Underlying mechanism of sucrose esters on myofibrillar protein O/W emulsion gel behaviour under different ionic strengths: Focus on emulsion characterisation, protein structural changes and molecular interactions

The effects of sucrose ester concentrations (0.1, 1.0 and 10 mM) on myofibrillar protein emulsion gel at 0.3 and 0.6 M ionic strengths were investigated‌. At 0.3 M ionic strength, an elevated sucrose ester concentration increased the droplet size (from 31.86 to 55.97 μm) and absolute zeta potential (from 29.60 to 47.57 mV). Furthermore, it promoted protein folding at 0.3 M ionic strength but induced unfolding at 0.6 M. Elevated sucrose ester concentration reduced the α-helix content (from 45 % to 20 %) at 0.6 M ionic strength. Molecular dynamics simulations showed that high ionic strength promoted stable binding between sucrose ester and myosin. Moreover, higher sucrose ester concentrations weakened gels, increased free water content and enhanced viscous dominance in rheology. These findings provided meaningful insights into the mechanism of the surfactant-mediated formation of myofibrillar protein emulsion gels under varying ionic strengths.