Baking technology bread

Raw Materials - Processing - Recipes

3.0 Baking technology bread

3.1 Recipe balance and general proportions

3.1.1. Introduction
In the bakery many varieties of products are made. For these products many different recipes are used. often very bakery use their one recipes. Some bakeries do very secret about those recipes and are scared that other people will use them.

3.1.2. Primary and secondary raw materials
The raw materials can be divided into primary and secondary raw materials. Primary raw materials are absolutely necessary ingredients. Without those materials it is not possible to produce good quality products.

The primary raw materials for bread are:-
- flour;
- yeast;
- salt;
- water.
So without these materials no bread can be made.
Secondary raw materials are materials which improve the dough or final product in one way or another.

 In general the quality improvements are:
- a better taste;
- an increased softness;
- a bigger volume;
- a better internal structure;

The secondary raw materials for bread are:
- fats, improvers including emulsifiers;
- sugars;
- milk products;
- malt products.
But you have to realise that if you are preparing a raisin loave, raisins are also a primary raw material. And if you are preparing a milk loave, milk powder is also a primary raw material.

3.1.3. Recipes
All recipes should be given in percentages and grams.
The recipes are in percentages because it is easily to compare different recipes.
It is also easier to turn a recipe in a bigger or smaller    number.

For example

Are these recipes the same or not?  How can you see that?
In a recipe the amount of flour is always 100 %.
If in a recipe is a mixture of flour and wholemeal flour, they should be together 100 %. The other ingredients are always in % of the flour.
If the amount of flour is 100 g, the amount of yeast is 1 % of the flour which is 10 g. It is important to know the right proportions of all the ingredients.
It is important to get good in calculations with grams and percentages if you work in a bakery.
Calculate the following recipies

3.1.4. Raw materials

Yeast
It is important to have a certain carbon dioxide production within a certain time. Sometimes we have to increase the amount of yeast.
When do we need more yeast?
1.      To improve the carbon dioxide production;
2.      To have the same carbon dioxide production in a stiffer  dough;
3.      To get more volume out of 1 kg of flour;
4.      To have th same or more carbon dioxide production in highly enriched doughs and to have a faster carbon dioxide production for doughs which have to be processed.

Fat
The fat will make the dough softer because of reduced water evaporation. The amount of fat is dependent on the type of bread.

Milk powder
The most important reason for using milk products are:
1.      to improve the taste;
2.      to increase the softness.
The amount depends on the type of bread. It should be noted that milk powder is an expensive ingredients.

Sugar
The addition of sugar will affect:
1.      the fermentation
2.      the crust colour
3.      the taste
High percentages of sugar will decrease the fermentation speed, give a dark crust colour and a sweeter taste.

Water
The amount of water used will effect the:
a. stiffness(harshness) of the dough;
b. the fermentation speed.
It is important to use the maximum possible amount of water to reduce the raw materials price. Weak and very stiff doughs cannot be processed. The more water used the higher the fermentation speed.

3.2 The function of wheat flour

3.2.1 Introduction

The most important characteristic of wheat flour and wholemeal flour is the capability to keep the produced gas in the dough. In a bucket with water and sugar the yeast will produce a lot of carbon dioxide and alcohol out of the sugar which is dissolved in the water. The carbon dioxide produced comes out of the water and disappears into the air. The same process takes place in the dough which is capable of keeping the produced gas in the dough.

3.2.2 Composition of flour 

Flours contain a lot of nutrients such as saccharides, protein and fat. The human body is capable of breaking down food and during this process energy is released. Thus the function of flour for the human body is mainly that of supplying energy.

