This research aimed to assess and determine rheological properties of chocolate pistachio produced from various volumes of monoglycoside (1% and 2%), date powders (34, 38 and 42%) and pistachio pastes. The analyses were performed at temperatures of 45oC, 65oC after 3 and 5 hours of processing. These products were found to exhibit non- Newtonian, pseudo-plastic behavior at all treatments. Apparent viscosities versus speed data were successfully fitted to a power law model. The flow behavior index, n, varied in the range of 0.8-0.94. The consistency index, k, was in the range 101.495-167.738 pa - sn. According to statistical analysis, the exponential model was a better model to describe the effect of the soluble solids on the viscosity of chocolate pistachio containing varying percentages of date powder. The activation energy (Ea) was 446.2-41330 j/mol.

Grape molasses is one of the famous by products of grape that more produced by traditional methods. In this research, some physicochemical properties of grape molasses such as SG, pH, total sugar, ash and rheological properties by using of a single cylinder rotary viscometer at three temperatures (25, 45 and 65oC) and three concentrations of 35, 50 and 76 were measured. Mathematical calculations in basis of Mitchka method shown that it is non-Newtonian and have dilatant behavior. Arrhenius model used for temperature dependence of consistency coefficient and activation energy calculated in range of 15.197 to 34.070 kJ/mol. Finally, by using of exponential relationship concentration dependence of consistency coefficient was evaluated.

Introduction: The maintenance of the quality of fresh products is still a major challenge for the consumers. The most important quality attributes contributing to the marketability of fresh fruit include appearance, color, texture, flavor, nutritional value and microbial safety. Strawberry fruits should be firm but not crunchy....

Wild medlar fruit (Mespilus germanica) is rich in sugars and organic acids. In this study, wild medlar concentrates in four concentrations of 14, 28, 42 and 56% (oBrix), preparation and physicochemical properties including pH, acidity, density and color, and rheological properties (at 20, 30, 40, 50, 60 and 70oC) were studied. The pH was in the range from 3.37 to 3.62 and acidity according to citric acid was in the range of 1.05 to 3.90%. Density of concentrated sample (56%) was 1277 kg/m3. Color of samples was analyzed using image processing technique and image parameters including L*, a* and b* for the sample with a concentration of 56% was 20.54, 1.69 and 1.36, respectively. With increasing in concentration, the sample was darker and L* index decreased. Concentrate used in all concentrations showed Newtonian behavior and viscosity increases with increasing concentration. With increasing in temperature from 20 to 70oC, the viscosity of the concentrate (56%), decreased from 2517 to 223 mPa.s. The magnitude of activation energy was found in the range of 9.59-43.39 kJ/mol K.