Lipid Oxidation of Fish Oil-in-Water Pickering Emulsions Stabilized With Protein-Based Janus Particles

Pickering emulsions stabilized with solid particles have a significant advantage over conventional emulsions due to their high coalescence stability. However, their chemical stability, especially in fish oil-in-water Pickering emulsions, needs improvement. Janus particles, with their anisotropic structure that enhances interface binding and allows for antioxidant inclusion, offer a promising solution for improving both physical and oxidative stability in these emulsions. In this study, fish oil-in-water Pickering emulsions were produced with zein-caseinate Janus particles. The latter were produced by electrohydrodynamic co-jetting technique. Confocal laser scanning microscopy and scanning electron microscopy analysis confirmed anisotropic structures of these particles. Emulsions with 2.5 wt% oil and 1.0 wt% protein emulsifier were assessed for the physical and oxidative stability. Emulsions produced with zein-caseinate Janus particles had unchanged size distribution during the entire storage experiment and low number of coalescence events compared to emulsions with sodium caseinate. These results indicate that emulsions stabilized with zein-caseinate Janus particles enhanced physical stability compared to those stabilized with caseinate only. The formation of hydroperoxides and depletion of tocopherols were at the same level for both emulsions, while formation of volatile compounds was slower in the Pickering emulsions with Janus particles. This implies that Janus particles may hinder the degradation of lipid hydroperoxides to secondary oxidation products.

Practical Applications: Zein-caseinate Janus particles can be produced with electrohydrodynamic co-jetting technique. The significant enhancement of both physical and oxidative stability in Pickering emulsions stabilized by these particles suggests their potential as effective Pickering emulsifiers for food emulsions rich in polyunsaturated fatty acids.