Study Of Biologicai Characteristics、functional Mechanism Of Cholesterol-lowering Lactobacillus And Its Application In Fermented Sausage

To screen out eight potential strains used as starter culltures for fermented sausage from native Inner Mongolia sausage, identify the strains and study the cholesterol removal performance, the strain with better performance for further study. Safety assessment, effect of Lactobacillus on cholesterol levels in cholesterol-administered rats. Moreover, after producing mutton dry fermented sausage by selected strains, physiochemical and cholesterol content of fermented sausage under processing and storage conditions were tested.The results showed that:L.planturam X3-2B has the best ability of removal cholesterol of eight screened strains. Fermentation performance and cholesterol removal performance of L.planturam X3-2B was better in the culture of simulating conditions of sausage. L.planturam X3-2B has better cholesterol removal performance when inoculums size was 2%、salt and glucose content was 2%、pH was 5 or 5.5、temperature 30℃. Total organic acids content increased significantly after cultivation for 24 and 48 hours, content of lactic acid, ascorbic acid and malic acid were more than other organic acid. The relative quantitative expression of BSH was highest after fermented 12 hours, membrane permeability of L.planturam X3-2B was better than standard bacteria, L.planturam X3-2B are more likely to removal cholesterol by cell membrane.Evaluate the acute oral toxicity of these strains to mice, and also to investigate bacterial translocation in mice fed L.planturam X3-2B for 14 consecutive days. Results showed that L.planturam X3-2B had no adverse effect on general health status. No viable bacteria were recovered from blood and tissue samples of mice, and no treatment-associated illness or death was observed, intestinal villus length of duodenal was longer than the colon, significantly longer than the cecum (p< 0.05), intestinal villus length of duodenum and cecum which fed L.planturam X3-2B were higher than the control group. Intestinal wall thickness of colon was thicker than cecum and thicker than duodenum and intestinal wall thickness of duodenum and colon which fed L.planturam X3-2B were lower than the control group. Serum cholesterol levels and organic levels were significantly influenced by L.planturam X3-2B, and strain increasing faecal TC,TG and TBA content. We found that inclusion of L.planturam X3-2B in the diet decreased serum TC,TG and TBA and ameliorating the effect of fatty liver. Bile acid content in the colon was higher than the ileum and TBA content of colon of high fat group was higher other groups. Serum lipid levels and liver lipid levels have certain relevance.Mutton dry fermented sausage was produced by L.planturam X3-2B(LP group) or the standand L.planturam(CLP group), with the products without LAB starter culture as control group. Viable count of lactobacilli and total plate count in LP and CLP groups were significantly higher than that of control group during processing and storage of mutton dry fermented sausage. pH value, Aw, nitrite content and TVB-N of trial groups were significantly lower than those of control group. But their texture and color were significantly higher than control group(P<0.05). Free fatty acid content of LP and CLP groups were higher than that of control group, cholesterol content during processing and storage of mutton dry fermented sausage was decreasing, while the control group had no significant change. The relative quantitative expression of BSH genes of LP group was higher than CLP group, higher than control group. There was a positive correlation (p<0.01) between relative quantitative expression of BSH genes in vitro and cholesterol content in sausage, there was a negative correlation between number of lactic acid bacteria in sausage and quantitative expression of BSH genes in vitro (p<0.01) and cholesterol content in sausage(p<0.05).