The growing phenomenon of honey adulteration prompts the search for simple methods to confirm the authenticity of honey. The aim of the study was to evaluate the changes in thermal characteristics, physicochemical parameters, antioxidant and enzymatic activity of honey subjected to artificial adulteration. Two series of products were prepared with the use of two different sugar syrups with an increasing dosage of adulterant (0 to 30%). After 24 months of storage, the quality of adulterated samples (partially crystallized) was assessed in comparison to the control honey (solid). Used adulteration changed physicochemical parameters and reduced antioxidant and enzymatic activity of honey (p < 0.05). The admixture of syrup and invert (p < 0.05) reduced the viscosity of liquid phase of delaminated honey in a dose-dependent manner. In the study, artificially adulterated honeys were controlled using the standard differential scanning calorimetry, DSC. In all adulterated honeys, a specific glass transition, TG, was observed in the range of 34-38.05 °C, which was not observed for control honey and pure adulterants. Moreover, the additional Tgs were observed in a wide range from -19.5 °C to 4.10 °C for honeys adulterated by syrup only. In turn, the Tg in range of 50.4-57.6 °C was observed only for the honeys adulterated by invert. These specific Tg seem to be useful to detect honey adulteration and to identify the kind of adulterant used.
Keywords: adulteration; fructose; glucose; honey; sucrose; sugar syrup; temperature of glass transition; viscosity.