室温条件下储藏年限对湄潭翠芽品质及三维荧光指纹图谱的影响

Effect of Storage Time on Quality and Three-dimensional Fluorescence Fingerprint of Meitancuiya Tea

为探究湄潭翠芽在室温条件下生化成分随贮藏年限的变化规律,通过应用三维荧光光谱技术,结合传统茶叶品质测定方法,研究了贵州湄潭翠芽新茶(2019年加工)、陈茶(2018年、2016年加工)在研磨成粉状后沸水浸提所得茶汤的三维荧光指纹图谱特征及茶叶的色素、茶多酚、氨基酸、咖啡碱、水浸出物含量。研究表明,随着储藏年限的增加,茶汤荧光特性峰强度有增强的趋势,3年的陈茶出现特有的荧光峰位于440nm/470nm,荧光峰值为171.8。新茶香气浓郁、水浸出物、游离氨基酸、茶多酚含量高、酚氨比低,储藏1年后香气大幅度下降、储藏3年后香气全无,茶叶叶绿素、游离氨基酸随贮藏年限变化最为明显,表现为大幅度下降。储藏年限对茶多酚的下降影响不大,陈茶表现在茶汤香气不高,但仍具有很大的保健作用。三维荧光技术可以作为鉴定新茶和陈茶的一类新方法。

In order to explore the variation of biochemical components of Meitan Cuiya tea with storage time at room temperature,the characteristics of three-dimensional fluorescence fingerprints and tea pigments,tea polyphenols,amino acids,caffeine and water extracts.of Meitan Cuiya new tea(processed in 2019)and old tea(processed in 2018 and 2016)extracted by boiling water after grinding into powder were investigated by using three-dimensional fluorescence spectroscopy and traditional tea quality determination methods.The results showed that with the increase of storage life,the fluorescence peak intensity of tea soup had an increasing trend.The unique fluorescence peak of 3 years old tea was 440 nm/470 nm,and the fluorescence peak was 171.8.New tea has strong aroma,high value of water extract,free amino acid,high content of tea polyphenols and low ratio of phenol to ammonia.After one year’s storage,the aroma of new tea decreases dramatically.After three years storage,the aroma of new tea is completely absent.The changes of chlorophyll and free amino acid of tea are most obvious with the storage years,showing a significant decline.The storage life has little effect on the decline of tea polyphenols.The aroma of old tea is not high,but it still has a great health function.Three-dimensional fluorescence technique can be used as a new method to identify new and old tea.