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Monthly
Feature:
"Multi-tasking," the managerial buzzword these days, isn't a new
concept if you're talking about cooking. Eggs have been multi-tasking
forever. And their importance in preparing a wide spectrum of foods
proves that eggs can perform any number of diverse and demanding roles.
This is pretty impressive for something as compact as an egg.
Egg whites are 88 percent water. Yolks nearly 50 percent. So the
task of contributing liquid to batters and doughs is an easy one for
eggs. As flour absorbs liquid in baking, starch granules swell to form
the framework that becomes a cake, a muffin, a cookie. Eventually
moisture converts to steam, a leaven so powerful that just one part
liquid explodes into 1,600 parts steam. Break into a cream puff or a
popover (high ratio of eggs) and their hollow centers provide dramatic
testimony to steam's immense power. On a smaller scale, the steam
created from the liquid in just one or two eggs works quietly in most
batters and doughs to boost rising.
The proteins in eggs also enable them to act as leavens but in a completely
different manner. Proteins unwind and stretch to form the
flexible, elastic film that encases air bubbles. When eggs
are beaten, they can expand to a foam that's up to eight times
their original volume. Beaten egg whites hold millions of
tiny air bubbles, which lift angel-food and sponge cakes,
meringues, and souffles. Even in batters containing baking
powder, beaten eggs whites are an additional source of leavening.
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Each
month, we've featured a different kitchen science article
by the
Inquisitive Cooks, Anne Gardiner
and Sue Wilson
, with tips, facts, and unique ideas
to give you a whole new perspective on cooking.
View
other articles.
Also
visit
Ask the Inquisitive Cooks
for a weekly kitchen science Q&A!
What happens if you leave a bottle of milk in the fridge too long, or if your
yogurt sits out in the sun? You get rancid yuck, right? But somehow, if done just
the right way, a similar process can result in fragrant, pungent, yummy cheese.
How can this possibly happen?
View
the Webcast
and watch as we investigate the creamy,
rich--and sometimes stinky world of cheese.
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While the elastic quality of proteins is lost when eggs are cooked,
the firming of proteins allows eggs to perform yet another function. As
their proteins coagulate, eggs bind ingredients together. Meat loaves
are less likely to crumble. Casseroles serve in tidier portions. And a
crumb coating holds more tightly to a veal cutlet when its been dipped
in egg before being rolled in breadcrumbs.
In creme caramel and quiche, egg proteins unwind, then bond
to form a mesh that traps milk or cream in a soft gel. And in a stirred
custard or creme anglaise, eggs thicken just as effectively, but at
lower temperatures than flour or cornstarch.
Lecithin and the other emulsifiers in egg yolks come in handy too.
Tiny droplets of fat stay suspended throughout emulsions such as
mayonnaise, hollandaise, and bearnaise when coated with a thin film of
yolk. Without the emulsifying properties of eggs, these special sauces
wouldn't be as luxurious, nor as smooth.
It's eggs, not lemon, that add the rich yellow color to a lemon pie
filling. And of course they contribute flavor to any food in which
they're used.
Looking at just some of the ways we use eggs makes us think perhaps
we give too little credit to their special qualities. They might not
look as splashy as a frilly head of lettuce or announce their presence
with a searing burn of a hot pepper. But the humble little egg is surely
handy in the kitchen and confirms that in cooking, this one
extraordinary character can indeed accomplish the work of many.
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