Design and optimization of advanced emulsion systems for food applications

This study aimed to deeply evaluate the potential of octenyl succinic anhydride (OSA) starch, chickpea protein isolate (CP), and citrus fibers (CF) as emulsifiers in different advanced emulsions (i.e., Pickering, cold-filled gel, and hot-filled gel emulsions), as a function of their concentration (i.e., 5, 15, and 25 g/L water for OSA; 40, 60, and 80 g/L water for CF; 120, 140, and 160 g/L water for CP) and oil volume phase (15, 37.5, 60% v/v). As reference, single emulsions prepared with soy lecithin (SL; 5, 15, and 25 g/L oil) were considered. Experiments were planned by face-centered Central Composite Designs (CCDs) considering emulsifier concentration and corn oil volume phase as experimental factors. A total of 13 runs, comprising 5 replicates of the central point, were performed for each type of emulsion. All samples were analyzed for pH, apparent viscosity, particle size, and stability of the oil and water phase. CP in hot-filled gel emulsions and CF resulted in the highest apparent viscosity (mean values of 626 and 692 mPa s, respectively) and stability index values (mean values of 100 and 96%, respectively). Based on the highly significant models obtained for apparent viscosity and droplet size (D90), emulsion formulations were optimized through the Response Surface Methodology (RSM) coupled with the desirability function. All the optimized advanced systems showed higher apparent viscosity (1300–2400 vs 144 mPa s) and stability index (98–100 vs 89%) than the single emulsion made with SL.