Crystallization behavior of 1,3-dipalmitoyl-2-oleoyl-glycerol and 1-palmitoyl-2,3-dioleoyl-glycerol

Abstract

A model margarine was stored under a temperature fluctuation cycle of 5—20 °C until granular crystals were observed. Using information obtained from the granular crystals, the crystallization behaviors of major triacylglycerols of palm oil, 1,3-dipalmitoyl-2-oleoyl-glycerol (POP), 1-palmitoyl-2,3-dioleoyl-glycerol (POO), and their mixtures were then investigated. It was shown that in the model margarine, the POP content in the granular crystals was higher than in their surrounding materials, and the X-ray diffraction pattern of the granular crystals revealed that they were the most stable polymorph, β. 99% pure POP, POO, and their mixtures were then stored under the above-mentioned temperature cycle. POP was found to form the unstable polymorph, α, when cooled rapidly from the melt. Within 24 hours transformation into the γ polymorph and then into the β polymorph was observed. POO was shown to transform into the β' polymorph from α. When POP and POO were mixed, the β polymorph did not emerge, instead it was shown that POP and POO were both agglomerated in the mixtures, giving rise to the formation of granular crystals.