I would like to acknowledge that the material presented here is the work of Willie Prejean, a retired professional baker. Willie has many years of practical experience in the art and science of baking. The information below is from his own work on bakingandbakingscience (which is no longer in service).
Part One - Information below - Bread Baking Ingredients and Dough Strengtheners and Anti-Staling Ingredients
Part One (A) - Temperature -Heat Transfer and High Altitude Baking
Part One (B) - Maintenance Engineering Scholarships worth $4,000 offered by American Institute of Baking
Part Two - Principles of Bread Production-Latest Developments in Dough Processing Procedures & Dough Processing Equipment
Part Three - Bread Formula Construction
Part Four - Variety Breads and Formulas
Flour. 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:
1. Mix a small amount of flour (about 8 ounces) with just enough water to form a stiff ball of dough.
2. Soak the ball of dough in water for about 30 minutes.
3. 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. Thisresults in a higher percentage of protein and a lower percentageof starch than wheats grown in the Southwest where more rain falls.Hard spring wheat generally produce loaves with greater volumethan 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. Duram 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.
Patent flour is 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.
Clear flour is 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 thequality 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 qualitybreads 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 artifically age and whiten the flour. This results in flour that can be used immediately after milling to produce aquality product.
Strength of flour is 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.
Tolerance is 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 is 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 underwhich 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 breadwith acceptable volume, not more than 20 percent dark rye flour, 30 percent medium rye flour, and 40 percent light rye flour canbe used in the formula. White bread flour must be used in theformula 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 weekens 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 (acedic 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, zymaseand protease. There are others, but they are not important in bread production. The protease enzyme in yeast is only activeif 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 entercelluar 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.
Sugar. Cane or beet sugar (sucrose) are basically the same. They are both compound sugars and must be changed to simple sugars by the yeast enzyme invertase before the yeast can convert them to carbon dioxide gas and alcohol by the yeast enzyme zymase.
Dextrose also known as corn sugar is produced by converting corn starch into sugar. It is interchangeable with cane and beet sugar in bread production. However, its sweetening value is only about 72 as compared to a sweetness value of 100 for cane or beet sugar.
Fructose or levulose, found in fruits, molases, and honey is a left handed sugar which means it reflects polarized light to the left whereas dextrose reflects polarized light to the right. High fructose has in recent years been produced from corn starch by a special process which was unknown just a few years ago. It has a sweetening value considerably higher than any other type of sugar ( about 172 ).
Lactose sugar is sugar found in milk, and is not fermentable bybakers yeast. At the end of the baking process it remains as lactose sugar in the baked bread. Its sweetening value is very low compared to the other sugars.
Functions of sugar. Sugar is not considered an essential ingredient in bread baking. This is because flour contains a small amount of natural sugars and some starch is converted to sugar during the fermentation process. It does have many important functions.Some of the added sugar is converted to carbon dioxide and alcohol by the yeast enzymes. It provides necessary sweetness, helps to produce a golden brown color of the crust, improves the textureof the crumb, helps to retain moisture in the crumb and adds to the nutritional value of the bread. High percentage of sugar as used in sweet doughs and Danish pastry doughs retard yeast activity.That is the reason why when increasing the percentage of sugar in doughs, the percentage of yeast must be increased by the same proportion.
Milk. Several years ago non fat dry milk was the type of milk generally used in bread baking, but today it has become too expensive to use by most commercial bread bakeries. In its place they use milk subsitutes such as milk whey in combination with other ingredients such as soy flour.
Functions of milk are many. It has a stabalizing effect on fermentation, preventing wild fermentation. It improves crust color because of the lactose sugar it contains. The lactose sugar is not fermentable by baker's yeast. It also improves texture, crumb color, flavorand taste, and keeping quality of the baked loaf. If non fat dry milk is used in bread it must be heated to a high enough temperature during the drying process to destroy bacteria which weakens the gluten in the dough. Milk dried by the vacuum drying process must be properly heat treated prior to being dried otherwise considerable difficulty can be expected during mixing and fermentation of the dough.
Shortenings are available from many sources. Most any type of shortening can be used in bread production with satisfactory results.
Functions of shortening. Shortening acts as a lubricant in the dough, making the dough more pliable, prevents stickeness,and reduces the amount of dusting flour necessary during the make-up process. When shortening is used, the dough expands more easily and smoothly. In the baked product it makes the crust more tender, improves the keeping quality and produces a crumb that is soft and chewy. Because of the cutting effect on the bran in wholewheat flour, it is almost impossible to produce a loaf of whole wheat bread with acceptable volume without using shortening in the formula.
Optional ingredients: To produce a variety of quality breads,optional ingredients are required. They result in uniformity of products and efficiency of operations, assist in increasing the tolerances of doughs due to production variables, and help to satisfy the demand for variety in the flavor and taste of breads. Mold inhibitors prevent bread from becoming molded.
