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.

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The effects of the added β-cyclodextrin (β-CD) in the tea infusion extraction on color quality of green tea (Camellia sinensis) infusion have been investigated in detail. Due to the added β-CD, the color of the tea infusion can be brightened effectively, and meanwhile, compared to conventional extraction, the retentions of tea polyphenols, catechins, and chlorophyll have also been proved to be increased greatly. Furthermore, the additive β-CD can also increase the viscosity of the tea infusion. In addition, the existing β-CD can lower the oxygen solubility ratio in tea infusions effectively, from which a high-quality tea infusion can be prepared ready for further processing.

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The important quality of green tea is freshness, but high temperature, light, oxygen, and humidity during storage may reduce the freshness of green tea. Thus, this study investigated the freshness loss of green tea (FLGT) under an accelerated shelf-life testing (ASLT) by sensory evaluation and acceptability test. The FLGTs of the samples stored at 20°C, 30°C, and 40°C, were determined as 67 days, 55 days, and 45 days, respectively by the Q10 method. In addition, they were further determined as 67 days, 57 days, and 42 days, respectively, by the Weibull Hazard Analysis (WHA). The sensory evaluation and acceptability test confirmed the correctness of the above results by 2-alternative choice analysis and chemical analysis. The Q10 method was applied to predict the FLGTs stored at 4°C and −20°C which were 93 days and 150 days, which was further verified by 2-alternative choice analysis and chemical analysis. The results show that it is possible to predict the suitable drinking period of green tea during storage by the Q10 method.