植物乳杆菌和酿酒酵母发酵菠萝汁的性能比较及产物分析

采用植物乳杆菌（Lactobacillus plantarum）和酿酒酵母（Saccharomyces cerevisiae）分别进行单菌与混菌发酵菠萝汁，并比较分析不同接菌方式下菠萝汁的发酵性能及发酵体系中的产物。结果表明，相同接种量发酵72 h后，植物乳杆菌单独发酵活菌数可达108 CFU/mL，分别约为酿酒酵母单独发酵和二者混合发酵活菌数的3倍和10倍；植物乳杆菌的接入使发酵液pH降至3.21，而酿酒酵母的接入使菠萝汁中氨基酸态氮降至3.15×10-4 mg/L，糖类物质几乎被消耗殆尽。发酵产物分析结果发现，植物乳杆菌单独发酵产生大量乳酸（每升增加12.02 g/L）和少量乙酸（每升增加0.40 g/L），影响了口感，而酿酒酵母单独发酵则使菠萝汁中原有的香气物质损失较多（4种）。综合分析，采用二者混合发酵，既可保有菠萝本身的营养物质和特有香气，又可赋予其一定的发酵风味，获得口感良好的菠萝发酵饮品。

Performance comparison and products analysis of pineapple juice fermented by Lactobacillus plantarum and Saccharomyces cerevisiae

Pineapple juice was fermented by single and mixed inoculation of Lactobacillus plantarum and Saccharomyces cerevisiae, and the fermentation performances and products of fermented pineapple juice with different strains were analyzed and compared. The results indicated that after 72 h fermentation with the same inoculum, the viable count of L. plantarum was up to 108 CFU/ml, which were 3 times and 10 times of that of S. cerevisiae single strain fermentation and mixed fermentation with L. plantarum, respectively. The pH of fermentation broth inoculated with L. plantarum decreased to 3.21, while the amino acid nitrogen content of pineapple juice inoculated with S. cerevisiae decreased to 3.15×10-4 mg/L. The carbohydrates were almost exhausted in fermented pineapple juice. The analysis results of fermentation products showed that L. plantarum produced a large amount of lactic acid (increased 12.02 g/L) and a small amount of acetic acid (increased 0.40 g/L), which influenced the taste, while S. cerevisiae caused much loss of aroma substances in pineapple juice (4 kinds). Based on the comprehensive analysis, co-fermentation with L. plantarum and S. cerevisiae could not only maintain the original nutrients and special aroma but also give a certain fermented flavor and the fermented pineapple drink had good taste.