Mineral yeast food was developed to stabilize water by adding mineral salts, which are essential in dough fermentationand conditioning. Mineral salts condition soft water, and acid salts neutralize the alkalinity of alkaline water which is harmful to yeast and gluten. Doughs made with mineral yeast foods are not sticky and are very soft. They go through machines with less trouble and will mold up free of air pockets. Following are some of the improved loaf characteristics resulting from the use of mineral yeast foods: Greater loaf volume and ovenspring, improved texture and crumb color, better crust color, and greater uniformity.
Dough Strengthening Enzymes.Wheat Flour contain between 2 and 3 percent Pentosans which are the residual cell wall material that is left as a result of milling wheat into flour. When an enzyme named Xylanases is added to the dough, it breaks down the Pentosans resulting in strengthening doughs and improving the baked product. Xylanase enzymes also strengthen multi-grain doughs and doughs for rolls and buns. This a very powerful enzyme therefore only 100 to 200 parts per million can be used to achieve the desired results.
Malt cereal syrup is available with low diastatic activity,high diastatic activity, and non diastatic activity depending upon the amount of diastase enzymes they contain. Low diastatic malt is produced for use with flour which has a fair amount of diastatic enzymes. High diastatic malt is used with flours which have a relatively small amount of diastatic enzymes. Non diastatic malt would be used with flours having a relatively high amount of diastatic enzymes. The amount of enzymes contained in maltis controlled by the manufacturer by heating the malt to various temperatures during production. Malt syrups are concentrated products made by evaporating the water extract of malted barley and other cereal grains. In addition to containing diastatic enzymes, diastatic malt also contain enzymes which assist in adjusting proteolytic action of the dough to compensate for flours of different proteolytic content. High diastatic malts will also be high in proteolytic activity and vice versa. As mentioned in previous paragraphs,diastase enzymes convert some of the starch to dextrins and maltose sugar while protease enzymes condition the gluten in dough. In addition to enzyme functions, malted cereal syrup contain a high percentage of fermentable maltose sugar as well as soluble proteins and natural salts which serve as valuable yeast nutrients.
Rye flavoring is a concentrated flavoring ingredient in powdered form. It gives rye bread an acetic taste as well as a spiced flavor. A preliminary sour dough is not required to enhance the flavor and aroma of rye bread.
Poppy seeds are used as a topping for French breads androlls. They produce a nutty flavor in the baked product. Just before the loaves or rolls are loaded in the oven, they are washed with a cooked cornstarch wash which is thin enough to brush on or spray on. Egg wash can also be used. The seeds are then sprinkled on. The wash keeps the seeds from falling off the loaf or rolls.
Sesame seeds are small oval-shaped seeds of the sesamum family. The seeds are pearly white in color and produce a rich, toasted nut flavor. They are like poppy seeds, sprinkled on washed French breads and rolls.
Staling of Bakery Products and Mold Infectnion
There are three ways in which bakery products stale. They are, Starch Retrogradation (firming of the crumb), getting infected by molds and rope; See Below.
In simple terms, staling of crumb (firming of crumb) is the process the starch molecules go through when they shrink upon cooling. Starch molecule consists of a very long chain of Carbon, Hydrogen and Oxygen that are stretched out when warm and feel soft. Upon cooling, the chain shrinks and thus become firm which is called staling. You have probably experienced that when a stale product is warmed, it becomes soft. The starch chain has stretched again. Upon cooling, it shrinks again and become firm.
1. Emuliifiers. For the past several years bakers used emulsifiers called bread softeners to produce bread that will remain soft for a longer period of time. It is added to the dough during mixing. Some of the more common ones are monoglycrides, calcium steroyl lactylate, and sodium steroyl lactylate. The softening action takes place after the bread is baked. Also, Potato bread will resist staling because potatoes act as anti-staling ingredients to some degree. Some anti-staling ingredients also perform as dough conditioners or dough strengtheners.
2. Enzymes. Enzyme manufacturers are hard at work on generic engineering and protein engineering producing enzymes to extend the shelf life of bread many fold. In a paper presented at the 1999 American Society of Baking's Annual Convention, it was stated that some of these enzymes are available now. However, since every baker wants to have one better, enzyme manufacturers will continue to work on developing better ones. It was also stated that there is a lag time of between 2 and 3 years between the time a specific enzyme is identified and actually having it available for the baker to use.
Advantages of Using Enzymes instead of Chemicals. Since enzymes are produced from natural ingredients, they will find greater acceptance by the housewife than when chemicals are used.
