Extraction, modification, and property characterization of dietary fiber from Agrocybe cylindracea

Dietary fiber (DF) has gained a great attention owing to its potential health benefits. Agrocybe cylindracea is an edible fungus with high protein and low fat contents, which is also an enriched source of DF. However, limited study has been conducted on optimizing the conditions of A. cylindracea-derived DF extraction and modification as well as characterizing its properties. In this study, ultrasound-assisted enzymatic method for DF extraction was optimized as the following conditions: liquid material ratio of 29 ml/g, α-amylase concentration of 1.50%, protamex concentration of 1.20%, and ultrasonic power of 150 W, which improved the DF extraction yield to 37.70%. Moreover, high temperature modification (HTM) and cellulase modification (CEM) were applied to modify A. cylindracea-derived DF. The results showed that HTM had more potential capacity in converting insoluble DF into soluble DF, and DF with HTM exhibited more advantages in its physicochemical properties than DF with CEM. The DF with both HTM and CEM showed antioxidant activities, reflected by the increased reducing power as well as DPPH radical, hydroxyl radical, and ABTS⁺ scavenging capabilities in vitro. These findings could offer a reference for the extraction, modification, and characterizing various properties of DF from A. cylindracea, which would establish the foundation for the comprehensive application of fungi-derived DF.