【作者】 金鑫；

【导师】 段开红； 韩秀萍；

【作者基本信息】 内蒙古农业大学 ， 发酵工程， 2008， 硕士

【摘要】 随着人们生活水平的提高,膳食摄入日渐增多,相关调查数据显示由高胆固醇血症引发的动脉粥样硬化、冠心病、脑中风等心脑血管疾病,已成为威胁人类健康的“第一杀手”。乳酸菌作为人及动物肠道中极为重要的菌群之一,与机体的许多生理功能有着密切的联系。大量的实验都表明乳酸菌在体内和体外都有降解胆固醇的作用。酸马奶酒作为一种少数民族地区传统的乳制品,保留着许多优良特性的乳酸菌资源,鉴于酸马奶酒的独特医疗保健功能,及其在分离筛选降胆固醇乳酸菌菌株的重要作用,进行了以下几个方面的研究,对采集于内蒙古锡林浩特市正蓝旗、阿巴嘎旗的9份酸马奶酒样品进行了微生物组成分析,通过传统生理生化性状分析对其中分离到的11株乳杆菌进行了属种的鉴定。从中筛选出一株体外降解胆固醇能力较强的乳杆菌,绘制了该菌株的生长曲线,并对其耐酸性,耐胆汁盐等益生特性做了初步研究。结果表明:9份酸马奶酒样品中,1份样品中乳酸菌数为2.18×108cfu/mL,其余8份样品中乳酸菌数在1.15～9.12×107cfu/mL间;9份酸马奶酒样品中,1份样品中的酵母菌数为6.68×104cfu/mL,3份样品酵母菌数在1.50～5.34×105 cfu/mL间,5份样品的酵母菌数在1.87～4.05×106cfu/mL间。11株乳杆菌分离株中,9株归为嗜酸乳杆菌(Lactobacillus acidopHilus),2株归为瑞士乳杆菌(Lactobacillus. Helveticus)。11株乳杆菌在含胆汁盐和不含胆汁盐的胆固醇筛选培养基中均有降解胆固醇的能力,但其能力的大小有所不同。在含胆汁盐的胆固醇筛选培养基中,11株菌株胆固醇的脱除率均有所降低。其中一株胆固醇脱除率为35.2%的乳杆菌在发酵4～16h为生长期,16～20h为对数生长期,20～24h为稳定期,24h后为衰亡期,具有一定的耐酸、耐胆汁盐降胆固醇的特性,可以保证一定数量的菌体到达小肠,从而发挥其作用。更多还原

【Abstract】 With improvement of people living standard, more foods were intaked. Simultaneously It was showed that cerebrovascular and heart disease, such as artherosclerosis (AS), coronary artery disease (CAD), cerebral apoplexy were more universal and was first killer for human health. Lactic acid bacteria are one of major microbial population in intestinal tract of animal and human and closely related to physiological function of boty. Lots of experiments showed that LAB has functions on Cholesterol removal ability in vivo and vitro.Koumiss was traditional fermented milk with more medical care function. So some exprements were conducted on 9 samples from Zhenlan, Abaka county, inner mongola.Biologicial characteristics and microbiological compositions of 11 samples of koumiss from Inner Mongolia were determined. 11 strains of lactibucilli were obtaind by traditional physiological and biochemical isolation and identification method, in which 2 strains was L. acidophilus and 1 strain was L. helveticus. Furthermore, one strain with high acid tolaronce and bile-acid resistance characteristic were scanned from thease strains. And that the cholesterol removal ability was conducted in vitro. The ruslts showed that the counts of lactic acid bacteria were 2.18×108 in a sample kumiss, as for the other 10 samples the counts of lactic acid bacteria were 2.49×108～2.98×109 cfu/mL. The counts of yeast were 2.60×106～1.63×108cfu/mL. Experement of acid tolerance and bile release property of this strain showed that rate of bile release by this strain was 35.2%. Namely, this strain can tolerate lower pH (2.5), high bile-acid resistance property and cholesterol removal ability.更多还原