Unlocking the aroma secrets of gardenia tea: scientists decode its signature scent
Innovative combination of gas chromatography, mass spectrometry, and sensory analysis
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They identified over 200 volatile components, pinpointed 24 key aroma compounds, and constructed a detailed aroma wheel highlighting six main scent attributes: fruity, green, floral, roasted, woody, and other, visually representing the sensory essence of this centuries-old tea.
Tea is one of the world’s most widely consumed beverages, valued not only for its flavor and health benefits but also for its complex aroma. Among them, Chinese scented teas—especially gardenia tea (GET)—are created by layering tea leaves with fragrant flowers through an intricate scenting process. Although GET is known for blending the mellow base of green tea with the floral elegance of gardenia, its aroma profile has never been fully explored. Traditional aroma evaluation methods rely on subjective human senses and can be inconsistent. Due to these limitations, it is necessary to employ advanced analytical and statistical methods to comprehensively study the volatile profiles of GET.
A study published in Beverage Plant Research on 2 January 2024 by Yanqin Yang’s & Yongwen Jiang’s team, Tea Research Institute, Chinese Academy of Agricultural Sciences, not only enhances the sensory science of gardenia tea but also offers a novel approach for evaluating and improving the aroma profiles of other scented teas.
To characterize the aroma profile of GET, researchers employed a suite of analytical methods including gas chromatography electronic nose (GC-E-Nose), comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS), gas chromatography-olfactory-mass spectrometry (GC-O-MS), and chemometric analyses such as principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). GC-E-Nose enabled rapid and effective differentiation between GET and its unscented base tea (GE), with PCA revealing distinct spatial distributions and a high cumulative contribution rate of 86.74%. GC×GC-TOFMS further identified 202 volatile compounds in GET, primarily esters, alkenes, and alcohols, with esters being the most abundant. Compared to GE, GET exhibited higher levels of certain esters like methyl tiglate and benzoic acid methyl ester, but lower levels of most alkenes, alcohols, and ketones. Multivariate PLS-DA modeling confirmed clear separation between GE and GET, supported by 55 volatile compounds with high discriminative value (VIP > 1.2). Additionally, odor activity value (OAV) analysis identified 57 key volatile components (OAV ≥ 1), among which 24 were deemed primary contributors to GET’s aroma. These were further validated through GC-O-MS sniffing and used to construct an aroma wheel featuring six sensory attributes: fruity, green, floral, roasted, woody, and other. Notably, compounds such as linalool, cis-jasmone, and methyl salicylate were highlighted as major contributors to GET’s floral and fruity character. This multi-method approach not only quantified the aromatic complexity of GET but also visualized its scent profile with scientific precision, laying the foundation for future quality control and flavor enhancement strategies in scented teas.
The study’s findings have practical implications for the tea industry, particularly in improving quality control and developing consistent aroma profiles in scented teas. The aroma wheel of GET can be used as a reference model for other floral teas, helping producers identify and replicate desirable sensory characteristics. Furthermore, the integration of advanced chemometrics and sensory analysis provides a replicable method for profiling complex aromas in food and beverage products.
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