Rheology of tomato and wheat dietary fibers in water and in suspensions of pimento purée

The flow behaviour of the tomato and wheat dietary fibers in water and its effect on the rheology of the pimento purée were studied. Water retention, swelling, and fat adsorption capacity were determined for the characterization of the fibers. The flow behaviour of the fibers in water was measured with a concentric cylinder viscometer at 10-50 °C temperature range. It was shear thinning and fitted well to the power-law model for all fibers. The Arrhenius model described the effect of temperature on the apparent viscosity. The activation energy of flow range from 4.54 to 12.23 kJ/mol depending on the concentration. In all cases, the effect of concentration on apparent viscosity was more important than the effect of temperature. An exponential expression was given for the combined effect of temperature and concentration on the apparent viscosity. The rheological behaviour of suspensions of pimento purée with added dietary fibers was studied before and after sterilisation to prevent the separation for sedimentation. The experimental data were fitted to power law being the behaviour index similar to before sterilisation. The texture of pimento pure with fibers was determined at 20 °C. Sterilisation influenced the texture.