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

‘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。

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.