Studies on the hygroscopicity of some black teas in terms of their storage stability

The aim of the study was to evaluate the hygroscopicity of black tea samples in terms of storage stability based on the sorption kinetics determined by the dynamic and static methods for 48 hours. In order to describe empirically determined sorption isotherms, the equation of Brunauer, Emmett and Telleta (BET) was transformed in the range of water activity 0.07≤aw≤0.33. The equation was characterized based on the correlation coefficient (R2 ) and the fit standard error (FitStdErr). Based on extensive investigations, it was found that the higher storage stability characterized the tea from Indonesia, which may be due to differences in the microstructure of the surface resulting from the tea origin and parameters of the drying process.