不同贮藏温度对常见低温酸奶品质的影响

Effects of Different Storage Temperatures on Common Low-temperature Yogurt Quality

[目的]探究不同贮藏温度对4种常见低温酸奶品质的影响。[方法]以4种苏州地区常见低温酸奶为研究对象,在不同恒定贮藏温度(4℃、28℃)及温度波动(37℃、4 h、2次)情况下,测定酸奶酸度、pH值、持水性、乳酸菌、霉菌和酵母菌变化趋势。[结果]保存温度为4℃时,酸奶各项品质指标较好,28℃存储后,乳酸菌数快速增加,酸度升高更明显;且模拟冷链断裂(37℃、4 h)当天,酸度明显升高,乳酸菌数量有快速增加趋势。此外,试验期内未检测到霉菌和酵母菌,说明只要酸奶生产过程未污染霉菌和酵母菌,温度升高不会造成霉菌和酵母菌数量超标。[结论]贮藏温度对低温酸奶的酸度、pH值和乳酸菌数有明显影响,为保证酸奶品质,应加强生产过程的污染控制及贮运过程中的温度控制。

[Objective]This study aimed to investigate the effects of different storage temperatures on four kinds of common low-temperature yogurt quality.[Method]Four kinds of common low-temperature storage yogurts in Suzhou district were taken to study here.The variation trend of acidity,pH value,water holding capacity,the quantities of lactic acid bacteria,mold and yeast of yogurt under different constant storage temperatures(4℃and 28℃)and temperature fluctuations(37℃,4 h;2 times)were determined.[Result]The quality indexes of yogurt was good when storage temperature was 4℃.After storage at 28℃,the quantity of lactic acid bacteria increased rapidly,while the acidity increased more obviously.On the day of simulated cold chain break(37℃,4 h),the acidity of yogurt would obviously increased,and the quantity of lactic acid bacteria would also have a rapid increment trend.In addition,no mold/yeast was detected during the test,indicating that as long as no mold/yeast was contaminated during the yogurt production process,the increase of storage temperature would not induce the amount of mold/yeast to exceed the national standard.[Conclusion]The storage temperatures have significant influence on acidity,pH value,and the quantities of lactic acid bacteria.In order to ensure the quality of yogurt,the manufacturers should strengthen pollution control in the production process,and temperature control in the storage and transportation process.