Competitive adsorption of sodium caseinate or ovalbumin by Tween 80 impact the mechanical and microstructural properties of emulsified surimi gel systems

Summary This study first explored the competitive displacement of sodium caseinate (SC) and ovalbumin (OVA) by Tween 80 (TW) on the mechanical and microstructural properties of emulsified surimi systems. The interfacial tension of TW (8.02 ± 0.58 mN m −1 ) was significantly lower than that of SC (10.45 ± 0.62 mN m −1 ) and OVA (11.78 ± 0.69 mN m −1 ), and TW's addition significantly decreased the interfacial protein concentration in SC emulsion from 2.04 ± 0.18 to 1.31 ± 0.28 mg m −2 and OVA emulsion from 3.53 ± 0.04 to 2.51 ± 0.12 mg m −2 respectively ( P < 0.05). The SC‐ and OVA‐emulsified gels exhibited higher hardness, adhesiveness, chewiness, gel strength, equilibrium stress, recovery rate and quality factor (Q) than TW/SC‐ or TW/OVA‐emulsified gels. Emulsion droplets are embedded in the gel matrix and evenly distributed in SC‐, OVA‐ and SC/OVA‐emulsified gel. However, in TW‐, TW/SC‐ and TW/OVA‐emulsified gel, local phase separation occurs between aggregated protein particles and oil droplets, resulting in highly heterogeneous structures. This study provides a valuable reference for utilising compound emulsifiers in the surimi industry.