Microwave treatment enhances human gut microbiota fermentability of isolated insoluble dietary fibers. (May 2021)

• Record Type: Journal Article
• Authors: Cantu-Jungles, Thaisa Moro; Zhang, Xiaowei; Kazem, Ahmad E.; Iacomini, Marcello; Hamaker, Bruce R.; Cordeiro, Lucimara M.C.
• Is Part Of: Food research international. Volume 143(2021)
• Publication Date: 2021-05
• Subjects: Gut microbiome -- Prebiotics -- Fecal fermentation -- Short chain fatty acids -- Three-dimensional structure -- Bacterial shifts; Food -- Analysis -- Periodicals; Food industry and trade -- Periodicals; Food industry and trade -- Canada -- Periodicals; Food Technology -- Periodicals; Food -- Periodicals; Food-Processing Industry -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Industrie et commerce -- Canada -- Périodiques; Aliments -- Recherche -- Périodiques; Food industry and trade; Canada; Periodicals; Electronic journals; 664.005
• DOI: 10.1016/j.foodres.2021.110293
• Languages: English
• ISSNs: 0963-9969

Abstract

Graphical abstract: Highlights: Insoluble dietary fibers were poorly fermentable in vitro by the human gut microbiota. Dietary fibers remained insoluble after microwave treatment (MW). MW increased insoluble fiber fermentability leading to a high SCFA production. Specific bacterial shifts were observed depending of the dietary fiber fermented. Butyrate and butyrogenic bacteria were specifically promoted by the xylan A-MW. Abstract: Most insoluble dietary fibers are known to be relatively poorly fermented by the human gut microbiota. Here, the potential of microwave (MW) treatment to enhance the susceptibility of insoluble fruit polysaccharides to fermentation by the human gut microbiota was evaluated. Insoluble fruits dietary fibers before (xylan A, xylan T, and arabinan) and after MW (xylan A-MW, xylan T-MW, and arabinan-MW) treatment were fermented using an in vitro fermentation model. Gas production, shifts in pH, and short chain fatty acids (SCFAs) production showed an increase in fermentability of all tested dietary fibers, with an average 4-fold increase in SCFAs production after microwaving with total SCFAs ranging from 17.1 mM in the arabinan-MW to 40.4 mM in the xylan T-MW. While arabinan-MW and xylan T-MW promoted all three SCFAs proportionally (acetate:propionate:butyrate), xylan A-MW led to a marked and slow increase in butyrate reaching 28.1% of total SCFAs at 24 h. Rearrangements in three-dimensional structure that potentially facilitate bacterial accessibility to the dietary fiber were observed by scanning electron microscopy in xylan A-MW, forming coin-like particles with ~1.1 µm diameter. 16S rRNA gene sequencing indicated that microbiota shifts were related to both treatment (native versus MW) and dietary fiber type with many butyrogenic species being promoted by xylan A-MW. Overall, MW treatment enhanced insoluble dietary fiber fermentability promoting increased SCFAs production and bacterial shifts which are related to health benefits.