Probing early-stage casein micelle aggregation during milk acidification with differential dynamic microscopy
- Author(s)
- Matteo Brizioli, Sigrid Nørgaard Beldring, Valeria Rondelli, Roberto Cerbino, Vojislav Vojinovic, Milena Corredig, Fabio Giavazzi
- Abstract
The sol-gel transition of casein micelles during milk acidification is relevant to many dairy manufacturing processes. However, the early microscopic events that precede visible gelation remain poorly resolved due to milk's intrinsic turbidity, which hinders conventional light-scattering methods. Here, we show that Differential Dynamic Microscopy (DDM) enables direct, in situ quantification of casein micelle dynamics and aggregation throughout acid-induced gelation of skim milk, without dilution or tracer particles. Time-resolved DDM measurements reveal a progressive reduction in the micellar diffusion coefficient, accompanied by the emergence and growth of fractal aggregates that ultimately form a continuous gel network. Comparison of heated and unheated milk shows that heat treatment, which is known to shift the onset of aggregation to higher pH, subtly alters the coupling between cluster size and mobility. Besides providing multi-scale quantitative insight into the microstructural aspects of acid milk gelation, these results establish DDM as an accessible yet powerful tool for probing gelation and network formation in moderately turbid colloidal systems.
- Organisation(s)
- Computational and Soft Matter Physics
- External organisation(s)
- Università degli Studi di Milano-Bicocca, Aarhus University, Novonesis
- Journal
- Journal of Colloid and Interface Science
- Volume
- 722
- No. of pages
- 10
- ISSN
- 0021-9797
- DOI
- https://doi.org/10.1016/j.jcis.2026.140842
- Publication date
- 11-2026
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103015 Condensed matter, 211202 Food technology
- Keywords
- ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials, Biomaterials, Surfaces, Coatings and Films, Colloid and Surface Chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/625fce01-ef81-4d90-96c8-598442c97cb0