Starches with high amylose content resist complete digestion in the small intestine with a fraction (resistant starch) entering the large intestine, where it is fermented by the human gut microbiota resulting in perceived beneficial health effects. However, the effects of food form on the large intestinal digestion of products with different amounts of resistant starch are unknown. Here, wheat flours with 32%, 71%, 74% and 84% amylose content were used to prepare bread, tortillas and noodles, and after in vitro treatment simulating small intestinal digestion, were subjected to in vitro fermentation with a pooled human faecal inoculum. The results showed that food form rather than initial amylose content significantly affected both fermentation rates and short chain fatty acid (SCFA) production. Acetate concentrations were significantly greater in the noodle-based fermentations, whereas propionate concentrations were significantly greater in the tortilla-based fermentations (p < 0.05). Butyrate concentrations were also significantly increased for both the noodle and tortilla-based fermentations when compared to bread (p < 0.05). The microbial communities supported by these different food forms were examined by metagenomic sequencing (MGS) of fermentation samples collected over 48 h. Among the top 20 most abundant species, Enterococcus faecium was significantly increased by bread and tortilla, whereas Ruminococcus spp. and Faecalibacterium prausnitzii were increased for noodles. Although the amount of resistant starch reaching the large intestine is a relevant consideration in pursuit of promoting digestive health, our findings suggest that food form has a major influence on the gut microbiota that is reflected in substantive changes in SCFA profiles.

直链淀粉含量高的淀粉难以在小肠中完全消化，其中一部分（抗性淀粉）进入大肠，在此被人类肠道菌群发酵，从而产生有益的健康影响。然而，尚不清楚食物形式对具有不同量抗性淀粉的产品在大肠中的消化作用。在这里，使用直链淀粉含量分别为32％，71％，74％和84％的小麦粉制备面包，玉米饼和面条，并在模拟小肠消化的体外处理后进行了体外处理。用人类粪便接种物发酵。结果表明，食物形式而不是初始直链淀粉含量显着影响发酵速率和短链脂肪酸（SCFA）的生产。在基于面条的发酵中，乙酸盐的浓度显着较高，而在基于玉米饼的发酵中，丙酸的浓度显着较高（p <0.05）。与面包相比，基于面条和玉米饼的发酵中丁酸盐的浓度也显着增加（p <0.05）。通过宏基因组测序（MGS）对48小时内收集到的发酵样品进行检测，从而研究了这些不同食物形式所支持的微生物群落。在前20个最丰富的物种中，粪肠球菌面包和玉米饼显着增加，而Ruminococcus spp。面条增加了Paecalibacterium prausnitzii和Faecalibacterium prausnitzii。尽管到达大肠的抗性淀粉的量是追求促进消化健康的相关考虑因素，但我们的发现表明，食物形式对肠道菌群有重大影响，这反映在SCFA图谱的实质性变化上。