乳酸菌发酵驼乳工艺优化及抑制α-淀粉酶和α-葡萄糖苷酶活性的研究

[目的]以实验室前期从驼乳中分离得到的乳明串珠菌、副干酪乳杆菌为对象,并通过体外实验对发酵驼乳抑制α-淀粉酶和α-葡萄糖苷酶活性以及抗氧化能力进行测定。[方法]以α-淀粉酶抑制率和α-葡萄糖苷酶抑制率为考察指标,在单因素试验的基础上,采用正交试验优化发酵驼乳的参数条件。测定在不同储藏时间下试验组乳明串珠菌、副干酪乳杆菌发酵驼乳、对照组乳明串珠菌、副干酪乳杆菌发酵牛乳和嗜热链球菌、保加利亚乳杆菌发酵驼乳pH值、酸度、活菌数、α-淀粉酶抑制率、α-葡萄糖苷酶抑制率、羟自由基和超氧阴离子自由基清除率的变化。[结果]驼乳发酵的最佳工艺条件为乳明串珠菌∶副干酪乳杆菌比例2∶3、接种量2%、发酵温度39 ℃,发酵时间24 h,此条件下测得对α-淀粉酶和α-葡萄糖苷酶的抑制率分别达到87.20%和20.85%,与未优化前相比,α-淀粉酶的抑制率提高14.10%,α-葡萄糖苷酶抑制率提高4.4%。在4 ℃储藏期间发酵驼乳α-淀粉酶抑制率在第6d时最高为90.39%,对α-葡萄糖苷酶的抑制率最高为36.32%,抑制率显著高于对照组。各组对羟自由基的清除率达到70%以上,最高为94.91%,超氧阴离子自由基清除率最高达到78.10%,整个测定过程中试验组的抗氧化活性均显著高于对照组。[结论]经乳酸菌发酵驼乳抑制α-淀粉酶和α-葡萄糖苷酶活性提高,在储藏期间抗氧化活性显著高于对照组（P<0.05）。

Process Optimization and Inhibition of Alpha-amylase and Alpha-glucosidase Activities in Camel Milk Fermentation by Lactic acid bacteria

[Objective] To determine the inhibition of α-amylase and α-glucosidase activities and antioxidant capacity of fermented camel milk by in vitro experiments using Lactobacillus lactis and Lactobacillus paracasei isolated from camel milk in the pre-laboratory stage. [Methods] The inhibition rates of α-amylase and α-glucosidase were used as indicators to optimize the parameters of fermented camel milk based on a single-factor test using an orthogonal test. The changes of pH,acidity,viable bacteria,α-amylase inhibition rate,α-glucosidase inhibition rate,hydroxyl radical and superoxide anion radical scavenging rate of fermented camel milk by Lactobacillus lactis and Lactobacillus parviflorus in the experimental group,Lactobacillus lactis and Lactobacillus parviflorus in the control group,and Streptococcus thermophilus and Lactobacillus bulgaricus in the fermented camel milk were measured under different storage times. [Results] The results showed that the optimum process conditions for camel milk fermentation were 2：3 ratio of Lactobacillus lactis：Lactobacillus paracasei,2% inoculum,39 ℃ fermentation temperature and 24 h fermentation time, and the inhibition rates of α-amylase and α-glucosidase were 87.20% and 20.85% respectively. The inhibition rates of α-amylase and α-glucosidase were increased by 14.10% and 4.4% respectively compared to the pre-optimisation period. The inhibition rate of α-amylase and α-glucosidase in fermented camel milk was 90.39% and 36.32% on the 6th day of storage at 4 ℃,which was significantly higher than that of control group. The scavenging rate of hydroxyl radicals in all groups reached more than 70%,with the highest being 94.91%,and the scavenging rate of superoxide anion radicals reached 78.10%. The antioxidant activities of the experimental group were significantly higher than those of the control group throughout the whole assay. [Conclusion]Lactobacillus fermented camel milk inhibited α-amylase and α-glucosidase activity and had significantly higher antioxidant activity during storage than the control group（P<0.05）