Temporal Changes in Aroma Release of Longjing Tea Infusion: Interaction of Volatile and Nonvolatile Tea Components and Formation of 2-Butyl-2-octenal upon Aging

Abstract

The temporal change in the headspace composition of an aroma model mimicking Longjing green tea aroma was studied in the presence of nonvolatile Longjing green tea constituents. Upon storage at 50 degrees C, the formation of 2-butyl-2-octenal was found, which increased with time. This enal was generated by crotonization of hexanal as demonstrated in model experiments. The formation of 2-butyl-2-octenal was also detected in Longjing tea infusions and Longjing tea leaves upon storage at 50 degrees C. The presence of nonvolatiles induced a strong decrease in aroma release. These effects were mainly due to catechins, major constituents of green tea infusion. Free amino acids, that is, glycine, contributed only to significantly decrease alpha,beta-unsaturated carbonyl aroma compounds, that is, 1-octen-3-one and geranial. Model reaction containing a mixture of 1-octen-3-one and glycine indicated on the basis of NMR and MS data the formation of the tentatively identified N-1-(3-oxo-octyl)glycine resulting from a 1,4-addition. The perceived aroma of green tea infusion is very likely to be affected by the formation of new aroma compounds and the changes in aroma release affected by interactions with tea nonvolatile components. This deserves further investigations on the sensory level.

Volatile profile analysis and quality prediction of Longjing tea (Camellia sinensis) by HS-SPME/GC-MS

“…The chemical odorants observed in our study were quite different from the most active odorants detected in Longjing tea infusions in the previous studies (Kumazawa and Masuda, 1999;Cheng et al, 2008). The difference may be attributed to the different forms of tea aroma used for extraction.…”

“…Linalool and nonanal have been characterized as aroma-active compounds contributing to floral or fruity odors in Longjing tea infusions (Table 2), and linalool has a high flavor dilution (FD) factor ≥100 (Kumazawa and Masuda, 1999;Cheng et al, 2008). Furthermore, they were also reported to have significant positive correlation with the perceived aroma of Longjing tea or oolong tea (Wang and Ruan, 2009; Wang et al, 2010).…”

“…β-Ionone has been determined to have tea leaves and woody odor in Longjing tea (Cheng et al, 2008). (Z)-3-Hexenyl hexanoate was determined to have a fruity and green odor in green tea (Kumazawa and Masuda, 1999;Zhu, et al, 2008).…”

Volatile compounds and sensory characteristics of various instant teas produced from black tea

“…This could be explained by the fact that acids are less volatile as compared with the rest of compounds. Most acids identified in this study have previously been reported in green and black teas (Alasalvar et al, 2012;Cheng, Huynh-Ba, Blank, & Robert, 2008;Schuh & Shieberle, 2006). It is well-established that branched-chain acids including 2-and 3-methylbutanoic acids found in tea samples are usually generated from the degradation of branched-chain amino acids.…”

Formation Mechanism of Aroma Compound during Tea Manufacturing Process

“…Oleic acid와 palmitoleic acid는 n-nonanal, n-nonanol, n-heptanal, 및 n-heptanol의 전구체이다. 일반적으로 오래 된 녹차에서는 1-octen-3-one, hexanal, 및 carbonyl 화합물 농 도는 아주 낮게 나타난다 [17]. 지질분해는 methyl jasmonate, cis-jasmone, 및 jasmine lactones등을 생성한다.…”