Effects of interesterification with solid base catalyst on physicochemical properties of lard and high-oleic sunflower oil blends

Interesterified blends of lard (LA) and high-oleic sunflower oil (HOSO) were prepared by using a self-synthesized solid base catalyst (K2CO3/GCN). The effect of interesterification on the physicochemical properties of blends was investigated by analyzing the triacylglycerol (TAG) composition, slip melting point (SMP), solid fat content (SFC), thermal properties, crystal polymorphism, and micromorphology. The results proved that interesterification significantly modified the physicochemical properties of the blends. The interesterified products had lower SMPs and steeper SFC curves than the individuals. The interesterified product (CIE-5:5) had the widest plastic range (5.7-18.6 degrees C), and its increase rate of OPO and OPL total content was up to 38%. The differential scanning calorimetry melting and cooling thermograms showed an obvious change after interesterification. These changes were mostly due to the alternations in TAG compositions. The wide-angle X-ray diffraction results indicated that the crystal form of blends transformed from beta ' to beta-form after interesterification. Because of the transformation of crystal polymorphism, the micromorphology of interesterified blends differed greatly from the physical blends at the same ratio. The changes in crystal morphology are beneficial for the application of LAHOSO blends. This work provides an alternative option for extending the use of native lard and high-oleic sunflower oil.