Identification of Key Odorants Isolated from the Headspace above Gyokuro by Using Solid-Phase Microextraction

Abstract

Gyokuro is cultivated in the shade and has green laver-like, hay-like and sweet odor. The aroma of gyokuro differs from that of standard sencha. To identify the key odorants isolated from gyokuro, the aroma in the headspace was extracted using three different types of solid-phase micro extraction fibers, followed by analysis using gas chromatography-olfactometry and mass spectrometry. Aroma extract dilution analysis (AEDA) was applied to fifteen products of gyokuro. Principal component analysis of the flavor dilution factors, obtained by AEDA, revealed that (Z)-1,5-octadien-3-one, dimethyl sulfide, 3-methylnonane-2,4-dione, 4-mercapto-4-methyl-2-pentanone, furaneol, and 2-acetyl-1-pyrroline were the potent odorants in the headspace above gyokuro.