超声辅助酶法优化提取核桃分心木多酚及其抗氧化活性研究

Optimization of Ultrasound-assisted Enzymatic Extraction of Walnut Diaphragm Polyphenols and Its Antioxidant Activity

【目的】优化核桃分心木多酚提取工艺,并研究其抗氧化活性。【方法】以云南漾濞核桃分心木为原料,利用单因素试验探究纤维素酶添加量、料液比、超声功率、超声时间和乙醇体积分数对核桃分心木多酚提取率的影响,采用响应面法对多酚提取工艺进行优化;通过D101大孔树脂对粗提物进行初步纯化得到核桃分心木多酚,并分析其纯度;利用DPPH·自由基清除能力、ABTS+自由基清除能力及铁还原能力评价其抗氧化活性。【结果】超声辅助纤维素酶法提取核桃分心木多酚的最佳工艺为:酶添加量0.6%、料液比1∶80(g∶mL)、超声功率600 W、超声时间60 min、乙醇体积分数60%,多酚提取率为7.26%,初步纯化得到的多酚纯度为89%。核桃分心木多酚对DPPH·自由基和ABTS+自由基清除率的IC_(50)值分别为11.11和183.12μg/mL,铁离子还原能力达到同等质量浓度抗坏血酸的59.62%,表明核桃分心木多酚具有较强的抗氧化活性。【结论】得到核桃分心木多酚的最佳提取工艺,为核桃产业的发展和核桃分心木有效成分的开发利用提供了试验依据。

[Purpose]To optimize the extraction process of walnut diaphragm polyphenols(WDP)and to study its antioxidant activity.[Methods]Walnut diaphragm from Yangbi,Yunnan Province,was used as material,the effects of cellulase addition amount,solid-liquid ratio,ultrasonic power,ultrasonic time and ethanol volume fraction on the extraction rate of WDP were explored by singlefactor experiment.The polyphenol extraction process was then optimized by response surface method.The crude extract was initially purified by D101 macroporous resin,getting WDP,which were then analyzed for purity.The antioxidant properties were evaluated by the scavenging ability of DPPH·radicals,the scavenging ability of ABTS+ radicals,and the iron reducing ability.[Results]The optimal extraction process for WDP by ultrasound-assisted cellulase method included:enzyme addition was 0.6%,solid-liquid ratio was 1∶80(g∶mL),ultrasound power was 600 W,ultrasound time was60 min,and volume fraction of ethanol was 60%.The rate of polyphenol extraction was 7.26%,and the polyphenol purity obtained from the preliminary purification was 89%.IC_(50) values of the scavenging ability of DPPH· radicals and ABTS+ radicals was 11.11 and 183.12 μg/mL,respectively.Furthermore,the iron reducing ability reached 59.62% of that of the same mass concentration of ascorbic acid,which indicated that the WDP had strong antioxidant activity.[Conclusion]The optimal extraction process of WDP is identified,providing a foundation for the development of the walnut industry and the utilisation of active ingredients of walnut diaphragm.