Молекулярная гастрономия для креативных шеф-поваров (англ. язык) - страница 98

Молекулярная гастрономия для креативных шеф-поваров (англ. язык)

xxxiii BELITZ H-D, GROSCH W, Food chemistry, chap 11 eggs ; 11.2.3.1 Proteins table 11.3 p405

xxxiv THIS H., Molecular Gastronomy, ascientific look on cooking, The 6X°C egg.

IV/I - 1 (of 2)

What should be known about culinary ingredients: Water

Water structure?

Pure water is filled with water molecules which are constantly moving around. Each of these water

molecules is composed of two hydrogen atoms and one oxygen atom, organised in a “V” shape as

shown below.

O

H H

Although this molecule is neutral, and is not charged overall, its charge is actually evenly distributed

throughout its structure – the oxygen (O) atom carries a weak negative charge, whereas each

hydrogen (H) carries a weak positive charge. This makes the water molecules attract one and other. In

water, which contains many of these molecules, the negative oxygen atom on some water molecules

will be attracted to the positive hydrogen atoms on other water molecules (in a similar way to the north

and south poles of magnets) and this attraction is called a hydrogen bond.

Water properties

When water is heated, the molecules will start to move around with more energy and speed, so these

links will start to break, freeing the water molecules, and some of these water molecules will escape

(this is water vapour). At 100 °C, all these links are broken - so water is no longer a liquid and it

becomes a gas. In contrast, when water is cooled, the water molecules...

°C, all these links are broken - so water is no longer a liquid and it

becomes a gas. In contrast, when water is cooled, the water molecules will have less and less energy

to move around, so will form even more bonds with each other. The water molecules will be no longer

free to move, so the water will become solid. This is ice.

Water molecules will always move in a direction from where there are more water molecules to where

there are less, if it can, by a process known as osmosis. For example, if a strong coffee is added to a

glass of water, the large number of water molecules in the water will redistribute themselves evenly in

the coffee, and the resulting solution will be an evenly distributed mixture of coffee and water….or a

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