Among these compounds, 20 compounds were determined to contribute significantly to the perceived aroma quality of OTD black teas. On the basis of these 20 compounds, a PLSR model was constructed to predict the aroma quality of OTD black teas. The results showed that this model is a useful reference for aroma quality prediction of OTD black tea grades. | Journal of Science and Technology 54 (6) (2016) 708-718 DOI: A PREDICTION MODEL FOR AROMA QUALITY OF VIETNAMESE ORTHODOX BLACK TEAS BY COMBINED MULTIVARIATE ANALYSIS OF GC/MS AND SENSORY EVALUATION DATA Hoang Quoc Tuan*, Nguyen Duy Thinh, Nguyen Thi Minh Tu Hanoi University of Science and Technology, School of Biotechnology and Food technology, Department of Quality Management, No 1, Dai Co Viet, Hanoi, Vietnam * Email: ; tuanhqibft@ Received: 26 October 2015; Accepted for publication: 6 May 2016 ABSTRACT Relationships between sensory aroma and the volatile composition of 04 black tea grades from North Vietnam were studied. Consumer preference test was carried out with 80 consumers to evaluate the aroma quality of these samples. Aroma concentrate was prepared by Brewed Extraction Method (BEM) and analyzed using GC/MS. Partial Least Squares Regression (PLSR) was used to determine the relationship between the preference scores and peak area percentage data of 39 detected volatile compounds. Among these compounds, 20 compounds were determined to contribute significantly to the perceived aroma quality of OTD black teas. On the basis of these 20 compounds, a PLSR model was constructed to predict the aroma quality of OTD black teas. The results showed that this model is a useful reference for aroma quality prediction of OTD black tea grades. Keywords: black tea, aroma quality, PLSR, prediction model. 1. INTRODUCTION Black tea is a fermented tea that is consumed round the world. The major quality attributes of black teas are their appearance, colour, aroma, and taste. Among these characteristics, aroma is an essential criterion in the evaluation of sensory scores and the commercial description of tea [1]. In the case of Vietnam black tea, these important factors were determined and scored by multiplication with a weight number of on a scale of 1-5. Therefore, a tea quality grade and its market price .
