核桃壳多酚的提取、含量测定及其抗氧化活性研究

Study on the extraction,determination and antioxidant activity of polyphenols from Walnut Shell

目的优化核桃壳多酚的提取工艺,测定其中各成分的质量分数,并对其抗氧化活性进行研究。方法以核桃壳为原料,采用超声波辅助技术,乙醇为提取溶剂,从核桃壳中提取多酚物质,结合单因素和正交试验,确定核桃壳多酚提取的最佳工艺;采用超高效液相色谱法(UPLC)对核桃壳多酚的成分进行鉴定;用DPPH·、FRAP和ABTS·+3种方法测定其抗氧化能力。结果核桃壳多酚的最佳工艺为:料液比1∶30(g∶m L),乙醇体积分数40%,超声时间25 min(超声功率46 k Hz,200 W),提取温度60℃;FRAP、DPPH·和ABTS·+法测得核桃壳多酚的抗氧化活性分别为19.80、21.91、29.30μmol/g;UPLC法测得各组分及其质量分数分别为:原儿茶酸(18.37±2.23)μg/g、咖啡酸(5.50±0.12)μg/g、芦丁(148.50±3.41)μg/g、异槲皮苷(154.09±21.56)μg/g和槲皮苷(193.26±14.92)μg/g。结论核桃壳多酚具有较强的抗氧化性能,尤其是对ABTS·+自由基的清除能力较强。

Objective To optimize the extraction technology of polyphenols from walnut shell,investigate the components and their antioxidant activities. Methods Ultrasonic assisted technology was employed with ethanol as solvent in single factor tests and orthogonal test,and the optimal extraction process of polyphenols from walnut shell was determined. Ultra performance liquid chromatography（ UPLC） was used to determine the components of polyphenols,and DPPH·,FRAP,ABTS·＋methods were used to evaluate their antioxidant activities. Results The optimal extraction process of polyphenols from walnut shell were as follows： material to solvent ratio of 1 ∶ 30（ g ∶ m L）,40% of ethanol concentration,extraction time for 25 minutes and 60 ℃ of extraction temperature（ Ultrasonic power 46 k Hz,200 W）. Trolox equivalent antioxidant activity of walnut shell polyphenols measured by FRAP,DPPH·and ABTS·＋method were19.80,21. 91,29. 30 μmol / g,respectively. The contents of protocatechuic acid,caffeic acid,rutin,isoquercitrin and quercitrin were（ 18. 37 ± 2. 23）,（ 5. 50 ± 0. 12）,（ 148. 50 ± 3. 41）,（ 154. 09 ± 21. 56）,（ 193. 26 ± 14. 92） μg/g,respectively. Conclusion The polyphenols from walnut shell showed strong antioxidant properties,especially in scavenging ABTS·＋free radical.