酸牦牛乳中乳酸菌降胆固醇作用及胆盐耐受性研究

为了从分离自甘肃酸牦牛乳中的23株乳酸菌中筛选能够同时降低胆固醇并耐受胆盐的乳酸菌,通过邻苯二甲醛法测定降胆固醇能力,并比较各菌株对三种形式的胆盐:牛胆汁、胆酸、甘胆酸钠的耐受性。结果表明,这些菌株在不同条件下的降胆固醇能力差异显著(P<0.05),多数菌株在不含牛胆汁的培养基中培养比添加牛胆汁时有着更好的对胆固醇的去除能力;死菌体对胆固醇的去除能力较弱;对各菌株对不同形式的胆盐耐受能力比较分析得出,各种形式的胆盐对乳酸菌的生长均有抑制作用,抑制顺序由强到弱依次为:甘胆酸钠>胆酸>牛胆汁;各菌株对胆盐的耐受力与降胆固醇能力没有相关性。通过比较选择出H1,I10和W2三株菌,作为功能性菌株为开发应用进行深入研究。

Cholesterol removing ability and bile tolerance of lactic acid bacteria isolated from fermented yak milk

In order to screen the strains with cholesterol assimilating ability and bile tolerance,23 strains of lactic acid bacteria isolated from fermented yak milk of Gansu Province were examined.The cholesterol assimilating ability of strains was determined by o-phthalaldehyde,and the tolerance of all the strains to three kinds of bile which were oxgall,cholic acid and sodium glycocholate were also examined.Results showed that all strains had significant varied capabilities to remove the cholesterol in vitro(P<0.05).The ability of cholesterol assimilation of most of the strains cultured in the media with oxgall was better than those without.The heat killed cells of strains assimilated less cholesterol than the normal ones.All types of bile salts could inhibit the growth of strains,the most powerful of which was sodium glycocholate,bile acid took the second place,oxgall was the weakest.And there was no relationship between bile salts tolerance and cholesterol assimilation of all the strains.Finally,it was found that the strains of H1,I10,and W2 had better cholesterol assimilating ability and bile tolerance among all the strains,indicating that these strains may be promising candidates for use as a dietary adjunct to lower serum cholesterol in vivo.