Effects Of Hydrothermal Treatment On In Vitro Fecal Fermentation Characteristics And Gut Microbiota Regulation Of Intact Pulse Cotyledon Cells

The whole food of pulse has attracted wide attention because of its rich nutrition.The starch contained in the pulse cells is wrapped by cell wall,which can resist the degradation of digestive enzymes in the stomach and small intestine well,and can be used as type 1 resistant starch into the colon for fermentation by gut microbiota.By promoting the production of shortchain fatty acids(SCFAs)and the proliferation of beneficial bacteria,the fermented pulse cotyledon cells can regulate the bacterial flora environment and intestinal health in a beneficial way,thus reducing the risk of obesity,diabetes,inflammatory bowel disease and other chronic diseases.Hydrothermal treatment is one of the common food processing methods.Exploring the regulation mechanism of hydrothermal treatment on the fermentation characteristics and gut microbiota of pulse cotyledon cells can provide certain theoretical guidance for the development of new miscellany pulse whole food and functional ingredients.The research was conducted as the following two aspects:We chose smooth peas,red kidney beans,chickpeas,white hyacinth bean,runner bean,adzuki bean,broad bean,large white kidney bean and mung beans as raw material to isolate its complete cotyledon cells.The starch content,protein content,dietary fiber content,particle size,crystallinity,morphology changes,gas production and SCFAs production were determined in this study.The results showed that the particle size of the cells was 85.1?175.0 ?m,the contents of starch,dietary fiber and protein ranged from 51.6 to 71.9%,11.6 to 25.0% and 11.5 to 22.2%,respectively.After cooking,the crystalline structure of starch in pulse cells almost disappeared.After in vitro fermentation,three kinds of pulse(broad bean,red kidney bean and mung bean)with higher protein content(>19%)were showed slower fermentation rate and higher total branched fatty acid yield.The in vitro fermentation rate and SCFAs production of adzuki bean were the highest.The result of PCA showed that the fermentation rate of the samples was almost inversely proportional to the yield of branched chain fatty acids.The contribution rates of smooth pea,adzuki bean and runner bean to the yield of acetate and butyrate were greater,and the contribution rate of broad bean to the yield of branched chain fatty acids(BCFAs)was the largest.Redundancy analysis showed that the key factor leading to the difference of total gas production and propionate production was starch content.The key factor leading to the yield difference of acetate was the crystallinity of starch in cells,dietary fiber content was the main reason for the yield difference of butyrate after fermentation,and protein content was the key factor affecting the yield difference of BCFAs.Processing could affect food structure of whole pulses,and regulates the in vitro fecal fermentation outcomes as well as microbiota composition.In the present study,intact cotyledon cells from pinto bean were isolated as the whole pulse food model and subjected to a series of hydrothermal treatment.The results showed that with the increase of hydrothermal temperature,the fermentation rate of intact pinto bean cotyledon cells increased significantly.Based on the FITC-dextran probe diffusion analyses,it was concluded that the cell wall permeability increased with the increase of hydrothermal temperature,which could make the difference in fermentation characteristics of encapsulated starch.In vitro fecal fermentation performance and microbiota responses were tested,and we reported that the cell wall permeability controls the in vitro fecal fermentation rate of pinto bean cells.The SCFAs produced by pulse cells fermentation enhanced,C100 produced the highest concentration of total SCFAs(111 mM),and the branch chain ratio decreased(<1.6).And the abundance of certain beneficial microbiota such as Bifidobacterium and Coprococcus was significantly promoted with the increase of hydrothermal temperature.Thus,manipulating the processing can help to designed the foods with desired fermentation profile to beneficially regulate the gut microbiota composition.