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Food Funct

Title:		Differences of characteristic aroma compounds in Rougui tea leaves with different roasting temperatures analyzed by switchable GC-O-MS and GC x GC-O-MS and sensory evaluation
Author(s):		Yang P; Song H; Lin Y; Guo T; Wang L; Granvogl M; Xu Y;
Address:		"Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Research Center for Food Additive Engineering Technology, Laboratory of Molecular Sensory Science, Beijing Technology and Business University (BTBU), Beijing, 100048, China. songhl@th.btbu.edu.cn. College of Tea and Food Science, Wuyi University, Wuyishan, 354300, China. Fachgebiet Lebensmittelchemie und Analytische Chemie (170a), Fakultat fur Naturwissenschaften, Institut fur Lebensmittelchemie, Universitat Hohenheim, 70599 Stuttgart, Germany. National Engineering Research Center for Tea Industry, Chinese Academy of Agricultural Sciences Tea Research Institute, 9 South Meiling Road, Hangzhou 310008, China. yqx33@126.com"
Journal Title:		Food Funct
Year:		2021
Volume:		12
Issue:		11
Page Number:		4797 - 4807
DOI:		10.1039/d1fo00165e
ISSN/ISBN:		2042-650X (Electronic) 2042-6496 (Linking)
Abstract:		"Roasting, an important process to refine Wuyi Rock tea, could impart different types of aroma to the final products. This study focuses on the differences in aroma characteristics among three kinds of refined teas, named light fire (LF), moderate fire (MF), and high fire (HF). A combination of solid phase microextraction (SPME) and a switchable system between GC-O-MS and GC x GC-O-MS was utilized to identify the odorants. In total, 97 aroma-active compounds could be smelled at the sniffing port, comprising alcohols, aldehydes, ketones, esters, heterocycles, and terpenes. However, only 52 obtained r-OAV >1. Significant differences were uncovered by the application of principal component analysis (PCA) and partial least squares regression (PLSR). Thereby, MF and HF had a more similar aroma profile, while in LF samples, alcohols, aliphatic aldehydes and some ketones were responsible for the aroma profile, such as (E,E)-2,4-hexadienal, octanal, hexanal, (E,Z)-2,6-nonadienal, (E)-beta-ionone, 3-octen-2-one etc. Strecker aldehydes had a great impact on the aroma of MF, including 2-methylpropanal, 2-methylbutanal, 3-methylbutanal etc. Some N-heterocyclic compounds also affected the overall aroma, for instance, 6-methyl-2-ethylpyrazine. In HF, the majority of aroma compounds increased with increasing roasting temperature, especially N-heterocyclic compounds as well as furfural and 5-methyl-2-furancarboxaldehyde, which are all closely related to the Maillard reaction. Besides, 5-methyl-2-(1-methylethenyl)-4-hexen-1-ol, trans-linalooloxide and 2-nonanone also remarkably influenced the aroma of HF. In addition, it was supposed that most amino acids that participated in the Maillard reaction during roasting were decomposed from the compounds that combined with tea polyphenols and amino acids"
Keywords:		Alcohols Aldehydes Gas Chromatography-Mass Spectrometry/*methods Norisoprenoids Odorants/*analysis Plant Leaves/*chemistry Polyphenols/analysis Smell Solid Phase Microextraction Tea/*chemistry *Temperature Volatile Organic Compounds/*analysis;
Notes:		"MedlineYang, Ping Song, Huanlu Lin, Yanping Guo, Tianyang Wang, Lijin Granvogl, Michael Xu, Yongquan eng England 2021/04/17 Food Funct. 2021 Jun 8; 12(11):4797-4807. doi: 10.1039/d1fo00165e"