微波辅助提取橄榄苦苷及其抗氧化性能研究

摘要

以油橄榄叶为原料,研究微波辅助提取橄榄苦苷的最佳工艺.通过单因素实验考察了溶剂种类,提取时间、提取温度、提取功率、乙醇浓度和料液比对橄榄苦苷得率的影响.在单因素实验的基础上,选取提取时间、提取温度和料液比进行L9(33)正交实验,结果表明,最优提取条件为:乙醇浓度75％,料液比1∶50 g/mL,提取温度40℃,提取时间3 min,提取功率600 W在该条件下橄榄苦苷得率为(8.06％±0.06％),总多酚、总黄酮含量为(7.85％±0.01％)和(2.20％±0.1 1％),而热浸提橄榄苦苷的得率为(6.61％±0.16％),总多酚、总黄酮含量为(6.99％±0.13％)和(1.25％±0.11％).同时探讨了不同干燥方式对DPPH自由基清除能力的影响,发现鼓风干燥(30 ℃C)的效果高于真空干燥和真空冷冻干燥,其IC50值分别为0.65、0.71和0.69 mg/mL.微波辅助提取橄榄苦苷等活性物质的含量高于热浸提,鼓风干燥(30℃)优于其他干燥方式,本文为油橄榄叶活性物质的提取和保存提供借鉴.%The operation conditions of microwave-assisted extraction of oleuropein from olive leaves were studied.According to single factor experiment design,the effects of solvent,extraction time,temperature,solid-liquid ratio,ethanol concentration and extraction times on extraction yield of oleuropein were investigated.Based on the results of single factor experiment,three more significant factors,extraction temperature,extraction time and solid-liquid ratio,were selected in L9 (33) orthogonal experiment.The optimal extraction parameters were determined as follows:ethanol concentration 75％,solid-liquid ratio 1∶50 g/mL,extraction temperature 40 ℃,extraction time 3 min,microwave power 600 W.Under this operational condition,the oleuropein yield was(8.06％ ±0.06％),the total polyphenols content was(7.85％ ± 0.01％)and the total flavonoids content was(2.20％ ± 0.11％),however,the oleuropein yield was (6.61％ ± 0.16％),the total polyphenols content was (6.99％ ±0.13 ％)and the total flavonoids content was (1.25％ ± 0.11％) by thermal circumfluence extraction.The effects of the drying methods on DPPH free radical scavenging ability were discussed.It was observed that the olive leaf extract obtained by oven drying(30 ℃,IC50 =0.65 mg/mL)was found to have more scavenge DPPH capacity than that obtained by freeze vacuum drying (IC50 =0.69 mg/mL)and vacuum drying(IC50 =0.71 mg/mL).Microwave-assisted extraction of oleuropein and other active components is better than thermal circumfluence extraction.In three drying methods,oven drying(30 ℃)is better than other drying methods.A method is provided for extraction and preservation of olearopein in this article.