Steady and dynamic oscillatory shear rheological properties of ketchup–processed cheese mixtures: Effect of temperature and concentration

The steady and dynamic shear properties of ketchup–processed cheese (K–PC) mixtures were investigated at different temperatures (10–50 °C) and PC concentrations (0–30%). The K–PC mixtures showed a shear-thinning behavior with low magnitudes of yield stress. The consistency coefficient (K) and apparent viscosity (η50) decreased with increase in temperature and concentration. The mixtures followed the Arrhenius temperature relationship, indicating that the magnitudes of activation energies (Ea) were in the range of 8.83–17.16 kJ mol−1. Storage (G′), loss (G′′) and complex (G∗) modulus increased with increase in frequency while complex viscosity (η∗) decreased. The K–PC mixtures at concentrations of 0–15% exhibited weak gel-like behavior. Increase in the PC concentration resulted in a decrease in G∗, G′, G′′ and η∗ up to the 15% of PC concentration, showing a plateau value between 0% and 30% concentrations. Cox–Merz rule was not applicable to K–PC mixtures.