO 4.Besides,the inoculation amount of Lactobacillus brevis was 8%at 36℃,and the fermentation time was 6 d.In above conditions,the total acid and reducing sugar of apple juice was 2.61 g/100 g and 5.027 g/100 g respectively.After fermentation treatment,the quality of apple juice superior to the control sample.Lactic acid,fumaric acid,acetic acid and quinic acid content increased significantly after fermentation treatment accompanied by malic acid and succinic acid marked decreased,while tartaric acid did not change.