Optimization Of Fermentation Technologies And Cryoprotectants And Studies On Activities Of Probiotics

Probiotics,also known as microbial preparation,are a class of beneficial microorganisms for the body.It can promote the balance of host intestinal microbial flora and produce beneficial effects on host health.Probiotics mainly include Lactobacillus probiotics,Bifidobacterium probiotics,some Gram-positive cocci probiotics.Probiotics have a variety of functions,such as probiotics can inhibit the growth of harmful bacteria in the host intestinal tract,maintain the intestinal micro-ecological balance and promote human digestion and absorption.It has been found that probiotics also have the ability to lower cholesterol levels and promote immune function.The physiological functions of probiotics make the social demand increase,now,how to improve the number of probiotics and extend its survival time to become the main problem.In this study,four probiotics were selected to solve this problem,including L.rhamnosus BMBL0606,L.reuteri BMBL0612,L.acidophilus BMBL0618,and B.Lactis BMBL0624.The culture conditions and the medium components were optimized to obtain a higher viable count.By optimized the cryoprotectants to extend its storage time.By fed high fat mice,to explore its role in reducing blood lipids and blood glucose.1.Based on the optimization of the culture conditions and medium components,the orthogonal experiment was designed.It was determined that probiotics could obtain higher viable bacteria.1)The L.rhamnosus BMBL0606 was cultured 16 h under the conditions of oligo galactose,peptone,the ratio of carbon and nitrogen was 1:3,phosphate content of 0.4%,initial pH 7.5,37 oC,3% inoculation,the number of viable bacteria was 5.25×1014 cfu/g?2)The L.reuteri BMBL0612 was cultured 12 h under the conditions of oligo galactose,pancreatic peptone,the ratio of carbon and nitrogen was 2:1,phosphate content of 0.4%,initial p H 7.5,34 oC,3% inoculation,the number of viable bacteria was 7.8×1012 cfu/g.3)The L.acidophilus BMBL0618 was cultured 12 h under the conditions of oligo galactose,pancreatic peptone,the ratio of carbon and nitrogen was 1:3,phosphate content of 0.4%,initial p H 6.5,34 oC,3% inoculation,the number of viable bacteria was 9.2×1014 cfu/g.4)The B.Lactis BMBL06248 was cultured 16 h under the conditions of oligo galactose,soya peptone,the ratio of carbon and nitrogen was 1:3,phosphate content of 0.5%,initial pH 7.5,37 oC,4% inoculation,the number of viable bacteria was 6.4×1014 cfu/g.2.Based on the optimization of cryoprotectants to design orthogonal experiment to determine the optimal composition of cryoprotectants.By measured the number of viable bacteria in different time,the effect of cryoprotectants on probiotics was obtained.1)The optimal cryoprotectant of L.rhamnosus BMBL0606 was 1% skim milk powder,4% glycerin,4% mannitol,and 20% trehalose,the viable bacteria number was about 3.45×1014 cfu/g after six months.2)The optimal cryoprotectant of L.reuteri BMBL0612 was 10% skim milk powder,3% glycerin,8% mannitol,and 20% trehalose,the viable bacteria number was about 3.1×1012 cfu/g after six months.3)The optimal cryoprotectant of L.acidophilus BMBL0618 was 5% skim milk powder,3% glycerin,6% mannitol,and 10% trehalose,the viable bacteria number was about 4.1×1014 cfu/g after six months.4)The optimal cryoprotectant of B.Lactis BMBL0624 was 5% skim milk powder,1% glycerin,10% mannitol,and 5% trehalose,the viable bacteria number was about 2.7×1014 cfu/g after six months.3.Effects of probiotics on blood glucose and blood lipid were studied.The results showed that L.rhamnosus BMBL0606 and B.Lactis BMBL0624 can reduce the weight of mice in high fat control group.It can improve the level of triglyceride,high density lipoprotein cholesterol and total cholesterol in the experimental group.Triglyceride content in the experimental group was significantly lower than that in high fat group.High density lipoprotein cholesterol was increased and high dose group let the high density lipoprotein cholesterol reached normal level.The high dose group let total cholesterol reach the normal level.In summary,we used four probiotics as the research object,through the optimization of the culture medium and culture conditions to determine the best culture process to improve the number of bacteria.The optimization of cryoprotectants can make the powder stored for a long time.L.rhamnosus BMBL0606 and B.Lactis BMBL0624 showed a good effect on reducing blood lipids.This will provide an important scientific basis and support for the development of probiotics.