产GABA乳酸菌工艺优化及其产物抗氧化活性研究

Optimization of GABA-Producing Lactic Acid Bacteria Process and Study on Its AntioxidantActivity

取甘肃合作当地特色牦牛酸奶为原材料,筛选产GABA的乳酸菌,优化发酵条件,分析发酵产物的抗氧化活性,以期为GABA的微生物合成和开发利用提供参考。结果表明,从原材料中分离到的4株产GABA乳酸菌中菌株XBMU436-2产GABA含量最高, GABA含量可达1.80 g/L。在单因素试验结果基础上,采用Box-Behnken响应面分析法优化XBMU436-2的发酵条件。结果发现, MRS发酵培养基中以葡萄糖作为碳源,接种量2.5%,初始pH 6.0, L-谷氨酸钠10 g/L, 37℃培养36 h,优化后GABA含量可达4.11 g/L,产量比优化前有明显增加。发酵培养液对羟自由基、DPPH自由基和超氧阴离子的半抑制浓度分别为0.12, 0.52和0.20 mg/mL,表明GABA有很好的抗氧化能力,在延缓食品氧化变质方面具有巨大的应用潜力。

In order to provide reference for the microbial synthesis,development and utilization of GABA,lactic acid bacteria producing GABA were selected from local yak yogurt in Gansu Province.The results showed that strain XBMU436-2 of the four Gaba-producing lactic acid bacteria isolated from raw materials had the highest GABA content,with GABA content up to 1.80 g/L.On the basis of single factor test results,Box-Behnken response surface analysis was used to optimize the fermentation conditions of XBMU436-2.The results showed that in MRS Fermentation medium,glucose was used as carbon source,the inoculation amount was 2.5%,the initial pH was 6.0,L-glutamic acid sodium was 10 g/L,and the fermentation temperature was 37℃ for 36 hours.After optimization,the GABA content reached 4.11 g/L,and the yield was significantly increased compared to before optimization.The semi-inhibitory concentrations of hydroxyl radical,DPPH radical and superoxide anion in fermentation medium were 0.12,0.52 I and 0.20 mg/mL,respectively,indicating that GABA had a good antioxidant capacity and had great application potential in delaying food oxidation deterioration.