Food Science- proteins




·       Proteins have a complex structure.  When the food is cooked, proteins denature, which means that the chemical bonds holding their structure together break down.

·       The proteins unravel and their shape changes

·       This can be done in different ways including physical agitation, changes in temperature, acids

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·       Once they have denatured, protein molecules collide with other protein molecules and coagulate (join)

·       During this process, water becomes trapped between the protein molecules.

·       Coagulation also changes the appearance and texture of the food.

·       However, if food is overcooked and coagulation happens too much, the protein tightens.  This forces water out of the molecules, making it dry and chewy.

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Foam Formation

·       Foams form when gas becomes trapped inside liquid

·       When liquids containing proteins are agitated, the proteins inside the liquid denature and this causes them to stretch and air becomes trapped in the liquid.

·       When the proteins coagulate, this air becomes trapped, creating a foam.

·       However, over-whisking causes these new protein bonds to break- air escapes and the foam collapses.

·       Some foams form a solid structure when they’re cooked

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Gluten Formation

·       Gluten is a protein found in wheat flours

·       It’s formed when water is mixed with the flour to make dough and can be found in foods like bread, pasta, cakes and pastries

·       Molecules of gluten are coiled- this means they are able to stretch and bend- this gives all doughs elasticity

·       Doughs need to be kneaded to ‘work’ the gluten- this causes gluten strands to get longer, stronger and stretchier

·       When it reaches a high temperature, gluten coagulates, and the dough stays stretched.  This gives foods like well-risen bread a light, airy texture.

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