超声处理核桃仁及其提取物的抗氧化性分析

摘要

[目的]提取活性较高的核桃多酚，提高核桃的利用价值。[方法]采用添加0．05 mol／L盐酸的70％乙醇溶液超声辅助的方法处理核桃仁，Folin－Ciocalteau法测定总酚含量，并测定其清除自由基能力及铁离子还原能力表征抗氧化活性。[结果]4次超声提取（65℃，10 min）的核桃多酚提取液多酚含量为（12．03±0．16） mg／g，核桃仁中的多酚残留量为0．38 mg／g，低于碱处理后的核桃仁多酚残留量。此外，核桃多酚提取物在清除1，1－二苯基－2－三硝基苯肼（DPPH）自由基、2，2－联氮－二（3－乙基－苯并噻唑－6－磺酸）二铵盐（ABTS）自由基能力及铁离子还原能力均高于叔丁基对苯二酚（TBHQ）、VC 和VE。[结论]酸化乙醇超声处理核桃仁不仅可以有效去除核桃多酚，还为食品工业提供了高活性的天然抗氧化剂。%Objective] To extract polyphenols from Juglans regia L.with realtivley high activity, and to enhance the utilization value of J.regia. [ Method] Ultrasonic extraction was applied directly to process J.regia kernel by adding 70% ethanol containing 0.05 mol/L hydrochloric acid. The total phenol content was measured by Folin-Ciocalteu method.The antioxidant activity was evaluated using free radicals scavenging capacity and iron ion reducing ability.[Result] As for the four times ultrasonic extraction (65 ℃, 10 min) of J.regia extracting solution, polyphenols content was (12.03 ±0.16)mg/g walnut kernel;The remained polyphenols in the kernel was 0.38 mg/g walnut kernel, which was lower than that in walnut kernel treated with conventional alkali soaking method.Compared with t-butyl hydroqumone (TBHQ) and vitamin C, walnut poly-phenol extract showed superior antioxidant capacity in terms of scavenging free radicals and reducing iron ion .[ Conclusion] Direct ultrasonic ex-traction of walnut kernel not only removed polyphenols with high efficiency but also provided potential antioxidant additive for food industry .