Crystallization behavior of monoacylglycerols in a hydrophobic and a hydrophilic solvent

Abstract

Systems containing monoacylglycerols (MAGs) in both a hydrophobic solvent (liquid oil) and a hydrophilic solvent (water) can be used for the development of calorie-reduced food products. In this study, the crystallization behavior of MAGs in a hydrophobic solvent (rapeseed oil) and a hydrophilic solvent (water) was studied and compared. Pure monopalmitin (MP) and a commercial MAG containing MP were used for this study. Differential scanning calorimetry (DSC) data were coupled with X-ray diffraction (XRD) data obtained using synchrotron radiation and cryo-scanning electron microscopy (cryo-SEM) images were recorded to illustrate the microstructural characteristics of the systems. Although the polymorphic behavior of the MAGs was found to be the same in both solvents, the crystallization onset temperature was found to be concentration-dependent in the systems with liquid oil as solvent, in contrast to the systems with water as solvent. On the other hand, the temperature of the polymorphic transition from the α to the sub-α polymorph was constant in both systems. Differences in microstructure could be attributed to the inherent properties of the hydrophobic or hydrophilic solvent.