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. Highlights 1. Potato residues have higher content of dietary fibers and no gluten.

The structural, physicochemical, and functional properties of potato residue with different mesh sizes (<180 µm, <150 µm, <106 µm, <75 µm, ultrafine) obtained from starch isolation were investigated, and its effects on the shear strength, tensile strength, cooking time, and in vitro digestibility of 5% potato residue-based starch noodles were further compared. The results showed that the protein, ash, dietary fiber, water holding capacity, and water solubility of fractionated potato residue were decreased with decreasing particle size, while the starch, fat, polyphenols, and α-amylase activity inhibition ratio were increased. Ultrafine particles exhibited the highest phenolic content (2.26 mg chlorogenic acid equivalent/g), glucose adsorption capacity (7.03 mmol/g), cholesterol adsorption capacity (16.54%), and better performance on starch noodles formulation. However, oil holding capacity and microstructure did not show any significant differences. Therefore, potato residues with desired particle sizes could be successfully used to develop fiber-enriched food products for reducing food waste.