Rheological and Microstructural Properties of Thermal and Mechanically Treated Shea Butter

Shea butter, like other polymorphic fats are susceptible to morphological changes due to post harvest practices to produce either smooth and consistent fat containing predominantly β'-crystals or coarse and grainy fat containing predominantly β-crystals. The aim of this study was to determine the effect of temperature control (tempering) and agitation on the rheological and microstructural properties of Shea butter. Shea butter was heated at 80°C for 30 minutes and then fast cooled to room temperature. Tempered Shea butter was kept constant at tempering temperature with continuous agitation for 6 hours. Slip melting point and viscosity of tempered Shea butter was significantly reduced. The hardness index (mm) showed twice reduction compared to control. Rheological properties of tempered butter in comparison with control were in agreement with differential scanning calorimetry, X-ray diffraction results and micrographs.