Tuning Gelation of Insect Proteins: Effect of Ionic Strength on Acheta domesticus Protein Extracts

Protein gelation is a key mechanism for structuring food systems, as it determines texture, water retention, and overall product stability. Therefore, understanding how processing factors influence gelation is essential for designing functional protein-based matrices. In this work, the effect of ionic strength on the gelation and techno-functional properties of Acheta domesticus (house cricket) protein extract is investigated. Protein gels were prepared with increasing NaCl concentrations (0 – 0.5 M) and evaluated using rheological analysis. Additionally, techno-functional properties of the cricket protein extract, including solubility, emulsifying properties and water/oil holding capacity, were determined. Small-amplitude oscillatory shear tests revealed that moderate salt levels enhance gel elasticity, while excessive ionic strength produces brittle structures with reduced deformability. Frequency sweeps revealed decreasing tan δ and n values, confirming a transition from weakly entangled to strong, solid-like networks. These molecular changes were mirrored by functional responses: water-holding capacity increased at high salt concentration, whereas solubility and emulsifying activity declined. Collectively, the results highlight ionic strength as a tunable parameter linking protein interactions to macroscopic texture. By adjusting salt concentration, elasticity, hydration, and interfacial stability can be strategically modulated, enabling the rational design of insect-based food gels for different applications, from emulsified matrices to fibrous meat analogues.