3. Mold and Mold Inhibitors. Sanitation plays a very important role in preventing mold in bread. Mold spores do not survive baking temperatures. The interior of the loaf, when it comes out of the oven is about 210 to 212 degrees F. which will destroy any mold spores which may be present in the dough. Therefore, bread and other bakery products can only be contaminated after they leave the oven.
Some of the more dangerous areas for mold contmination are storage rooms, and slicing machine blades which come in direct contact with the interior of the loaf where there is an abundant supply of food and moisture. Mold spores also thrive in dark places. You can extend the length of time that it takes bakery products to mold by several days by using Mold Inhibitors such as Calcium Propionate for yeast raised doughs and sodium propionate in chemically leavened products. Propionates are present in many foods, but in very small amounts. Swiss Cheese, however is an exception. For this reason, Swiss Cheese rarely molds, unless it is improperly developed. Propionates may be obtained by the oxidization of propyl alcohol, forming propionic acid. The propionic acid is in turn combined with other chemicals to form the well known Sodium and Calcium propionates sold under different Trades Names. Mold Inhibitors react as an alkaline in doughs, and since yeast doesn't like an alkaline condition, Mineral Yeast Foods containing monocalcium phosphate are added to the dough. Monocalcium Phosphate reacts as an acid in doughs therefore counter-acting the alkaline which is formed by the propionates. Also, vinegar can be used at the rate of about 1 pint per 100 pounds of flour. Inhibitors are called inhibitors, because not enough is used to kill the mold. They only retard the growth of molds. Bread will mold eventually if kept in a warm moist invironment. The amounts of Calcium Propionates to use in bread varies with the climate, season of the year, or type of product. Dark Breads require more than White Breads. For average climates, 2.5 to 3.5 ounces are used per 100 pounds of flour in White Breads and 4.0 to 5.0 ounces are used in Dark Breads.
Types and Color of Molds. There are many different types of molds and they have different colors. Mold spores are practically everywhere, because they are very tiny and are carried in the air. They are so tiny that they can only be seen under a microscope. Mold Spores are like seeds that you plant in the garden. When they come in contact with the proper food, moisture and warmth, the spores produce mold plants which you can see with the naked eye.
Rope. Rope is a bread disease caused by the bacteria, Bacillus mesentericus. This disease breaks down the cells of the bread and leaves a sticky, pasty mass. When the crumb is pressed together, and pulled apart, it will stretch into long, sticky, web-like strands. The product will have the odor of over-ripe cantalope. The rope bacteria are too small to see with the naked eye, but they can be seen with a microscope. The bacteria can be present in the ingredients, especially flour and yeast. Unlike mold, rope spores are not destroyed by baking temperatures. Calcium propionate, sodium diacetate or one pint of vinegar per 100 pounds of flour can be used in bread doughs to increase the shelf life of the product. If the bakery is contaminated, thorough cleaning with special chemicals will be necessary and/or the bakery may have to be steam cleaned.
NOTE: SODIUM PROPIONATE IS USED IN CAKE BAKING (NOT CALCIUM PROPIONATE).
To lower the Ph to 6.5 (Most effective Ph) in cakes when using Sodium Propionate is to use an acid ingredient and then you would have to do some experiments to determine how much to use.
Some of the acid ingredients which you might use in the event you wanted to try to lower the Ph of your products are listed below.
1. Monocalcium phosphate
2. Anhydrous monocalcium phosphate, has greater stability by being coated with potassium and aluminum phosphates.
3. Sodium aluminum phosphate.
4. Cream of tartar or potassium acid tartrate.
Representative Ph ranges of various types of finished cakes (not their batters) follows: White layer cakes 7.0 to 7.5; Devil's food cake 8.0 to 9.0; Angel food cake 5.2 to 6.0; yellow layer cake 6.7 to 7.5 and chocolate cake 7.5 to 8.0.
One Text Book on Baking (Breadmaking Technology) by Wulf T. Doerry published by the American Institute of Baking recommends using a 5 percent solution of potassium sorbate to spray the products as they leave the oven. This method is quite effective against mold growth, since the preservative is concentrated on the surface of the product where recontamination with mold spores takes place. Sorbate Spray Applicators are available for spraying the potassium sorbate solution.
One text book (Baking Science and Technology), Third Addition, Volume 1 by E. J. Pyler published by Sosland Publishing Company suggest using 0.03 to 0.125 percent of Sorbic Acid based on batter weight in cakes, pies. pie fillings, fruit cakes and icings. At that level it will not affect the taste and flavor of the finished product. The problem with sorbic acid is that it is not effective at high Ph (9.0 or higher) such as in devils food cake.
Acknowledgments. Material on Mold and Mold Inhibitors was also derived from the following sources:
1. A Treatise on Baking by The Fleischman Division of Standard Brands, Inc.
2. Conversion Factors and Technical Data of the Industry by The Research Department, Pillsbury Mills, Inc.