自然发酵肉制品中乳酸菌的体外降胆固醇特性

为筛选出具有高效降胆固醇作用的乳酸菌，以自然发酵肉制品中分离出的13株乳酸菌为实验对象，采用邻苯二甲醛法对其体外降胆固醇能力进行测定，并对其中2株菌（M12、M23）的作用机理进行初步探讨。结果表明，2株菌均通过同化吸收和共沉淀作用协同降低培养基中的胆固醇；添加0.3 g/100 mL胆盐可极显著增加菌体对胆固醇的去除作用（P＜0.01），去除率分别为56.05%和58.49%；添加胆固醇和胆盐均可显著提高菌株经超声波处理后的存活率（P＜0.05），存活率分别为32.09%和37.93%；2株菌的热灭活菌体和休眠菌体也具有一定的胆固醇去除能力，且休眠菌体的去除率高于热灭活菌体。经16S rRNA序列分析，菌株M12为弯曲乳杆菌（Lactobacillus curvatus），菌株M23为戊糖片球菌（Pediococcus pentosaceus）。

Cholesterol-degrading characteristics of lactic acid bacteria from natural fermented meat products in vitro

In order to screen the strains with high effective cholesterol-degrading capability, a total of 13 strains of lactic acid bacteria were isolated from naturally fermented meat products, and the in vitro cholesterol-degrading capability was determined by o-phtshalaldehyde method. The action mechanism of 2 strains (M12 and M23) was discussed preliminarily. The results showed that the 2 strains (M12 and M23) were synergistic to reduce the cholesterol in the medium by assimilation absorption and coprecipitation. The addition of bile salts 0.3 g/100 ml could significantly increase the removal effect of strains on cholesterol (P＜0.01), the removal rates were 56.05% and 58.49%, respectively. Adding cholesterol and bile salts could both significantly improve the survival rate of strains treated by ultrasonic wave (P＜0.05), and the survival rates were 32.09% and 37.93%, respectively. The thermal inactivated cells and dormant cells of strains M12 and M23 also had certain cholesterol removal capability, and the cholesterol removal rate of dormant cells was higher than that of thermal inactivated cells. By 16S rRNA sequence analysis, strains M12 and M23 were identified as Lactobacillus curvatus and Pediococcus pentosaceus, respectively.