At what temperature do egg whites coagulate?

• A. 50°C
• B. 60°C
• C. 70°C
• D. 80°C

Answer: (B)

Egg white coagulation happens when heat denatures the proteins and they start to link together to form a solid network. This process begins around 60°C, as the main protein, ovalbumin, unfolds and bonds with others to trap water and turn the liquid into a firm, opaque solid. At lower temperatures like 50°C, there isn’t enough unfolding to form a stable network yet, so the mixture remains runny. At higher temperatures such as 70–80°C, the network tightens further, creating a firmer, sometimes rubbery texture and more moisture loss. So the temperature where coagulation starts and the characteristic setting occurs is about 60°C.