The Unique Crystallization Behavior of Buffalo Milk Fat

Abstract

A full comprehension of milk fat crystallization is important for the structural development of dairy products such as butter, ice cream, and cheese. The influence of triacylglycerol (TAG) composition on the dynamic of milk fat crystallization and the nanostructure of the formed crystals was investigated using two chemically different types of milk fat, namely buffalo and cow milk fats (BMF; CMF). The TAG composition was determined using liquid chromatography and mass spectrophotometry (LCMS), whereas differential scanning calorimetry (DSC), small- and wide-angle X-ray scattering (SAXS and WAXS), and polarized light microscopy (PLM) were used to characterize the crystallization behavior of the two milk fats. A total of 37 TAG species were identified in both BMF and CMF, but in different proportions. In particular, BMF was found to have a higher amount of low-molecular-weight TAGs in comparison to CMF. This difference in chemical composition explains the different kinetics of polymorphic transformation in the two samples. Specifically, it clarifies the delay in the nucleation of the β′-polymorph in BMF in comparison to CMF. BMF also showed a higher nucleation rate due to its higher proportion of saturated TAGs and higher melting range. Finally, this work presents a novel interpretation of the mechanism of formation of the β-polymorph (53 A), which has recently become the subject of a vivid debate in milk fat crystallization studies.