Temperature-Driven Changes in the Polymorphism, Microstructure and Thermal Properties of Cocoa Butter/Shea Butter Stearin Blends

Abstract

The increasing application of cocoa butter alternatives in confectionery products requires a deep understanding of their crystallization behavior in order to maintain and promote desirable quality attributes. Through the combination of X-ray diffraction, microscopic, and thermal analysis techniques, this study explored the polymorphic, microstructural, and melting properties of cocoa butter and shea butter stearin blends with varying compositions. Results showed a more complex polymorphic behavior in blends than in the pure fats, with the coexistence of β′-2L and β′-3L forms, whose occurrence was strongly influenced by both the cocoa butter/shea stearin ratio and the thermal treatments applied. The solid fat content analysis evidenced, at all the analyzed samples, an abrupt falling typical for CB-like melting profile, which occurred between 30 and 35 °C in CB, and shifted to above 35 °C in ShS. Blends with increasing amounts of shea stearin showed a higher thermal resistance, a smoother thermal profile and a delayed β-phase development under isothermal conditions. Moreover, moderate variations of the composition modified the microstructure of the blends, which suggests potential impacts on the texture and sensory perception of products including this fat system.