Abstract: In order to better analyze the quality and predict the shelf life of yogurt, changes in the number of lactic acid bacteria, pH value and acidity in yogurt at different storage temperatures were analyzed, and the temperature dependence and shelf life of yogurt were studied by the combined use of kinetic analysis and the Arrhenius equation. The results showed that the number of lactic acid bacteria was maintained, and the decrease of pH value and the increase of acidity value were slowed down during storage at 9 ℃. The acidity value could well reflect the quality changes of yogurt, and the activation energy of yogurt was 67.5 kJ/mol as determined by chemical kinetics. Furthermore, a shelf-life model based on the acidity of yogurt was obtained.

Key words: yoghurt; lactic acid bacteria; pH value; acidity; kinetics; temperature dependence

摘要： 为了更好地对酸乳的品质和货架期进行分析和预测，分别对不同贮藏温度下酸乳的乳酸菌数、pH值及酸度等品质参数的变化进行分析，结合食品动力学和Arrhenius方程对酸乳的温度依赖性及货架期进行研究。结果表明：9 ℃的贮藏温度能够很好地维持酸乳中乳酸菌数量、减缓pH值的降低和酸度的上升，酸乳的酸度能很好地反映酸乳的品质变化，并且通过化学动力学研究得到酸乳的活化能为67.5 kJ/mol，同时也得到基于酸乳酸度的货架期模型。

关键词: 酸乳；乳酸菌；pH值；酸度；动力学；温度依赖性