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A Preliminary Study On Intestinal Probiotics Of Konjac Glucomannan And Konjac Oligoglucomannan And Their Effects On Improvement Of Lactose Intolarence

Posted on:2021-01-05Degree:MasterType:Thesis
Country:ChinaCandidate:D X ZhangFull Text:PDF
GTID:2381330611464817Subject:Food Science
Abstract/Summary:PDF Full Text Request
Lactose intolerance(LI)refers to gastrointestinal symptoms related to incomplete digestion of lactose,that is,due to lack of lactase in the small intestine,lactose in milk cannot be completely decomposed and absorbed,thus entering the colon.and After being decomposed by intestinal bacteri,a large amount of shortchain fatty acids and hydrogen are produced,causing an increase in osmotic pressure and increasing the water content in the intestinal cavity,causing symptoms such as abdominal sounds,bowel sounds,abdominal cramps,and diarrhea.The mechanism of LI is still unclear.At present,some studies have shown that colon fermentation may play a role in lactose intolerance.Therefore,it is a novel and potentially useful improvement to change colon bacteria to effectively metabolize lactose in lactose intolerance.Konjac glucomannan(KGM)is a kind of water-soluble polymer polysaccharide.It is a kind of polymer of glucose and mannan which is connected by ?-1,4-glucoside bond in Konjac tuber.Konjac oligoglucomannan(KOGM)was prepared from mannose to mannose by semi dry enzymatic hydrolysis of KGM,which overcome the limitations of KGM,such as high relative molecular weight,high viscosity and low solubility.KGM and KOGM,as natural and safe food materials,can be widely used in the food industry and play a unique role in health care.Clinical research shows that KGM has the physiological effects of relieving constipation,reducing the weight of overweight and obese people,preventing diabetes,reducing the risk of cancer and so on.KGM is a good prebiotic for health.In the past decades,some studies have shown that oligosaccharides have prebiotic effects,and KOGM foods and functional foods have been listed in the US.In addition,KGM and KOGM can selectively stimulate the growth of Bifidobacterium,Lactobacillus and other beneficial bacteria and promote the production of short-chain fatty acids(SCFA).Bifidobacterium can promote the proliferation of intestinal villi epithelial cells,secrete lactase,and form a microecological cycle equilibrium system of "lactase-galactooligosaccharide-Bifidobacterium" in the intestinal tract.The three have a synergistic effect to maintain the microecological balance in the intestinal tract.Therefore,appropriate supplementation of bifidobacteria can improve the occurrence of lactose intolerance.In this paper,the effect of prebiotics on the treatment of lactose intolerance was studied.KGM and KOGM were used as raw materials to study their in vitro fermentation characteristics in fecal microflora of different populations.Furthermore,the metabolic characteristics of KGM and KOGM in mice and their effects on intestinal microflora of mice were observed.Finally,the effect of KGM and KOGM on lactose degradation was studied through in vitro fermentation experiments of feces of mice.The conclusions are as follows:(1)The study on the effect of colon fermentation on lactose intolerance showed that within the same fermentation period,there was no significant difference in the pH value of fermentation liquid between the healthy group and the intolerant group in the blank group(p > 0.05);at the 5th hour of fermentation,there was no significant difference among the groups in the concentration of acetic acid,propionic acid and butyric acid;There was no significant difference in lactate concentration between the healthy group and the lactose intolerant group at 1-3 h of fermentation(p > 0.05).After 3 h,the lactate content in the healthy group was significantly higher than that in the intolerant group.During the cultivation period,the production rate of lactic acid in the fermentation broth of the healthy group was higher than that of the lactose intolerant group,and the content of lactic acid in the healthy group was significantly higher than that of the lactose intolerant group(p < 0.05).(2)The results of the in vitro fermentation test of KGM and KOGM in the fecal flora of different subject showed that the addition of KGM and KOGM could effectively reduce the pH value of fermentation broth in healthy group and lactose intolerance group(p < 0.05),and promote the fecal fermentation of lactose intolerance group to produce more acetic acid and butyric acid.This showd that KGM and KOGM also had a prebiotic effect on lactose intolerance.(3)By measuring the lactase activity of small intestine in mice of different weeks,it was suitable to select male KM mice of 5-week-old as the object of this study.The results of animal experiments showed that KGM and KOGM had no significant effect on the body weight of mice(p > 0.05),and in a short period of time(4 weeks)did not significantly improve the activity of lactase in the small intestine of mice.However,the results showed that KGM and KOGM increased the villus height and wall thickness of ileum(p < 0.05),and decreased the crypt depth(p < 0.05).the organ index increased significantly(p < 0.05),the total hepatic sterol(T-CHO)and triglyceride(TG)contents decreased in serum and liver,and the immunoglobulin G(lg G),immunoglobulin A(lgA)and free fatty acid(FFA)values increased significantly(p < 0.05).These results suggested that KGM and KOGM could improve immunity and inhibit diseases caused by cholesterol and triglycerides,which may play a protective role in colon fermentation of lactose intolerant patients.(4)The diversity and abundance of intestinal microflora in mice were analyzed by 16 S rRNA sequencing.The results showed that the intake of drugs,KGM and KOGM significantly improved the composition and proportion of intestinal microflora in mice,which indicated that KGM and KOGM could improve the colonic fermentation by promoting the growth of intestinal beneficial microflora,thus affecting the symptoms of lactose intolerance and playing a beneficial role in the body.At the level of phylum,the dominant phylum in all samples were Firmicutes,Bacteroides and Proteobacteria,and their relative abundance in each sample was more than 80%.At genus level,KGM and KOGM significantly increased the abundance of Lactobacillus and Bifidobacterium(p < 0.05),and decreased the abundance of Bacteroides and Akkermansia(p < 0.05).(5)After 4 weeks,the intake of KGM and KOGM significantly reduced the pH value of mice feces(p < 0.05),and at the same time increased the fecal water content(p < 0.05)and fecal SCFA production(p < 0.05),especially acetic acid and butyric acid,which indicated that KGM and KOGM had a positive effect on promoting intestinal health.The results showed that the addition of KGM and KOGM in lactose accelerated the rate of pH reduction,and the pH value was the lowest.Meanwhile,the production of SCFA and the activity of lactase were significantly increased(p < 0.05).In short,KGM and KOGM intake could provide a suitable acidic environment for the body,effectively improve the metabolism of intestinal microflora in mice to produce SCFA,and promote colon fermentation.KGM and KOGM as natural and safe ingredients could increase the activity of lactase.Thus,KGM and KOGM have potential application in the development of prebiotic products for the treatment of lactose intolerance.
Keywords/Search Tags:Konjac glucomannan, Konjac oligoglucomannan, Lactose intolerance, Gut microbiota, In vitro fermentability
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