Phospholipids delay crystallisation of milk fat.

Differential scanning calorimetry studies demonstrated that isothermal crystallisation at 22 degrees C and non-isothermal crystallisation onset of anhydrous milk fat added 0.2 w/w% milk phosholipid were postponed compared to anhydrous milk fat without addition. Furthermore, pulsed nuclear magnetic resonance measurements also showed that addition of milk phospholipid to anhydrous milk fat delays crystallisation, since the increase in solid fat content was slower at isothermal crystallisation at 22 degrees C. To explain the mechanism responsible for delayed crystallisation of milk fat when phospholipid is added, small angle time resolved synchroton x-ray diffraction was used. The control sample started crystallizing in double lamellar structure of 46.3 angstrom followed by triple lamellar structure of 36.5 angstrom and 72.9 angstrom while the double lamellar structure of 46.3 angstrom was not present in milk fat added phospholipid. This indicates that the initial formation of a metastable double lamellar structure is inhibited by phospholipids, and this is a responsible mechanism for delaying of milk fat crystallisation in the presence of phospholipids.