Analyses of milk fat crystallization and milk fat fractions

Abstract

The aim of this study was to determine the possible extent of changes in the composition and physicochemical properties of unmodified milk fat (UMF) and to evaluate the influence of such modifications on the crystallization of solid fractions (SF) and liquid fractions (LF) obtained from UMF by dry fractionation at a temperature of 30°C, 25°C, and 20°C. The evaluation was based on the results of gas chromatography, differential scanning calorimetry (DSC), firmness/hardness values measured with a texture analyzer, and optical microscopy analysis. The results of the above analyses, in particular the evaluation of fatty acid (FA) composition, revealed that dry fractionation produces fractions with different composition and different ratios of saturated fatty acids (SFAs) to unsaturated fatty acids (UFAs). These variations also induced differences in the physicochemical properties of the analyzed samples, mostly changes in melting and solidification curves, as well as differences in the microstructure of milk fat (MF) analyzed under a microscope at a temperature of 10°C. The present findings indicate that FA composition is clearly correlated with firmness/hardness and the microscopically determined crystallization of MF and its fractions.

Keywords

• milk fat
• fractionation
• fractions
• fatty acids
• crystallization
• firmness