Having their cake and eat it too: Effects of different cations in reduced-salt myofibrillar protein microgel pickering emulsion under high-intensity ultrasound

Abstract

Health concerns have increased the demand for low-salt emulsified meat products emulsions; however, salt-soluble myofibrillar proteins (MP) are less than optimal emulsifiers under low-salt conditions. In this study, four different cations (Na⁺, K⁺, Ca²⁺, and Mg²⁺) were added to a Pickering emulsion and high-intensity ultrasound (HIU, 20 kHz, 600 W) was used to determine the quality of the final emulsion. The divalent cation group was found to significantly (P < 0.05) improve the emulsification performance of the emulsion; in particular, the emulsion activity index and emulsion stability index of Mg²⁺-H group increased to 16.24 ± 1.22 m²/g and 89.66 ± 3.01%, respectively. Measurements of the particle size and zeta potential confirmed that the emulsion particle size of the Mg²⁺-H group decreased, and the electrostatic repulsion force increased. Based on the surface hydrophobicity and endogenous tryptophan spectra, the particle structure of the MP microgel was determined to be a more stable emulsifier. What's more, the divalent cations promoted the droplets to become evenly dispersed under high-intensity ultrasound. The micrograph confirmed this result: the divalent cation group emulsion was more uniform and stable than the monovalent cation group emulsion. Divalent cations are more suitable than monovalent cations for improving the quality of reduced-salt Pickering emulsions.