In vitro gastrointestinal digestion of whole grain noodles supplemented with soluble dietary fiber and their effects on children fecal microbiota

In order to increase children's daily intake of dietary fiber and protein, the effects of soluble dietary fiber (SDF) supplement including high-amylose corn starch (HACS), inulin, fructo-oligosaccharides (FOS), galactose oligosaccharides (GOS), β-glucan (BG), arabinogalactan (AG), arabinoxylan (AX), and xylo-oligosaccharides (XOS) on protein digestion of multigrain noodles and the fecal microbiota of school-age children were evaluated by in vitro digestion and fermentation in this study. The addition of SDF in multigrain noodles retained a high protein content, which is beneficial for children intake. Except HACS and inulin, the addition of other SDFs significantly increased protein hydrolysis (p < 0.05) during gastrointestinal digestion, which will enhance the protein digestion for the children. In addition, noodles (after digestion) containing SDF could reduce fermentation pH, increase short-chain fatty acid levels, and regulate microbiota composition during in vitro fermentation for 24 h. Noodles with HACS resulted in the highest short-chain fatty acids production during fermentation. Noodles containing FOS, GOS and HACS significantly increased the abundance of Bifidobacterium, Lactobacillus and Clostridium-sensu_stricto_1 (p < 0.05) at genus level in fecal microbiota during fermentation. Results indicated that FOS, GOS and HACS are more suitable to be added to multigrain noodles to improve protein and fiber intake for school-age children.