有机酸的HPLC检测方法优化及其在白茶检测中的应用  

Optimization of HPLC Method for Determination of Organic Acid and Its Application in Detection of White Tea

作　　者：田宇倩 刘天然 范方媛[1] 龚淑英[1] 宋楚君 Tian Yuqian;Liu Tianran;Fan Fangyuan;Gong Shuying;Song Chujun(Institute of Tea Science,Zhejiang University,Hangzhou 310058)

机构地区：[1]浙江大学茶叶研究所,杭州310058

出　　处：《中国食品学报》2021年第7期320-327,共8页Journal of Chinese Institute Of Food Science and Technology

基　　金：财政部和农业农村部:国家现代农业产业技术体系资助项目(CARS-19)。

摘　　要：茶叶中的有机酸对茶叶品质的形成起重要作用。为研究茶叶中的有机酸,优化其HPLC分析方法,结果显示,设置流动相10 mmol/L KH2PO4,pH 2.65,等度洗脱,流速0.8 mL/min,进样量5μL,检测波长210 nm,柱温30℃;可同时检测茶叶中草酸、酒石酸、奎尼酸、丙酮酸、苹果酸、乙酸、柠檬酸、延胡索酸、琥珀酸等9种有机酸。利用该方法分析不同嫩度白茶及其萎凋过程中有机酸含量,结果显示白牡丹等级有机酸含量最高,寿眉等级有机酸含量最低。柠檬酸、奎宁酸是影响有机酸总量变化的主要成分,丙酮酸、乙酸、柠檬酸含量随嫩度下降而呈下降趋势,苹果酸呈上升趋势,草酸在中等嫩度的白茶中含量较高。在白茶萎凋过程中,萎凋前2/3时段为有机酸代谢转变的活跃时期。其中草酸、奎宁酸、苹果酸、乙酸在萎凋前半程含量显著上升,丙酮酸、延胡索酸在萎凋全程先降后升,而苹果酸萎凋全程先升后降。Organic acids are important metabolites participating in the biochemical metabolism of tea,which are affect the aroma and taste of tea.In this study,the method for determination of organic acids was optimized.The system conditions:mobile phase:isocratic elution with 10 mmol/L KH2PO4,pH 2.65,flow rate:0.8 mL/min,injection volume:5μL,determine wavelength:210 nm,column temperature:30℃.This method can simultaneously detect 9 organic acids including oxalic acid,tartaric acid,quinic acid,pyruvate,malic acid,lactic acid,acetic acid,citric acid,fumaric acid and succinic acid.The contents of organic acids in white teas were detected by the optimized method.The results showed that the content of organic acid in Baimudan was the highest,while that in Shoumei was the lowest.Citric acid and quinine acid were the main components that affected the total amount of organic acids.The contents of pyruvate,acetic acid and citric acid were decreased with the decrease of tenderness,while malic acid was increase.The highest content of oxalic acid was showed in Baimudan and Gongmei.During withering process in white tea,active organic acid metabolism occurred during the first 2/3 period of withering process.The contents of oxalic acid,quinine acid,malic acid and acetic acid increased significantly in the first half of withering,pyruvate and fumaric acid decreased first and then increased during withering,while malic acid decreased first and then decreased.

关 键 词：有机酸 高效液相色谱法 白茶 嫩度 萎凋 

分 类 号：O657.72[理学—分析化学] TS272.7[理学—化学]