2种焙火工艺下武夷岩茶的物质转化

Compounds transformation in Wuyi rock tea under two baking processes

  • 摘要: 【目的】比较急火快攻和文火慢炖2种焙火工艺对武夷岩茶感官特征和物质转化的影响,为岩茶制作工艺优化和标准化生产提供参考依据。【方法】采用急火快攻和文火慢炖2种焙火工艺对武夷肉桂毛茶进行焙火加工,以毛茶为对照,通过感官审评、靶向定量和非靶向代谢组学方法,对2种焙火工艺样品的儿茶素、咖啡碱和游离氨基酸含量变化,黄酮及其糖苷、酯类化合物、氨基酸衍生物、有机酸、核苷类及其衍生物构成进行研究。【结果】感官审评结果显示,急火快攻工艺加工的武夷岩茶滋味的刺激性明显强于文火慢炖茶。急火快攻和文火慢炖2种焙火工艺加工的武夷岩茶没食子酸含量(0.82和1.01 mg/g)、表儿茶素没食子酸酯含量(2.60和2.40 mg/g)、游离氨基酸总量(2.78和5.35 mg/g)与毛茶存在显著差异(P<0.05,下同),2种烘焙工艺间的咖啡碱含量(11.69和13.29 mg/g)、没食子酸含量、表儿茶素含量(1.90和1.30 mg/g)和游离氨基酸总量差异显著。对存在极显著(P<0.01)差异的6897个物质特征峰进行KEGG代谢通路富集分析,共富集到107条代谢通路,鉴定到的焙火工艺所致差异代谢物涉及黄酮及其糖苷、酯类化合物、氨基酸衍生物、有机酸、核苷类及其衍生物等;所构建的偏最小二乘法判别模型,可通过无色花青素、二氢杨梅素、天竺葵素、山柰酚-3-O-龙胆双糖苷-7-O-鼠李糖苷、槲皮素-3-鼠李糖苷-7-鼠李糖苷、无色飞燕草素等黄酮及其糖苷类物质较好地区分出2种焙火工艺。【结论】急火快攻和文火慢炖2种焙火工艺导致武夷岩茶在咖啡碱、没食子酸、黄酮及其糖苷类、游离氨基酸组分上产生差异,表现在感官上急火快攻工艺的茶刺激性略强于文火慢炖,其中黄酮及其糖苷类组成的差异是造成刺激性差异的关键。

     

    Abstract: 【: Objective】This study aimed at comparing the effects of two baking processes,fast baking and slow baking, on their sensory characteristics and chemical transformation. Wuyi rock tea were compared,through which to provide a reference for optimizing corresponding producing process and standardized production.【Method】Wuyi Rougui raw tea was baked by fast baking and slow baking,with raw tea as control. The changes of catechin,caffeine and free amino acid contents,the composition of flavonoids and its glycosides,ester compounds,amino acid derivatives,organic acid, nucleosides and corresponding derivatives of the samples by two baking processes were investigated by sensory evaluation,targeted quantification and non-targeted metabolomics methods.【Result】According to sensory evaluation,the sensory irritation of fast baking tea was obviously stronger than that of slow baking tea. The results of component quantitative analysis showed that both baking processes resulted in gallic acid(fast baking,0.82 mg/g,slow baking,1.01 mg/g;following data in the same order),epicatechin gallate(2.60 mg/g,2.40 mg/g)and total free amino acids(2.78 mg/g,5.35 mg/g)significantly different from that of raw tea(P<0.05,the same below). There were significant differences between these two baking processes included caffeine(11.69 mg/g,13.29 mg/g),gallic acid,epicatechin(1.90 mg/g,1.30 mg/g) and total free amino acids. KEGG metabolic pathway enrichment analysis of 6897 characteristic peaks with extremely significant(P<0.01)differences enriched 107 metabolic pathways,the identified differential metabolites caused by the baking process involved flavonoids and their glycosides,ester compounds,amino acid derivatives,organic acids,nucleosides and their derivatives. And the least partial square discriminant model mainly applied flavonoids and corresponding glycosides such as colorless anthocyanin,dihydromyricetin,geranithin,kaempferol-3-rhamnoside,disaccharide-7-MelO-rhamnoside,quercetin-3-rhamnoside-7-rhamnoside,colorless sphingosin and their glycosides to distinguished two baking techniques from each other.【Conclusion】The two baking processes lead differences mainly in caffeine,gallic acid, flavonoids and corresponding glycosides,free amino acids,resulting in distinct taste characteristics between these two teas. Differences in the composition of flavonoids and their glycosides appear to be the primary contributing factor.

     

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