苜蓿叶蛋白提取工艺参数优化试验研究

Experimental study on parameter optimization of extraction process of leaf protein from alfalfa

以水为提取溶剂,对热絮凝法提取苜蓿中叶蛋白的工艺参数进行优化。分别考察了加水倍量、打浆时间、苜蓿汁液pH、保温时间和温度对提取效果的影响;在单因素基础上,采用四因素三水平正交试验对工艺进行了优化。试验结果表明:保温10 min蛋白提取率达24.4%;随着苜蓿汁液pH的增大,叶蛋白中蛋白提取率和质量分数总体上呈下降趋势:pH为3时提取率最高,为23.3%,pH为6(原浆)时质量分数最高,为61.5%;pH对叶蛋白中叶黄素质量分数有显著影响,pH为6时叶黄素质量分数最高,为1 022.1μg/g,碱性时次之,酸性最小。综合考虑的优化工艺参数为:温度90℃、pH6、打浆时间3 min、加水倍量2.5,此条件下蛋白提取率为33.1%,叶蛋白中叶黄素质量分数为1 200μg/g。

Using water as extracting solvent, the extraction processing parameters of leaf protein from alfalfa were studied. The effects of the ratio of water to alfalfa, pulping time, pH of juice, heat preservation time and temperature were investigated, respectively. Based on these experiments, the orthogonal experimental design was adopted in an extraction process with heat preservation time of 10 min. The results show that pH of juice has significant effects on the yield of protein, protein content and lutein content of leaf protein. But the other parameters have a remarkable influence on the yield of protein only. From the analysis by synthesis the optimized extraction processing parameters, at constant pH value of 6, are temperature of 90℃, pulping time of 3 min. and the ratio of water to alfalfa of 2.5.