Restructuring butterfat through blending and chemical interesterification. 2. Microstructure and polymorphism

Blending of butterfat with canola oil and subsequent chemical interesterification modified the crystal morphology and X-ray diffraction patterns of butterfat, 90∶10 (w/w), and 80∶20 (w/w) blends of butterfat-canola oil. The morphology of 50∶50 (w/w) was also greatly influenced by interesterification. Polarized light microscopy revealed that addition of canola oil led to gradual aggregation of the crystal structure. Scanning electron microscopy revealed all samples to be mixtures of defined crystalline regions and amorphous areas with greater amorphism as oil content increased. Most samples revealed segregation of solid from liquid. Confocal laser scanning microscopy of butterfat revealed complex aggregated structures that were composed of outwardly radiating filaments from a central nucleus. X-ray diffraction analysis revealed a predominance of β′ and a small proportion of β crystals for all samples examined except interesterified butterfat, which consisted solely of β′ crystals.