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Flour
People have been grinding various seeds, as well as dried fish and other
foods, to make flour for thousands of years. Initially, the seeds were
roasted and ground between two stones to make them easier to eat;
eventually, water was added to the flour, and the paste baked into a type of
crude bread. As agricultural societies developed, they devised increasingly
sophisticated methods of grinding and sifting grains and seeds. Today, huge,
fully automated mills are responsible for producing tons of flour, which are
then transformed into breads, pasta, pastries and other baked goods, and
chickening agents and other food additives.
NUTRITIONAL VALUE
In general, flour is a more concentrated source of calories than its source
material because the moisture has been removed. For example, 1 lb (450 g) of
potato flour contains 1,6000 calories, compared with 350 in a pound of raw
potatoes; one cup of cornmeal has about 400 calories, while a cup of cooked
corn only has 100. This increased density of calories is the reason food
relief organizations often prefer to provide flour made from grains,
legumes, tubers, or dried fish rather than the raw products.
On the other hand, many nutrients are lost in flour milling and processing.
Wheat flour, our most common variety, is milled by using steel rollers to
crack the grain. The bran and germ are then sifted out and the remaining
part of the seed (the endosperm) is passed through a series of rollers and
sifters to make a fine, powdery product. Removing the bran and germ from
wheat reduces the fiber and the amounts of the 22 vitamins and minerals
found in the whole grain. Because of this depletion, wheat flour is usually
enriched with iron, riboflavin, thiamine, niacin, and folic acid (important
nutrients that might not be provided otherwise). Manufacturers may also add
vitamin B6, calcium, and magnesium; the label specifies whether or not the
flour is enriched and what nutrients have been restored or added.
Whole-grain flour, which is made by restoring the germ and bran at the end
of the process, provides more fiber, protein, vitamin E, and trace minerals
than enriched white varieties do. Depending upon the type of flour, other
ingredients are added; these include salt and baking soda or baking powder
to make self-rising flour, extra gluten for special baked products, or
bleaching agents such as benzoyl peroxide for whiteness.
TYPES OF FLOURS
Almost any type of grain or seed can be ground into flour, although those
with a high fat or moisture content must first be defatted and roasted or
dehydrated. Because most grains lack gluten, the protein that makes flour
ideal for baking, they are usually mixed with varying amounts of wheat
flour, which is high in gluten. Some of the more common flours include the
following :
Amaranth is higher in protein, including the amino acid lysine, than
most other flours.
Arrowroot, made from maranta roots, is one of the most digestible
flours
Barley, a soft, bland flour, is used for unleavened baked goods.
Buckwheat, made from the same seeds as kasha, is high in lysine.
Cornmeal is not as nutritious as many other types of flour, but it
provides a complete protein when combined with beans and other legumes.
Cottonseed flour is made from bulled seeds after oil is extracted and
contains very high levels of protein.
Fish flour is produced from whole dried defatted fish; it contains
very high levels of calcium and protein.
Oat, which is high in soluble fiber, is used mostly in cereals and
breads
Potato, made from steamed and dried potatoes, is used in baking and
is also a common thickening agent.
Rice is manufactured mostly from broken polished grains; typically,
this flour is used to make noodles, cookies, and unleavened baked goods.
Rye is high in fiber as long as the bran and germ have been retained.
it is usually combined with wheat flour to form a mixture used in
bread-baking.
Soy, made from soybeans, is often combined with wheat flour to
increase the protein content of baked goods.
Triticale is a hybrid of wheat and rye and is also very high in
protein; triticale is often mixed with wheat flour to increase its
nutritional content. |
