Influence of the Volume Fraction, Size and Surface Coating of Hard Spheres on the Microstructure and Rheological Properties of Model Mozzarella Cheese

Abstract

This study investigated the influence of model filler particles (glass beads) on the microstructure and rheological properties of Mozzarella cheese. Model Mozzarella cheese composites with increasing volume fractions of glass beads of various sizes and surface properties were processed in a Rapid Visco Analyser (RVA). Confocal laser scanning microscope images showed that all the hard spheres were dispersed in the protein phase, rather than in the fat phase. Dynamic oscillatory rheology revealed that the volume fraction of the glass beads had a major influence on the complex modulus (G*) of the cheese composites, whereas the size and the coating of the glass beads had no influence. However, the zero shear viscosity (η 0), measured using the creep-compliance test, was affected by both the size and the volume fraction of the glass beads. This indicated that there were some interactions between the glass beads and the cheese matrix. Filler–matrix interactions played a major role in the fracture properties of the cheese composites. The fracture stress (σ f ) was highly dependent on the coating and the size of the glass beads. Simple equations for filled gels from the literature fitted well with the experimental results and could be successfully applied for future predictions. According to this study, the transfer of knowledge from filled polymer composites to model cheese appears relevant. This can provide a good basis for designing new dairy product structures.