Recovery of total, soluble, and insoluble dietary fiber from potato ( Solanum tuberosum ) residues and comparative evaluation of their structural, physicochemical, and functional properties

Abstract

The structural, physicochemical, and functional characteristics of total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) isolated from potato residues were investigated. Potato dietary fiber consisted of IDF (73.18 g/100 g) and SDF (19.60 g/100 g); the main components were cellulose (42.93%) and pectin (27.82%), while lignin content was the lowest (5.74 g/100 g). The SDF contained much more rhamnose and galacturonic acid, whereas the major monosaccharide in IDF was glucose. The hydration properties of TDF, IDF, and SDF were increased with the increasing of temperature and pH, while negatively related to NaCl concentration. Furthermore, SDF exhibited more porous structure in the surface, thereby exhibiting better glucose absorption ability, α-amylase activity inhibition ratio, and cholesterol absorption ability compared with TDF and IDF. Overall, the TDF, IDF, and SDF from potato residues could be used as new functional additive in food industry according to their nature. Practical applications China is the largest potato producer in the world, most of potatoes are used to extract starch, and about 3 million tons of fresh potato residues are generated every year. While most of them are discarded, resulting in serious environmental pollution. Previous studies mainly focused on the extraction methods and characteristics properties of total dietary fiber (TDF) from potato residues, which indicated that potato TDF might exhibit wide applications in food and health products industry. However, the physicochemical and functional properties of potato dietary fiber affected by environmental conditions, such as temperature, pH, ionic strength, dielectric constant, and types thereof. Therefore, it is important to investigate the above properties of potato dietary fibers in order to make better use of it. As far as we know, the related information is rarely reported. The results of this study could provide some data about structural, physicochemical, and functional characteristics of total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble dietary fiber (SDF) isolated from potato residues, showing that it could be used as new functional additive in food industry according to the nature.