On food and cooking the science and lore of the kitchen ( PDFDrive ) 169

runny liquid, do nothing more than add heat, and presto: the liquid rapidly stiffens into a solid that you can cut with a knife No other ingredient is as readily and drastically transformed as is the egg This is the key to its great versatility, both on its own and as a structure builder in complex mixtures To what does the egg owe its constructive powers? The answer is simple: to its proteins and their innate capacity to bond to each other Protein Coagulation Pulling Proteins Together… The raw egg begins as a liquid because both yolk and white are essentially bags of water containing dispersed protein molecules, with water molecules outnumbering proteins 1,000 to 1 As molecules go, a single protein is huge It consists of thousands of atoms bonded together into a long chain The chain is folded up into a compact wad whose shape is maintained by bonds between neighboring folds of the chain In the chemical environment of the egg white, most of the protein molecules accumulate a negative electrical charge and repel each other, while in the yolk, some proteins repel each other and some are bound up in fat-protein packages So the proteins in a raw egg mostly remain compact and separate from one another as they float in the water When we heat the egg, all its molecules move faster and faster, collide with each other harder and harder, and eventually begin to break the bonds that hold the long protein chains in their compact, folded shape The proteins unfold, tangle with each other, and bond to each other into a kind of threedimensional network There’s still much more water than protein, but the water is now divided up among countless little pockets in the continuous protein network, so it can’t ... maintained by bonds between neighboring folds of the chain In the chemical environment of the egg white, most of the protein molecules accumulate a negative electrical charge and repel each other, while... When we heat the egg, all its molecules move faster and faster, collide with each other harder and harder, and eventually begin to break the bonds that hold the long protein chains in their compact, folded shape... chains in their compact, folded shape The proteins unfold, tangle with each other, and bond to each other into a kind of threedimensional network There’s still much more water than protein, but the water is now divided up among countless little pockets in