Wheat flour is essential because it is milled from the only cereal grain known to contain the proteins glutenin and gliadin which when combined with water form gluten, the elastic material which holds the gas produced by the chemical reaction of the yeast enzymes on sugar. As in building a house, the framemust be built. Gluten forms the framework of bread and also thecell structure of the interior of the loaf. Rye flour contains both glutenin and gliadin but is incapable of forming gluten because there are substances in rye flour that interferes with it's ability to form gluten. That is the reason why wheat flour must be included as a large percentage of the flour in rye bread formulas.
How to separate the gluten from wheat flour.
First you must wash out all the starches from a mixture of flour and water as follows:
- Mix a small amount of flour (about 8 ounces) with just enough water to form a stiff ball of dough.
- Soak the ball of dough in water for about 30 minutes.
- Over a fine mesh sieve, and under running water from a faucet, wash out all the starch. When all the starch has been removed the water will run clear. Warning, if you try to wash gluten from soft wheat flour (cake flour), you will be able to get only a tiny bit of gluten from it. Hard wheat flour (bread flour) will yield a large amount of gluten. Rye flour will yield zero amount of gluten.
If you bake the ball of wet gluten at about 400 degrees F. until all the mositure has evaporated and cut the dry gluten in half, you will see how gluten forms the frame work (structure) of baked products.
How to separate glutenin and gliadin from gluten.
Once you have washed out the starches, you end up with raw wet gluten. If you soak the ball of gluten in pure ethyl alcohol, the glutenin and the gliadin will separate out. The gliadin is the sticky part and will form long tiny silky looking strands when touched with the finger. The glutenin on the other hand will look and feel like tough raw rubber.
Types of wheat used to produce bread flour.
Hard spring wheat and hard winter wheat are the best types of wheat for producing quality breads. Spring wheats are grown in the Northwest where there is less rainfall than in other wheat growing areas. This results in a higher percentage of protein and a lower percentage of starch than wheats grown in the Southwest where more rain falls. Hard spring wheat generally produce loaves with greater volume than winter wheats, but with slightly more open crumb texture. Millers combine the two types of wheat in their blend to improve interior loaf characteristics. Hard White Wheat grown in some Western States, is also used in bread production. It is slightly lower in protein than spring and winter wheats. Bakers add Vital Wheat Gluten and/or Dough Strengtheners to doughs to make up for the deficiency. Durum Wheats which contain a higher percentage of proteins than does most other types of wheats are used primarily in making spaghetti and macaroni products.
Milling of wheat into flour.
Basically, after the wheat has been cleaned and tempered, and the percentage of moisture within the grain has been adjusted, the wheat passes through several reduction rollers. The grounded middlings are separated into several streams of flour by sieving and bolting. The bran particles which have been removed are used in cereals. Some are also used for animal feed. 100 pounds of cleaned wheat generally yield only about 70 to 76 pounds of middlings which can be ground into various grades of flour.
Grades of flour.
Whole wheat flour is flour produced from100 percent of the wheat. By adding Vital Wheat Gluten to their formulas bakers are producing high quality White Whole Wheat Bread.
Straight grade of flour.
This is all of the flour. Straight flour is similar to all purpose flour found in grocer stores.
A highly refined flour which remains after all the clear flours have been removed. Patent flours are produced from the inner-most part of the wheat where the best quality proteins are located. 100 pounds of wheat will produce only about 40 to 60 pounds of patent flour, and the middlings that remain go into clear flours.
The portion of the flour remaining after the patent flour streams have been separated. Clear flour generally contain a higher percentage of protein than the other grades, but the quality of the protein is lower. This type pf flour is generally used to produce French bread. It is also mixed with wheat flour and rye flour by the baker to produce loaves with greater volume.
Flour bleaching and maturing.
In order to produce quality breads from fresh milled flour it must be allowed to age or mature in storage for about a month. Bleaching and maturing agents are used to artificially age and whiten the flour. This results in flour that can be used immediately after milling to produce a quality product.
Strength of flour
Its ability to be made into well piled loaves. The flour should have a high content of quality protein to retain gas and contain enough natural sugars and diastatic enzymes to produce enough sugar from the starch for uniform gas production.
