Differential scanning calorimetry study on caprylins

Monoacylglycerols (MAG) and diacylglycerols (DAG) are nonionic surfactants with several applications in the food, pharmaceutical and other chemical industries. They can be produced by alcoholysis, esterification or partial hydrolysis of triacylglycerols, alternatively using lipase instead of chemical catalysts, generating purer and less degraded lipids. Differential scanning calorimetry (DSC) is a widespread method extensively used for studying the thermal properties of several materials, including the various classes of lipids. In this field, however, the use of DSC has generally been limited to the analysis of the thermal profiles of fats and oils, as well as the characteristics of interesterification reaction products. Therefore, the present study reports the melting and crystallization behavior of chromatographic standards of monocaprylin (MC), dicaprylin (DC) and tricaprylin (TC), as well as binary mixtures of MC and DC in proportions (w/w) of 2:1, 1:1 and 1:2, respectively, aiming to propose the use of DSC as a first step to monitor esterification or hydrolysis reactions for the production of MAG and DAG, as well as the subsequent indispensable purification procedures. It is worth to highlight that little is known about the physical behavior of MAG and DAG of caprylic acid presented herein. The remarkable differences between the behaviors of pure components and binary systems during cooling and heating can be possibly attributed to interactions between molecules by weak chemical bonds such as hydrogen bonds, van der Waals force or hydrophobic interactions, as well as phase transitions or polymorphism. This study indicates that DSC can be a valuable tool to supply important information on catalytic reaction evolution, which should be complemented by other techniques to provide a complete depiction of the reaction under research.