银杏果肉中游离酚与结合酚的提取与抗氧化活性的测定

Extraction and Antioxidant Activity of Free Phenols and Bound Phenols from Pulp of Ginkgo Biloba

以银杏果肉为原料,首先提取游离酚,然后研究提取时间、料液比、NaOH浓度和提取温度对残渣中结合酚得率的影响;最后以没食子酸丙酯为对照,分析2种多酚提取物的抗氧化能力。结果表明,银杏果肉中结合酚的最佳提取工艺条件为NaOH浓度1.25 mol/L,料液比1∶30(g∶mL),提取时间3.5 h,提取温度35℃,在此条件下,银杏果肉结合酚提取率达(388.30±9.75)μg/g。抗氧化活性试验结果表明,银杏果肉中游离酚比结合酚均具有更高的ABTS+自由基和超氧根离子自由基清除能力;而结合酚具有较高的Fe2+络合能力和DPPH自由基清除能力。此外,二者均表现出较高的还原力。

In this experiment,the pulp of ginkgo biloba was used as raw material to extract free phenol,and then the effects of extraction time,solid-liquid ratio,alkali concentration and extraction temperature on the yield of binding phenol in the residue were studied.Finally,the antioxidant capacity of the two polyphenol extracts was analyzed with propyl gallate as the control.The results showed that the optimum extraction conditions were as follows:the concentration of NaOH was 1.25 mol/L,the ratio of solid to liquid was 1:30(g:mL),the extraction time was 3.5 h,and the temperature was 35℃.Underthese conditions,the yield of binding phenol from the pulp of ginkgo biloba reached(388.30±9.75)μg/g.The results of antioxidant activity showed that free phenols had higher scavenging activity on ABTS+and super oxide radicals;while the bound phenols exhibited higher ability to reduce DPPH·radical and Fe2+.Both free and bound phenols showed high reducing power.