tailieunhanh - Differentiation of black teas by volatile profile analysis using HS-SPME/GC-MS

The results showed that CTC teas have a lower number of volatile components detected, lower contents of aldehydes and alcohols, and higher content of esters than OTD teas. Both Orthodox and CTC teas could be classified using principal component analysis (PCA) and cluster analysis of their volatile profiles. The data presented in this studied also suggest that Terpene Index might be used as an additional mean for the determination of the geographical origin of teas. | Journal of Science and Technology 54 (4) (2016) 483-493 DOI: DIFFERENTIATION OF BLACK TEAS BY VOLATILE PROFILE ANALYSIS USING HS-SPME/GC-MS Hoang Q. Tuan*, Nguyen D. Thinh, Nguyen T. M. Tu Department of Quality Management, School of Biotechnology and Food Technology, Hanoi University of Science and Technology, No 1 Dai Co Viet Road, Hanoi, Vietnam * Email: tuanhqibft@; Received: 3 October 2015; Accepted for publication: 23 April 2016 ABSTRACT A total of fourteen different commercial brands of black teas including Orthodox (OTD) and Crush Tear Curl (CTC) teas were collected at different markets with origin from 07 countries, and their volatile flavour compounds (VFC) were compared by analyses using headspace solid-phase micro-extraction coupled with gas chromatography - mass spectrometry (HS-SPME/GC-MS). Among the 60 volatiles identified, terpenes ( % - %), ketones ( % - %) and esters ( % - 418 %) represented the most abundant compounds. The results showed that CTC teas have a lower number of volatile components detected, lower contents of aldehydes and alcohols, and higher content of esters than OTD teas. Both Orthodox and CTC teas could be classified using principal component analysis (PCA) and cluster analysis of their volatile profiles. The data presented in this studied also suggest that Terpene Index might be used as an additional mean for the determination of the geographical origin of teas. Keywords: black tea, volatile compounds, geographic origin. 1. INTRODUCTION Normally, the quality of black tea is determined by human sensory evaluation based on “shape, colour, aroma and taste”. Among these characteristics, aroma is an essential criterion in the evaluation of sensory scores and the commercial description of black tea. Besides the conventional sensory evaluation of aroma quality, gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA) are