Final answer:
The coagulation of proteins that causes the skin to turn white during certain chemical peels happens when substances like TCA or phenol denature proteins such as albumin and globulins, leading to an opaque, solidified mass in the skin.
Step-by-step explanation:
In the context of skin peels, the coagulation of proteins that leads to the skin turning white is often seen during chemical peels, particularly medium to deep peels. These peels use substances like trichloroacetic acid (TCA) or phenol which denature proteins, causing a rapid coagulation.
When the proteins in the skin, like albumin and globulins, are subjected to these chemicals, they undergo a process similar to when egg white turns white upon boiling. The proteins are denatured and unfold, exposing hydrophobic areas that then bind together, forming an opaque, solidified white mass. This white appearance, often referred to as frosting, is an indicator that the peel has penetrated to the desired depth. It is important to note that not all proteins are heat coagulable, but in the case of skin peels, the denaturation is chemically induced rather than by heat.