Physical aging of even saturated monoacid triglycerides

Abstract

Abstract The polymorphism and kinetics of phase transformations of triglycerides have been investigated using a polarizing microscope equipped with a variable temperature gradient stage. Differential thermal analysis, X‐ray, NMR, and IR data supplement the visual observations. The α‐polymorphic transformation was observed to change with time in the cases of trilaurin, trimyristin, tripalmitin, tristearin, triarachidin, and tribehenin and can be described by the equation: urn:x-wiley:0003021x:equation:aocs0128-math-0001 The greater stability of the α‐polymorph chain triglycerides can be attributed to the larger energy of activation needed for the transition to occur. Estimates of the energy of activation (14–76 kcal/chain) imply that, not only does the transformation process involve simple Van der Waals CH 2 ‐CH 2 interactions, but one must also consider chain‐chain entanglement.