A lumped model of the lipase catalyzed hydrolysis of sardine oil to maximize polyunsaturated fatty acids content in acylglycerols

•DHA content of diacylglycerols increased 1.9-fold.•Lumped model predicted the time evolution of TAG, DAG, MAG and FFA.•The concentration of each fraction was also calculated by the model.•The release of the second fatty acid was dependent on its unsaturation degree.

The aim of this work was to produce diacylglycerols (DAG) and monoacylglycerols (MAG) with a high content of polyunsaturated fatty acids (PUFA). Rhizomucor miehei lipase mediated-hydrolysis of sardine oil was conducted at several water activities. The system was mechanistically modeled to predict the time evolution of the concentration of triacylglycerols, DAG, MAG and free fatty acids (FFA) and the concentration of saturated, mono- and polyunsaturated fatty acids. The release of the first fatty acid from the triacylglycerol was independent on the unsaturation degree. Contrary, the hydrolysis of the second one was highly affected by the degree of unsaturation, PUFA being the fatty acids that showed the highest resistance to hydrolysis. MAG percentage was maximum (7 mol%) at lower water activities, while DAG content was favored at higher water activities (35 mol%), achieving a 2-fold concentration of DHA.