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

Abstract

Casein micelles and their rennet modification into para-casein micelles play a central role for the production of dairy products. They both hold a great potential as functional materials in many applications from coating to biomaterials, presenting a completely biological and sustainable alternative to petrochemicals. Whatever their application is, characterizing their dynamics, stability and ultimately their assembly is essential for their processing. In this study, casein-and paracasein micelle dispersions are characterized by differential dynamic microscopy (DDM). Conversely to conventional dynamic light scattering, DDM allows the characterization of highly turbid media and the simultaneous acquisition of the intermediate scattering function on a large 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 food industry and for diagnostic purposes.