微波辅助提取栀子皂甙的工艺优化及其抗氧化性

Optimization of Microwave-assisted Extraction of Saponins from Gardenia jasminoides Ellis and Its Antioxidant Activity

以栀子粉末为原料,运用微波辅助提取栀子中的皂甙,并对其抗氧化性进行研究。在单因素试验基础上,以微波时间、浸提时间、液固比和乙醇浓度为因素,皂甙得率为响应值,采用Box-Behnken试验设计进行响应面分析。并以抗坏血酸为对照,用铁氰化钾还原法和DPPH自由基的清除率考察栀子皂甙的抗氧化活性。实验结果表明,栀子皂甙微波辅助提取最优条件为微波功率450 W、微波时间40 s、浸提时间9.6 min、浸提温度50℃、液固比21∶1 (m L/g)、乙醇浓度80%,所得最佳得率为13.92%±0.04%,与模型预测皂甙得率相对误差仅为2.05%。微波辅助法提取栀子皂甙简便、提取得率高,回归模型合理可靠,可用于实际预测。抗氧化活性研究表明,栀子皂甙对羟基自由基的还原能力和DPPH自由基清除能力均较好,但其总体抗氧化性低于抗坏血酸。

The microwave-assisted extraction of saponins from Gardenia jasminoides Ellis powder was studied.On the basis of single factor experiment,response surface analysis was carried out with Box-Behnken design,taking microwave time,extraction time,liquid-solid ratio and ethanol concentration as factors,and saponin yield as response value. The antioxidant activity of gardenoside was studied by potassium ferricyanide reduction method and DPPH free radical scavenging rate with ascorbic acid as control.The results showed that the optimal extraction conditions for the extraction of saponins from Gardenia were microwave power 450 W,microwave time 40 s,extraction time 9.6 min,extraction temperature 50 ℃,liquid-solid ratio 21∶1(m L/g) and ethanol concentration 80%,respectively. Under these conditions,the yield of Gardenia saponins was 13.92% ± 0.04%,which had 2.05% of the relative error to the model predictive yield. The study revealed that this microwave-assisted methodology,which was simple and highly efficient,was suitable for extraction of Gardenia jasminoides Ellis saponins. And the regression model was reliable for the yield prediction in practice. The antioxidant activity study showed that abilities of saponins in Gardenia jasminoides Ellis to scavenge hydroxyl radical and DPPH were good,but its overall reducibility was lower than that of ascorbic acid.