茶叶游离氨基酸含量测定中的提取方法

以烘青成茶为材料，采用不同粉碎细度（不粉碎、０．９ｍｍ、０．４ｍｍ）、不同浸提水温（８０℃、９０℃、１００℃）和不同浸提时间（３０ｍｍ、４５ｍｍ、６０ｍｍ）三因素三水平的正交试验，对茶叶游离氨基酸的提取方法进行了研究。结果表明，其最佳浸提方案是：成品茶样经粉碎过４０目（０．４５ｍｍ）筛，称取样品３ｇ茶样用４００ｍｌ沸蒸馏水冲泡，置于１００℃恒温水浴锅中浸提３０ｍｉｎ后抽滤定容至５００ｍｌ，而后用茚三酮比色法测定其含量。该方法定量准确，不仅适用于常规水溶性成分测定，而且适合于游离氨基酸组份分析。

Methods of Extracting Free Amino Acids From Tea

The methods of extracting the free amino acids (FAA) in baked green tea were investigated with the orthogonal design tests of three factors and three levels, i.e. different powder size level (unpowdered, 0.9 mm, 0.45 mm), different extracting temperatures (80 ℃, 90 ℃ and 100 ℃) and different extracting time (30 min, 45 min and 60 min). Results showed that the best extracted design was: the baked green tea was sifted through a 0.45 mm sieve, the 3 g of sample tea were infused by 400 ml boiling deionized water, and extracted in boiling water bath for 30 min and then the extraction was sucked with suction pump and settled to the volume of 500 ml. The FAA contents were determined by the ninhydrin colorimetric method. This method was proved to be quantitatively accurate and suitable not only to the routine determination of water soluble components but also to the analysis of FAA composition and content in tea.