采用顶空-固相微萃取-气质联用法测定陈年普洱茶中挥发性组分,其中烷烃类化合物含量较高,但它对茶叶香气几乎没有贡献,为此陈年普洱茶香气以芳烃类及其衍生物和萜烯类化合物为主,以酯类及其衍生物为辅。芳烃类及其衍生物以2,2',5,5'-四甲基联苯和1,2,3-三甲基-4-丙烯基-萘为主,萜烯类化合物以α-雪松烯和长叶烯两种异构体为主,并以α-雪松烯含量作为陈年普洱茶的检测指标。陈香味关联成分1,2,3-三甲氧基苯的含量随着萃取温度的提高而增加,最高约1.73%。同时采用比色法测得普洱茶的茶多酚、总黄酮、可溶性总糖及游离氨基酸含量分别为50.87、11.7、5.09、1.69 mg·g-1。%Volatile compounds of aged Pu-erh tea were analyzed by solid-phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Alkanes were the most abundant volatile components in aged Pu-erh tea, however, it contributes scarcely to the aroma of tea. Aromatic hydrocarbons an d their derivatives and terpenes were two major aromatic groups characterized, then the esters and their derivatives. Aromatic hydrocarbons and their derivatives are mainly consisted of 1,1'-Biphenyl, 2,2',5,5'-tetramethyl- and Naphthalene, 1,2,3-trimethyl-4-propenyl-, (E)-, terpene compound are mainly consisted of α-cedrene and longifolene, and the relative content ofα-cedrene was selected as the index for analyzing aged Pu-erh tea. The content of the key constituents of age-aroma, 1,2,3-Trimethoxybenzene was increased with the raise of temperature, and the highest relative abundance of 1,2,3-Trimethoxybenzene is about 1.73%. The contents of polyphenols, total flavonoids, total soluble saccharide and free amino acid were 50.87, 11.7, 5.09 and 1.69 mg·g-1, respectively, which were measured by colorimetric method.
展开▼