The difference between cocoa butter and salatrim® lies in the microstructure of the fat crystal network

The solid fat content of Salatrim® at 22°C is 9% higher than that of cocoa butter; however, its storage modulus, G′ (1 Hz), or solid‐like character, is one order of magnitude lower (2.5 MPa vs. 52 MPa). This difference may be explained by structural differences in the microstructure of the fat crystal network of the respective fat systems. Polarized light micrographs of these two confectionery fats show that cocoa butter forms a fat crystal network characterized by discrete crystalline particles which aggregate to large microstructures which then form a three‐dimensional network, while Salatrim®’s network is composed of randomly arranged noncrystalline, translucent platelets. Rheological measurements on both fat networks yielded fractal dimensions of 2.37 for cocoa butter and 2.90 for Salatrim®. Image analysis of the microstructure of cocoa butter yielded a fractal dimension of 2.31; however, the microstructure of Salatrim® does not lend itself to fractal analysis via image analysis. It was observed that the microstructure of Salatrim® is random instead of fractal. The proposition is made that the macroscopic mechanical properties of Salatrim® are related to the mechanical properties of the platelets that make up the network and the nature of the links between the platelets. Furthermore, the random spatial distribution of the platelets does not provide an indication of the strength of the network. For cocoa butter, the macroscopic mechanical properties are integrally related to the fractal spatial distribution of the solid mass in the network, the nature of the links between the microstructures, and the strength of the microstructures.