Abstract:To improve the yield and explore the development and utilization of mulberry leaf protein，extracts were prepared from mulberry leaves using ultrasonic cell fragmentation，and the antioxidant activity of the extracted enzyme was studied in vitro.The effects of the pH value of the extraction liquid，the ratio of liquid to material，ultrasonic power，crushing time，extraction temperature，and extraction time on the yield of mulberry leaf protein were investigated.The extraction process was optimized using an orthogonal design.Enzymolysis of the mulberry leaf protein was performed using papain to obtain mulberry leaf enzyme.The antioxidant activities of the mulberry leaf enzyme in vitro were evaluated using the 2，2-diphenyl-1-picrylhydrazyl（DPPH）free radical scavenging method and the total reducing ability determination method.The results showed that the optimum extraction conditions were as follows:a pH value of 8 for the extraction liquid，a 12∶1（mL/g）extraction liquid to material ratio，5 min of ultrasonic treatment at a power of 200 W，an extraction temperature of 30 ℃，and extraction time of 15 min，and two extractions.The yield of mulberry leaf protein was 9.85%under these conditions.The mulberry leaf enzyme had reducing ability and a strong ability to scavenge DPPH free radicals.