西藏牦牛乳制品中高产胞外多糖乳酸菌的筛选及多糖抗氧化特性研究  

Screening of Lactic Acid Bacteria with High Producing Exopolysaccharide and Antioxidant Properties of Exopolysaccharides in Tibetan Yak Dairy Products

作　　者：王艳 郑砚学 张悦[1] 贺银凤[1] 顾悦[1] WANG Yan;ZHENG Yanxue;ZHANG Yue;HE Yinfeng;GU Yue(College of Food Science and Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China)

机构地区：[1]内蒙古农业大学食品科学与工程学院,内蒙古呼和浩特010018

出　　处：《食品科技》2022年第1期1-7,共7页Food Science and Technology

基　　金：国家自然科学基金项目(31960467);内蒙古自治区自然科学基金项目(2019BS03002)。

摘　　要：西藏地区传统牦牛乳制品由于高营养价值和丰富的生物活性物质深受消费者青睐,其中乳酸菌资源丰富且胞外多糖(Exopolysaccharide,EPS)含量高已成为分离筛选高产EPS乳酸菌的来源。采用苯酚-硫酸法对分离自西藏地区传统牦牛乳制品的50株乳酸菌产EPS的能力进行评价,筛选、鉴定高产EPS菌株,并研究目标菌株所产EPS的体外抗氧化活性。结果显示,从50株乳酸菌中筛选出3株高产EPS的乳酸菌:RJ2-1-4、TG4-1-1和TG12-1-5,产量分别为:206.875、199.457、198.57 mg/L。通过分子生物学鉴定得出RJ2-1-4和TG4-1-1为发酵乳杆菌(Lactobacillus fermentum),TG12-1-5为粪肠球菌(Enterococcus faecium)。体外抗氧化试验结果表明,3株菌所产EPS均具有一定的总还原能力以及对羟基自由基、DPPH自由基、ABTS自由基的清除能力;其中菌株TG4-1-1的EPS浓度为12 mg/mL时,总还原能力为54.51%,对OH、DPPH和ABTS 3种自由基的清除率分别为52.57%、58.40%、68.21%,均显著高于同浓度下其他菌株EPS的抗氧化活性。因此TG4-1-1所产EPS可作为潜在抗氧化剂应用于食品工业中。Traditional yak dairy products in Tibet are favored by consumers due to their high nutritional value and rich biologically active substances,among which,the abundant lactic acid bacteria resources and the high exopolysaccharide (EPS) content have become the source of isolating and screening lactic acid bacteria with high EPS yield.EPS production capacity of 50 strains of lactic acid bacteria isolated from traditional yak dairy products in Tibetan was evaluated by phenol-sulfuric acid method.The strains with high EPS production were screened and identified,and the antioxidant activity of the EPS produced by the target strains was studied.The results showed that three strains of lactic acid bacteria with high EPS yield were screened out from 50 strains:RJ2-1-4,TG4-1-1 and TG12-1-5,with yields of 206.875 mg/L,199.457 mg/L and 198.57 mg/L,respectively.Through molecular biological identification,RJ2-1-4 and TG4-1-1 were identified as Lactobacillus fermentum,and TG12-1-5 as Enterococcus faecium.The results of in vitro antioxidant test showed that the EPS produced by the three strains had certain total reducing ability and scavenging ability on hydroxyl radical,DPPH radical and ABTS radical.When the concentration of EPS of TG4-1-1 was 12 mg/mL,the total reducing ability was 54.51%,and the scavenging rates of OH,DPPH and ABTS were 52.57%,58.40% and 68.21%,respectively,which were significantly higher than the antioxidant activities of other strains at the same concentration.Therefore,the EPS produced by TG4-1-1 can be used as a potential antioxidant in the food industry.

关 键 词：乳酸菌 胞外多糖 抗氧化活性 

分 类 号：TS201.3[轻工技术与工程—食品科学]