EFFECT OF DRYING TEMPERATURE ON THE VOLATILE COMPOSITION OF ORTHODOX BLACK TEA

Abstract

      The effects of drying temperature on the profile of volatile compounds produced by black tea were evaluated at 80, 90, 100, 110, 120, 130, and 140^oC. Aroma concentrate was prepared by the Brewed Extraction Method (BEM) method and analyzed by GC/MS. The volatile compounds content increased as the drying temperature increased from low to high temperatures. However, the relative content of group II volatile compounds, which are the degradation products of carotenoids and amino acids, rapidly increased more than the group I volatile compounds which are mainly the products of lipid breakdown, but when the drying temperature was higher than 120^oC, the relative content of some volatile compounds belonging to group II rapidly decreased more than the volatile compounds belonging to group I. The highest flavour indice, which is defined as the ratio between desirable to undesirable volatile compounds, was obtained in samples dried at 120, followed by 110^oC. Given the above results, in the present study, the optimal temperature condition to dry black tea was 120^oC or 110^oC.