Insights into the Mechanisms and Functional Effects of Insoluble Dietary Fiber Modification: A Review

Dietary fiber is an essential component of the human diet, and insoluble dietary fiber (IDF) accounts for a significant proportion. However, its poor solubility and rigid structure limit its high-value applications. In recent years, modification technologies have become key strategies for enhancing the functional properties of IDF and expanding its applications. This review systematically summarizes the latest advances in the field of IDF modification, emphasizing how different modification strategies precisely regulate the multilevel structure of IDF to selectively improve its physicochemical properties and physiological functions. The principles and mechanisms of physical, chemical, biological, and combined modification methods are explained, and the unique advantages and limitations of each method in terms of structural changes, functional enhancement, and application scenarios are compared. Using high-pressure hydrostatic pressure-assisted cellulase treatment on potato dietary fiber can effectively disrupt fiber rigidity, increase soluble dietary fiber (SDF), and markedly enhance cholesterol and glucose adsorption capacities, outperforming single-treatment approaches. Microwave-assisted enzymatic treatment of millet bran IDF raises its intestinal fermentation rate from 36% to 59% and doubles butyrate production, significantly boosting prebiotic activity and offering a new pathway for targeted modulation of gut microbiota; combined modification strategies further demonstrate synergistic benefits. Modified IDF can serve not only as a low-calorie fat replacer in foods but also, through specific structural alterations, be incorporated into plant-based meat products to improve their fiber attributes and nutritional density. Moreover, this review explores the emerging potential of modified IDF in pharmaceutical carriers and gut microecology regulation. The aim is to provide theoretical guidance for selecting and optimizing IDF modification strategies, thereby promoting the high-value utilization of agricultural processing by-products and the development of high-quality dietary fiber products.