What term describes the process where protein in eggs contracts, resulting in a tough product?

The correct term that describes the process where protein in eggs contracts, resulting in a tougher product, is coagulation. During coagulation, when eggs are heated, the proteins denature and then aggregate, forming a solid structure. This process contributes to the firmness and texture in dishes such as scrambled eggs or custards.

Curdling refers to the separation of milk or cream into solids (curds) and liquid (whey), often due to acid or heat, but it is not specifically about the proteins in eggs contracting. Syneresis involves the expulsion of liquid from a gel-like substance, which can occur in certain food preparations but does not directly relate to the toughening of proteins in eggs. Gelation involves the formation of a gel, which is a different process that may involve proteins but does not focus specifically on the contraction or toughening aspect. Therefore, coagulation effectively captures the concept of protein contraction in eggs leading to a firmer and tougher product.