Abstract
In this research, rheological properties of blends of pine honey (3%, 6%, and 9%) with sesame pastes (tahin) produced from hulled roasted sesame seeds, called simply tahin, and from unhulled roasted sesame seeds, so-called Bozkir tahin, were determined at temperatures ranging from 10A degrees C to 60A degrees C and at speeds ranging from 0.5 to 100 rpm. Tahin and Bozkir tahin blends with pine honey were found to exhibit non-Newtonian, pseudoplastic behavior at all temperatures. Apparent viscosities versus speed data were successfully fitted to the power law model. The flow behavior index, n, varied in the range of 0.4226-0.6228 for the tahin-pine honey blends, and in the range of 0.4661 to -0.7266 for the Bozkir tahin-pine honey blends. The consistency index, K, was in the range of 9.34-36.42 Pa center dot s(n) for tahin-honey blends, and in the range of 9.92-37.53 Pa center dot s(n) for Bozkir tahin-honey blends. The consistency index (K) increased with increasing honey levels in both tahin types. According to statistical analysis, the exponential model was a better model to describe the effect of the soluble solids on the viscosity of tahin samples represented by the pine honey percentage. The emulsion stability of both tahin types improved with the addition of pine honey. It was also correlated with activation energy (E (a)), Arrhenius constant, some sensory properties such as spreadibility, firmness and overall acceptance, and color parameters such as the C and h. Temperature sensitivity of the consistency index was assessed by applying an Arrhenius type equation, and E (a) value appeared in the range of 7.61-10.05 kJ/mol for tahin-honey blends and in the range of 9.02-10.50 kJ/mol for Bozkir tahin-honey blends.