denaturing protein... sounds highly technical, doesn’t it? But you’ve done it a million times when you’ve barbecued your sausages, boiled an egg or cooked a bit of tofu. Protein is one of the main components of food. It’s found in meat, fish, pulses, eggs, beans, nuts, seeds, soya products and vegetable protein foods, such as Quorn. These proteins are made up of chains of small molecules called amino acids. Folds in the amino acid chain produce the shape of the protein and it’s the shape that determines the protein’s chemical and biological properties. Several of the processes used in cooking break the bonds holding the chains in shape, and therefore they change the properties of the protein. And this is known as ‘denaturing’ the protein. Heating a protein gives the molecules more energy and as they vibrate, the weak bonds in between the amino acid chain break and the protein unfolds. At high temperatures proteins can gain enough energy to form strong covalent bonds with other adjacent molecules – this is why an egg turns hard when you boil it. Certain chemicals can also be used to denature protein. The most commonly used in cooking is vinegar, a weak acid. The protein in egg white is denatured by mechanical means when you whisk an egg. The beating action tears the protein apart and the surface tension of the little bubbles breaks the bonds holding the amino acid chains. And makes it perfect for meringues! << Go Back