Chemical Composition and Antioxidant Activity of Crude Polysaccharides Extracted from Pumpkin Peel as Affected by Different Extraction Methods

The influence of different extraction methods,including conventional water extraction,ultrasound-assisted water extraction,and microwave-assisted water extraction,on chemical composition and antioxidant activity of crude polysaccharides extracted from pumpkin peel(CPPPs) was investigated.The results showed that the extraction yield of CPPPs was significantly affected by extraction method and the highest extraction yield(4.52%) of CPPPs was obtaiend with microwave-assisted water extraction.It was found that the monosaccharide composition and molecular size distribution of CPPPs were also significantly affected by extraction method.The DPPH radical scavenging activity of CPPPs from conventional water extraction,ultrasound-assisted water extraction,and microwave-assisted water extraction presented IC50 values of 0.18,0.27 mg/mL,and 0.24 mg/mL,respectively.Therefore,CPPPs obtained by conventional water extraction possessed much higher DPPH radical scavenging activity than those obtained by the two other methods.