Rheological study of orange juices for a better knowledge of their suspended solids interactions at low and high concentration

A better comprehension of the interactions between suspended solids is necessary to optimize the performance and reduce energy requirement during different operations in fruit juice processing (thermal treatment, sedimentation, centrifugation, filtration, spray drying, etc.). In this context, the aim of this study was to propose a rheological approach to get more insight into the energy of cohesion of orange juice suspended solids (SS). The specific energy of cohesion of suspended solids was obtained from rheological measurements in dynamic mode carried out on orange juices fractions with different suspended solids concentrations and size-classes. Results showed that the specific energy of cohesion increased as the SS content increased, independently of the particles size. However, the solid-like behavior of the juice was enhanced by the presence of large particles. The results obtained show that particles network strength and the viscoelastic behavior of juice result of complex interactions between all juice particles. Even if it was demonstrated that these complex interactions depend on the size of the particles, they might depend also on the physicochemical nature of these latter. The knowledge, for the studied fruit juices, of the evolution of their viscoelastic behavior as function of the SS content might be useful to control and optimize the different operations of their transformation chain. (C) 2015 Elsevier Ltd. All rights reserved.