Probing the dynamics and stability of micellar casein and para-casein dispersions with differential dynamic microscopy

Abstract

Casein micelles and their rennet modification into para-casein micelles play a central role in the production of dairy products. They both hold great potential as functional materials in many applications from coatings to biomaterials, presenting a completely biological and sustainable alternative to petrochemicals. Regardless of their application, characterizing their dynamics, stability and ultimately their assembly is essential for their processing. In this study, casein- and para-casein micelle dispersions are characterized by differential dynamic microscopy (DDM). In contrast to conventional dynamic light scattering, DDM allows the characterization of highly turbid media and the simultaneous acquisition of the intermediate scattering function over a wide range of scattering vectors as illustrated by the investigation of concentrated casein micelle dispersions. We further demonstrate the application of this technique to investigate the colloidal stability of para-casein micelle dispersions, opening up for a potential use of this technique in the food industry and for diagnostic purposes.