The ability to produce a quality product for some time after the optimum fermentation time has elapsed and in the event that the dough was overmixed.
Enrichment of flour
The process of replacing the vitamins and minerals removed during the milling process. Most of the vitamins and minerals are located in the outer portions of the wheat, and since most of the outer portions of the wheat are not used to produce the best grades of flour, these essential elements must be replaced. The exception is whole wheat flour.
Enzymes in flour. The two most important enzymes in flour are protease and diastase. Protease conditions the gluten, improving its elasticity and its ability to retain the gas produced during fermentation. Diastase changes some of the starch in flour to dextrins and maltose sugar. Some flours do not contain a sufficient amount of diastase enzyme due to poor climatic conditions under which the wheat was grown. Sprouted wheat can be added to the flour by the miller or the baker can add a specially prepared diastatic malt in his formula.
Rye flour is a finely ground flour prepared from the rye grain. It contains about the same amount of protein as wheat flour. However, the flour contains gummy substances which prevent formation of gluten, accounting for the small compact loaves of bread made from a dough containing only rye flour. To produce rye bread with acceptable volume, not more than 20 percent dark rye flour, 30 percent medium rye flour, and 40 percent light rye flour can be used in the formula. White bread flour must be used in the formula so enough gluten can be formed to hold the gas during fermentation, and to form the structure of the texture.
Water. Water is a basic ingredient in bread baking. It would be impossible to produce a loaf of bread without water in some form. There are several types of water. Hard water produces better quality bread than any type of water. Soft water weakens the gluten during mixing and fermentation. This can be corrected to some degree by increasing the percentage of salt in the formula slightly and by using mineral yeast food in the formula. Alkaline water is the most harmful, because it doesn't only weaken the gluten, but retards fermentation. Yeast likes a slightly acid medium to perform at its best. The weakening of the gluten and retarding effect on yeast can be corrected by using an acid ingredient such as vinegar (acetic acid) or lactic acid. Special types of mineral yeast food has been developed to correct this problem.
Yeast is one of the essential ingredients in bread production. It is a one cell plant which multiplies by a process known as budding. Under the right conditions of water, sugars, warmth, and dissolved minerals, yeast causes fermentation. Yeast is available in compressed form which must be kept under refrigeration until it is ready to be used and active dry yeast which need not be refrigerated. Active dry yeast has an extended shelf life. Both will generally produce satisfactory results. However, a majority of large Commercial Bread Bakeries use compressed yeast in their formulas. When using active dry yeast half as much active dry yeast is required as compared with compressed yeast.
Enzymes in yeast consist of invertase, maltase, zymase and protease. There are others, but they are not important in bread production. The protease enzyme in yeast is only active if the cell wall of the yeast is damaged in some way. That is the only time it can penetrate the cell wall of the yeast. There are always a few damaged yeast cells especially in dry yeast where some cells are damaged during the drying process, or in yeast that has gotten a little old. If the protease enzyme does penetrate the cell wall of the yeast, it will weaken the gluten.
Invertase enzyme is an intracellular enzyme. Sucrose, (cane or beet sugar) when dissolved enter the cell wall and are changed to dextrose and fructose, which are later changed by the enzyme zymase (below). Maltase attacks malt sugar. The malt sugar is changed to two molecules of the simple sugars dextrose.
Zymase is the enzyme which changes the simple sugars, dextrose and fructose into carbon dioxide gas and alcohol, and several esters which result in producing the unique aroma flavor and taste of breads. Also, the gas produced causes the dough to rise.. Fermentation will be discussed in more detail in a later paragraph on bread production procedures.
Salt is another essential ingredient in quality bread production. It has several functions. It regulates fermentation. Too little salt causes the dough to ferment too fast and wild, while too much salt slows down the fermentation process. Salt is a very powerful ingredient and it must be scaled very carefully when weighing the ingredients for the dough. In the proper amount, salt produces good grain and texture, because it strengthens the gluten allowing it to fully mature during fermentation. It also prevents the growth of wild yeast and bacteria. A whiter crumb is produced and last but not least, it brings out the taste and flavor of bread.