碱提酸沉法提取茶叶蛋白质的研究

Extraction of Tea Protein using Alkali Extraction-acid Precipitation Method

以绿茶为原料,采用碱提酸沉的方法提取茶叶蛋白质,以料液比、碱液浓度、温度、时间为考查因素,研究茶叶蛋白质的最佳提取工艺条件,并对提得的茶叶蛋白质进行了氨基酸分析。结果表明:碱提酸沉法提取茶叶蛋白质的最佳工艺条件为料液比1:25(m/V),碱液浓度0.3 mol/L,提取温度50℃,提取时间1 h,连续提取两次,茶叶蛋白质的提取率达到85.50%。茶叶蛋白质的最佳等电点为3.0,蛋白质沉淀率为67.85%,粗提取物中蛋白质质量分数为47.76%。氨基酸分析表明:茶叶蛋白质含有18种氨基酸,其中必需氨基酸含量占40.68%;氨基酸评分高于大豆,接近母乳和牛奶,是一种优质的叶蛋白质资源。综合考虑,此方法操作简单,生产成本低,提取效果好,适用于茶叶蛋白质的工业化生产。

Extraction of tea-protein from green tea by using alkali extraction and acid precipitation was investigated. Amino acid compositions of the tea protein ware also analyzed. The results showed that the optimum extraction parameters were NaOH 0.3 mol/L, green tea/water solution （m/V） 1：25, temperature50℃, stirring time 1 h and extraction times twice, under which the protein extraction efficiency was 85.50%. The best pI of the tea protein was 3.0, the protein concentration precipitation rate was 67.85% and the protein content was 47.76%. The tea protein contained 18 kinds of amino acid, in which essential amino acids were 40.68%. Amino acid score of tea protein was higher than soybean protein and close to those of breast milk and milk, which indicated that tea protein was one of high quality leaf proteins. This method is easy to operate, low-cost and highly efficient, thereby being suitable for the massive industrial production of tea protein.