Measurement of dynamic rheology during cooling of honey-invert sugar mixtures by small-deformation oscillatory rheometry

Dynamic rheological properties of honeys in the presence of invert sugar at different levels (0, 10, 20, 30, and 40%) were evaluated by small-deformation oscillatory measurements of dynamic moduli (G′ and G″) during cooling from 0 to -14°C. The storage modulus (G′) and loss modulus (G″) thermograms of honey during cooling showed more pronounced G″ values when compared to G', indicating that the presence of invert sugar in honey reduced G″. Such a reduction in G″ can be taken as a good indicator for the adulteration of honey with invert sugar. Therefore, dynamic rheometry for small-deformation oscillatory measurement in the cooling process at sub-zero temperatures appears to be a useful method for detecting the effect of invert sugar adulteration on the structural properties of honey.