Abstract: 【Objective】Optimize the extraction process of banana peel polysaccharides and study the antioxidant activities,in order to provide references for the industrial extraction and utilization of banana peel polysaccharides.【Methods】Using the polysaccharides yield as the indicator,the effects of grinding time,solid-liquid ratio,cellulase addition amount,ultrasonic time,ultrasonic temperature on the yield of banana peel polysaccharides were investigated through single factor experiment.Response surface method were used to optimize three factors,solid-liquid ratio,ultrasonic time,and ultrasonic temperature,to determine the optimal process for ultrasonic assisted enzymatic extraction of banana peel polysaccharide. The antioxidant activities of the extracted banana peel polysaccharides were tested as well.【Results】Under different factor levels,the yield of banana peel polysaccharides was the highest at 4.15% when the grinding time was 60 s. When the solid-liquid ratio was 1∶40（g∶mL）,the yield of banana peel polysaccharides was the highest at 5.87%. When the cellulase addition amount was 2.5%,the yield of banana peel polysaccharides was the highest at 5.49%. The yield of banana peel polysaccharides was the highest at 5.72% when the ultrasonic time was 20 min. The yield of banana peel polysaccharides was the highest at 5.97% when ultrasonic temperature was 30 ℃. Under the conditions of 60 s grinding time,solid-liquid ratio of 1∶38（g∶mL）,cellulase addition amount at 2.5%,19 min ultrasonic time,and ultrasonic temperature at 26 ℃,the yield of banana peel polysaccharides was the highest at 6.51%. The scavenging abilities of banana peel polysaccharides on hydroxyl radicals,DPPH radicals and ABTS radicals increased with the increase of banana peel polysaccharides concentration.【Conclusion】Response surface method determined that the optimal conditions for ultrasonic assisted enzymatic extraction of banana peel polysaccharides were：60 s grinding time,solid-liquid ratio of 1∶38（g∶mL）,cellulase addition amount at 2.5%,19 min ultrasonic time,and ultrasonic temperature at 26 ℃. Banana peel polysaccharide had obvious scavenging effect on hydroxyl radicals,DPPH radicals and ABTS radicals.

Key words: Banana peel, Polysaccharide, Response surface method, Process optimization, Antioxidant activity