Study On The Effect And Mechanism Of Kelp Dietery Fiber In Reducing Fat And Losing Weight

Kelp farming was one of the pillar industries in China and wasted due to under-utilization,which resulted in environmental pollution and economic losses.Therefore,this study extracted soluble kelp dietary fiber(SDF)from waste kelp residue by alkaline hydrolysis process optimization for the first time.We studied physical and chemical properties research,weight loss and lipid reduction efficacy exploration,molecular mechanism discover and intestinal flora influence.The main research contents were as follows.(1)The production process included decalcification and alkali hydrolysis of kelp residue.Based on the amount of calcium as a reference,the decalcification process was studied by single factor experiment test method,the results showed that the decalcification material-liquid ratio was 1:30,temperature was 70 ?,time was 7h,sodium chloride concentration was 5%,and final average calcium content of kelp residue was 0.0209 g / kg;Based on the yield of SDF,the alkaline hydrolysis process was studied by response surface comprehensive analysis method,the results showed that the alkaline hydrolysis temperature was 90 ?,material-liquid ratio was 1:28.90,time was 355.60 min,pH was12.70,the average yield was 15.24% and SDF content was about 82.41%.Compared with the enzymatic hydrolysis method,the method had simple production operation and low cost.(2)By studying the physical and chemical properties of SDF,the results showed that the solubility of SDF increased with the increased of temperature and pH,the viscosity increased with the increased of concentration,increased firstly and then decreased with the increase of pH.It was a polysaccharide polymer with many folds microscopic surfaces.The average water retention rate was 6.00mL/g,oil retention rate was 1.70mL/g,swelling degree was 9.80mL/g,glucose average adsorption rate was 24.70mmol/g,cholesterol average adsorption rate was 5.07 mg/g at pH 7 and 2.42 mg/g at pH 2,the molecular weight 73.50% was distributed from 31519 to 54000.Water and oil holding capacity could motivate intestinal motility,loose stools,reduce the absorption of glucose and cholesterol.So,it had the functions of losing weight and protecting intestinal health.(3)In this study,SDF was fed daily to obese ob/ob mice to study the effect of reducing fat and losing weight: the results showed that their body weight significantly reduced after 3 weeks,TG,TC,FFA,LDL-C and HLD-C of serum increased by detecting serum,insulin levels,insulin resistance index HOMA-IR reduced significantly,fat cell size decreased,fatty liver improved effectively.So,the SDF could significantly improve blood lipid level,insulin resistance and fat accumulation,which demonstrated that SDF had a good effect on improving obesity.(4)The molecular mechanism of SDF reduced weight was used real-time fluorescence quantification PCR and Western blot,the results showed that in SDF group,the expression of triglyceride synthase(FAS and ACC1),inflammatory factors(MCP-1,TNF-?,NF-?B,IL-6 and IL-1?)had reduced,the expression of triglyceride hydrolase(PKA,HSL,ATGL),adiponectin(ADI),insulin and glucose receptors(IR,p-irs-1 and GLUT4)and insulin resistance negative correlation index(PPAR?)had elevated.(5)The effect of SDF on the intestinal flora of mice was studied by using the stool of mice for 16 S detection.The results of LEfSe analysis showed that SDF could increase the beneficial bacteria such as Butyricicoccus,Akkermansia,Parabacteroide,Parasutterella and Bacteroides acidifaciens in the intestine.The results of Alpha and Beta diversity analysis showed that SDF could increase the diversity of mice flora,and reduce the differences between OTUs composed of intestinal flora and normal mice compared with the model negative control group.In summary,the SDF extracted from waste kelp residue for first time used alkaline hydrolysis,with major molecular weight of 31519 ? 54000.There were many advantages,such as regulating lipid metabolism and improving intestinal flora significantly.So the study had very broad prospects in the development of medical specialty foods.