Exploring the role of NaOH in modulating the properties of metal-free preserved egg white gels: physicochemical, rheological, and structural properties

< 0.05). Further increasing the NaOH concentration led to obvious gel liquefaction, accompanied by a sharp decline in these properties. FTIR analysis revealed that the ordered gel structure was mainly stabilized by β-sheet structures, together with the continuous transformation of α-helices. The gel formed at 0.8% NaOH exhibited the highest β-sheet content (28%) and excellent structural stability. Rheological measurements indicated that gel viscosity increased with increasing NaOH concentration, and egg white proteins treated with high alkali concentrations showed the earliest flow behavior. Control group comparisons confirmed that simply adjusting the NaOH concentration could produce protein gels with properties comparable to those induced by metal ions. These findings provide important theoretical support and practical guidance for the industrial production of safe, metal-free preserved eggs.