Flour Terms and Treatments

Bleached

Bleaching and maturing agents are added to whiten and improve the baking quality quickly, making it possible to market the freshest flour. Even fine wheat flours vary in color from yellow to cream when freshly milled. At this stage, the flour produces doughs that are usually sticky and do not handle well.

Because storing flour is expensive, toward the close of the 19th century, millers began to treat freshly milled flour with oxidizing agents to bleach it and give it the handling characteristics of naturally aged flour. Under the category of maturing agents are included materials such as chlorine dioxide, chlorine gas plus a small amount of nitrosyl chloride, ammonium persulfate, and ascorbic acid. No change occurs in the nutritional value of the flour when these agents are present.

There are two classes of material used to bleach flour:

• A common one, an organic peroxide, reacts with the yellow pigment only, and has no effect on gluten quality.
• Chlorine dioxide, the most widely used agent in North America, neutralizes the yellow pigment and improves the gluten quality. Additionally, it destroys the tocopherols (vitamin E complex).

Enriched

Iron and three of the most necessary B vitamins (thiamin, riboflavin, and niacin), which are partially removed during milling, are returned to white flour by a process known as enrichment. No change occurs in taste, color, texture, baking quality, or caloric value of the flour.

Pre-sifted

During the milling process, flour is sifted many times through micro-fine silk. This procedure known as pre-sifting. Sifted flour yields more volume in baked bread than un-sifted flour, simply because of the increased volume of air. The mesh size used for sifting varies from flour to flour. There are more holes per square inch for cake flour than, for example, bread flour. A cup of cake flour has significantly more minute particles than a cup of bread flour and is liable to be denser and weigh slightly more.

Rye Flour

Rye flour is the powder milled from whole rye berries or grains from rye grass. Rye flours differ from wheat flours in the type of gluten that they contain. Rye flour is the only flour, other than wheat flour that can be used without blending (with wheat flour) to make yeast-raised breads. Although some dark rye flours can have a gluten content as high as 16%, this is only gliadin. The glutenin, which forms the elasticity in dough, is absent, and therefore doughs made only with rye flour will not hold the gas produced by the yeast during fermentation. This results in a small and compact loaf of bread.

Rye flour used to produce rye and sourdough bread, providing a distinctive flavor and nutritional content compared to bread baked with wheat flour. Nutritionally, it is a grain comparable in value to wheat. In some cases, for example, its lysine content (an amino acid), is even biologically superior. The brown grain: cleaned, tempered, and milled much like wheat grain. One difference is that the rye endosperm is soft and breaks down into flour much quicker that wheat. As a result, it does not yield semolina, so purifiers are seldom used. The bran separate from the flour by the break rollers, is further rolled, and sifted while being graded: chop meal, light flour, medium flour, and dark flour.

The following list the differences between rye and wheat:

• Rye pulverize easily
• Rye does not yield semolina.
• Gluten content in rye is not a significant dough-making factor.
• Starch is more important for bread making in rye flour than in wheat flour.
• The pentosan level in rye flour is higher and more important for bread making.
• Rye flour has greater water binding capability than wheat flour, due to its starch and pentosan content.