冷藏与冷冻贮藏条件下酸奶质量比较研究

目的]明确冷藏（4℃）贮藏与冷冻（-20℃）贮藏条件下酸奶营养质量的差别。方法]对比分析酸奶贮藏在冷藏（4℃）与冷冻（-20℃）条件下感官指标、酸度、蛋白含量和乳酸菌含量的变化。结果]第3天开始,冷冻贮藏条件下酸奶的感官指标显著好于冷藏贮藏条件下的;蛋白含量差别不显著;冷藏贮藏条件下,酸度和乳酸菌含量前期随时间延长而升高,贮藏后期逐渐降低,而冷冻贮藏条件下酸奶的酸度和乳酸菌含量基本不变化。结论]冷藏贮藏条件下的酸奶营养成分随时间延长发生了不同程度的变化,而冷冻贮藏条件下的酸奶各指标无明显变化。

Comparative Studies on the Quality of Yogurt Kept in Refrigerated and Frozen Condition

Objective] To explore the difference of nutritional quality of yogurt kept in refrigeration(4 ℃) and frozen(-20 ℃) conditions.Method] The appearances,acidity,protein content,lactic acid bacteria content of yogurt kept in refrigeration(4 ℃) and frozen(-20 ℃) conditions were compared.Result] The appearances of yogurt kept in frozen condition were significantly better than that kept in refrigeration condition from the third day.The protein content was not significantly different among the two conditions.The acidity and lactic acid bacteria content of yogurt kept in refrigeration condition were influenced by the length of time,on the contrary,that kept in frozen condition were not influenced.Conclusion] Extending storage time could lead to gradual deterioration of yogurt quality kept in refrigeration condition,no significant changes when compared with that stored in frozen condition.