Study On Composition And Microbial Metabolism Of Bound Phenolics Binding To Dietary Fibre Of Black Bean

Black beans are rich in anthocyanins,phenolic acids,flavanols and saponins and other phytochemicals with good anti-inflammatory,anti-oxidant,anti-tumor and neuroprotective effects.Epidemiology and interventional studies have shown that regular consumption of soy products,including black beans,have been negatively correlated with the occurrence of various chronic diseases such as Alzheimer's disease and diabetes.At the same time,black beans are used in traditional Chinese medicine to prevent and treat cardiovascular diseases,like atherosclerosis,high-blood lipids and estrogen metabolism-related diseases such as breast cancer,prostate cancer,and osteoporosis.Black beans have the highest phenolic compound content and antioxidant activity compared to other edible beans.Research on plant polyphenols is currently focused on free polyphenols.On the other hand,Bound Phenolics,which are linked to macromolecules such as dietary fibers via ether bonds or ester bonds,must be treated with acid,alkali or enzymatic hydrolysis,it can be released and extracted.Its existence and contribution are mostly ignored and underestimated by researchers.In fact,most of the bound polyphenols that are less efficient in digestion and release in the stomach and small intestine are transported to the colon and exert important physiological activities after being released by intestinal microbial fermentation.Studies have shown that dietary fiber is mainly used as a carrier for polyphenols to transport active bound polyphenols to the colon,thereby exerting important physiological activities.Therefore,this paper have selected black beans as the research object,systematically studied the composition of black bean dietary fiber and the composition of polyphenols in black bean dietary fiber,and uses the singlefermentation fermentation model and the human fecal intestinal bacteria outfermentation model to explore the release law of bound polyphenols of black beans.The specific results are as follows:1.The dietary fiber composition of black bean seed coat and cotyledon was analyzed by gravimetric method.The total dietary fiber content of black bean cotyledon was 18.90g/100 g and the soluble dietary fiber content was 0.44g/100 g.Insoluble dietary fiber content was 18.46g/100 g.The content of total dietary fiber inblack bean seed coat was 85.91g/100 g,the content of soluble dietary fiber was7.93g/100 g,the content of insoluble dietary fiber was 77.98g/100 g,and the ratio of IDF/SDF was 9.83.The hemicellulose content of black bean seed coat was39.73g/100 g,the cellulose content was 55.46g/100 g,the lignin content was4.81g/100 g,and the hemicellulose content of black bean cotyledon was 93.82g/.100 g,cellulose content was 6.27 g/100 g,lignin content was 0.24 g/100 g.The pectin content of black bean seed coat was 1.47±0.00g/100 g,and the pectin content of black bean cotyledon was 0.33±0.07g/100 g.Qualitative and quantitative analysis of monosaccharides in insoluble dietary fiber and soluble dietary fiber of black bean seed coat and cotyledon dietary fiber was carried out by GC-MS.Dietary fiber monosaccharides in black beans mainly include arabinose,ribose,xylose,mannose,galactose,rhamnose,and glucose.Among them,the highest content of monosaccharides in black bean seed coat insoluble dietary fiber was arabinose,followed by galactose,xylose,mannose,glucose,rhamnose,and ribose showed the lowest content;the soluble sugar fiber of black bean seed coat has the highest monosaccharide content.It was mannose,followed by galactose,arabinose,xylose,glucose,rhamnose,and ribose showed the lowest content;the highest content of monosaccharides in black bean cotyledon-insoluble dietary fiber was mannose,followed by galactose,arabinose,and xylose.Glucose and rhamnose had the lowest ribose content;the highest content of monosaccharides in soluble dietary fiber of black bean was mannose,followed by galactose,arabinose,glucose,xylose and rhamnose with ribose showed the lowest content.2.UPLC-ESI-QTOF-MS and HPLC-ESI-QQQ-MS were used to identify the combination of polyphenols combined with insoluble dietary fiber in black bean seed coat,and a tolal of 16 phenolic compounds were identified: including myricitrin,cinnamic acid-O-xylosylhexoside,shikimic hexosemalonate-carboxyl,dimer of ferulic acid,dihydrocaffeic acid hexoside,citric acid,anhydrous,hesperetin,(+)-epicatechin,2,5-dihydroxy benzoic acid,4-hydroxybenzoate,myricetin,sinapic acid,(-)-citramalic