Молекулярная гастрономия для креативных шеф-поваров (англ. язык) - страница 161

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

naked eye (however investigation under a microscope will reveal that they are still present)

b) by adding acid (like the lemon juice or vinegar added in bearnaise and hollandaise sauces). The

H+ ions present will encourage the egg yolk proteins to denature before they lump together, which

results in them forming an extended network (as forms when egg yolks thicken sauces) rather than

thick lumps.

The key to making successful hot emulsions is therefore very controlled heating. Controlled heating

will ensure that temperatures are sufficiently high that the butter will stay liquid and disperse easily, yet

will not allow the egg proteins to coagulate and produce lumps. Good temperature control is most

easily achieved by heating the sauce in a bain marie – heating a sauce in a hot liquid such as water

will transfer heat more gradually and in a more uniform way than if a sauce is heated directly on the

stove.

V/I - 4 (of 5)

Other emulsions stabilised by denatured proteins

Example 1 - Gravy

Gravy is an example of an emulsion commonly found in the kitchen that is stabilised by denatured

proteins.

When meat is cooked, collagen from the animal’s connective tissue will slowly degrade into a

substance called gelatine. When meat is cooked in a stock, the degraded gelatine can dissolve directly

into the surrounding liquid, whereas when meat is dry roasted, there is no surrounding liquid into which

the gelatine can dissolve – it will...

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into the surrounding liquid, whereas when meat is dry roasted, there is no surrounding liquid into which

the gelatine can dissolve – it will just stay at the bottom of the pan. If boiling water (or wine for more

flavour) is added to pan after removing the joint of meat, it will dissolve the gelatine (along with many

of the tasty Maillard reaction products, mineral salts and fat that has melted from the meat and flowed

into the pan during cooking). If this mixture of fat and water is whisked, a stable emulsion can be

formed, where the emulsifier is provided by the denatured gelatine protein.

Too liquid?

If the resulting emulsion is not thick enough, it could be because the particular joint of meat that has

been cooked had a fairly low fat content, so the resulting emulsion will have a much larger water

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