Notes - Bread

CHAPTER 21 (B) : BREAD

Good food needs good bread and to make good bread one needs to understand the components (ingredients) that are used in bread making, and their functions. The basic ingredients are Flour, Salt, Yeast and Water.

Before we go on to discuss the different components of bread, let us first list the different types of dough.

Bulk Fermented Dough: This is the process that most bakers use to prepare bread. Flour and salt are blended with yeast and water and mixed to smooth clear dough. The dough is then covered to prevent drying out and a skin forming, and then giving a period of bulk fermentation. Here all the ingredients are mixed at once and allowed to ferment. The dough is then knocked back (de gassed) after about two thirds of the fermentation has taken place and then kneaded to encourage further yeast activity. And to equalize the dough temperature. When the fermentation is complete, the dough is weighed off into loafs/rolls. The total fermentation can vary from one to twelve hours, depending on the recipe.

No Time Dough :This process speeds up the fermentation process by adding an improver that contains chemicals that would naturally be produced by fermentation, given a little more time. Flour, Yeast, Salt and water with the improver are blended into a dough, but the mixing is continued for almost double the time. until the gluten is developed sufficiently. It is preferable to use a machine rather than mixing by hand. When mixing is complete, the dough is ready for scaling (weighing). A little extra yeast is added in recipes using improvers, as the quick fermentation does not allow the yeast to grow to its normal levels. As this process does not allow time for the gluten to mellow properly, about 4% extra water must be added to compensate. The extra water will increase the yield, which should pay for the improver. No time dough is ideal for those kitchens with limited time, space and facilities. Improvers also assist prolonged quality maintenance. Improvers also help make reasonable quality bread that has less gluten (weak flour).

Ferment and Dough: This process is meant for heavily enriched dough’s, to allow yeast to become accustomed to the high amount of fat and sugar, which have been added, and which will slow yeast activity. In the first stage, the ferment yeast is blended into a thin batter and fermented with about 20% of the flour mentioned in the recipe and with all the water. Fermentation depends on the yeast content. It is best fermented in a prover or in similar conditions. The first ferment is then blended with the rest of the flour, salt, fat and perhaps milk powder to form a dough. This is the second or the dough stage and is bulk fermented for roughly the same time as the ferment. The dough can then be scaled.

TEMPERATURE

It is important to maintain the ideal dough temperature, which controls the speed of fermentation. Even for basic bread dough, it is necessary to be exact to get the best from the raw material. The best temperature for fermentation is between 25°C and 28°C. Above 32°C, fermentation is rapid but gets progressively weaker. Under 24°C, fermentation is slow. As water temperature can be readjusted, it is the medium that controls the temperature of the dough, determines the water temperature and the rule of thumb is the doubling method. Double the required dough temperature, take the temperature of the flour and subtract that from the above number. The result is the required water temperature. If the dough is required at 28°C, and the flour temperature is 18°C, then 2x28=56, 56-18=38. Therefore the water temperature should be 38°C. Water is essential to bread making to hydrate the insoluble wheat portions forming gluten. Dissolve the salt, sugar and soluble proteins and form an elastic dough. Water has a marked effect on the speed of fermentation – a thin batter fermenting faster than a tight dough. The water content in dough will vary according to the water Absorption Powers (WAP) of various flours.

THE COMPONENTS

SALT – good bread needs salt to offset the blandness and bring out the flavors present. It is also necessary to stabilize the gluten, help retain the moisture and control the fermenting yeast, which in turn will affect the crumb or texture of bread and the crust color. Fermentation is too rapid in dough with too little salt, which checks the growth of yeast so more sugar is converted to gas. Because the gluten is also weakened, it offers less resistance to the gas expansion, leaving too much volume and loose crumb texture. The bread lacks brightness and the flavor is insipid. Too much salt seriously retards yeast activity. Excessive amounts will stop fermentation. With the yeast activity slowed down, there is a corresponding of the tightening of the gluten resulting in a smaller volume. At worst, the result is a heavy, rubber like mass with a taste of excessive salt.

YEAST – is a living organism of the fungal family of plants, which changes sugar into CO2 (carbon di oxide), alcohol and other by-products. The gas is caught up in the gluten network, which aerates the dough. The second function of yeast, equally vital to producing a quality bread, is to assist the ripening or mellowing of the gluten in the dough, so that when the item is baked, the gluten is in a condition which gives evenly to the expanding gases and at the same time retains them (gases). For fermentation to occur, yeast needs a source of glucose (a simple sugar). Small amounts of glucose and fructose in the dough are fermented directly by the yeast. Other sugars and carbohydrates are converted to glucose by enzymes in the flour. Yeast must be in a good condition to work efficiently. It should be cool to the touch and a creamy color. If it is dark ad of a soft sticky consistency, with an unpleasant odor, then it should not be used. Small quantities can be kept pressed into a small bar and stored in a cool place. Yeast works best between 25C and 28C. Above this, the fermentation is rapid but gets progressively weaker as the temperature increases until 55C to 60C, when yeast get killed. Between 23C and 25C, yeast works slowly, till at 25C, fermentation stops. It should never be mixed with dry salt or sugar or dispensed in a strong solution of either, which will kill the yeast. As a living organism, it can never be dissolved in liquid.

