贮藏温度对真空冻干发酵剂发酵乳杆菌grx07活性的影响

以真空冻干的发酵剂grx07为研究对象,通过测定该发酵剂在20、4、-20℃三种温度下贮藏的存活率、活菌数、水分活度、发酵活力及影响乳酸菌代谢活力的关键酶活(乳酸脱氢酶、β-半乳糖苷酶、ATP酶的酶活),来探讨不同的贮藏温度对发酵乳杆菌grx07菌粉活力的影响。结果表明,发酵剂grx07在20℃贮藏3个月时存活率低于1%;在4和-20℃保藏12个月时菌粉存活率分别为4.45%和51.05%。在-20℃贮藏12个月的活菌数仍能达到3.78×1011 cfu/g,菌粉水分活度为0.210;活化后发酵pH达到4.30,乳酸脱氢酶、β-半乳糖苷酶、ATP酶的活力分别为贮藏前酶活力的80.24%、74.60%、87.10%。因此,真空冻干发酵剂grx07长期贮藏的适宜温度为-20℃。

Effects of Storage Temperature on the Viability of Lactobacillus fermentum grx07 under Vacuum Freeze-dried Start

To investigate the effect of different storage temperatures on the viability of vacuum freeze-dried fermenting agent Lactobacillus fermentum grx07,the survival rate,viable cell count,water activity,fermentation activity and the key enzyme activities of vitality related(lactate dehydrogenase,β-galactosidase,ATPase)were measured at 20,4 and -20℃,respectively. The results showed that the three-month survival rate of starter grx07 was less than 1% at 20℃,while the survival rates was seperately 4.45% and 51.05% at 4 and -20℃ for 12 months. The number of viable cells stored at -20℃ for 12 months were still reached to 3.78×1011 cfu/g,the water activity of the powder was 0.210,and the fermentation pH was 4.30. Moreover,the activities of lactate dehydrogenase,β-galactosidase,and ATPase were separately 80.24%,74.60%,87.10% of that prior to the storage. Therefore,the suitable temperature for long-term storage of the vacuum freeze-dried starter grx07 was -20℃.