Abstract:

The role of selected emulsifiers on fat polymorphic transformations was studied. Tristearin was heated or aged under controlled conditions using differential scanning calorimetry (DSC) and x-ray techniques, and the extent of transformation was evaluated with respect to the possible pathways of $\alpha$ transforming into $\beta$. The temp. regime controls the extent of mobility of fat mols., the local crystal imperfections and the degree of liquefaction. As a result, it dictates the kinetics of the polymorphic transformation. The surfactant added as an impurity does not have a straightforward effect, as thought previously, but rather varies with the kinetic conditions. During aging some selected solid emulsifiers will retard the $\alpha$-$\beta$ transformation while others still enhance it (during heating, all of them will inhibit $\beta$ form crystn.). Their effect probably is related to different cryst. organizations and the creation of imperfections. Liq. emulsifiers in any case will enhance the $\alpha$-$\beta$ transformation, due probably to their weak structure compatibility with tristearin, which causes a higher mobility of triglyceride mols. [on SciFinder(R)]