Stability enhancement of pickering emulsions based on κ-carrageenan microgel: Synergistic effect of l-lysine and potassium ions at low ionic strength

Abstract

The study utilized the synergistic effect of l-lysine and K+ to improve the stability of Pickering emulsions based on κ-carrageenan microgels. The gel strength of κ-carrageenan gels, the zeta potential and particle size revealed that the microgel particles prepared with l-lysine and K+ had the potential to be Pickering particles. l-lysine formed electrostatic interactions and hydrogen bonds with κ-carrageenan. Structural modifications of microgel particles by l-lysine (0.05%–0.10%) and low K+ strength (≤40 mmol/L) promoted the formation of a dense interface layer at the oil-water droplet surface to prevent the accumulation of oil droplets and further significantly enhance the appearance and centrifugal stability of Pickering emulsions. The microstructure and rheological analysis showed that K+ at low ionic strength, in cooperation with l-lysine, formed a more tightly structured layer between the microgel particles wrapped on the surface of oil droplets, thereby enhancing the stability of emulsions. In conclusion, these Pickering emulsions with prolonged stability are expected to be suitable healthy animal fat substitutes for use in food applications.