Abstract：
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 Mw 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.
摘要：
在这项研究中,通过人粪便分批发酵模型评估了高鼠李糖醛酸I果胶多糖（RGI）和自由基降解RGI（DRGI）的发酵特性，并对其结构特性进行了研究。因此,RGI的Mw从246.8下降到11.6kDa，树枝被戏剧性地折断了。发酵表明，RGI比DRGI降解更快，产生更多的乙酸盐和丙酸盐。两者都降低了厚壁菌/拟杆菌的比例，促进了拟杆菌的发展，双歧杆菌,和乳酸菌，给肠道生态系统带来好处。然而,RGI和DRGI中微生物群的组成和代谢途径不同。RGI的大多数优势细菌（例如[Eubacterium]_eligens_group）参与了碳水化合物的利用，导致更好的表现在糖脂代谢和能量代谢。这项工作阐明了大分子量在体外RGI型果胶多糖的肠道菌群调节作用中的作用。
