Rheology of Ketchup

The book titled Rheology of Ketchup is structured into five chapters. Ketchup a complex food product exhibits non-Newtonian shear-thinning behavior-its viscosity decreases under shear stress. It is also thixotropic meaning its viscosity decreases over time when sheared. This behavior is influenced by ingredients such as pectin hydrocolloids and other stabilizers which affect its flow during handling storage and processing. Unlike Newtonian fluids (e.g. water) whose viscosity remains constant regardless of shear rate ketchup's viscosity changes with applied force. That's why it becomes easier to pour when the bottle is shaken tilted or squeezed. At rest ketchup is more viscous; under force it flows more readily. Thixotropy further implies that even if the shear rate remains constant viscosity continues to decrease over time which is critical in understanding its behavior in real-world applications like packaging and consumer use.