FLOUR - there are two basic types of flour used for bread making, whole meal and strong white flour. Whole meal flour contains whole-wheat grains, with nothing added or taken away during processing, Strong with flour has higher protein content and therefore more gluten than soft cake flour. Whole meal flours have a higher water absorption rate than white flours so the dough may be stickier. Extra enzymes in the bran coating of the grain speed up the dough ripening so the dough temperature should be a little cooler to slow down the fermentation. Because the physical and chemical changes in the dough are more rapid, whole meal dough needs shorter fermentation.

GLUTEN - Without gluten in the dough, there could be no bread. Gluten is developed in bread during the manipulation (mixing) of the dough, when two proteins – glutenin and gliadin combine in the presence of moisture (water) to form gluten. Gluten strands traps the gas generated by the yeast and holds it in the dough structure. When it coagulates, it becomes the framework of the dough, so that it does not collapse. Gluten is conditioned by many factors including the amount of yeast and how active it is, the amount of salt and water in the dough, fermentation time, dough temperature, the acidity of the dough and manipulation (kneading). Given good material and correct balance, nothing contributes to good bread making than properly made dough. The kneading, fermentation and the knocking back are also important. Proper mixing gives gluten the opportunity to absorb the maximum water and become thoroughly hydrated.

IMPROVERS - contain chemicals, which would be produced in dough naturally, given time, under the skilled eye of the baker. The are used in no Time dough, 1 to 1 1/2 % for rich dough and 2½% in leaner dough. For basic bread goods 2% improver are added to the flour, water salt and yeast, and is calculated on the basis of the flour only. For dough that is enriched with fat and sugar and eggs, 1 to 1 1/2% is enough. The active ingredients in a typical improver would include sugar, pure emulsifier, soya or guar flour, ascorbic acid (vitamin C) and enzyme active malt flour.

RETARDATION

Retardation is the arresting of fermentation at temperatures between 2°C and 4°C. It enables the dough to be made in bulk, retarded and then baked through the day as and when required. This ensures freshness and standard quality. Enriched dough which ferments slowly, retard the best and can be kept for up to 72 hours. Retardation can be done in two ways: the dough is given between 50-70% of its Bulk Fermentation Time (BFT), then rolled out in 3 kgs-4kgs pieces to quickly take out its heat, and then refrigerated. In the second method, the dough is again given 50-70% of its BFT and then made into pieces, refrigerated and then kneaded, and then brought back to room temperature. The final proving should not be forced. The dough should be cooled before retarding as a high temperature will extend fermentation before retardation is effective. To avoid crusting of the dough, it should be kept in the refrigerator at 75% humidity or in polythene bags.

DOUGH ENRICHMENT

Dough is sometimes enriched with fat, milk or egg yolks, to increase the food value, add to the taste and flavour, and to produce a softer crumb (texture) and also to retard staling. Salt will have to be reduced when using salted butter. Fermentation is slower in enriched dough, so the dough should be kept a little softer and for a slightly longer time.

POINTS TO NOTE

- Take careful note of the formula/recipe and the method,

- See that the scales are accurate and the scale pans are clean.

- Carefully weigh the flour, sieve it, take temperature,

- Calculate water temperature and measure.

- Disperse yeast in a little water, add salt in the rest of the water and add to the flour,

- Mix thoroughly until clear and elastic.

-Take the dough temperature and cover the dough to prevent skin formation. - Prove in a place at the correct temperature or in the prover.

- Knock back when proved according to the BFT.

- Prove rolls in the prover or at controlled temperature and humidity.

- Cover with greased polythene sheet to prevent skin formation

- Egg/starch wash and cutting is best done when the dough is ¾ proved.

- Rolls are baked at 230°C with steam.

STEPS IN BREAD MAKING OPERATIONS

To start with, the ingredients should be correctly scaled and weighed as per a good recipe. Baking is a science, it is essential to begin correctly with the right ingredients in the correct proportions.

1. FERMENTATION: the dough should be fermented for the proper length of time, during which the yeast cells act on the sugars and produce carbon dioxide and alcohol. A number of physical and chemical changes take place during this time.

Physical changes include:

- steady increase in the volume of the dough and can be up to five times its original volume

- increase in temperature by about 5°C to 6°C

- increase in the number of yeast cells by about 26% in straight dough and 56% in sponge dough.

- Loss of moisture

- Change in the consistency of the dough – it becomes soft, elastic and extensible

Chemical changes include:

- the PH of the dough reduces from 5.5 to 4.7 due to the production of acetic acid, lactic acid, sulphuric acid and hydrochloric acid

- formation of maltose by diastatic enzymes by acting on starch

- production of carbon dioxide and alcohol by enzymatic reactions

- mellowing of the gluten by proteolytic enzymes present in the flour and yeast.

