1, 3-二飽和アシル-2-オレオイルグリセリン混合系の多形現象 : POP, POS, SOS

概要

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The polymorphism of mixtures of POP, POS and SOS was analyzed by using samples composed of pure compounds (>99%). Three mixture systems were prepared, A : POP (18.2%), SOS (34.0%), POS (47.8%), B : POP (44.5%), SOS (39.2%), POS (16.3%) and C : POP (58.1%), SOS (41.9%). The presence of polymorphism and its thermal transformation were examined by X-ray diffraction (XRD) and DSC, both applicable to the same sample at the same time, The three mixture systems exhibited almost identical polymorphic behavior : namely, α, pseudo-β, β2 and β1 occurred either via melt crystallizaion or polymorphic transformation. Melting points increased in the order, α to β1. In mixture C, the γ form was also detectable, with its melting point lying between those of α and pseudo β.<BR>The transformation rates from β2 to β1 were highest in mixture C, and slowest in mixture A.<BR>Both XRD short spacing patterns and DSC melting behavior of β2 and β1 of the three mix-tures were completely identical to those of pure POP and SOS, and to Forms V and VI of cocoa butter. Since mixture A has the same triacylglycerol composition as cocoa butter, the conversion from Form V to Form VI may be concluded to be the same as a solid-state-transformation.