RGI-Type Pectic Polysaccharides Modulate Gut Microbiota in a Molecular Weight-Dependent Manner In Vitro

• Published in: Journal of agricultural and food chemistry Vol. 71; no. 4; pp. 2160 - 2172
• Main Authors: Wu, Jiaxiong, Yu, Chengxiao, Shen, Sihuan, Ren, Yanming, Cheng, Huan, Xiao, Hang, Liu, Donghong, Chen, Shiguo, Ye, Xingqian, Chen, Jianle
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.02.2023
• Subjects: Bacteria - metabolism; Fermentation; Functional Structure/Activity Relationships; Gastrointestinal Microbiome; Humans; Microbiota; Molecular Weight; Polysaccharides - chemistry; rhamnogalacturonan I; molecular weight; gut microbiota; pectic polysaccharides
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.2c07675

In this study, the fermentation characteristics of high rhamnogalacturonan I pectic polysaccharides (RGI) and free-radical degraded RGI (DRGI) were evaluated by a human fecal batch-fermentation model, and their structural properties were also investigated. As a result, the M w of RGI decreased from 246.8 to 11.6 kDa, and the branches were broken dramatically. Fermentation showed that RGI degraded faster and produced more acetate and propionate than DRGI. Both of them reduced the Firmicutes/Bacteroidetes ratio and promoted the development of Bacteroides, Bifidobacterium, and Lactobacillus, bringing benefits to the gut ecosystem. However, the composition and metabolic pathways of the microbiota in RGI and DRGI were different. Most of the dominant bacteria of RGI (such as [Eubacterium]_eligens_group) participated in carbohydrate utilization, leading to better performance in glucolipid metabolism and energy metabolism. This work elucidated that large molecular weight matters in the gut microbiota modulatory effect of RGI-type pectic polysaccharides in vitro.