Aroma quality evaluation of Dianhong black tea infusions by the combination of rapid gas phase electronic nose and multivariate statistical analysis

Aroma is one of the most important quality attributes of black tea infusions. In this study, the aroma quality of 44 Dianhong black tea (DBT) infusions were investigated by rapid gas phase electronic nose (GC-E-Nose) combined with multivariate statistical analysis for the first time. Among 61 volatile compounds identified, the most abundant ones were aldehydes. Both partial least squares discriminant analysis (PLS-DA) and Fisher discriminant analysis (FDA) could effectively classify the aroma quality of DBT infusions. The prediction accuracy of FDA (95.2%) was higher than that of PLS-DA (78.6%). Moreover, stepwise multiple linear regression was shown to accurately predict the quality score of DBT infusions, and the Rp value of the sensory score of the predicted model was 0.94. Furan, methyl acetate, 2,3-pentanedione, limonene, and linalool were found positively correlated with the aroma quality of DBT infusions, while 3-ethylpentane, 1-pentene, (E)-2-hexene, and methyl eugenol were negatively correlated with the aroma quality of DBT infusions. These results contribute to understand that rapid GC-E-Nose technology is a supplement to the objective sensory evaluation, and provide a new technical method for the quality evaluation and control of tea infusions.