酶法催化柚皮苷制备根皮素及其抗氧化活性分析

Enzymatic Preparation of Phloretin from Naringin and Their Antioxidant Activity Analysis

本文阐述一种高效,环保制备高价值天然抗氧化剂根皮素的方法。以天然的柑橘提取物柚皮苷为原料,经一锅法加氢反应制得柚苷二氢查尔酮,再以α-鼠李糖苷酶(α-rhamnosidase)和纤维素酶(cellulase)高效催化水解而制得根皮素。采用单因素和正交实验对α-鼠李糖苷酶和纤维素酶酶解反应的p H、温度、酶与底物比进行优化,同时对根皮素、三叶苷、柚苷二氢查尔酮、柚苷的抗氧化性进行了研究,结果表明:α-鼠李糖苷酶(α-rhamnosidase)酶解最佳工艺为温度60℃、p H 4、酶与底物比为0.6:1;纤维素酶(cellulase)最佳工艺为温度45℃、p H 5.5、酶与底物比为0.3:1。在此工艺下根皮素的转化率为96.10%,比原工艺提高了10.53%。抗氧化性研究结果为:清除DPPH自由基能力根皮素(0.18±1.45)>三叶苷(0.3±1.63)>柚苷二氢查尔酮(0.95±1.24)>柚苷(8±1.97),还原铁离子能力为根皮素(7.1±0.68)>三叶苷(2.51±0.75)>柚苷二氢查尔酮(2.05±0.58)>柚苷(0.11±0.92)。本方法条件温和,周期短且转化率高,易于放大生产。抗氧化性结果表明根皮素具有较高的抗氧化性。这对根皮素的放大生产及应用具有重大意义。

A highly efficient and environmentally friendly method for the preparation of high-value natural antioxidant phloretin was described in this work.Naringin dihydrochalcone was prepared from naringin which is a kind of natural citrus extract by one pot hydrogenation,and then was hydrolyzed byα-rhamnosidase and cellulase to product phloretin.The process conditions including pH,temperature and substrate to enzyme ratio ofα-rhamnosidase and cellulase were optimized by single factor and orthogonal experiments.The antioxidant activity of phloretin,trilobin,naringin dihydrochalcone and naringin were also studied.The results showed that the optimum conditions ofα-rhamnosidase were as follow:temperature of 60℃,pH of 4.0,and the substrate to enzyme ratio of 0.6:1.The optimum conditions of cellulase were as follow:temperature of 45℃,pH of 5.5,and the substrate to enzyme ratio of 0.3:1.Under these optimum conditions,the conversion of phloretin was 96.1%,which increased by 10.53%compared to the original method.The orders of antioxidant activity were as follows:the DPPH free radical scavenging capacity of phloretin(0.18±1.45)>trilobatin(0.3±1.63)>naringin dihydrochalcone(0.95±1.24)>naringin(8±1.97),the reduced iron ion capacity of phloretin(7.1±0.68)>trilobatin(2.51±0.75)>naringin dihydrochalcone(2.05±0.58)>naringin(0.11±0.92).The new preparation method of phloretin was mild,short-cycle,high-conversion and was easy to scale up.Phloretin produced by this method had a good antioxidant activity.This work will be helpful to the enlarge production and application of phloretin.