Doughs and batters if not of the required texture can
lead to making and baking of worse breads. Must have observed at home how chapathi
dough when too hard produces a dry rough chapathi and when too soft it is a
sticky mass of mess. So, for these doughs and batters to rise and form a
required texture, a leavening agent
is required. In the presence of moisture, heat, acidity, or other triggers the
leavening agent reacts to produce gas (often carbon dioxide) that becomes
trapped as bubbles within the dough. When a dough or batter is baked, it “sets”
and the holes left by the gas bubbles remain. This is what gives breads, cakes,
and other baked goods their soft, sponge-like textures.
The alternative or
supplement to leavening agents is mechanical leavening by which air is
incorporated by mechanical means. Remember? the proper mixing of cake batters
and kneading of dough. Most leavening agents are synthetic chemical compounds,
but carbon
dioxide can also be produced by biological agents.
Biological
Agents
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Chemical Agents
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Other Leaveners
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Saccharomyces cerevisiae producing
Carbon dioxide found in:
Baker’s yeast
Beer (unpasteurized – live yeast)
Buttermilk
Ginger bread
Sourdough Starter
Clostridium perfringens producing
hydrogen found in salt-rising bread
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Chemical leaveners are mixtures or
compounds that release gases (usually carbon dioxide) when they react with
each other, with moisture, or with heat. Most are based on a combination of
acid and a salt of bicarbonate. After they act, these compounds
leave behind a chemical salt. Chemical leaveners are used in quick breads and cakes, as well
as cookies and numerous other applications where
a long biological fermentation is impractical or undesirable.
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Steam and air are used as leavening agents when they expand upon
heating. To take advantage of this style of leavening, the baking must be
done at high enough temperatures to flash the water to steam, with a batter
that is capable of holding the steam in until set.
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Creaming is the process of beating sugar crystals and
solid fat (typically butter)
together in a mixer.
This integrates tiny air bubbles into the mixture, since the sugar crystals
physically cut through the structure of the fat. Creamed mixtures are usually
further leavened by a chemical leavener like baking soda. This is often used in cookies.
Using
a whisk on certain liquids, notably cream or egg whites can also create foams through mechanical action. This is
the method employed in the making of sponge cakes, where an egg protein matrix produced by
vigorous whipping provides almost all the structure of the finished product.
Below are
leavening agents found in a variety of foods:
There are foods or ingredients not leavened, although they are mistaken for leavening or leavened food:
Puffed cereals: Some food products are “puffed up” by
mechanical means. They are just puffed up by air and are not
chemically leavened. They include: popcorn, beaten eggs, and air
puffed cereal like puffed rice or wheat.
Brewer’s yeast (Saccharomyces
cerevisiae): is inactive yeast, meaning the yeasts have been killed and
have no leavening power. It is the yeast remaining after beer making. It is
used as a nutrient supplement to increase the intake of B vitamins.
Yeast extract, autolyzed yeast extract: When yeast cells die, they automatically break
up, a process called autolysis in which the yeasts’ digestive enzymes break
their proteins down into simpler compounds. What remains is a collection of
protein, fats, vitamins, minerals, and monosodium glutamate (MSG), a flavor
enhancer.
Post by Faiz Lahori