Formation of β polymorphs in milk fats with large differences in triacyiglycerol profiles

In this study, we characterized the polymorphism of milk fat (MF) with various TAG compositions during isothermal crystallization at 20 degrees C. TAG composition of MF from seven individual cows was determined using GC-FID and MALDI-TOF MS, and MF polymorphism was studied using X-ray diffraction. Results showed that TAG profile determines the polymorphic behavior of MF. Saturated TAG with carbon numbers 34-38 promoted the formation of alpha polymorphs, whereas unsaturated TAG with 52-54 promoted the formation of the beta polymorphs. Furthermore, MFs with unsaturated fatty acid profiles were increased in unsaturated TAG with 52-54 carbons. The presence of MF crystals in the beta polymorph has been controversial over the years as most authors mainly find MF crystals in the alpha and beta' form. In our work, we showed that the beta polymorph is formed in MF on the basis of its TAG composition