Grain factors in food and feed that influence digestion and gut fermentation outcomes

Abstract

Background and ObjectivesGrains are typically the main component in both human diets and animal feed. The factors in grains that influence digestion and fermentation in the gastrointestinal tract are incompletely understood, limiting both product innovation and rational selection of grains for desired nutritional outcomes. This review summarizes the current understanding of the multiple mechanisms operating within the digestive tract of humans and monogastric production animals, with a focus on the effects of grains.FindingsMolecular composition and residual cellular structures in grain‐based food and feed each have impacts on digestion and fermentation processes. There is a complex interplay between enzyme digestion rates, fermentation rates, and digesta transit processes in the gastrointestinal tract based on the material properties of grain foods/feeds and hormonal signals triggered by nutrient and fermentation product uptake. Opportunities for modulation of nutritional value in grain food and feed can be identified based on particle size, local molecular density, and hydration properties.ConclusionsMany advances in understanding the factors in grains that influence enzyme digestion and gut microbial fermentation have been made recently. Current nutritional labeling based on molecular composition and not digestion or fermentation properties ignores the important role that residual grain cellular structure plays in both human and animal nutrition.Significance and NoveltyBy comparing the effects of grain‐based foods and feeds on gastrointestinal digestion, fermentation, and digesta transit, opportunities and challenges for addressing nutritional targets for human health and monogastric animal production through grain innovation are discussed.