European journal of lipid science and technology vol:107 issue:9 pages:660-672
The aim of this research was to get more insight into the crystallization parameters of the model of Foubert et al. (2002) by examining the isothermal crystallization of two cocoa butters at different temperatures. The nucleation in the alpha polymorph was studied by scanning diffusive light scattering and was shown to agree with the Turnbull-Fisher equation. In accordance with the solubility principle, the amount of a crystals decreases as a function of temperature. The four parameters of the crystallization model were used to describe the influence of temperature on the beta' crystallization. The parameter a(F) decreases from temperatures of 20.5 degrees C onwards. The induction time increases with temperature while the rate constant K decreases as the temperature increases, especially at higher temperatures. Three hypotheses on the nature of the reverse reaction as described in the model were formulated and tested based on the temperature and cocoa butter dependency of the reverse reaction order n. The temperature dependence itself does not allow us to rule out one of the hypotheses, but the clear temperature dependence of the influence of the chemical composition is in favor of the hypothesis that the reverse reaction is dominantly either a re-melting or a redissolving reaction, depending on the crystallization temperature.