紫娟(熟茶)人工发酵过程中挥发性香气组分特征分析

Characteristic Aroma Components in Ripe Zijuan Tea during Artificial Fermentation

为探明人工发酵过程对紫娟(熟茶)挥发性风味的形成作用,以同一批从原料入堆(0 d)到发酵结束(42 d)的7个紫娟(熟茶)加工阶段样为材料,利用顶空-固相微萃取-气相色谱-质谱技术进行挥发性成分检测。共鉴定出7大类92种已知挥发性成分:醇类、酮类、醛类、碳氢化合物、酸类、酚醚类和含氧杂环化合物。经发酵后,紫娟茶的香气丰富性增强。通过相关性分析,7(F1)~35 d(F5)的过程,是紫娟(熟茶)香气品质形成的关键时期。通过香气定性结合感官审评分析,脱氢芳樟醇、β-石竹烯及甜没药烯是紫娟茶类辛香的标志性贡献物;发酵过程中产生发酵独有的坚果香——苦杏仁香(苯甲醛)、动物香——奶香(对甲氧基苯乙烯)及微生物发酵气味;花香、果香及辛香的紫娟晒青经发酵形成紫娟(熟茶)花香(紫罗兰花、玫瑰花)、甜香、温和木香及微弱辛香的香气特征。本研究结果为进一步开展紫娟(熟茶)发酵风味香与微生物之间的代谢关系研究提供一定理论依据。

In order to explore the role of artificial fermentation in the formation of the volatile flavor of ripe Zijuan tea,seven samples from the same batch were collected at different processing stages from the raw material piled up(day 0)to the end of fermentation(day 42)to analyze their volatile components by headspace solid-phase microextraction(HS-SPME)coupled to gas chromatography-mass spectrometry(GC-MS).A total of 92 volatile components were identified including alcohols,ketones,aldehydes,hydrocarbons,acids,phenol ethers,and oxygen-containing heterocyclic compounds.The fermentation process enriched the aroma of the tea.According to correlation analysis,the period from day 7(F1)to day 35(F5)was key to forming the aroma characteristics.Aroma qualitative analysis and sensory evaluation indicated that dehydrolinalool,β-caryophyllene,and myrrholene were the signature contributors to the spicy aroma of Zijuan tea.During the fermentation process,a nutty aroma namely bitter apricot kernel-like aroma(benzaldehyde),uniquely produced by fermentation,an animal-like aroma namely milky aroma(p-methoxystyrene)and a microbial fermentation-derived odor were produced.Sun-dried Zijuan tea leaves had floral,fruity and spicy aromas,and during fermentation into ripe Zijuan tea,floral(violet flower-like and rosy),sweet,mild woody and faint spicy aroma characteristics were generated.The results of this study lay the foundation for further research on the relationship between the flavor of ripe Zijuan tea and microbial metabolism.