Effects of Enzymatic Hydrolysis of Fish Oil on the Formation, Structural Properties, and Oxidative Stability of Composite Aggregate Fish Oil Microcapsules

This study investigated the effects of enzymatic hydrolysis on the formation, structural properties, and oxidative stability of fish oil microcapsules prepared by complex coacervation. Gelatin O/W emulsions were prepared separately using hydrolysed and unhydrolysed fish oils, followed by the addition of sodium hexametaphosphate to induce complex coacervation. Both emulsions and resulting microcapsules were characterised. The results showed that 10SD-modified glycerides interacted most strongly with gelatin, promoting more intense complex coacervation and producing microcapsules with well-defined boundaries and uniform particle size distribution. Fourier transform infrared spectroscopy and thermogravimetric analysis confirmed strong interactions between 10SD glycerides and the wall material, resulting in minimal thermal mass loss and a denser encapsulation structure. Oxidative stability was significantly improved, with induction time increasing from 16.20 h in unhydrolysed fish oil microcapsules to 42.84 h in 10SD microcapsules. These findings demonstrate that enzymatic modification of lipid composition is an effective strategy for tailoring microcapsule structure and enhancing oxidative stability in fish oil delivery systems.