余甘子果渣多酚提取工艺优化及其抗氧化活性分析

余甘子果实榨汁后剩余的果渣中含有大量的多酚类物质,为进一步提高余甘子资源的利用率,本研究以多酚提取量为指标,对余甘子果渣多酚的提取工艺进行优化。首先通过单因素试验,考察了乙醇体积分数、提取温度、提取时间及料液比对多酚提取量的影响。在单因素试验的基础上,采用三因素三水平的Box-Behnken响应曲面试验,对余甘子果渣多酚的提取工进行优化,优化得到的最佳余甘子果渣多酚提取工艺条件为:提取温度60℃,乙醇体积分数60%、提取时间80 min,料液比1∶33 g/mL,在此条件下进行三次平行验证试验,结果多酚提取量为126.25 mg/g,与预测值的相对标准偏差仅为0.59%。采用抗氧化能力指数(ORAC)、铁离子还原能力(FRAP)、ABTS自由基清除能力和β-胡萝卜素漂白试验对提取物的抗氧化活性进行了分析评价,提取物的ORAC指数达到VC的50%以上,FRAP达到了VC的40%以上,ABTS自由基的半抑制浓度IC50显著低于(p<0.01)VC和Trolox,对β-胡萝卜素漂白抑制的IC50高于常用的脂类抗氧化剂BHT,但未达到BHT的2倍,而且显著低于Tolox,表明余甘子果渣多酚提取物具有较高的抗氧化活性。本研究结果为余甘子果渣多酚的进一步研究利用提供了试验基础。

Optimization of Polyphenols Extraction from Phyllanthus emblica L. Pomace and Its Antioxidant Activity Analysis

The remaining Phyllanthus emblica pomace after juicing contains a large amount of polyphenols. In order to further improve the resources utilization of Phyllanthus emblica,the extraction process of polyphenols from Phyllanthus emblica pomace was optimized for increased extaction amount of polyphenols. The influence of ethanol volume fraction,temperature,extraction time and ratio of material to solvent on extraction efficiency was investigated initially by single-factor test. On the basis of the single-factor test,the Box-Behnken response surface methodology was used to optimize the extraction technology,mathematical model was established by implementing three factors and three levels. The optimum technological conditions were extraction temperature of 60 ℃,ethanol volume fraction of 60%,extraction time of 80 min,ratio of material to solvent of 1∶33 g/mL. Under these optimized conditions,the average extaction amount of polyphenols was 126.25 mg/g,the relative standard deviation was 0.59% compare with the predicted value. The antioxidant activity of extractive was evaluated by oxygen radical absorbance capacity(ORAC),ferric ion reducing antioxidant power(FRAP),ABTS and β-carotene bleaching test. The ORAC and FRAP of extractive was more than 50% and 40% of VC respectively. The IC50 of ABTS of extractive was less than that of VC and Trolox significantly. The IC50 of β-carotene bleaching of extractive was less than 2 times of BHT,and was significant less than Trolox.The result indicated the extractive had high antioxidant activity. The results of this study provide a test basis for further research and application of polyphenols in Phyllanthus emblica.