Quantitative Measurement Reveals Dynamic Volatile Changes and Potential Biochemical Mechanisms during Green Tea Spreading Treatment
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ABSTRACT:
SUBMITTER: Chen M
PROVIDER: S-EPMC9647863 | biostudies-literature | 2022 Oct
REPOSITORIES: biostudies-literature
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Project description:Leaf spreading is a key processing step that affects the aroma formation of green tea. The effects of a single-light wavelength on the aroma and taste of tea have been extensively studied. Less attention has been paid to the effect of different complex light intensities on the formation of green tea's volatile aroma during leaf spreading. The current study was designed to evaluate how leaf spreading under different complex light intensities relates to the quality of green tea. Using headspace solid-phase micro-extraction and gas chromatography-mass spectrometry (HS-SPME/GC-MS), volatile flavor compounds in green tea were analyzed during leaf spreading in five different light conditions. Multivariate statistical analysis and odor activity values (OAVs) were used to classify these samples and identify key odors. Eight distinct groups, including ninety volatile compounds, were detected. The most prevalent volatile compounds found in green tea samples were hydrocarbons and alcohols, which accounted for 29% and 22% of the total volatile compounds, respectively. Fourteen volatile compounds (OAV > 1) were identified as key active differential odorants. The chestnut-like aroma in green tea was mostly derived from 3-methyl-butanal and linalool, which were significantly accumulated in medium-intensity light (ML).
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Project description:As an important process for enhancing aroma of Wuyi rock tea, roasting has gradually been applied to the processing of bud green tea (BGT). However, there is a lack of comprehensive research on the impact of roasting on BGT aroma. This research provides a detailed analysis of the changes in aroma perception and compounds during the low-temperature roasting process (105°C, 90 minutes) of BGT. First, the changes in aroma perception were studied using quantitative descriptive analysis (QDA). The aroma perception of BGT transformed from fresh to chestnut like. Next, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) analysis was conducted to characterize the volatile compounds during roasting. A total of 313 volatile compounds were identified, among which 72 showed significant differences. Compounds such as linalool, benzyl alcohol, ionone, and ethyl salicylate (floral aroma) and 2,6-dimethylpyrazine, 2,3-dimethylpyrazine, 2-acetylpyrrole, and 3-furfural (caramel-like aroma) were confirmed to be involved in the formation of the chestnut-like aroma during roasting process. In addition, representative aroma compounds with different characteristics were selected based on monomolecular olfactory results to simulate sensory-level aroma interactions. The results showed that fresh and tender aromas exhibited mutual enhancement at low concentrations, while sweet and chestnut-like aromas showed mutual enhancement at all concentrations.
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