Comparison Of Intestinal Glycolysis Characteristics Of Different Pectins And Their Enzymolysis Products In Vitro

In recent years,polysaccharides as dietary prebiotics have received special attention.Pectin is a plant cell wall polysaccharide that can be fermented by the gut microbiota and has probiotic effects by producing short-chain fatty acids and regulating the intestinal microbiota,maintaining and enhancing host health.According to the report,not only the fermentation characteristics of different types of pectin are different,but also the pectic oligosaccharides have better fermentation characteristics than the parent pectin,therefore,in this paper,sunflower stalk core,apple,orange peel,hawthorn and okra as raw materials,the original pectins were extracted with acid extract and alcohol sink from them,and enzymolysis products were further prepared by pectinase,the chemical composition,structural characterization and in vitro fermentation characteristics of pectins were compared and analyzed,aiming to provide new insights into the structure-activity relationship between pectin structure and pectin regulating intestinal glycolysis,and lay a research foundation for expanding the application of pectin in food processing.The main results are as follows:1)The chemical composition and structural characteristics of five pectins and their enzymolysis products were systematically studied.The results showed that they had higher sugar content(>74%),lower protein(<5%)and polyphenols(<5%)content,indicating that the extracted pectins had good purity.High performance liquid chromatography showed that the original pectins had a high molecular weight(46.6-3477.8 k Da),which were significantly reduced after enzymatic degradation by pectinase,but the functional group composition of pectins were not changed.In addition,the glucuronic acid content of them were above 30%,and the esterification degree were less than 50%,indicating that they belonged to low methoxy pectin.2)The results of simulated human intestinal fermentation in vitro showed that p H of all pectins decreased during the fermentation process,which was significantly lower than that of the blank group,which might be related to the production of short-chain fatty acids by pectin fermentation.With the prolongation of fermentation time,the main peak of pectins and inulin shifted to the lower molecular weight region,indicating that they were degraded,indicating that pectins could be digested and utilized by intestinal microorganisms,which was consistent with the total sugar and uronic acid content;The concentration of short-chain fatty acids of all pectins increased,after 48 h of fermentation,the concentration of total short-chain fatty acids of them were higher than that of blank group(≥1.23 times),indicating that these pectins have potential as intestinal prebiotics.3)The changes of intestinal flora before and after pectin fermentation were measured by 16 S r DNA sequencing technology.The results showed that both pectins and enzymolysis products can promote the production of different beneficial bacteria after 24 h of fermentation,and enzymatic hydrolysis of pectin can promote the growth of beneficial intestinal microorganisms,inhibit the growth of potential pathogenic bacteria.Overall,the fermentation effects of apple pectin,okra pectin,enzymolysis sunflower stem core and enzymolysis okra pectin products were better.