 Saccharides
Saccharide is another name for sugar. The flour sugars can be divided into:
1.      Soluble sugars
2.      Insoluble sugars

1.      Soluble sugars:
The soluble sugars are mono- and disaccharides like glucose and maltose. These sugars dissolve in the dough moisture and serve as a nutrient for the yeast.
2.      Insoluble sugars:
These are the poly-saccharides, dextrine and starch.  Flour contains 60 to 72 percent starch.  It is obvious that such a high quantity of one constituent will have an enormous influence on the dough.  Starch is for the greater part present as granules.  The granules consist of a hard skin, which is impermeable for water.  Part of the starch is damaged during the milling process allowing the water to penetrate the damaged starch granules.
The broken damaged starch granules can absorb about 20% of their own weight in moisture during kneading. The damaged starch granules can be broken down by enzymes into maltose and glucose. These sugars can be used as yeast food.
During the baking process the dough temperature will increase and the starch will absorb water, e.g. it will gelatinize.  By gelatinizing all the free water will be absorbed, resulting in a well-done bread product.  This is the main function of the flour starch.

Flour protein:
The average amount of protein in flour is between 10 and 13%. The amount of protein is dependent on:
1.      the kind of wheat
2.      the climate in which the wheat is grown
3.      the part of grain out of which the flour is ground

The flour proteins can be divided into:
1.      Soluble proteins;
2.      Insoluble proteins.

1.      Soluble protein:

 These proteins dissolve well in water and are used during the bread making process as:
- Yeast food
-  Colour makers for the crust
During the baking process these proteins take part in the formation of the crust colour at temperatures above 100^oC.

2.      Insoluble protein:

These proteins are the most important ones for the baker. They build up together with water and energy the gluten.  The presence of gluten in wheat flour is the main characteristic.  The main characteristic of gluten is its gas keeping capability.  A dough made out of wheat flour, yeast and salt will give a light, tasty bread with a good volume.

The functions of wheat protein in bread products can be summarized as follows:
1.      The protein absorbs water in a dough;
2.      The protein forms the gluten in a dough; an elastic network that encloses all other flour and  dough constituents;
3.      The gluten gives extensibility and elasticity to the dough;
4.      The gluten is able to keep all the carbon dioxide and air, through which the volume of the dough and bread can increase.

3.2.3 The gluten stretching
Good gluten is extensible and elastic.

Chewing gum  is extensible

A balloon  is extensible and elastic
Extensibility is important to give the dough the opportunity to extend by the increased gas pressure of the carbon dioxide, whereby the volume of the dough and the bread can become bigger. Elasticity is important in connection with the shape of the dough cells, but also with the dough and bread product. Weak gluten is very extensible and less elastic.

Gas retention
The generation of CO2 would be useless unless it is retained in the dough fabric. Gas retention then becomes of equal importance to gas production.  For the gluten to hold the gas it must be so conditioned by the fermentation process and by manipulation that it is resilient enough to extend to the expanding gas pressure and strong enough to retain the gas produced. Other factors which influence the gas retention (= quality of the gluten) are:
1.      The amount of yeast, its speed and quality;
2.      The activity of the proteolytic enzymes;
3.      The mill grist and the extraction rate;
4.      The water content for the hydration of the insoluble proteins to form gluten and to  soften the gluten;
5.      Salt and mineral improvers that have a stabilizing effect on gluten and will increase its resistance to undue expansion. This is useful in the case of weak gluten;
6.      Time and temperature, both have an effect on gas retention; an excessive period of fermentation degrades the gluten strength such that it becomes incapable of retaining the gas.
7.      Temperature is important, for the colder the dough the weaker the gluten.  A hot dough has a reverse effect of the gluten becoming very tough
8.      Manipulation is an important factor in gas retention, for knocking back, handing up and moulding assist to a large degree in the ripening of gluten.

3.2.4 The formation of the gluten
All proteins are made up of long amino acid chains. Amino acids are the building units of the proteins. There are about 20 different types of amino acids. The amino acids build up the protein under the isolation of water.
The criteria that distinguish one protein from another are:
1. the identity of the amino acids it contains;
2. the frequency with which the amino acids occur in the chain;
3. the sequence within the chain;
4. the total number of amino acids present;
5. the way the chain is coiled and convoluted in space;
It can well be imagined that all these variables allow an almost unlimited number of permutations and combinations and     account for the myriad of protein species found in nature.

