杀青方式对夏季绿茶化学成分及滋味品质的影响

杀青是绿茶加工的关键工序,对绿茶品质的形成具有重要作用。为探究杀青方式对夏季绿茶化学成分及滋味品质的影响,采用超高效液相色谱-四级杆-飞行时间质谱(UPLC-Q-TOF/MS)对微波杀青、滚筒杀青、蒸汽杀青3种杀青方式加工后的夏季绿茶进行化学成分分析,同时,分别采用咖啡碱、表没食子儿茶素没食子酸酯和谷氨酸钠为标准苦味、涩味和鲜味物质对3种杀青方式加工的夏季绿茶进行滋味强度分析。液质联用分析结果表明,蒸汽杀青、滚筒杀青、微波杀青对夏季绿茶中的儿茶素、黄酮糖苷、原花青素、聚酯型儿茶素、氨基酸、酚酸和有机酸等化学成分含量具有明显的影响。滋味等效量化结果表明,杀青方式可以较明显地改变夏季绿茶的滋味,不同杀青方式加工绿茶的苦味强度为:滚筒杀青蒸汽杀青微波杀青;涩味强度为:蒸汽杀青滚筒杀青微波杀青;鲜味强度3种杀青方式间无统计学显著差异。

Study on the Effects of the Fixation Methods on the Chemical Components and Taste Quality of Summer Green Tea

As a key processing craft, fixation plays a key role in the formation of green tea quality. To study the effects of fixation methods on the summer green teas, a method based on ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) combined with equivalent-quantification of the tea taste, in which caffeine, epigallocatechin gallate and sodium glutamate were used as bitter, astringent, and umami reference, respectively, was applied to investigate the difference of the chemical components and taste quality in summer green teas made by microwave fixation, rotary continuous fixation and steam fixation, respectively. Results of LC-MS analysis demonstrated that the contents of catechins, flavonol/flavone glycosides, procyanidins, theasinesins, amino acids, phenolic acids, and organic acids were significantly influenced by the fixation methods. Equivalent-quantification of the tea taste (umami, bitterness and astringency) also showed that fixation methods could change the taste quality of the summer green teas: the bitterness was higher in the green teas produced by rotary continuous fixation than by steam fixation then by microwave fixation; the astringency was higher in the green tea produced by steam fixation than by rotary continuous fixation then by microwave fixation; the umami scores did not exhibited statistical differences among these three groups of tea.