Plant-sourced intrinsic dietary fiber: Physical structure and health function

Plant-sourced intrinsic dietary fiber (PIDF), mainly composed of nondigestible polysaccharides in a cell wall form, is often existed in plant tissue particles in which the physical structure of the particle size, density and spatial organization of food component as well as the intactness and porosity of cell wall are critical to its physicochemical properties and health functions. However, there is limited information of PIDF compared to isolated and purified DF that is a chemical entity without association with the food context. The health benefit and physical structures of PIDF are emerging as a new research area in the field of DF although there is still limited information in the literature reports. In the current article, available information on the relationship between the physical structure and the physiological function as well as resulted health benefits of PIDF in a whole food context were reviewed in conjunction with food processing. The physical structure of PIDF is a critical factor modulating the intestinal digestion and bioavailability of intracellular nutrients. PIDF can exert its health function through a physical structure-specific microbial fermentation and/or microbiota-independent pathways. A holistic approach to reveal the relationship between the physical structure and health function of PIDF will shed novel insight into the designing of PIDF enriched functional foods. • Plant-sourced intrinsic dietary fiber (PIDF) is an physical entity presented as plant tissue particles • The physical structure is crucial for the functions of plant-sourced intrinsic dietary fiber (PIDF) • Encapsulation mechanism is involved in PIDF's impact on the metabolic fate of intracellular nutrients • The colonic fermentation-dependent and independent pathways are the basis for PIDF's health function