1     2     3     4     5      6     7     8     9     10

                          Amino Acids

1     1     2     2     3     ooo    7     7      11    11

1     1     1     2     2     ooo    3     5      5      5

20    19    18    17    18     ooo    8     8      7      1

Three different proteins
Position of the protein chain in the flour.  During dough kneading the protein chains absorb water and are partially enrolled. Kneading results in the stretching of the protein chains. The breaking of the crosslink allows unfolding of the loop in the protein chain. Interaction between other protein chains takes place and results in other new crosslinks on bridges.
This results in the final dough structure with cells containing starch, moisture, yeast, salt and sugar.  The produced CO2 stays in the dough cell.  Without this phenomenon it is not possible to produce light, tasty bread products.

3.2. 5 Types of flour- protein content and quality
External characteristics.

Volume
High protein. High volume due to more gluten resulting in more gas retention.
Low protein. Low volume due to less gluten resulting in less gas retention.

Colour of the crust
High protein. Darker due to more protein available for maillard browning reaction. Also larger volume increases surface area resulting in faster surface temperature buildup allowing more caramelization and browning.
Low protein. Lighter due to less protein available for Maillard browning reaction. Also smaller volume decreases surface area resulting in slower surface temperature buildup  delaying caramelisation and browning.

Symmetry of  shape
High protein. Good shape(with correct absorption, mixing and fermentation).
Low protein. Good shape(with correct absorption, mixing and fermentation).

Break and shred
High protein. A good to large break with smooth shred due to better gas retention caused by higher protein.
Low protein. No break to a good break with a smooth shred due to less gas retention caused by lower protein.

Evenness of bake
High protein.  Even but darker due to higher browning caused by higher protein content.
Low protein.  Even but lighter due to lower  browning caused by lower protein content.

Character of crust
High protein. More tough (with correct absorption, mixing and fermentation) due to higer protein causing more strength.
Low protein. More tender (with correct absorption, mixing and fermentation) due to lower protein causing  less strength.

Internal characteristics:

Texture
High protein. Smooth (with correct absorption, mixing and fermentation) due to thinner cell walls.
Low protein. Slightly harsh (with correct absorption, mixing and fermentation) due to thicker cell walls.

Color of crumb
High protein   White ( with correct absorption, mixing and fermentation). Ash content - darker: bleaching- lighter; enrichment- darker, yellowing. Due to thin cell walls causing less shadowing effect.
Low protein. White to creamy (with correct absorption, mixing and fermentation). Ash content - darker; bleaching - lighter; enrichment- darker, yellowing.
Due to open grain and thich cell walls causing higher shadowing effect.

Aroma
High protein. More aroma due to more fermentation and more protein for browning reaction.
Low protein. Slightly less aroma due to less fermentation and less protein for browning reaction.

Eating qualities
High protein. Tougher, more chewy due to more protein.
Low protein. Not as tough, easy to bite due to less protein.

Taste
High protein.  Stronger flavour due to more fermentation and more protein for browning reaction.
Low protein. Less flavour due to less fermentation and less protein for browning reaction.

3.3 The function of yeast

3.3.1 Introduction

A long time ago people baked bread without yeast. The Egyptians were the first who used a kind of yeast to make the loaf softer and more tasty, (sourdough). Modern yeast is developed out of sourdough. Sourdough is a mixture of water and flour which is put in a warm environment for some time. In the air a lot of micro-organisms are present and these include many kinds of yeast. These are able to develop themselves into nutritious dough.  Many kinds of micro-organisms can be developed in the dough. Yeasts absorb sugars out of the dough and break them down into carbon dioxide, alcohol and organic acids. So the dough becomes sour. In this sour environment not all micro-organisms are able to live. The yeasts feel very much at home so that a rapid multiplication of the yeast cells will take place in that sourdough.

3.3.2 What is yeast and what is fermentation?
Yeast is a one-cell organism that absorbs dissolved nutrients from its environment and through a complicated internal process makes matter which will be given to its environment.  The nutrients should   always be present in a dissolved state.  The yeast cells are dispersed in the water phase of the dough and that water is an essential requirement for yeast metabolism. Dissolved in the water phase are other materials such as salt, sugar, soluble proteins, etc. Food and nutritious materials are carried in solution into the yeast cell through the cell membrane and only certain materials are allowed in.  Products of fermentation, such as carbon dioxide and alcohol, pass out of the cell into the surrounding medium. The carbon dioxide then comes out of solution into the dough structure.

