Abstract:This study aimed to systematically optimize the compound enzymatic extraction process of polysaccharides from the green peel of Xizhou cantaloupe，using the crude polysaccharide extraction yield as the primary index. Through single-factor experiments and an orthogonal array test，the optimal extraction conditions were determined. The obtained crude polysaccharides were purified by decolorization and deproteinization to obtain decolorized polysaccharides and decolorized-deproteinized polysaccharides，respectively. Furthermore，the particle size distribution，Zeta potential changes，and DPPH and ABTS+radical scavenging capacities of the polysaccharides were analyzed. The results indicated that the optimal extraction conditions were as follows：enzyme mass ratio 1∶2，enzyme dosage of 2.8%，hydrolysis time of 16 min，pH6.5，and hydrolysis temperature 40 ℃. Under these conditions，the polysaccharide extraction yield reached （12.40±0.10）%. For the decolorized-deproteinized polysaccharides，the average particle size decreased from 421.7 nm to 310.8 nm，while the Zeta potential increased from -17.54 mV to -13.77 mV. Antioxidant activity analysis showed that the scavenging rates of the crude polysaccharides against DPPH and ABTS+free radicals were 59.52% and 61.71%，respectively，both higher than those of the decolorized and the decolorized-deproteinized polysaccharides. In conclusion，the green peel polysaccharides of Xizhou cantaloupe exhibit promising in vitro antioxidant activity.