Effects of alkaline concentration, temperature, and additives on the strength of alkaline-induced egg white gel

Egg whites can undergo gelation at extreme pH. In this paper, the effects of NaOH concentration (1.5, 2, 2.5, and 3%), temperature (10, 20, 30, and 40°C), and additives (metallic compounds, carbohydrates, stabilizers, and coagulants) on the strength of alkaline-induced egg white gel were investigated. Results showed that NaOH concentration and induced temperature significantly affected the rate of formation and peak strength of the egg white gel. Of the 6 metallic compounds used in this experiment, CuSO4 exhibited the optimal effect on the strength of alkaline-induced egg white gel, followed by MgCl2, ZnSO4, PbO, and CaCl2. When CuSO4 concentration was 0.2%, the gel strength increased by 31.92%. The effect of Fe2(SO4)3 was negligible. Of the 5 carbohydrate additives, xanthan gum (0.2%) caused the highest increase (54.31%) in the strength of alkaline-induced egg white gel, followed by sodium alginate, glucose, starch, and sucrose. Meanwhile, propylene glycol (0.25%) caused the highest improvement (15.78%) in the strength of alkaline-induced egg white gel among the 3 stabilizing agents and coagulants used, followed by Na2 HPO4 and glucono-δ-lactone.