Rheological properties of microgel suspensions: Viscoelastic modelling of microstructural elements from casein micelles to fermented dairy products

The mechanical spectra from rheological measurements of fermented dairy products are described by a viscoelastic response function in the frequency domain, namely, the Cole–Cole model. The suitability of this model for application in dairy products was validated by using casein micelle suspensions, mixed casein micelle and glass microspheres suspensions and microgel suspensions (fresh cheese) as examples. In addition, the microgel particles were substituted with similar-sized glass microspheres at different ratios. The accuracy and stability of the fitting algorithm, used for the complex valued and finite-bandwidth data, was discussed. Different superimposed sub-models with independent parameter sets were attributed to each microstructural element in fermented dairy products, namely casein micelles and microgel particles. The Cole–Cole model was established for dairy products and possible correlations with an altered microstructure were demonstrated.