微波辅助提取橄榄苦苷及其抗氧化性能研究

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%±0.11%),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℃)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。

Microwave-assisted extraction of oleuropein from olive leaves and its antioxidant properties

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.