BIOPHYSICAL PROPERTIES OF DATE PASTE: ASSESSMENT OF FLOW BEHAVIOR AND TEXTURE
The rheological properties of two commercial date pastes were investigated in the temperature range of 20-70°C. From typical flow behavior curves, it was observed that date pastes exhibited pseudoplastic behavior. The shear stress-shear rate data were fitted using six common rheological models. The Casson model best described the experimental data at all temperatures. The Arrhenius model described successfully the temperature dependence of apparent viscosity of date pastes (R2>0.99) with an Ea value in the range of 25392.6-25485.7 kJ/kmol. The textural attributes measured were: hardness, springiness, gumminess, cohesiveness, chewiness, adhesiveness for TPA test and firmness, adhesive force, mean load and total positive area for Ottawa test. There was a significant difference in textural attributes between two varieties studied. TPA results showed that all parameters obtained for Black date pastes were higher than Golden date pastes except for springiness and cohesiveness. However, the Ottawa results showed that Golden date pastes were firmer and less adhesive than Black date pastes.
Karazhiyan, H. (2010). BIOPHYSICAL PROPERTIES OF DATE PASTE: ASSESSMENT OF FLOW BEHAVIOR AND TEXTURE. Acta Hortic. 882, 1053-1061
date paste, textural profile analysis, forward extrusion, Casson model, flow behavior, Ottawa test