Ingredients --
Bread
Bread
The smell of a home baked loaf, the taste of a flaky crescent,
the texture of a slice of whole grain bread, all of these
experiences can come from very basic ingredients.
Things get
a little more complicated when the bread must be made to last
for days without going stale, to be inexpensive, to be consistent
at any time of the year with grain from any supplier.
The simplest breads are made from flour, water, yeast, and
salt.
These breads are generally eaten the same day they are baked.
Wheat flour contains
starch
and protein, which form the structure
of the bread. Two of the proteins in flour,
gliaden, and the
enzyme
glutenin, form the elastic protein
gluten when
water is added and the mixture is stirred. Kneading the bread
stretches the gluten into elastic sheets that can be filled with
gas to form bubbles, making the bread lighter in texture.
The yeast supplies the gas. The yeast feeds on
sugars
in
the flour, and produces carbon dioxide gas and
alcohol
as waste
products.
The last ingredient,
salt,
is added to slow down the rate of
fermentation of the yeast. This gives the baker a certain
amount of control over the rising process, ensuring that the
bread has the desired texture, and cooks evenly.
Flour
Wheat flour can be made from whole wheat, or the germ and bran
can be separated from the endosperm, which is then ground into
flour. Without the fibrous bran, and the oily germ, the
resulting flour has fewer nutrients, but will keep longer, and
make a lighter textured, higher rising bread.
If the flour is allowed to age for about a month, its natural
yellowish color will fade to white due to the effects of oxygen.
This aging period can allow insects to spoil the flour, and
is often eliminated by adding bleaching agents such as
benzoyl peroxide.
Malted barley flour is often added to bread because it gives
the yeast more nutrients (primarily sugars), and gives the
bread a different taste. Malting a grain is the process of
letting the grain soak in water until it starts to sprout.
The young sprouting barley plant converts some of the starch
in the barley endosperm into sugars. The barley is then
cooked or ground into flour, which stops the sprout from
eating the sugars, leaving them available to the yeast.
Sometimes
sugar, or high fructose corn syrup are added
as yeast nutrients, or to make the crust of the bread
brown more easily.
Flour made from soybeans is sometimes found in breads to
give them added protein, and to change the texture of the
bread. Soy flour absorbs water to make a gel, making the
bread denser.
Some of the nutrients lost when the wheat germ and bran are
discarded are returned to the flour by adding small amounts
of vitamins and minerals. Commonly, the vitamins niacin,
thiamine, riboflavin, and folic acid are added, along with the
minerals iron and calcium.
Vegetable oils are added to breads to shorten the strands of
gluten, to make the bread more cake-like. Adding fats or
oils also keeps the bread from getting stale, allowing it to be
kept longer than a day before being eaten.
How bread gets stale
Stale bread tastes and feels dry, even though the moisture
content is actually the same as in fresh bread.
What happens in bread to make it stale is the recrystallization
of the
starch. Fats and oils added to bread
form a complex with the starch in its gelled form, and this
slows down the recrystallization, keeping the starch in the
flexible gel form.
Fats and oils, however, interfere with the gluten, making the
gluten strands shorter, preventing the loaf from getting
volume. Emulsifiers are commonly used instead of fats to
control staling.
Emulsifiers have a fatty acid at one end that
can combine with the starch, and a water-loving end that helps
to keep it dispersed in the dough. Emulsifiers aid in distributing
fats and oils throughout the dough, so less fat or oil is needed.
Some emulsifiers commonly used in baked goods are:
Another way to control staling is to add humectant (water attracting)
agents to the dough. To recrystallize, starch needs water.
By attracting water away from the starch, humectants keep it
from recrystallizing, and at the same time add more moisture to the
product. A moist bread tastes and feels better, and it weighs
more without adding expensive ingredients. Thus a one pound loaf
of bread that has a higher water content is less expensive than
a drier one pound loaf.
Salt and
sugar are good humectants.
Sugars that are less sweet, such as
dextrose (glucose) can be used for their
humectant properties if sweetness is not desired.
Dough conditioners
To give the baker more control over the baking process, some
additives are used to change the dough in certain ways.
Some of these dough conditioners are:
- sodium stearoyl lactylate
- calcium dioxide
- calcium iodate
- potassium iodate
- ammonium sulfate
Yeast nutrient.
- potassium persulfate
Strong oxidizer. Used as a strengthening agent.
- ammonium persulfate
Strong oxidizer. Used as a strengthening agent.
- calcium sulfate
- ascorbic acid
- amylase
- azodicarbonamide,
Preservatives
By Simon Quellen Field