Investigating volatile compounds’ contributions to the stale odour of green tea

Summary This study aimed to characterise the volatiles that contribute to stale odour of green tea. Volatiles were extracted using headspace solid‐phase microextraction ( HS ‐ SPME ) and analysed using gas chromatography‐mass spectrometry ( GC ‐ MS ) and gas chromatography‐olfactometry ( GC ‐O). Results showed that a total of ninety‐six volatiles were identified by GC ‐ MS , in which forty‐four volatiles were screened out based on Principal component analysis ( PCA ) and orthogonal projections to latent structures–discriminant analysis ( OPLS ‐ DA ), and thirty‐nine volatiles had a significant variation at the level of 0.05 by analysis of variance ( anova ). From GC ‐O analysis, fifty‐four aromatic volatiles with strong aroma intensity (aroma intensity above 2) were perceived. Further investigation revealed that fifteen volatiles, including 1‐octen‐3‐ol, benzyl alcohol, benzaldehyde, safranal, β‐cyclocitral, ( E,E )‐3,5‐octadien‐2‐one, ( Z,E )‐3,5‐octadien‐2‐one, dimethyl adipate, dihydroactinidiolide, β‐ionone, α‐ionone, geranyl acetone, phenylethyl alcohol, methyl decanoate and α‐terpineol were responsible for stale odour, besides the former nine compounds were only found in stored tea.