Microstructure and polymorphism of blended and restructured palm olein and palm kernel oil

Blending and chemical interesterification are used to modify the physical properties of fats and oils. Chemical interesterification modified the physical characteristics such as polymorphism and microstructure of palm olein, palm kernel oil and their blends upon static crystallization. Refined, bleached and deodorized palm olein, palm kernel oil and their blends crystallized principally in the beta-polymorphic form, which was not altered significantly by chemical interesterification. Polarized light microscopy showed differences in crystal aggregates of chemically interesterified and non-chemically interesterified samples. It was therefore concluded that in a physical blend of palm olein and palm kernel oil, the microstructure is a combination of fat particles as well as regions of void crystalline materials which may contain liquid fat or very small crystals. In completely randomized palm olein and palm kernel oil systems where most tracylglycerols have identical fatty acids in similar spatial distribution, the microstructure is equivalent to a fat particle without regions of void crystalline material. Chemical interesterification can be used to improve the physical properties of palm olein, palm kernel oil and their mixtures for food and non-food applications.