Comparison of gas chromatographic volatile profiling methods for assessing the flavour quality of kenyan black teas

Abstract

A comparison is made of the various ratios used to quantify black tea aroma such as the ratio of the sum of gas chromatographic peak areas of compounds eluting before linalool (3,7-dimethyl-1,6-0ctadien-3-01) to those eluting after linalool (Wickremasinghe-Yamanishi ratio); gas chromatographic peak areas of compounds imparting sweet flowery aroma (Group I1 volatile flavour compounds) to those imparting green grassy aroma (Group I volatile flavour compounds), Owuor’s flavour index; ratio of the sum of the gas chromatographic peak area of the terpenoids to non-terpenoids, i.e. Mahanta ratio; and gas chromatographic peak area of linalool to E-2-hexena1, i.e. Yamanishi-Botheju ratio. The Wickremasinghe-Yamanishi ratio and Owuor’s flavour index showed a significant relationship, the Mahanta ratio showed a significant but poor relationship, and the Yamanishi-Botheju ratio had no relationship with the tasters’ evaluation of Kenyan clonal CTC black teas. Similar results were obtained from orthodox black teas manufactured from different varieties.