Dynamic changes in amino acids, catechins, caffeine and gallic acid in green tea during withering
Dynamic changes in amino acids, catechins, caffeine and gallic acid in green tea during withering
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DOI：
10.1016/j.jfca.2017.12.008
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发表时间：
2018-03-01
影响因子：
4.3
通讯作者：
Tong, Huarong
中科院分区：
文献类型：
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作者：
Ye, Yulong;Yan, Jingna;Tong, Huarong
为了阐明萎凋过程与绿茶品质之间的关系，研究了绿茶中氨基酸、儿茶素、咖啡因（CAF）和没食子酸（GA）等主要化学成分在萎凋时间（0 ~ 21 h）和温度（15、20和25℃）下的动态变化。采用Duncan检验的单、双向方差分析（ANOVA）分析化学成分的变化。结果表明，在萎凋过程中，大部分游离氨基酸含量随萎凋时间和温度的增加而增加。茶氨酸（Thea）含量略有下降，谷氨酸（Glu）和天冬氨酸（Asp）含量呈增减趋势，脯氨酸（Pro）含量基本保持不变。总游离氨基酸在18h内增加，但在18h后下降。随着枯萎时间和温度的增加，大部分儿茶素含量降低。GA含量随时间和温度的增加而增加；CAF含量随萎凋时间的延长而增加，但与萎凋温度相关性不显著。本试验建议在25℃以下萎凋15-18 h，以获得高品质的绿茶。
In order to clarify the relationship between withering process and green tea quality, dynamic changes in the major chemical components of green tea, including amino acids, catechins, caffeine (CAF) and gallic acid (GA), were investigated during withering at different times (ranging from 0 h to 21 h) and temperatures (15, 20 and 25 degrees C). One-way and two-way analyses of variance (ANOVA) with Duncan's test were used to analyse the change of chemical components. Results showed that during the withering process, contents of most free amino acids increased with increasing withering time and temperature. Theanine (Thea) contents decreased slightly with fluctuations, glutamic acid (Glu) and aspartic acid (Asp) contents presented an increase decrease pattern, whereas proline (Pro) contents remained almost constant. Total free amino acids increased up to 18 h but declined thereafter. Most catechins decreased with increasing withering time and temperature. In addition, GA contents increased with increasing time and temperature; while CAF contents increased with increasing withering time, but were only slightly correlated with withering temperature. This experiment recommended withering for 15-18 h below 25 degrees C to produce high quality green tea.