Молекулярная гастрономия для креативных шеф-поваров (англ. язык) - страница 173

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

sources will tend to bind to the hydrophobic parts of the protein as it is denatured, reducing the

number of available hydrophobic groups that can surround and support the air bubbles.

However, once a stable mousse has been formed, the fat source may be added (and often is

when preparing cakes or souffles). Egg whites are whisked in the absence of egg yolks or else

the hydrophobic parts of the lecithin molecules will tend to link to the hydrophobic groups of

the denatured egg proteins, preventing these groups from forming the network stabilising the

air bubbles.

7. Sugar is often added to egg whites to make meringues. Sugar tends to destabilise the

formation of the denatured protein network, so should be added after the egg whites have

been whisked. As well as generally “diluting” the numbers of proteins, the sugar molecules

themselves surround the protein molecules, preventing them from binding with each other so

easily. This especially pronounced with icing sugar, where sugar particles are even smaller, so

are able to surround the protein molecules even more tightly. Sugar also increases the

viscosity of the liquid part of foams, limiting the “creaming” of air bubbles.

Use of eggs in cooking: how to cook egg white foams (e.g. meringues and souffles)

Meringues are prepared by whisking egg whites, adding sugar, and cooking the resulting mixture.

Souffles are slightly more complicated to prepare - whisked egg whites are added to a flavoursome

thick base, and the resulting mixture is cooked. When a souffle or a meringue is placed in the oven, it

will swell.

III/I - 7 (of 9)

Why does it swell?

When a mixture containing whisked egg whites is placed in a hot oven, the mixture will rise. Heating

causes the water in the mixture to evaporate (one gram of water makes about one litre of vapour) and

also it causes gases incorporated in the egg whites to expand.

Because the protein network surrounding the gas bubbles is still fairly delicate, the meringue will swell

and the souffle will rise.

Calculations have shown that gas expansion alone is not sufficient to account for the significant

Страницы: Пред. | 1 | ... | 171 | 172 | 173 | 174 | 175 | ... | 253 | След.

Еще статьи

Элемент не найден!