Mechanism Study Of In Vitro Fecal Fermentation Rate And Microbiota Composition Influenced By Cell Wall Integrity Of Pinto Bean

Pulse is an important part of dietary nutrition.Numerous epidemiological studies have shown that the consumption of whole pulse food can effectively increase the metabolic production of propionic acid an d butyric acid,the number of beneficial bacteria in the large intestine,and reduce the risk of obesity,inflammatory bowel disease,colon cancer and other diseases.The cell wall of pulse is still difficult to be destroyed after the digestion by human stomach and small intestine.Exploring the relationship between the cell wall integrity of pulse and fermentation rate as well as microbiota composition of gut microbiota can provide theoretical guidance for the design of the whole pulse food to meet the nutrition need of the large intestine and provide benefits for gut health.In this paper,pinto beans were used as raw materials to isolate intact cotyledon cells and obtain a series of pinto bean cells with different cell wall integrity through enzymatic treatment.After dry heat treatment(simulating baking condition),the effect of cell wall integrity differences on colorectal fermentation characteristics and microbiota were analyzed.The research was conducted as the following two aspects:Isolated intact pinto bean cotyledon cells and obtained pinto bean cells with different cell wall integrity by controlled enzymatic hydrolysis.All samples were dry-heated at 180 °C for 20 min followed by 24-hour in vitro fermentation.After analyzing the changes in cell morphology during fermentation,it was found that after treatment with cell wall degrading enzymes,the pinto bean cell surface tended to be smooth and holes appeared on the surface of the cell wall.After 24 hours of fermentation,the intact cells remained intact and the starch inside the highly damaged cells had been utilized.16 S r RNA gene sequencing and principal component analysis to study microbial changes.With the decrease of cell wall integrity,the fermentation capacity of pinto bean cells increased and all three cell samples fermented continuously during 12-24 h,and the butyric acid production increased significantly.The molar ratio of butyric acid of HDC at 24 h was 23.4%,which was higher than 19.8% of isolated starch of pinto bean.The result of 16 S r RNA gene sequencing and principal component analysis showed that pinto bean cells with lower cell wall integrity increased the abundances of Blautia and Roseburia and decreased the abundances of Fusobacterium.The in vitro fecal fermentation rate and microbiota changes of pinto bean cells with different cell wall integrity in the enterotype dominated by Bacteriodes had been investigated.We found that as the cell wall integrity decrease d,the fermentation rate increased,but the fermentation rates of pinto bean cells were still lower than starch.After 24-hour fermentation of SDC and HDC,the abundance of Firmicutes increased,while the abundance of Bacteroidetes and Fusobacteria decrease d.The change of bacteria was more closely related to the chemical components and original gut microbiota community of individuals with enterotype dominated by Bacteriodes.After fermentation of IC,the bacteria community maintained high levels of cofactors,vitamin and energy metabolism.