Image Number K7251-27
Leavened bread has been around a long while-since the days of ancient Egypt,
Babylon and Greece, in fact. Then, as now, it was made from wheat, or from a
mixture of wheat and rye. The elastic gluten in wheat is essential for bread to
But a lot has changed-today's bread is mass-produced. Brews of yeast, made
in huge vats, are mixed continuously with flour, water, and other ingredients at
one end of a machine. At the other end, dough is squished out of a tube, shaped,
and cut automatically into loaves. The loaves drop into pans, rise, and are
baked at the rate of thousands an hour.
Our bread also contains more ingredients and additives, which causes special
problems for the baker, miller, and farmer. Even the same classes of wheat can
vary significantly in baking qualities. And when these differences are great
enough, they can cause a lot of trouble in a bread factory!
For 50 years, ARS laboratories have worked with all segments of the industry
to help provide consumers with uniform, flavorful, nutritious bread and other
wheat products. They identified and isolated wheat proteins not previously known
to exist. They showed that these proteins-gliadin and glutenin-contain a
specific chemical structure that affects mixing properties of flours in forming
doughs. They discovered the role of fatlike constituents in flour in controlling
volume of bread and size of cookies. They found that certain water-soluble
proteins called albumins are as essential as gluten in producing a good loaf of
And, over the years, ARS technologists baked thousands of loaves of bread to
test different flours and to determine the effects of new additives.
Busy though scientists have been, research is accelerating. Today, with a
sample no larger than half a kernel, a chemist can analyze a type of gluten
protein and determine its baking properties. This can help wheat breeders get an
early indication of the kind of flour their most promising plants will produce.
"It provides us with an incredible amount of information," says one
researcher. "And it gives it to us in a day instead of in months or years."
Other scientists work with glutenin, the other important protein in wheat
gluten. Not all glutenins, it turns out, are created equal. A team of chemists
is exploring the structure of glutenins of assorted molecular weights, shapes,
and sizes. The research could help in the genetic engineering of glutenins that
can outperform those of today.
Photo by Scott Bauer.
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