Influence of the post-fermentation by four Aspergillus strains on the aroma of pu-erh tea

四种曲霉属真菌发酵对普洱茶香气成分的影响（英文）

Aroma is one of the most important factors for the flavor, taste, and quality of pu-erh tea, and the post-fermentation process has an important influence on the aroma of pu-erh tea. In the present study, the influence of fungi fermentation on the flavor of pu-erh tea was investigated and compared. Volatile compounds from pu-erh tea fermented by four Aspergillus strains, including A. niger, A. oryzae, /1. awamori, and A. glaueus, were extracted and analyzed using ultrasound-assisted extraction-dispersive liquid-liquid microextraction-gas chromatography-mass spectrometry （UAE-DLLME-GC-MS）, and a total of 63 volatile compounds were identified. In comparison with the sun-dried green tea, fermented pu-erh tea contained high levels of methoxyphenolic compounds, such as 1,2,3-trimethoxybenzene, which was the most abundant one. Our results confirmed that the characteristic methoxyphenolic compounds were produced by the activity of Aspergillus during the post-fermentation process, and A. niger and A. awamori were the most important strains for the formation of aroma quality of pu-erh tea.

香气是影响普洱茶风味、口感和质量的重要因素之一,而后发酵过程对于普洱茶香气的形成有着举足轻重的作用。本文旨在研究和比较不同真菌发酵对普洱茶香气成分形成的影响。研究采用黑曲霉、米曲霉、泡盛曲霉和灰绿曲霉固体发酵普洱晒青毛茶,并以超声波辅助萃取分散相液液微萃取结合气相色谱-质谱联用的方法提取和鉴定其挥发性成分。结果共从中鉴定了63个挥发性成分。与普洱晒青毛茶相比,4种真菌发酵茶在发酵过程中产生了大量的甲氧基苯类化合物,其为普洱茶特有的香气成分之一;其中1,2,3-三甲氧基苯的含量最高。普洱茶特征的甲氧基苯类香气成分的产生与曲霉属真菌发酵密不可分,其中黑曲霉和泡盛曲霉对普洱茶香气品质的形成至关重要。