          Dissolved                      Liquids:  Alcohol

         Nutrients                                Organic Acids

         Sugars                         Gasses :  Carbon dioxide

                          YEAST

         Nitrogen                       Energy :  Warmth

         Protein

         Minerals                      

The chemical reaction is as follows:

                                Zymase

C6H12O6                       CO2   +   C2H5OH + 113    KJoule

3.3.3 Volume and taste
The flavour function of fermentation in breadmaking has been the subject of controversy for many years. It is possible to produce a product which looks like bread using mechanical dough development and special baking powder. This bread contains the normal ingredients, except yeast, it has a similar texture to normal bread and is baked for normal time, the flavour is completely unacceptable in comparison with normal bread. The sensation of flavour is affected by the breadcrumb structure, the degree of baking and therefore crust thickness, the bread freshness and the bread ingredients, particularly salt.  Crust colour and flavour are the result of so-called Maillard reactions during baking between free amino acids (from the action of yeast) and the monosaccharides (simple sugars) present in the dough. Over-fermented doughs are characterised by a pale crust colour indicating a lack of reducing sugars to aid the Maillard reaction.

3.3.4 Factors which affect fermentation.     

Yeast level
Obviously the level of yeast in a dough will  irectly affect the rate of gas production. The more yeast that is added to a dough, the faster the carbon dioxide is produced.  When the yeast level is too high, or the fermentation process too short, the flavour is negatively affected.

Temperature
Dough temperature directly affects the rate of yeast fermentation. As the dough temperature increases so does the rate of gas production until the optimum is reached at about 40^oC, after which there is a progressive thermal killing of the yeast cells and therefore a decrease in gas production, until they are all killed at around 50^oC. Conversely, as the dough temperature decreases so does the rate of gas production until it almost stops at around  4^oC and this is made use of in the retardation and deep freezing of fermented goods.

Sugar
Sugar is the most important food requirement for yeast in a fermenting dough and flour is the principal source. Flour has a natural fermentable ugar content of around 1.5 percent. It provides further sugar through the production of maltose  by the flour amylase enzymes acting on the damaged starch.  Extra sugar or malt products may be added but when the yeast has an adequate supply of sugar, the addition of more will not persuade it to feed  faster and therefore produce gas at a higher rate. These sugars will have a beneficial effect on the finished products in terms of crust colour and crumb softness. Sugar addition to a dough has little effect on gas production until it reaches about 5 percent of the flour weight.  As the level increases further the rate of gas production decreases. This is why much higher yeast levels have to be used in bun doughs than in bread doughs.

Salt
Salt has a detrimental effect on the rate of  gas production; the higher the level, the lower the rate of gas production. This is due to the effect salt has on the osmotic pressure in the dough water phase.  Osmotic pressure applies when two solutions are separated by a semi-permeable mbrane through which their dissolved solids cannot pass, as is the case between the solutions inside a yeast cell and its surroundings medium.  If the level of dissolved solids is higher in one solution, water migrates from the lower concentration solution to the higher concentration one and the difference in concentration is referred to as osmotic pressure. An increase in the osmotic pressure in the medium surrounding the yeast cell in a dough causes water to migrate from the yeast cell. This results in an increase in the concentration of dissolved solids in the yeast cell and a decrease in gas production.  Sugar has a similar but less marked effect on the osmotic pressure.  Salt levels in dough therefore must be carefully controlled and the yeast should never be allowed to come in direct contact with salt  or sugar prior to dough mixing.

PH
Yeast fermentation rate is stable over the pH range of 4.4-6.  Outside this range the gassing rate decreases. Normal bakery dough has a pH of   5.2-5.8 which is well within the acceptable range.

Nitrogen
The fermentation time, the temperature and the  conditions in a fermenting dough mean that there is little production of new yeast cell, even in long fermentation doughs. Since enzymes are proteins, a supply of nitrogen is required and this is obtained from nitrogenous materials in flour. A deficiency of nitrogen in a dough would not stop fermentation but instead of the gassing rate increasing with time it would become constant.

