Lipase immobilized on ionic liquid-functionalized magnetic silica composites as a magnetic biocatalyst for production of trans-free plastic fats.

The main objective of this study is to develop an efficient and environmentally gentle process for production of trans-free plastic fats. To acheive this, the core-shell structured magnetic composites were prepared, and then imidazole-based ionic liquids (ILs) were covalently grafted on the magnetic composites. Thereafter, Candida rugosa lipase was immobilized on the magnetic IL-functionalized composites. The immobilized lipase could be facilely separated using an external magnetic filed. With the magnetic biocatalyst, enzymatic interesterifications of solid palm stearin and liquid rice bran oil blends were performed at 45 °C. It was shown that the total fatty acid (FA) compositions of the binary blends were almost unchanged after the interesterifications, whereas the FA positional distribution and triacylglycerol species were significantly varied. As compared with the physical blends, the interesterified products had a lower slip melting point, and the interesterification could result in an obvious change in the microstructure of the final products.