Abstract
A review is made of the different structural principles involved in the assembly of the casein micellar particles present in mammalian milks. The properties of the constituent casein proteins are described, and how these can lead to different structural models. The evidence for particular models is given, and it is concluded that a model based on calcium phosphate nanoclusters is the most appropriate in view of electron microscopic and scattering experiments. A modification of the nanocluster model is presented, which allows many of the known structural properties of the micelles to be incorporated.