Interesterification is an important technical means for the modification of edible oils and fats. Fatty acids in the triglyceride molecules can be rearranged which modifies the physical properties and nutritional functions of oils and fats and hence expanding the potential application in the food industry. The use of sn-1,3 specific immobilized lipase to catalyze interesterification has the advantages of mild reaction conditions and strong specificity. However, during the reactions, change of fatty acid at the sn-2 was observed which was due to the occurrence of acyl migration. In this work, palm olein (POL) was enzymatically interesterified using Lipozyme TL IM at 50°C for 2 h and the effect of different reaction conditions (enzyme loading, reaction temperature and time) on acyl migration was investigated. The degree of acyl migration (AMD) was defined by the change in the type and content of sn-2 fatty acid. The AMD increased with the amount of enzyme loading, recording the highest AMD of 63.41% when 11% of enzyme was added. At lower temperatures (50-70°C), the AMD increased followed by reaching maximum value of 80.71% at 80°C and then decreased at 90°C. As the reaction time was increased from 0h-3h, the AMD increased and achieved 98.24% at 3h. When the reaction time was further increased, the AMD remained constant at 100%, reaching a completely randomized interesterification. It is of great significance to explore the mechanism of acyl migration during a sn-1,3 specific lipase catalyzed interesterification process as to propose a theoretical foundation for implementing a technology to monitor and control the AMD.
.jpg "Yong Wang photo")