Fermentation time will depend on:

- type of flour

- quantity of the yeast

- temperature of the dough

- presence of yeast food (sugar)

2. FERMENTATION CONTROL

It is important to control the fermentation so that the gas production and the gas retention coincide as closely as possible. If the peak of gas production in the dough is reached before its gas retention capacity is at a maximum, then much of the gas will be dissipated and not enough will be left to aerate the dough when its extensibility is at its highest point. On the other hand if the dough reaches its optimum gas retention capacity before gas production is at its highest rate, much of the gas will be lost subsequently. Hence, fermentation control is important to have the development of gas production and gas retention capacities at a parallel and even rate.

3. GAS PRODUCTION:

Gas production will increase with:

- addition of malt and sugar

- the increase of yeast concentration

- the presence of yeast food

- high temperature of the dough (35°C)

Gas production decreases with:

- addition of salt

- excess amounts of yeast foods

- higher temperature of the dough (above 35°C)

4. GAS RETENTION

Gas retention is governed by chemical and physical factors such as minerals, moisture, PH, proteolytic enzymes and oxidising agents, mixing, dough expansion, punching (knocking back).

5. FERMENTATION LOSSES

The weight loss in fermented dough is in the range of 0.5 to 4%. However, under average conditions it is 1%. The loss in weight is normally attributed to the loss in moisture, which depends on the temperature and the relative humidity. Minor loss may be attributed to the escape of carbon dioxide.

6. KNOCK BACK

Punching of the dough in between fermentation periods:

- increases the gas retention of the dough

- equalises the temperature throughout the dough and ensures more even fermentation.

- Reduces the retarding effect of excessive accumulation of carbon dioxide

- Introduces atmospheric oxygen and stimulates yeast activity

- Aids the mechanical development of gluten by the stretching and folding actions

The first punch is normally given when 60% of the fermentation is complete and the second punch is given in half the time required for the first punch.

7. DOUGH MAKE UP

The function of dough make up is to transform the dough into properly scaled and moulded dough pieces which after prooving and baking will yield the desired bread. The operations involved include:

a) Scaling (dividing): the dough is divided into individual pieces of pre determined uniform weight and size. The weight of the dough depends on the final weight of the dough. Generally, 12% extra dough is weighted to compensate for the baking losses. Dividing should be performed in the minimum amount of time to ensure even weight as the dough is scaled on volumetric basis. Longer time changes the density of the dough due to production of carbon dioxide by yeast, thereby changing the weight of the divided dough. If there is delay n dividing, corrective steps such as de gassing the dough or increasing the size of the dough should be taken. The de gassers are essentially dough pumps which fed the dough into the hopper and in the process remove most of the gas. The advantage of using de gassers are:

- more uniform scaling

- uniform texture and grain of the bread.

b) Rounding The dough pieces which had lost a good part of the gas during the dividing, is irregular in shape and sticky with perhaps cut surfaces. The function of the rounding (using a rounder), is to impart a new continuous skin that will retain the gas as well as reduce the stickiness.

c) Intermediate Proof: Dough that has undergone dividing and rounding operations has lost much gas, lacks extensibility and will tear easily. It is rubbery and will not mould properly. To restore a more flexible and pliable structure, which will respond well to the manipulations of the moulder, it is necessary to let the dough rest while the fermentation continues.

d) Moulding: The dough is now moulded into the required shapes.

9. FINAL PROOF

The purpose of the final proof is to relax the dough from the stress received during the moulding operations and to facilitate the production of gas in order to give volume to the loaf. It also changes the tough gluten to a good, mellow and extensible character.

10 BAKING

It is the most important step in bread making and the heat transforms the unpalatable dough into a light porous readily digestible and flavoured product. The factors that influence the quality of baked products are the baking temperature, humidity and the duration of baking (baking time). There are two types of changes that take place during baking.

Physical Changes:

1. Film Formation: when the dough is placed in the oven, the effect of heat is the instantaneous formation of a thin expandable surface film. The length of the time that the film remains expandable depends on the temperature and the moisture conditions of the oven.

2. Oven Spring: Sudden expansion of the dough volume by about 1/3^rd of its original size in the oven is called oven spring. In short, it is the difference in height of the product, before and after baking. The dough piece containing millions of minute gas cells, under the influence of heat, begins to expand. As the pressure in the gas cells increases and causes expansion of cell walls, the carbon dioxide generated by yeast in the dough is liberated at about 50°C. the freed gas increases the pressure in the gas cells causing expansion of the dough. The evaporation of alcohol and other low boiling point liquid increases the gas pressure, leading to an additional expansion of gas cells.

Chemical changes:

1. Yeast Activity: the yeast in the dough will generate carbon dioxide and alcohol with the rate of generation increasing the temperature until the thermal death point of yeast (60°C) is reached.

2. Starch Gelatinization: the oven spring due to the softening of gluten in the early stages of baking is counter acted by the starch swelling which begins at about 54C. The degree of gelatinizaton is restricted by the limited availability of water.

3. Gluten Coagulation: Starch geltinization is associated with water absorption resulting in the removal of water in gluten as it denatures, Gluten coagulation sets in at about 74°C and continues till the end of baking. In this process, gluten is transformed into a semi-rigid cell structure. The major change that takes place during baking is the re distribution of water from gluten phase to starch phase.

Vernon Coelho

ihm mumbai

2009-2010