啤酒花茎多酚的提取优化及其抗氧化活性

为啤酒花加工废弃物的综合开发利用提供参考,以啤酒花茎为试验材料,采用超声辅助丙酮法提取多酚,通过单因素试验考察料液比、提取时间、丙酮体积分数和提取次数4个因素对啤酒花茎多酚含量的影响,并利用响应面法优化其提取工艺。结果表明:通对响应面法建立的啤酒花茎多酚提取回归方程为Y=106.5+1.64A+2.13B+2.63C+11.12D+0.51AB-2.53AC+0.19AD+4.37BC-0.87BD-0.24CD-3.85A~2-2.41B~2+1.04C~2-3.65D~2,模型决定系数R2=0.933 8,该回归模型的拟合程度良好;最佳提取工艺为提取时间20min、料液比1∶12、丙酮体积分数60%、提取4次,此条件提取啤酒花茎多酚的含量为115.89mg/g,与理论预测值116.56mg/g接近。啤酒花茎多酚对DPPH自由基的清除率为90.70%,半清除浓度(SC_(50))为22.81g/mL。采用响应面法优化的啤酒花茎多酚超声辅助提取工艺准确可靠,可用于啤酒花茎多酚的实际提取;啤酒花茎多酚具有较强的抗氧化活性,可作为天然抗氧化资源进行开发利用。

Extraction Optimization and Antioxidant Activity of Polyphenols from Stem of Humulus lupulus

To provide references for integrated exploitation and utilization of the processing wastes of H.lupulus,taking stem of H.lupulus as the test material,the ultrasound-assisted acetone method was employed to extract polyphenols from stem of H.lupulus,and the effects of extraction time,materialliquid ratio,acetone concentration and extraction number on the contents of polyphenols were investigated by single factor experiment.The extraction process was further optimized by response surface methodology.Results:Regression equation for extracting polyphenols from stem of H.lupulus established by response surface method is Y=106.5+ 1.64A+ 2.13B+2.63C+ 11.12D+0.51AB-2.53AC+0.19AD+4.37BC-0.87BD-0.24CD-3.85A2-2.41B2+1.04C2-3.65D2,with thedetermination coefficient of R2 =0.933 8,the regress model is of fine fitting degree.Optimal extraction conditions are 20 min of extraction time,1 ∶ 12 of material-liquid ratio,60％ of acetone concentration,and 4 times of extraction number.Under above conditions,the actual content of polyphenols is 115.89 mg/g that is close to the theoretical value (116.56 mg/g),the DPPH free radical clearance rate of polyphenols from stem of H.lupulus is 90.70％,with SC50 value of 22.81 g/mL.The ultrasound-assisted extraction process optimized by response surface method is accurate and reliable to extract polyphenols from stem of H.lupulus,which is available for extracting polyphenols from stem of H.lupulus in practice;Polyphenols from stem of H.lupulus is of strong antioxidant activity,and can be exploited and utilized as natural antioxidant resources.