Effect of Crystallization Temperature of Palm Oil on Its Crystallization. III. Crystallization of Triacylglycerin Comprised of Palmitic Acid and Oleic Acid in Palm Oil

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The crystallization of triacylglycerin comprised of saturated fatty palmitic acid and unsaturated fatty oleic acid was examined by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) using PPP (tripalmitoylglycerol), PPO (1, 2-dipalmitoyl-3-oleoyl-glycerol), POP (1, 3-dipalmitoyl-2-oleoyl-glycerol), POO (1, 2-dioleoyl-3-palmitoyl-glycerol) and OOO (trioleoylglycerol). Determination of the supercooling temperature, the difference in melting and solidifying points, was made based on DSC peaks. Supercooling was noted to increase with oleoyl chain number in a triacylglycerin molecule. With sample solidification, the subcell structure was found to change significantly with supercooling. Orthorhombic perpendicular packing (O⊥) occurred with increase in supercooling while hexagonal packing (H) took place with decrease in this cooling. Increase in supercooling was shown to arise with reduction in the crystalinity of triacylglycerin containing unsaturated fatty acid chains.