How anaerobic treatment is controlling the volatile components and key odorants of purple-colored leaf tea

Abstract

Special purple-colored leaf tea products rich in γ-aminobutyric acid (GABA) have recently gained popularity. Although anaerobic treatment could effectively increase the GABA content in tea products, it also imparted an unknown unpleasant aroma. This study aimed to elucidate the dynamic effects of anaerobic treatment on volatile components during the purple-colored leaf tea processing and reveal the key aroma-active components. A total of 112 volatile components were identified, and it was found that anaerobic treatment could facilitate the accumulation of 2-heptanol, (E)− 2-hexenal, ethyl salicylate, phenylethyl alcohol, and (E,E)− 2,4-decadienal, but inhibited the formation of (Z)− 3-hexenyl acetate and methyl jasmonate. Moreover, 17 potent odorants including (E)-β-ionone, linalool, hexanal, 2-heptanol, (Z)− 3-nonen-1-ol, and (E,E)− 2,4-decadienal were distinguished as the key odorants of purple-colored leaf tea products rich in GABA based on gas chromatography–olfactometry and odor activity value analysis. These results provide new insights into the effect of anaerobic treatment on tea volatile metabolites.