The effect of partial acylglycerols on the exchange between liquid and solid tripalmitoylglycerol

Exchange of molecules between liquid and solid components of a triacylglycerol (TAG) system is an important process in the degradation of many food components as well as for many industrial processes such as fractionation. NMR is a technique that can be used to measure the exchange between solid and liquid phases. In this work we show that monoacylglycerols (MAG) and diacylglycerols (DAG) have a retarding effect on the rate of exchange between solid and liquid TAG. In particular dipalmitoylglycerol significantly retards the rate of exchange. It is postulated that this result suggests that exchange occurs primarily through certain hotspots, probably kinks and defects on the crystal surface. MAG and, in particular, DAG can block these hotspots. It is suggested that because of their molecular structure they can partially co-crystallize with the TAG crystal during the exchange process and then block further exchange.