Formation and properties of milk fat crystal networks.
Upon crystallization, fats form three-dimensional networks of crystals entrapping oil. It is due to this complex multiscale structure that fats behave as viscoelastic materials. The physical properties of fat crystal networks are critical for several products (e.g. chocolate, butter, cream, spreads, cheese) where fat has an important structural contribution . In milk fat (MF), rheology and crystallization are determinant factors for processing, functionality and characteristics of several dairy products .
To achieve efficient process design and engineering of fat structured products, it is critical to understand the crystal network structure along a broad length scale, the mechanisms involved in its formation and the way in which certain factors affect it.
It has been commonly demonstrated that composition together with processing conditions greatly determine fats structure, crystallization and rheological properties . However, as was pointed out already in the late nineties, and remains valid today, there are no conclusive theories that can directly link triglyceride (TAG) composition and crystallization properties to the macroscopic rheology of the network .