Insoluble dietary fiber from five commercially cultivated edible mushrooms: Structural, physiochemical and functional properties

Mushroom is a high-fiber matrix, with its soluble dietary fiber (SDF) being well identified as prebiotic, leaving the abundant of insoluble dietary fiber (IDF) being overlooked. This study aims to evaluate the functional and structural characteristics of IDF from 5 commercial cultivated mushrooms, to help improve their application. The IDF from the five edible mushrooms constitutes 52.49%-86.13% of the total dietary fiber, primarily composed of cellulose, hemicellulose, lignin, and chitin. Among them, Pleurotus ostreatus IDF (PO-IDF) and Agaricus sub-rufescens IDF (AS-IDF) displayed remarkable absorption ability, presented by the higher water-holding capacity (12.66 g/g and 12.26 g/g), cholate absorption (26.74 mg/g and 26.94 mg/g), and cholesterol absorption (12.42 mg/g and 12.88 mg/g). These are might attributed to their smaller particle size, larger surface area, rough porous surface and relatively loose structure. FTIR analysis revealed that AS-IDF possesses appreciable O-H groups, which can enhance the adsorption performance of the sample. All these characteristics enable PO-IDF and AS-IDF to adsorb substances both physically and chemically. Notably, AS-IDF exhibited superior antioxidant activity compared to other samples, attributable to its bound polyphenol. All these results raised the possibility of uti-lizing mushroom IDF as an economically viable functional food ingredient.