The physical and chemical interactions between starch and dietary fiber: Their impact on the physicochemical and nutritional properties of starch

The physicochemical and nutritional properties of starch play a critical role in both the food industry and the improvement of human health. Dietary fiber, such as cell wall polysaccharides, is a major component in plant-based foods, which can interact with starch during food preparation and significantly affect starch properties. However, the specific mechanisms by which starch and fiber interact during food processing and within the human gastrointestinal tract, and their subsequent impact on the physicochemical and nutritional properties of starch, are not fully understood. In this review, the physical and chemical structures of various types of dietary fibers were first described, followed by a detailed discussion of their influence on starch gelatinization, retrogradation, digestion and fermentation. Intact plant cell walls could retard starch gelatinization by restricting swelling, heat transfer, and water ingress, while promoting starch retrogradation. Furthermore, intact cell walls could act as external barriers between starch and digestive enzymes or gut microbiota. In comparison, the influence of the chemical structure of dietary fiber on the physicochemical and nutritional properties of starch is determined by various factors, including but not limited to the chemical composition, preparation method, and concentration of dietary fiber. Future perspectives on the study of starch-dietary fiber interactions should include the potential development of ternary complexes with other macronutrients in the food matrix. This review provides important insights for a better understanding of the complex interactions between starch and dietary fiber, as well as their importance in determining the nutritional and functional properties of starch.