不同白化期的‘黄山白茶’代谢物差异分析

Metabolites Profiling of Green Tea Processed from ‘Huangshanbaicha No. 1’ Cultivar at Different Albino Stages

摘要:

‘黄山白茶1号’是温度敏感型白化茶树品种，由其鲜叶加工的绿茶，即‘黄山白茶’，具有清香持久、滋味鲜爽等特征。为探究不同白化时期加工绿茶的香气和滋味差异，分析了绿茶中挥发性代谢物、儿茶素、咖啡碱和游离氨基酸含量的变化。结果表明，3个白化时期的‘黄山白茶’在香气和滋味上存在差异。气相质谱（GC-MS）分析表明，共有29个高丰度挥发性化合物被鉴定；主成分分析（PCA）显示芳樟醇、顺-己酸-3-己烯酯、香叶醇、顺-3-己烯醇、（Z）-丁酸-3-己烯酯可能是导致3类绿茶香气存在差异的标志性化合物。滋味成分分析表明儿茶素类物质在白化早期绿茶中含量最低；在白化中期绿茶中略有增加但不显著，而在白化后期绿茶中则显著增加；咖啡碱在3类绿茶中无显著差异；游离氨基酸在白化早期绿茶中含量最高，为干质量的4.4%，而在白化后期绿茶中只占干质量的1.3%。因此，不同时期的‘黄山白茶1号’嫩梢中的代谢物积累存在差异，使得加工的绿茶风味不同。

Abstract:

Tea cultivar ‘Huangshanbaicha No. 1’ (HSBC#1) was bred from natural albino mutants of tea plants. The green tea processed from HSBC#1 possess umami, mellow taste and fresh odor. For investigating the metabolite profile of green tea produced from three albino stages (early, middle, and late) of HSBC#1, the main components in tea, such as volatile compounds, catechins, caffeine, and free amino acids, were analyzed. The green teas produced from different stages of HSBC#1 showed the different odor and taste via sensory evaluation. A total of twenty-nine volatiles was identified and quantified. The principal component analysis indicated that the top five differential volatiles were geraniol, (Z)-hexanoic acid, 3-hexenyl ester, linalool, (Z)-3-hexen-1-ol, and (Z)-butanoic acid, 3-hexenyl ester, approximately contributing to the differences in aroma among green teas. Catechins were lower concentrated in early-stage green tea, but their concentrations increased significantly in late-stage green tea. The amount of caffeine had no difference in three types of green tea. The total content of free amino acids in early-stage green tea accounted for about 4% of dry weight, while that in late-stage green tea only for 1.3% of dry weight. Therefore, the differences in metabolites among tender shoots of HSBC#1 at different albino stages lead to the difference in the flavor of green tea products.