Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, West Lafayette, IN 47907, USA; Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, CP 19.046, CEP 81.531-980, Curitiba, PR, Brazil.
Institute of Food and Nutraceutical Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Food Res Int. 2021 May;143:110293. doi: 10.1016/j.foodres.2021.110293. Epub 2021 Mar 9.
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.
大多数不溶性膳食纤维被认为是人体肠道微生物群相对较差的发酵物。在这里，评估了微波 (MW) 处理增强不溶性水果多糖对人体肠道微生物群发酵易感性的潜力。在 MW 处理之前（木聚糖 A、木聚糖 T 和阿拉伯聚糖）和之后（木聚糖 A-MW、木聚糖 T-MW 和阿拉伯聚糖-MW）的不溶性水果膳食纤维使用体外发酵模型进行发酵。气体产生、pH 值变化和短链脂肪酸 (SCFA) 产生表明所有测试膳食纤维的可发酵性增加，经过 MW 处理后 SCFA 产量平均增加了 4 倍，总 SCFA 范围从阿拉伯聚糖-MW 的 17.1mM 到木聚糖 T-MW 的 40.4mM。虽然阿拉伯聚糖-MW 和木聚糖 T-MW 促进了所有三种 SCFA 的比例增加（乙酸盐：丙酸盐：丁酸盐），但木聚糖 A-MW 导致丁酸盐的显著和缓慢增加，在 24 小时时达到总 SCFA 的 28.1%。扫描电子显微镜观察到三维结构的重排，这可能使细菌更容易接触膳食纤维，在木聚糖 A-MW 中形成直径约为 1.1μm 的硬币状颗粒。16S rRNA 基因测序表明，微生物群的变化与处理（天然与 MW）和膳食纤维类型都有关，许多产丁酸菌被木聚糖 A-MW 促进。总体而言，MW 处理增强了不溶性膳食纤维的可发酵性，促进了 SCFA 产量和与健康益处相关的细菌变化。
