Ultrasonic degradation of mulberry twigs polysaccharides: Effect on in vitro hypoglycemic activity and prebiotic potential

This study aimed to enhance the in vitro hypoglycemic activity of mulberry twigs polysaccharides (MTP) through ultrasonic degradation and to elucidate its underlying mechanisms and prebiotic potential. The results demonstrated that ultrasonic degradation effectively increased its inhibitory activity against α-glucosidase. Structural characterization of MTP revealed that ultrasonic degradation significantly decreasing its molecular weight and monosaccharide composition. Mechanistic studies indicated that the inhibition of α-glucosidase by the degraded product MTP-240 was reversible and followed a single static quenching process. In vitro fermentation assays revealed that MTP-240 promoted the production of short-chain fatty acids (SCFAs), surpassing the inulin control, with pentanoic acid accumulating most substantially. Additionally, MTP-240 enhanced the growth of Bifidobacterium, a beneficial gut bacterium associated with improved glucose levels and antioxidant capacity. These findings suggested that ultrasonic degradation was an effective method for enhancing the glycosidase inhibitory activity of polysaccharides, and the degraded MTP possesses the potential to be developed as a food additive with dual functions of glycosidase inhibition and prebiotic activity. This research provides a theoretical basis for the further development of mulberry resources and related functional foods.