钠离子是饮用水中的重要金属离子，为探明其对绿茶茶汤滋味品质的影响，本文分析了不同浓度钠离子（0~200 mg/L）对普通绿茶茶汤滋味品质的影响及其内在原因。研究结果表明，添加外源钠离子（NaCl）可以一定程度上影响普通绿茶茶汤的苦味、涩味和醇度等滋味强度；适量的钠离子（20 mg/L）可以有效降低普通绿茶茶汤的苦味和涩味强度、提高茶汤醇味程度，从而改善绿茶茶汤的整体滋味品质。通过分析，发现钠离子的添加对茶汤滋味品质成分的含量没有显著影响，而是通过改变儿茶素（EGCG）、咖啡碱和茶氨酸等主要滋味品质成分及其混合液的呈味特性来影响绿茶茶汤整体滋味品质。本研究还分析了不同阴离子钠盐对绿茶茶汤滋味品质的影响差异，结果发现氯化钠和硫酸钠对普通绿茶茶汤滋味品质的改善显著好于其他钠盐。本研究结果将为绿茶饮料的滋味品质调控提供理论基础。

Sodium ion (Na+) is an important metal ion in drinking water. In order to understand the effect of Na+ on the taste quality of green tea liquor, different mass concentrations (0~200 mg/L) of Na+ were added to common green tea liquor and the taste quality and underlying causes were investigated. The results showed that the addition of exogenous Na+ (sodium chloride) could influence the intensities of bitter taste, astringent taste, and mellow taste to some extent. An appropriate Na+ concentration (20 mg/L) could effectively reduce the intensities of bitter taste and astringent taste and increase the intensity of mellow taste, thus improving the overall taste quality of green tea liquor. The analysis showed that the addition of Na+ had no significant effects on the concentration of taste components in green tea liquor, but affected the overall taste quality by changing the main taste quality components, including epigallocatechin gallate (EGCG), caffeine, and theanine, and the taste characteristics of their mixture. The different effects of sodium salts with different anions on the taste of green tea liquor were also analyzed in this study, and the results showed that sodium chloride and sodium sulfate could better improve the taste of green tea liquor than the other sodium salts. The results of this study will provide a theoretical basis for improving the taste quality of green tea beverages.

国家自然科学基金项目（31101248、31671861）；中国农业科学院农业创新工程（CAAS-ASTIP-2014-TRICAAS）