Comparative Study on the Effect of Apple Polysaccharide and Yam Polysaccharide on Yoghurt Quality

通过研究乳清沉淀率、粘度、水含量和可滴定酸度，比较苹果多糖和山药多糖在室温和低温储存期间对乳酸菌发酵和酸奶质量的影响。结果表明：当在酸奶中分别加入0、0.4%、0.8%、1.2%、1.6%、2.0%的苹果和山药多糖时，苹果多糖的添加量在0.8%时，乳清的析出率最低，山药多糖的添加量在1.2%时，乳清析出率最低。其他指标均在多糖含量为1.2%时达到峰值，对比两种多糖同时为1.2%时，山药多糖对酸奶乳酸菌落数的结果优于苹果多糖，加入苹果多糖酸奶持水率为79%，加入山药多糖酸奶持水率为81%，对酸奶酸度的影响山药多糖也高于苹果多糖。综合分析得出，添加适量的苹果多糖和山药多糖在一定程度上可以延长酸奶保质期，在冷藏保存下酸奶保质期更长。The effects of apple polysaccharides and yam polysaccharides on lactobacillus fermentation and yoghurt quality during storage at room temperature and low temperature were compared by measuring whey precipitation rate, viscosity, water content and titratable acidity. The results showed that when 0, 0.4%, 0.8%, 1.2%, 1.6% and 2.0% apple polysaccharide and yam polysaccharide were added into yogurt, the whey precipitation rate was the lowest when apple polysaccharide was added at 0.8%, and the whey precipitation rate was the lowest when yam polysaccharide was added at 1.2%. The other indexes reached the peak when the polysaccharide content was 1.2%. When the two kinds of polysaccharides were 1.2% at the same time, the results of yam polysaccharide on the number of lactic acid bacteria in yogurt were better than apple polysaccharide, and the water retention rate of apple polysaccharide yogurt was 79%, and that of yam polysaccharide yogurt was 81%. The influence of Yam polysaccharide on the acidity of yogurt was also higher than apple polysaccharide. The results showed that adding apple polysaccharide and yam polysaccharide could prolong the shelf life of yogurt to a certain extent, and the shelf life of yogurt was longer under cold storage.