Fats
The addition of fat to a dough does not directly affect fermentation but it can affect it indirectly. Generally, as the level of fat in a dough increases, the dough water level is decreased to counteract the dough-softening effect of the fat. The lower water level mean that the dough water  is more concentrated and this reduces yeast activity in a way similar to increasing the salt or sugar level.

Bun spice
Spices have an inhibitory effect on yeast activity and should therefore be used with care.

Mould and rope inhibitors
Mould and rope inhibitors can have a retarding effect on yeast fermentation.  The fermentation speed is dependent on:
1.      temperature
2.      hardness of the dough
3.      The amount of other ingredients added such as salt, acids, a lot of sugar and fat.

3.3.4 Enzymes in the yeast cell
There are a few important enzymes which can be found in the yeast cell. These enzymes are:
- maltase;
- invertase;
- amylase;
- protease;
- zymase.
Maltase breaks down maltose into two molecules of glucose. Maltase works outside the yeast cell. So before acting maltase has to get outside the yeast cell.
Invertase breaks down sucrose into molecules of glucose and fructose. Sucrose works outside the yeast cell. So before acting invertase has to get outside the yeast cell.
Amylase breaks down starch into dextrine. Amylase works outside the yeast cell. So before acting amylase has to go outside the yeast cell.
Protease breaks down protein into amino acids. Protease works inside the yeast cell, and thus does not have any effect on the gluten network because its gluten forming proteins are insoluble.
Zymase breaks down glucose into carbon dioxide and alcohol. Zymase works inside the yeast cell.

3.3.5 The amount of yeast
It is possible to produce good quality bread with various percentages of yeast.  Sometimes it is necessary to reduce the amount of yeast because the dough handling (knocking back, scaling, moulding) is too long.
Each dough handling should not take more than 1/4 of the first and second bulk fermentation.
For example

If the handling time is more than 1/4 of the 1st + 2nd bulk fermentation the dough pieces get different proving times. But they have to be baked at the same time. The scaling and moulding in our example is 15 minutes so it is possible to use 1% dry yeast. It is not possible to use 1 1/2% dried yeast because the max. allowed time  is 5 minutes and the actual time is 15 minutes.
There are different possibilities of adjusting the dough handing time:
1.      reduce amount of yeast
2.      reduce the amount of dough:  smaller doughs
3.      increase handling speed by for example more bakers.
With manual dough processing you have to be very careful that the doughs are not too big and the scaling and moulding do not take more than 20 minutes.

3.4 Salt

3.4.1 Introduction
A loaf without salt is tasteless. That is why salt is a primary ingredient for bread. There are some people who are on a Natrium arm diet. The food they eat should be natrium arm or with out any natrium. Only for theses people do, we bake in small quantities, bread without salt.

3.4.2 The function of salt
Salt confers many qualities on the dough and on the resultant bread:
- it confers flavour
- it confers stability on the gluten
- it has a controlling influence on fermentation
- it assists in the retention of moisture
- because of its control of fermentation it has a marked 4eeffect on crumb and crust colour.

One of the main reason for using salt in breadmaking is to confer flavour and palatability; without it bread would be insipid and uninteresting. It also has a marked effect on the stability of the gluten. Salt also has a controlling effect on fermentation. With less salt the fermentation is stimulated, there is a greater breakdown of sugar into gas and, because the gluten is weakened, it offers less resistance to the gas expansion. With too much salt, yeast activity is seriously retarded; with excessive amounts, fermentation is stopped, due to a change in osmotic pressure. If, by chance, the salt is doubled, then the same weight of dough without salt should be made and the doughs should be thoroughly mixed together. If the speed of fermentation is retarded by the use of an increased amount of salt, there will be less sugar used by the yeast to produce gas.
Consequently, there will be more sugar caramelized on the crust, producing a high crust colour.  If there is too little salt used, the opposite happens and there is little crust colour. The crust colour is not only a matter of sugar caramelization but also is more a result of reactions between sugars and amino acids.  The average amount of salt in bread is 2% of the flour weight. To save yeast or to have a higher fermentation rate it is possible to reduce the amount of salt if the taste is accepted by the consumers and the processing method is changed. Salt has a damaging effect on yeast (fresh yeast) if allowed to come in direct contact with it and the two should be kept apart during ingredient weighing etc.

