Experimental Investigation of the Crystallization and Thermal Behavior of Animal Fat Mixtures Using a Multi-Technique Approach

Fats are essential ingredients widely used in the food industry, as well as in cosmetic and pharmaceutical formulations. Solid fats are complex multicomponent systems primarily composed of triacylglycerols (TAGs), which determine the types and properties of the crystalline structures formed. TAGs crystallize in different polymorphs and stacking configurations, with distinct thermal and mechanical properties that influence the macroscopic structure and sensory profile of fat-based products. In this study, a comprehensive multi-technique analysis of animal-derived fats, specifically chicken and beef fats, was conducted. Chemical characterization was performed and solid fat content (SFC) was determined. Thermal behaviour was investigated using differential scanning calorimetry (DSC), whereas crystallization experiments were conducted using in situ turbidity measurements and synchrotron small-angle and wide-angle x-ray scattering (SAXS/WAXS) for structural characterization. Three different synchrotron experimental setups were used for crystallization experiments, including static and sheared conditions. The results demonstrate that the crystallization behaviour of beef and chicken fat samples closely correlate with their TAGs composition. Synchrotron x-ray scattering provided structural insights, highlighting how the polymorphic behaviour is influenced by fat origin and crystallization conditions. For both animal fat types, all three main polymorphs and possible transitions were detected. Moreover, the presence of shear promoted crystallization of stable polymorphs.