Protein denaturation by heat

Heat increases the kinetic energy and causes the molecules to vibrate so rapidly and violently that hydrogen bonds and hydrophobic interactions are disrupted. This leads to the total unfolding of proteins, as quaternary, tertiary, and secondary structures are lost.

Heat is normally used in cooking to change the food texture, as in fried or boiled eggs, and also to facilitate protein digestion by enzymes.

In addition, some sterilization processes use heat to denature proteins in bacteria. This is commonly used in medicine to sterilize surgery materials, or in research to avoid bacterial contamination.