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 critical for designing functional protein-based matrices. This study investigates the effect of ionic strength on the gelation and techno-functional properties of <i>Acheta domesticus</i> (house cricket) protein extract. Gels were prepared with increasing NaCl concentrations (0-0.5 M) and characterized by rheological analysis. Additionally, solubility, emulsifying properties and water/oil holding capacity of the protein extract were assessed. Small-amplitude oscillatory shear tests revealed that G' increased from ~150 Pa at 0 M to over 1300 Pa at 0.5 M, indicating salt-induced network reinforcement. The loss factor (tan <i>δ</i>) reached its minimum (0.19) at high ionic strength, reflecting the formation of stronger, more elastic protein networks. These rheological trends aligned with the techno-functional responses: solubility peaked at 79.5% at 0.1 M NaCl before decreasing at higher salt levels, while emulsifying activity reached a maximum of 59.1 m² g^-1 at 0.3 M before dropping sharply. Collectively, these findings highlight ionic strength as a tunable parameter linking molecular interactions to bulk viscoelasticity and textural attributes. 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 systems to fibrous meat analogs.