Absolute Quantitative Volatile Measurement from Fresh Tea Leaves and the Derived Teas Revealed Contributions of Postharvest Synthesis of Endogenous Volatiles for the Aroma Quality of Made Teas

Abstract

Characteristic aroma is a well-appreciated feature contributing to tea quality. Although extensive studies have been made to investigate aroma biosynthesis and gene expressions during tea making processes, it remains unclear whether the endogenous volatile biosynthesis during postharvest tea processing contributes to the aroma quality of made tea. To critically evaluate this question, we used the same batch of fresh tea leaves and produced three different types of tea with different degrees of fermentation (green tea, oolong tea, and black tea). Total volatiles were extracted by solvent-assisted-flavor evaporation, then quantified by gas chromatography-flame ionization detector combined with response factor correction for quantitative measurement. Compared with fresh tea leaves, the volatile profiles of the made teas were dramatically altered, with significant loss for the majority of endogenous volatiles and simultaneous gain for non-endogenous volatiles. By calculation of odor-activity values, the potential volatiles contributing to the aroma characteristics of each tea type were identified. Our data suggest that postharvest synthesis of endogenous volatiles did not contribute to the aroma quality of made tea.

Identification of aroma‐active compounds responsible for the floral and sweet odors of Congou black teas using gas chromatography–mass spectrometry/olfactometry, odor activity value, and chemometrics

“…72) are significantly correlated with floral aroma. ( E )‐β‐Farnesene and α‐farnesene have floral fragrance, 15 and α‐farnesene is the main aroma components of Wuyi rock tea (Dangui), which is a special subcategory of oolong tea 16 . 3,7‐Dimethyl‐2,6‐octadienal has a rose‐like fragrance and is widely used in perfumes, 17 whereas propanal presents a fresh, fruity, and malty odor 8 .…”

Influence of reduced N-fertilizer application on foliar chemicals and functional qualities of tea plants under Toxoptera aurantii infestation

“…Dodecane and decane belongs to the class of alkane hydrocarbons. Dodecane, a liquid alkane hydrocarbon, has been reported as an aromatic volatile in green tea and Oolong tea and also a little proportion is reported in Pu-erh ripe tea [ 92 , 93 ]. Decane is also an alkane hydrocarbon, observed in Turkish green tea powder and is generally believed to be fairly nontoxic, compared to other aliphatic hydrocarbons [ 94 ].…”

Evaluation of Roasting Effect on Selected Green Tea Volatile Flavor Compound and Pyrazine Content by HS-SPME GC-MS

“…Usually, the flavor extracts of green tea infusions are prepared by steam distillation under reduced pressure followed by liquid-liquid extraction and concentration, or by using a solvent-assisted flavor evaporation (SAFE) device before the injection in the gas chromatographic system [18,19]. Recently, solid-phase microextraction (SPME) has gained acceptance in many fields as an accurate, rapid, sensitive and solvent-free sampling method and its application is reported by many researchers as a useful approach in sample preparation of volatile compounds from tea leaves and tea infusions [7,16,20].…”