Evaluation Of Probiotic Activity Of Banana Powder And Arabinoxylan Based On In Vitro Fermentation Of Intestinal Microbiome

There are abundant banana resources in China.As a kind of tropical fruit suitable for all ages,banana is loved by people.However,the banana is highly concentrated when it comes to market and perishable after harvest,which greatly restricts the development of banana industry.Therefore,there will be important market value by further processing bananas and then developing other functions besides fruit.Arabinoxylan is often removed as an anti-nutrient factor in animal nutrition studies and its beneficial effects on the intestinal tract have been neglected.Therefore,in order to more effectively use and develop the potential value of the banana and arabinoxylan,in this paper,from the perspective of probiotic function,the in vitro fermentation model of intestinal microorganisms and the high-throughput sequencing method of microbiome were used to investigate the probiotic activity of banana powder on human intestinal microorganisms and oat arabinoxylan on duck intestinal microorganisms.1.Banana powder's probiotic activity evaluation: Firstly,the banana powder was prepared from the banana(22.6 ± 0.2° Bé)produced in Hainan,China and its nutrient composition was determined.Secondly,six healthy adults' faeces were used to ferment banana powder in vitro,and the changes of polysaccharide content,the pH value,short-chain fatty acid(SCFA)production and intestinal microbiome in faecal fermentation broth were determined and analyzed.2.Arabinoxylan's probiotic activity evaluation: Five Beijing ducks aged 38 days were selected to ferment arabinoxylan in vitro using cecum,large intestine and small intestine chyme.Arabinoxylan degradation,the pH value,SCFA and branched-chain fatty acid(BCFA)production,and changes to intestinal microbial populations and species diversity were determined following the addition of arabinoxylan during different intestinal periods.Main results for this study are as follows:1.The nutrients in banana powder were determined.The results showed that the total sugar content of banana powder reached 64.09%,including 28.65% starch,7.02% dietary fiber,7.21% fructan,4.33% resistant starch,1.90% pectin,0.83% cellulose and 0.88% hemicellulose.2.Using banana powder as the substrate to culture human faecal microbiota for 24 hours,banana polysaccharides were gradually degraded by up to approximately 80%.And SCFA(acetate,propionate,and butyrate)was produced.Acetate was the most productive SCFA,which was three times and six times of propionate and butyrate,respectively.Changes in the human gut microbiota were assessed using high-throughput sequencing of the 16 S rRNA gene.The results showed that banana powder could regulate intestinal microbial flora,and significantly increased the relative abundance of Bacteroides(from 23.19% to 30.05%)and Bifidobacterium(from 0.63% to 2.71%)in the intestine compared with the control group.Meanwhile,the relative abundance of Lactobacillus also increased,but the difference was not significant.Eubacterium rectale,a genus associated with the production of butyrate,showed high relative abundance in faecal samples containing banana powder.3.Using arabinoxylan made from oat as the substrate to culture microbiota in duck cecum,large intestine and small intestinal chyme for 72 hours,the pH values decreased significantly in all intestinal samples.The contents of isobutyrate in the samples of cecum,large intestine and small intestine chyme increased significantly(from 0.56 mg/mL to 5.25 mg/mL,0.58 mg/mL to 1.88 mg/mL,and 0.47 mg/mL to 2.31 mg/mL,respectively),while the contents of other SCFA decreased.Gut microbiota were assessed using high-throughput sequencing of the 16 S rRNA gene,and the results indicated that compared with the control group,arabinoxylan significantly increased the relative abundance of Megamonas(from 13.9% to 63.80%,8.44% to 76.87%,6.59% to 28.07%)and Bifidobacterium(from 1.34% to 17.98%,0.09% to 1.51%,0.08% to 2.85%)in the cecum,large intestine and small intestine chyme,respectively,with Megamonas exhibiting the greatest stimulation.The results of this study suggest that banana powder and oat arabinoxylan can be used by specific intestinal bacteria and produce a certain probiotic effect,providing data support for the study of the effects of banana powder and oat arabinoxylan on the intestinal health of human and meat ducks.