Phase behavior and extended phase scheme of static cocoa butter investigated with real-time X-ray powder diffraction

A complete isothermal phase-transition scheme of cocoa butter under static conditions is presented, based on time-resolved X-ray powder diffraction ex periments. In contrast to what is known from literature, not only beta V, b ut also beta VI can be obtained directly through transformation from beta'. Another remarkable result is that beta' exists as a phase range rather tha n as two separate phases. Within this beta' phase range no isothermal phase transitions have been observed. More detailed information concerning the o bserved cocoa butter polymorphs was obtained by determination of melting ra nges, using time-resolved X-ray powder diffraction. Also standard X-ray pow der diffraction patterns of the gamma, the alpha, and the two beta phases a nd parts of the beta' phase range have been recorded. The observed phase be havior of cocoa butter has been explained based on the concept of individua l crystallite phase behavior of cocoa butter.