Ultrasound-induced modifications of Auricularia auricula polysaccharides: Implications for antioxidant and glucose-lowering activities

High molecular mass and poor solubility of Auricularia auricula polysaccharides (AAP) limit their physiological activity. This study employed ultrasonic degradation to address these challenges. Ultrasonic treatment reduced the molecular mass of AAP from 1 × 10 5 Da to 3.8 × 10 3 –8 × 10 4 Da, enhanced hydroxyl group exposure, and significantly improved solubility, with dissolution time reduced to one-ninth of the pre-degradation level at 20 °C. The antioxidant activities of AAP were enhanced after ultrasonic degradation, with DPPH scavenging IC 50 reduced from 3.58 mg/mL to 2.07 mg/mL and hydroxyl radical IC 50 from 2.28 mg/mL to 1.77 mg/mL. Hypoglycemic effects were improved, with α-amylase and α-glucosidase inhibition rates increasing by 5.06 % and 5.81 %, respectively. Bile acid binding for MBS improved by 28.6 %, indicating ultrasonic degradation enhanced hypolipidemic activity. This study demonstrates ultrasonic degradation is a green, efficient method to improve AAP's functional properties, which broadens its applications in functional foods and health supplements. • Ultrasonic degradation alters the structure and enhances the bioactivity of Auricularia auricula polysaccharides • Ultrasonic degradation reduces the molecular mass of Auricularia auricula polysaccharides. • Ultrasonic degradation improves solubility and physicochemical properties of Auricularia auricula polysaccharides.