High melting fraction in natural oil will be crystallized first when oil is cooled, and the crystallization of low melting fraction can be affected by these crystals. Thus we investigated the effects of triacylglycerol additive (0.3–10 wt.%) and cooling rates (2°C, 5°C, and 10°C min−1) on the crystallization and melting behavior of coconut oil (CO)[1]. The polymorphism was investigated using synchrotron radiation X‐ray diffraction (SR‐XRD). From the DSC results, two exothermic peaks for CO crystallization indicated two compositions in CO. SR‐XRD revealed that the α form crystallized first at a high crystallization temperature (HTc) followed by β′ crystallization at low temperature (LTc). Both HTc‐α and LTc‐β′ transformed into the β′ form of CO (CO‐β′) solid solution during heating. Although the addition of PPP increased crystallization temperature of CO, PPP did not change CO polymorphism. However, during slow cooling with the StStSt additive, CO‐β′ crystallization was induced from the melt directly. The difference between triacylglycerol and emulsifier in crystallization promotion will be discussed with our recent works [2,3].
Reference [1] Mahisanunt, B.; Hondoh, H.; Ueno, S. J. Am. Oil Chem. Soc., 96, 391-404 (2019). [2] Ishibashi, C.; Hondoh, H.; Ueno, S. Cryst. Growth Des., 17, 6363-6371 (2017). [3] Ishibashi, C.; Hondoh, H.; Ueno, S. J. Am. Oil Chem. Soc., 95, 709-720 (2018).
