决明子蛋白质提取工艺研究及其体外消化率的测定

Semen Cassiae's protein extraction and its digestibility determination in vitro

目的:优选决明子蛋白质的最佳提取工艺及体外消化率测定。方法:采用正交试验法,以凯氏定氮法测得决明子蛋白质的含量和得率为考察指标,对提取过程中缓冲液浓度、pH值、固液比及提取时间4个工艺因素进行优化研究,并用胃蛋白酶-胰蛋白酶法测定体外消化率。结果:决明子蛋白质最佳提取工艺为KH2PO4-NaOH缓冲液浓度为50 mmol/L,pH值为8.0,液固液比为1∶50,提取12h。影响决明子蛋白提取各因素的主次关系为:缓冲液浓度>pH值>固液比>提取时间,其中缓冲液浓度和pH值的影响达显著性水平。优化参数下提取的决明子粗蛋白含量为93.0%,提取率为94.2%,体外消化率为97.6%。结论:决明子是含蛋白质较高的植物种子,其蛋白质消化率较高,具有很好的开发前景。

Object： To optimize the technology of extracting protein from Semen Cassiae and determine the protein digestibility in vitro. Methods： Conditions for the extraction were studied by orthogonal experimental design of L9（3^4） as guided by the content and extraction efficiency of total protein of Semen Cassiae in the extract, and four factors were chosen, including the buffer concentration, pH value, the ratio of solid to liquid and the extraction time. Pepsin and trypsin were used together to determine the protein in vitro digestibility. Results： The optimum extracting condition obtained： The buffer KH2PO4-NaOH concentration was 50 mmol/L, pH value was 8.0, the ratio of solid to liquid was 1：50, and the extracting time was 12 h. The results showed that the order of factors influencing protein extraction is as follows： buffer concentration〉pH value〉 the ratio of solid to liquid 〉the extracting time. The buffer concentration and pH value show significant effect. The content of extracting protein from Semen Cassiae was 93.0%, the extraction yield was 94.2%, and the protein in vitro digestibility was 97.6%. Conclusion： Semen Cassiae is a plant seed which is good source of protein, and the protein digestibility in vitro is so high that it shows a promising prospect.