Viscoelastic Properties of Tomato Juice: Applicability of the Cox-Merz Rule

Tomato is one of the most important vegetables for the food industry. Rheological characterization of food is important for products, equipments, and unit operations design and evaluation. It is necessary for process optimization and high-quality products assurance. However, the works in literature present variable data, and some rheological characterization, as viscoelastic properties, are still scarce. The present work has evaluated the viscoelastic properties of tomato juice, as well as the applicability of the Cox-Merz rule. Tomato juice has shown dominant elastic properties rather than the viscous ones and could be classified as a weak gel (storage modulus higher then loss modulus). Moreover, due to the low pulp content, it has shown low viscoelastic behavior, with small dependency of oscillatory of the storage modulus. The rheological oscillatory and steady-state shear rheological properties of tomato juice were then correlated by two linear modifications on the Cox-Merz rule. The obtained values are in agreement with those described in the literature for other food products. The obtained data are potentially useful for future studies on food properties and process design.