LI Dalei, WENG Yanru, DU Liping, WANG Chao, MA Lijuan, XIAO Dongguang
In order to understand the differences in aroma components of different brands of Pu-erh tea, volatile compounds and characteristic aroma of three kinds of Pu-erh tea were analyzed and identified by electronic nose (E-nose) and headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). The results showed that E-nose could distinguish three brands of products well. The principal component analysis showed that the differences between different brands were obvious with good distinction. Further HS-SPME-GC-MS analysis showed that seventy-four compounds in total were identified from three brands of Pu-erh tea. Among them, thirty-eight compounds were shared between all brands of Pu-erh tea tested. Sixty-six, fifty-three, and forty-eight volatile compounds were identified in Dayi Pu-erh tea, Lao Tongzhi Pu-erh tea, and Lancang ancient tea, respectively. The main compounds were aldehydes, alcohols, ketones, and methoxy-phenolic compounds etc. Differences in varieties and contents of volatile compounds between different brands of Pu-erh tea were significant. The main compounds that showed differences including 2-hydroxy-6-methoxy-benzaldehyde, safranal,linalool oxide, terpinen-4-ol, 6-methyl-5-hepten-2-one, (E,E)-3,5-octadien-2-one, 1,4-dimethoxy-benzene, 1-methoxy-4-(1-propenyl)-benzene, 1-methyl-2-(1-methylethyl)-benzene, α-terpinene, dimethyl phthalate, and caffeine. Analysis of odour active values showed that different odors were caused by (E)-2-octenal, (E,E)-2,4-nonadienal, nonanal, α-ionone, and geranyl acetone.
