Preliminary Exploration Of Mechanisms For The Cholesterol-lowering Effects Of Lactobacillus Fermentum ZJUIDS06 And Lactobacillus Plantarum ZY08 And The Application In Monterey Jack Cheese

High level of Low-Density Lipoprotein Cholesterol of serum lipids is one of the important factors leading to Atherosclerosis and other cardiovascular diseases.Commercial cholesterol-lowering drugs reduce the serum lipid levels of LDL-cholesterol,but may result in varieties of adverse side effects.The application of probiotics with cholesterol-lowering characteristics has become increasingly popular over the past few decades due to their generally recognized as safe(GRAS)status and their contribution to the healthy microbiota of human mucosal surfaces.The objectives of this study were to investigate the cholesterol-lowering effect of Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08,preliminarily explore the mechanisms underlying the cholesterol-lowering effect,and to apply probiotics on cheese products.In this study,golden hamsters fed with high cholesterol diet were selected as the animal model,and lyophilized Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08 were orally administered individually for 8 weeks.The physiological characteristics of golden hamsters and short chain fatty acid(SCFA)in the colon were assessed by automatic Biochemical Analyzer and gas choromatograph,respectively.A Mi Seq sequencing-based analysis of the bacterial 16S r DNA gene(V3-V4 region)in the cecum content was performed to analyze the cecum microbiota.Correlations between sets of these variables were also investigated using the R package�corrplot�.Neither Lactobacillus fermentum ZJUIDS06 nor Lactobacillus plantarum ZY08 inhibited body weight increase.However,supplementation with Lactobacillus fermentum ZJUIDS06 for 8 weeks increased acetic acid,propionic acid,and butyric acid by 1.06,0.13,and 0.10 mmol/L,respectively,decreased serum low-density lipoprotein,total cholesterol,and triglycerides levels by 1.97 mg/d L,0.99mmol/L,and 3.21 mmol/L,respectively,and also altered the microbiota of golden hamsters fed with high cholesterol diet.Remarkably,oral delivery of Lactobacillus fermentum ZJUIDS06 increased the relative abundance of Parabacteroides in the cecum,which served as a biomarker for colon SCFA production and improvement of serum cholesterol levels.The influence of probiotics addition on cheese quality was further studied.Lactobacillus fermentum ZJUIDS06 or Lactobacillus plantarum ZY08 were used as co-starter to produce Monterey Jack cheese by co-fermentation.Cell counts of probiotics in the cheese with Lactobacillus fermentum ZJUIDS06 and Lactobacillus plantarum ZY08 were above 10~6CFU/g at ripening stage.Lactobacillus fermentum ZJUIDS06 reduced the cholesterol content per 100g cheese fat by 19.98 mg(P<0.05).Addition of probiotics did not affect the composition,functional characteristics,texture,flavor,degree of proteolysis and other quality characteristics.These results indicated that the cheese was a good carrier of probiotics,and the probiotics had no adverse effect on the quality of cheese.In conclusion,Lactobacillus fermentum ZJUIDS06 reduced the serum lipid in golden hamsters fed with high cholesterol diet,which may correlate to the increase in short chain fatty acid levels and relative abundance of Parabacteroides.MJ cheese was a good carrier of probiotics.Addition of Lactobacillus fermentum ZJUIDS06reduced the cholesterol content of the cheese without negative effect on cheese quality.All these indicate the potential use of Lactobacillus fermentum ZJUIDS06 in functional foods that can help lower cholesterol.