Phase behaviour of model triglyceride ternary blends: triolein, tripalmitin and tristearin.

We investigate the phase behavior of model ternary triacylglycerol blends, comprising triolein (C 57 H 104 O 6 , OOO), tripalmitin (C 51 H 98 O 6 , PPP) and tristearin (C 57 H 110 O 6 , SSS), building upon extensive characterisation of single and binary mixtures, in order to rigorously map the thermal transitions of model natural 'fats'. A combination of calorimetry, X-ray diffraction, and FTIR spectroscopy is employed to determine crystallisation and melting temperatures and identify the corresponding phases in the complex ternary system. We recover the eutectic behaviour of SSS-PPP blends and the invariability of OOO neat transitions, and resolve the complex β' + β ternary surface, reflecting the roles of unsaturation and polymorphism of its constituents. Our results provide a representation of the OOO:PPP:SSS:temperature phase behaviour into a triangular prism, consistent with binary pair-wise data, which can inform a range of food science, cosmetic, pharmaceutical and cleaning applications that depend strongly on the physical-chemistry of such multicomponent 'triglycerides'.