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为了研究茶叶内部可能存在的苦味抑制效应,采用定量感官分析法比较了蔗糖、D-葡萄糖酸钠、L-谷氨酸钠、乳酸锌和腺苷-5′-磷酸(AMP)对咖啡因、EGCG(表没食子儿茶素没食子酸酯)和茶汤的苦味掩盖作用。结果表明,低浓度的蔗糖(5 mmol.L-1)、葡萄糖酸钠(5 mmol.L-1)和谷氨酸钠(2 mmol.L-1)对苦味掩盖不明显,在高浓度下这3种物质的苦味掩盖效果明显,但对茶汤滋味的协调性产生不利影响。乳酸锌(0.5～1.5 mmol.L-1)和AMP(0.2～0.6 mmol.L-1)对苦味的掩盖作用均明显,但是乳酸锌即使在低浓度下涩感也较强,加重茶汤涩感;AMP是最为有效的苦味掩盖剂,可有效掩盖茶汤的苦味,且对茶汤滋味协调性没有明显影响。此外,还建立了茶叶中AMP的HPLC测定方法,1/15 mmol.L-1的磷酸盐缓冲体系(pH7.0,含5 mmol.L-1四丁基溴化铵,5%甲醇)为主要流动相,35℃条件下C18柱分离,254 nm测定AMP的方法。茶叶中AMP的含量(0.23～0.32 mg.g-1)尚未达到明显掩盖茶叶自身苦味的水平。
In order to study the possible inhibitory effect of bitterness inside tea leaves, the effect of sucrose, sodium D-gluconate, sodium L-glutamate, zinc lactate and adenosine-5’-phosphate (AMP) EGCG (epigallocatechin gallate) and tea bitter masking effect. The results showed that bitterness masking was not obvious at low concentrations of sucrose (5 mmol.L-1), sodium gluconate (5 mmol.L-1) and sodium glutamate (2 mmol.L-1) The masking effect of these three substances is obvious, but adversely affects the coordination of the taste of tea. The masking effect of bitterness of zinc lactate (0.5-1.5 mmol.L-1) and AMP (0.2-0.6 mmol.L-1) were all significant, but the zinc lactate had a strong sense of astringent even at low concentration, ; AMP is the most effective bitterness masking agent, which effectively masks the bitterness of tea and has no obvious effect on taste coordination. In addition, the HPLC method for the determination of AMP in tea was also established. The 1/15 mmol.L-1 phosphate buffer system (pH 7.0, containing 5 mmol.L-1 tetrabutylammonium bromide, 5% methanol) The main mobile phase, C18 column separation at 35 ℃, 254 nm determination of AMP. The content of AMP in tea (0.23-0.32 mg.g-1) has not yet reached the level that obviously masks the bitter taste of tea.