抗氧化乳酸菌的筛选及其发酵条件优化

Screening of antioxidative lactic acid bacteria and its fermenting condition optimization

以受试菌株DPPH清除能力为指标,筛选出一株具有较高清除自由基水平的嗜酸乳杆菌,并从多个方面对其发酵培养基和培养条件进行优化。发酵培养基最佳配比为葡萄糖2.5%,蛋白胨∶牛肉膏=1∶1,乳糖1%,豆芽汁12.5%(其余同MRS培养基);最适发酵条件为接种量3%,起始pH值6.4,发酵温度37℃,发酵时间18 h。经优化后,菌株DPPH清除率由37%增至(66.70±0.42)%左右,清除羟自由基的能力由(19.60±0.99)%提高至(33.30±1.84)%,还原能力由(105.75±1.34)%增至(159.50±22.20)%,抗氧化抑制力由(11.7±0.57)%增高至(17.35±1.06)%。

This experiment is aimed to screen a Laetobacillus acidophilus, which is capable of scavenging DPPH free radical, and optimize its medium and fermenting conditions from many aspects . The study showed that 2.5% of glucose, peptone ： beef extract of 1 ： 1,1% of lactose, juice of beansprout of 12.5% （the others are the same to MRS）. After optimizing,the bacteria＇s ability to scavenge DPPH free radical increases from about 37% to （66.70 ± 0.42）% , and the ability to reduce increases from （19.60 ±0.99）% to （33.30 ± 1.84）%, the ability to inhibit lipid peroxidation increases from （11.7 ±0.57）% to （17.35±1.06）%.