Physical Characterization of Lard Partial Acylglycerols and Their Effects on Melting and Crystallization Properties of Blends with Rapeseed Oil

This work attempted to examine the effects of lard partial acylglycerols on the melting and crystallization properties of blends with lard and rapeseed oil (LR). Partial acylglycerols [lard-monoacylglycerols (lard-MAG) and lard-DAG] were found to result in different melting and crystallization properties of LR. Lard-MAG exerted slight inhibitory effect on crystallization of LR. Nevertheless, it was not statistically significant (P > 0.05). In fact, the presence of lard-MAG did not change the solid fat content (SFC) of LR. Lard-DAG, on the other hand, exerted different effects on the crystallization of LR depending on its concentration and degree of supercooling. The presence of a low concentration of lard-DAG was found to significantly (P < 0.05) delay nucleation and crystal growth velocity of LR at low degree of supercooling, which was reflected by a reduced Avrami constant (k) and SFC and increased half-time of crystallization (t(1/2)). Meanwhile, a high concentration of lard-DAG was found to promote nucleation and crystal growth in LR at low degrees of supercooling with increased k and SFC and decreased t(1/2). The characteristics of the blends may have correlations with their properties in potential meat applications.