Formation of aroma components in roasted or pan-fired green tea by roasting or pan-firing treatment

摘要

Aroma concentrates were prepared from four kinds of. green tea (roten, roten-kuki, kabuse, and ooishita), their roasted teas (light-roasted and medium-roasted), and two kinds of pan-fired tea (roten and kabuse), using a brewed extraction method. Following GC/MS analysis, the aroma patterns of each tea infusion were determined. Eighty-six compounds and forty-four compounds were newly identified in roasted and pan-fired tea, respectively. All green tea samples analyzed contained high amounts of indole pyridine, linalool, geraniol, benzyl alcohol, 2-phenylethanol, 2-ethylhexanoic acid, and maltol. Sulfinylbismethane and sulfonylbismethane seem to be the important compounds contributing to the characteristic green tea aroma. The roasted teas contained high amounts of pyrazines, pyrroles, furans, and pyrans, which are formed via the Maillard reaction. Together with 1-ethyl-3,4-dehydropyrrolidone, the aroma component that was present in highest concentrations in both roasted and pan-fired teas, these compounds contribute to the roasted and pan fired aroma. Kabuse pan-fired tea contained higher amounts of nitrogen heating products such as pyrazines and pyrroles than roten.