The preparation and processing of fruits and vegetables produce high amounts of underutilized fractions, such as pomace and peel, which present a risk to the environment but constitute a valuable source of dietary fiber (DF) and bioactive compounds. The utilization of these fiber-rich products as functional food ingredients demands the application of treatments to improve their techno-functional properties, such as oil and water binding, and health-related properties, such as fermentability, adsorption, and retardation capacities of glucose, cholesterol, and bile acids. The enhancement of health-promoting properties is strongly connected with certain structural and techno-functional characteristics, such as the soluble DF content, presence of hydrophobic groups, and viscosity. Novel physical, environmentally friendly technologies, such as ultrasound (US), high-pressure processing (HPP), extrusion, and microwave, have been found to have higher potential than chemical and comminution techniques in causing desirable structural alterations of the DF network that lead to the improvement of techno-functionality and health promotion. The application of enzymes was related to higher soluble DF content, which might be associated with improved DF properties. Combined physical and enzymatic treatments can aid solubilization and modifications, but their benefit needs to be evaluated for each DF source and the desired outcome.
Keywords: by-products; cholesterol; dietary fiber; glucose reduction; non-thermal technologies; solubility.