Rapid characterization of the volatile profiles in Pu‐erh tea by gas phase electronic nose and microchamber/thermal extractor combined with TD‐GC‐MS

Abstract

Aroma plays an important role in the quality of Pu‐erh tea. However, the quality evaluation of Pu‐erh tea aroma is heavily relied on the experience of sensory evaluation, and the theoretical research is relatively scarce. In the present work, the volatile compounds in Pu‐erh tea were characterized by using gas phase electronic nose (e‐nose) and microchamber/thermal extractor (µ‐CTE) combined with thermal desorption coupled to gas chromatography‐mass spectrometry (TD‐GC‐MS). A satisfactory discrimination model (R2Y = 0.95, Q2 = 0.807) was obtained by using orthogonal partial least squares discriminant analysis (OPLS‐DA) based on the odor fingerprint of different brands of Pu‐erh tea. In addition, based on the double criterion of multivariate analysis with VIP >1.0 and univariate analysis with p ≤ 0.001, 39 volatile components were identified to contribute greatly to the discrimination of five brands of Pu‐erh tea. The results suggested that gas phase e‐nose and µ‐CTE combined with TD‐GC/MS were simple, rapid techniques to characterize the volatile compounds in Pu‐erh tea and were allowed to effectively distinguish different brands of Pu‐erh tea, which would provide an important reference on the quality assessment of Pu‐erh tea. Practical Application This work demonstrates that the volatile compounds in Pu‐erh tea are simply and rapidly characterized by using µ‐CTE/TD‐GC/MS and gas phase e‐nose, allowing to effectively distinguish different brands of Pu‐erh tea, which can provide an important reference for the quality assessment and authentication of Pu‐erh tea.

Variation in Volatile Compounds of Raw Pu-Erh Tea upon Steeping Process by Gas Chromatography–Ion Mobility Spectrometry and Characterization of the Aroma-Active Compounds in Tea Infusion Using Gas Chromatography–Olfactometry–Mass Spectrometry

“…It does not belong to dark tea, and chemical profiling such as flavan-3-ols and their derivatives also significantly differed with the traditional green tea . During the past decade, a lot of research has been focused on the flavor and bioactive substances of RIPT, whereas the flavor compounds of RAPT, especially the flavor of infusion, have not sufficiently been investigated. , …”

Discrimination between raw and ginger juice processed Magnoliae officinalis cortex based on HPLC and Heracles NEO ultra‐fast gas phase electronic nose

“…Combined with gas chromatography (GC) and e‐nose technology, 23,24 the Heracles NEO ultra‐fast gas phase electronic nose (Heracles NEO e‐nose) is an advanced olfactive tool that can be used to separate and identify the volatile compounds in TCMs. The chromatographic peaks obtained by GC are regarded as markers which can be used to obtain overall information about volatile constituents (also known as fingerprinting) 23 . Fingerprinting could replace the traditional sensor type e‐nose that has some limitations in the identification of components because of the limitation of sensor types 23 .…”

“…The chromatographic peaks obtained by GC are regarded as markers which can be used to obtain overall information about volatile constituents (also known as fingerprinting) 23 . Fingerprinting could replace the traditional sensor type e‐nose that has some limitations in the identification of components because of the limitation of sensor types 23 . Subsequently, integrated with the Kovats retention index and the inbuilt AroChemBase database, the collected chromatographic peaks are analyzed by looking for possible compounds and corresponding sensory description information to facilitate further study of TCMs 25 .…”

“…Electronic nose (e-nose) technology, which can digitize the empirical odor expression, has been widely used in food industry and introduced into the field of TCM to evaluate product quality rapidly and objectively. [19][20][21][22] Combined with gas chromatography (GC) and e-nose technology, 23,24 the Heracles NEO ultra-fast gas phase electronic nose (Heracles NEO e-nose) is an advanced olfactive tool that can be used to separate and identify the volatile compounds in TCMs. The chromatographic peaks obtained by GC are regarded as markers which can be used to obtain overall information about volatile constituents (also known as fingerprinting).…”

“…23 Fingerprinting could replace the traditional sensor type e-nose that has some limitations in the identification of components because of the limitation of sensor types. 23 Subsequently, integrated with the Kovats retention index and the inbuilt AroChemBase database, the collected chromatographic peaks are analyzed by looking for possible compounds and corresponding sensory description information to facilitate further study of TCMs. 25 Meanwhile, chemometric analysis, such as principal component analysis (PCA) and discriminant factor analysis (DFA), can be carried out to distinguish samples based on these data.…”