acid,DL-3-phenyllactic acid,2-isopropylmalic acid,sinapoyl malate.The black bean seed coat insoluble dietary fiber was hydrolyzed to produce 11 kinds of products by acid,namely cinnamic acid-O-xylosylhexoside,shikimic hexosemalonate-carboxyl,dimer of ferulic acid,dihydrocaffeic acidhexoside,2,5-dihydroxy benzoic acid,4-hydroxybenzoate,sinapic acid,(-)-citramalic acid,DL-3-Phenyllactic acid,2-isopropylmalic acid,sinapoyl malate;Alkaline hydrolysis gave a total of five products,namely hesperetin,(+)-epicatechin,2,5-dihydroxybenzoic acid,myricetin,sinapic acid;The feruloyl esterase hydrolyzed to form five kinds of products: anhydrous citric acid,(+)-epicatechin,2,5-dihydroxybenzoic acid,4-hydroxybenzoic acid,sinapic acid;xylanase hydrolyzed to form 6 kinds of hydrolyzed products,namely myricitrin,citric acid,anhydrous,(+)-epicatechin,2,5-dihydroxybenzoic acid,4-hydroxybenzoic acid,sinapic acid;there are3 kinds cellulase hydrolysates,which are 2,5-dihydroxybenzoic acid,4-hydroxybenzoic acid and sinapic acid;there are 4 kinds of hemicellulose hydrolysates,which are(+)-epicatechin,2,5-hydroxybenzoic acid,4-hydroxybenzoic acid,sinapic acid;4 kinds of pectinase hydrolysate,respectively(+)-epicatechin,2,5-dihydroxybenzoic acid,4-hydroxybenzoic acid,sinapic acid.Different hydrolysis treatments on the bound polyphenols,the products obtained are different in quantity and type,and the acid hydrolysis showed the highest efficiency.By further comparison,although the enzyme hydrolysis products are similar to the alkaline hydrolysis,the enzyme hydrolysis may be more effective than alkaline hydrolysis.3.UPLC-ESI-QTOF-MS and HPLC-ESI-QQQ-MS were used to characterize the extracts of the black bean seed coat and cotyledon,which were fermented with insoluble dietary fiber and polyphenols by Lactobacillus plantarum NCU116,and the short-chain fatty acid in the fermentation broth after fermentation of the bacillus was also identified by GC analysis.A total of 16 fermentation products and 2 short-chain fatty acids were identified.Among them,16 kinds of fermentation products are mainly citric acid,kaempferol-3-glucoside,DL-p-hydroxyphenyl lactic acid,kaempferol-3-rhamnoside,DL-4-hydroxy-3-methoxymandelic acid,orientin,kaempferol-3-glucuronide,2-hydroxyisohexanoic acid,D-glucuronic acid,creatine galactosyl dihydrate,chlorogenic acid hemihydrate,kaempferol-3-rhamnoside-4-rhamnoside-7-rhamnoside,p-hydroxybenzyl glucosinolate,esculinses quihydrate,isorhamnetin-3-Oglucoside and daidzin.The two short-chain fatty acids are mainly acetic acid and isobutyric acid.At the same time,in the non-inoculated control group,10 substances were identified from the extract,namely citric acid,azelaic acid,eriodictyol,4-deoxycorticoside,(2R)-2-hydroxy-2-phenylethylglucosinolate,kaempferol-3-glucuronide,hesperidin,kaempferol-3-glucoside-3-rhamnoside,quercetin-3-galactoside-6-rhamnoside-3'''-rhamnoside,kaempferol-3-rhamnoside-4-rhamnosyl-7-rhamnoside.Comparing the control group and the experimental group,it was found that the fermentation of Lactobacillus plantarum could break the glycosidic bond attached to the polyphenol,however,the effect of hydrolyzing the glycosidic bond was not strong.Among them,DL-4-hydroxy-3-methoxymandelic acid has been documented as a metabolite of polyphenols.At the same time,it was also found that the metabolites after fermentation of Lactobacillus plantarum were acetic acid and isobutyric acid,and isobutyric acid was only detected in the fermentation broth of black bean seed coat combined with polyphenols.Only acetic acid can be detected in the fermentation broth of black bean cotyledons combined with polyphenols.4.UPLC-ESI-QTOF-MS and HPLC-ESI-QQQ-MS were used to identify the extracts of black bean seed coat insoluble dietary fiber combined with polyphenols by colonic microbial fermentation.A total of 15 substances were identified,namely rosmarinic acid.Ferulic acid,sinapic acid,6,7-dihydroxycoumarin,caffeic acid-Ohexosides-O-rhamnoside,kaempferol-3-rhamnoside-4"-rhamnoside-7-Rhamnoside,azelaic acid,kumquat,kaempferol-3-galactoside-6''-rhamnoside-3'''-rhamnoside,naringenin,quercetin-3-arabinosine,Jasmonic acid,kaempferol,sinapicyl malate,kaempferol-3-rhamnosyl-7-rhamnoside.It can be seen from the different fermentation time period that there will be new with different fermentation time.The appearance of peaks and the disappearance of peaks suggest that certain phenolic components are continuously degraded by the action of intestinal microbial enzymes and may be broken down into smaller molecules that are absorbed by the body.