Effects of dehydration and extraction techniques on the physicochemical properties and antioxidant activities of Oudemansiella radicata polysaccharides

Oudemansiella radicata is a precious mushroom widely cultivated in China with mature cultivation techniques. The extraction efficiency and biological activity of polysaccharides are crucial for the utilization of O. radicata . In this study, the effects of dehydration (hot air drying and freeze-drying) and extraction methods (heat-reflux extraction, ultrasound-assisted extraction and maceration extraction) on the physicochemical properties and antioxidant activities of Oudermansiella radicata polysaccharides (ORPs) were investigated. Six polysaccharides were obtained, and experimental results indicated that physicochemical and antioxidant properties of ORPs were different from each other after the treatment of various dehydration and extraction techniques. Based on correlation analysis, the antioxidant activities of the ORPs could be attributed to the uronic acid content, molecular weight, and glucose and mannose contents. The freeze-drying and ultrasound-assisted methods are promising and alternative techniques for obtaining ORPs considering their high yield and notable antioxidant activity. Graphic abstract