The effect of cooling rate and rapeseed oil addition on the melting behaviour, texture and microstructure of anhydrous milk fat

Anhydrous milk fat and blends containing up to 40% (w/w) rapeseed oil (RO) were crystallized using a slow (0.05 °C min−1) or fast (5 °C min−1) cooling rate. Melting behaviour was examined using differential scanning calorimetry, texture was analysed by parallel plate compression tests, microstructure was studied by confocal laser scanning microscopy, and solid fat content was measured by pulse-NMR. Fast cooling of the blends decreased the peak melting temperature of both high and low melting fractions of milk fat as the content of RO increased, while increasing RO combined with slow cooling did not affect melting behaviour. Solvent effects dominating in fast cooled samples are suggested to be responsible for the change in melting behaviour. The texture of fast cooled samples correlated with solid fat content. In slow cooled samples addition of RO decreased the hardness, which was ascribed to an increase in crystal cluster size.