核桃青皮果胶提取工艺优化及其体外降脂、抗氧化活性分析

Optimization of ultrasound assisted acid extraction of pectin from walnut green husk and analysis of its in vitro lipid-lowering and antioxidant activities

[目的]实现核桃生产废弃物的高附加值资源化利用。[方法]采用超声波辅助酒石酸提取核桃青皮中的果胶,通过响应面试验优化提取工艺,并分析其降脂能力和抗氧化活性。[结果]在超声功率300 W,超声温度95℃,超声时间27 min,液料比19∶1(mL/g),pH值2的条件下,核桃青皮果胶得率最高,达25.92 mg/g。核桃青皮果胶对胆固醇的吸附能力、胆酸盐的结合能力和胰脂肪酶的抑制效果均较佳。核桃青皮果胶的抗氧化能力也较强,当样品质量浓度为2 mg/mL时,其对羟自由基、DPPH自由基、ABTS自由基的清除率分别可达(78.74±0.58)%,(91.56±1.27)%,(97.89±0.72)%。[结论]通过优化后的超声波辅助酒石酸提取工艺可获得高质量的核桃青皮果胶,该果胶具有较好的降脂功能和抗氧化活性,可作为天然果胶资源深入研究开发。

[Objective]This study aimed to realize the high value-added resource utilization of walnut production waste.[Methods]Ultrasonic assisted tartaric acid was used to extract pectin from walnut peel.The extraction process was optimized by response surface test,and its lipid-lowering ability and antioxidant activity were analyzed.[Results]Under the control of the conditions of ultrasonic power of 300 W,ultrasonic temperature of 95℃,ultrasonic time of 27 minutes,liquid to material ratio of 19∶1(mL/g),and pH of 2,the yield of walnut green peel pectin was the highest,reaching 25.92 mg/g.Walnut green peel pectin had good adsorption capacity for cholesterol,binding capacity for bile salts,and inhibitory effect on pancreatic lipase.Walnut green peel pectin also had strong antioxidant effects.When the concentration was 2 mg/mL,the clearance rates of hydroxyl radicals,DPPH radicals,and ABTS radicals reached(78.74±0.58)%,(91.56±1.27)%,and(97.89±0.72)%,respectively.[Conclusion]High-quality walnut green peel pectin could be obtained by optimizing the ultrasonic assisted tartaric acid extraction process.This pectin had good lipid-lowering function and antioxidant activity,and can be used as natural pectin resources for further research and development.