Effect of ultrasonic degradation on the physicochemical characteristics, GLP-1 secretion, and antioxidant capacity of Polygonatum cyrtonema polysaccharide

This study aimed to evaluate the influence of ultrasonic degradation on the physicochemical and biological characteristics of Polygonatum cyrtonema polysaccharide (PCP, 8.59 kDa). PCP was subjected to ultrasonic treatment for 8, 16, and 24 h and yielded the degraded fractions PCP-8, PCP-16, and PCP-24 (5.06, 4.13, and 3.69 kDa), respectively. Compared with the intact PCP, PCP-8, PCP-16 and PCP-24 had a reduced particle size (decrements of 28.03 %, 46.15 % and 62.54 %, respectively). Although ultrasonic degradation did not alter the primary structure of PCP, its triple helical and superficial structures were disrupted, with degraded fractions demonstrating reduced thermal stability and apparent viscosities compared with those of the intact PCP. Furthermore, the functional properties of the degraded fractions were different. PCP-16 most favourably affected GLP-1 secretion, while PCP-8 and PCP-24 exhibited the strongest antioxidant and enzyme inhibitory activities, respectively. Hence, controlled ultrasound irradiation is an appealing approach for partially degrading PCP and enhancing its bioactivity as a functional agent.