Analysis of Key Low-Boiling-Point Odorants in Matcha by Solid-Phase Microextraction

Abstract

An aroma extract obtained from matcha by diethyl ether extraction reproduced its characteristic aroma. However, the aroma dissipated after concentration with a Snyder column at 45 ℃, indicating that the key odorants of matcha are as volatile as diethyl ether. This study characterized key low-boiling-point odorants in matcha by gas chromatography–olfactometry (GC-O) and GC–mass spectrometry (GC-MS) using solid-phase microextraction (SPME). Five odorants were identified by GC-O: methanethiol, dimethyl sulfide (DMS), 2-methylpropanal (2-MP), 3-methylbutanal (3-MB), and 2-methylbutanal (2-MB). The concentrations of these key odorants (except methanethiol) were determined by GC-MS using stable isotopes: DMS (2.92–17.5 mg·kg^-1), 2-MP (0.06–11.1 mg·kg^-1), 3-MB (0.44–5.26 mg·kg^-1), 2-MB (0.97–7.08 mg·kg^-1). These key odorants would be affected by heating during manufacturing.