Application of WLF and arrhenius kinetics to rheology of selected dark-colored honey

The rheological properties of Common Black Horehound, Globe Thistle, and Squill types of dark-colored Jordanian honey were examined. The types of honey used were identified via assessing the source of nectar using pollen analysis (Melissopalynology). The apparent viscosity, η, was measured as a function of the shear rate, γ̇. In addition, the apparent viscosity was measured, at constant shear rate (6.12 s^-1), as a function of shearing time. Newton's law of viscosity (i.e., τ = ηγ̇) was found to adequately (R² ∼ 0.99) describe the flow behavior of honey samples. The apparent viscosity was found to decrease with temperature, and the temperature dependence of viscosity was contrasted versus both Arrhenius model (η = η_oe^Ea/RT) and WLF model (η/η_G = 10 ((C₁(T-T_G)/C₂+(T-T_G)))). Although Arrhenius kinetics may fit the viscosity versus temperature data for the examined types of honey, nevertheless, it gives a relatively high value of activation energy that is quite comparable with, if not even larger than, that of a typical chemical reaction. On the other hand, WLF-model was found to adequately describe the data while at the same time it gives quite reasonable values of both T_G and η_G, which are in agreement with those cited in literature.