青砖茶主要化学成分在储存及渥堆过程中代谢分析

Chemical changes of Qingzhuan tea with different storage and different pile time

选取不同年份青砖茶和不同渥堆陈化时间的毛茶为原料,用高效液相色谱法检测不同年份青砖茶儿茶素及氨基酸等理化成分,采用气相色谱-质谱联用技术检测挥发性成分组成,用超高效液相色谱法检测其不同渥堆时间的主要化学成分。结果表明,青砖茶在储存过程中,游离氨基酸、酯型儿茶素EGCG和ECG、非酯型儿茶素EC和C的含量均随着储存年份的增长呈现降低趋势,没食子酸GA的含量则呈现上升的趋势。青砖茶样可溶性糖、挥发性成分雪松醇的含量随着储存年份的延长整体上呈现增加趋势,而香叶基丙酮、芳樟醇、β-紫罗兰酮和叶绿醇等显著下降。在渥堆过程中,儿茶素呈现出逐步降解趋势,与毛茶相比较12个月后儿茶素含量仅剩余8.61%。

Qingzhuan tea samples with different storage and different pile ageing time were collected. Chemical compositions （catechins and free amino acids） were determined by high-performance liquid chromatography （HPLC）, and the volatile compounds in Qingzhuan tea were analyzed by gas chromatography and mass spectrograph （GC-MS）. The changes of catechins in the process with different pile time were determined by ultra-performance liquid chromatograpgy （UPLC）. The results indicated that the contents of free amino acids in Qingzhuan tea decreased with the prolongation of storage time. And caffeine maintained at a stable level, EGCG and ECG as well as EC and C also decreased with the prolongation of storage time. However, GA increased by prolonging the storage time, and the contents of EGC and tea total polyphenols increased firstly and then decreased. The soluble sugar content in Qingzhuan tea samples of different aging years showed a wavy trend with the prolongation of the storage time With the increase of the aging year, the content of cedrol gradually increased, and the contents of geranyl acetone, linalool,β-ionone and chlorophyll declined significantly. The total catechins showed a gradual degradation trend in different pile time, and the content of catechins was only 8.61% after 12 months compared with the control.