A bilayer emulsion containing encapsulated catfish oil, stabilized with whey protein isolates and fish gelatin for development of PUFA rich mayonnaise

This study investigated the impact of sequential deposition of whey protein isolate (WPI) and fish gelatin (FG) on primary o/w emulsions containing 5% catfish oil at concentrations of 0.1-0.75%. Initially, the emulsions were stabilized using 0.5% FG and WPI. The study also examined the influence of sequentially depositing WPI and FG within the emulsions on various parameters, such as stability, particle size, viscosity, electronegativity, and oxidative stability of bilayer fish oil emulsions. It was observed that the particle size increased significantly when FG was deposited onto the primary WPI emulsion, from 0.57 to 1.61 mu m. Furthermore, this process increased the apparent viscosity of the emulsion while reducing its droplet charge from - 24.93 to -12.17 mV. Conversely, depositing WPI onto the primary FG emulsion led to a reduction in the particle size and a slight increase in both electronegativity and viscosity. Concerning oxidative stability, a bilayer emulsion consisting of 0.5% WPI and 0.75% FG showed the lowest levels (hexanal concentration: 0.32 ppm) of oxidation after 21 days of storage. The mayonnaise fortified with a 20% bilayer emulsion consisting of 0.5% WPI and 0.75% FG exhibited rheological and microstructural properties comparable to those of commercial mayonnaise. Moreover, the fortification of mayonnaise with emulsified fish oil enhanced the fatty acid profile by increasing Polyunsaturated fatty acids (PUFA) and reducing Saturated fatty acids (SFA).