3.4.3 Salt – high and low variations
External characteristics
Volume
High salt, Low volume due to:
1)  Decreased gas production caused by higher osmotic pressure on yeast slowing fermentation.
2)  Increased toughening effect of salt on gluten limits dough expansion and possible overmixing.

Low salt, High volume due to:
1) Increased gas production caused by lower osmotic pressure on yeast speeding fermentation.
2) Decreased toughening effect of salt on gluten increases dough expansion and possible overmixing.

Colour of crust
Dark crust colour due to decreased caramelization and browning caused by lower residual sugars and higher Ph, because of decreased yeast activity due to higher osmotic pressure.
Low salt. Light crust colour due to decreased caramelization and browning caused by lower residual sugars and lower Ph, because of increased yeast activity due to lower osmotic pressure.

Symmetry of shape
Double salt.   Rounded corners and tapered ends due to poor pan flow caused by:
1)      the strong toughening effect of salt,
2)      also poor expansion due to poor gassing due to higher osmotic pressure on yeast,
3)      possible undermixing.

No salt. Sharp corners, pitted sides and flat top due to:
1) excess pan flow, extensible gluten caused by lack of salt's toughening effect,
2) excess gassing due to decreased osmotic pressure,
3) possible overmixing.

Break and shred
High salt. No break to capping due to:
1)     poor heat penetration caused by low volume which was a result of poor expansion of gluten (toughening effect),
2)     poor gas production caused by high osmotic pressure on yeast, capping results by sealing the crust and stopping expansion but decreased heat penetration allows yeast to be active longer allowing CO2 gas to build pressure and creating separation of top crust from rest of the loaf.

Low salt. Wild break and smooth shred due to:
1.      excess gassing caused by low osmotic pressure on yeast,
2.      lack of gluten strength caused by lack of salt's toughening effect.

Evenness of bake
High salt. White spots and dark areas due to:
1.      high residual sugar content caused by lack of fermentation,
2.      stiffness of dough preventing pan flow decreasing dough contact to pan surface.

Low salt. Pale colour with light areas due to:
1.      low residual sugar content caused by excess fermentation,
2.      slackness of dough possibly causing gas entrapment between dough and pan surface.

Character of crust
High salt. Thin and tough due to:
1.      thin because of low volume - less moisture bake out,
2.      tougher because of high salt.

Low salt. Thick, tender and crisp due to:
1.      thick and crisp because of high volume increasing moisture bake out,
2.      tender because of dough expansion and lack of salt.

Internal characteristics

Texture
High salt. Hard and firm due to tight grain, denser product.
Low salt. Soft but rough due to open grain, less dense product. 

Colour of crumb
High salt.  White due to:
1.      decreased shadowing effect caused by fine shallow cells due to decreased gas production and
2.      more toughening effect on the gluten.

Low salt. Gray due to:
1.      deep, large cells caused by excess gas production and
2.      lack of salt's toughening effect, stretching gluten until it ruptures.

Aroma
High salt. Less aroma due to lack of flavour compounds caused by decreased fermentation resulting from high osmotic pressure on yeast.
Low salt. More aroma due to the high level of flavour compounds caused by excess fermentation resulting from low osmotic pressure on yeast.

Eating qualities
High salt. Moist and tough due to:
1.      low volume creating poor bake out properties and
2.      high salt producing a tougher gluten.

Low salt. Dryer more delicate due to:
1.      high volume creating better bake out properties decreasing moisture in final product and
2.      decreased density and lack of salt's toughening effect on gluten.

Taste
High salt. Salty due to excess salt, above 2,5 %, will give most breads a salty taste.
Low salt. Bland, lack of flavour due to low salt. Usage below 1,5% will give most breads a bland flavour. (average salt range for most breads and rolls - 1,75 to  2,25%)

3.5 The function of water

3.5.Introduction
Water is obviously an essential ingredient in breadmaking but it is of interest to note the various roles of water in a dough. 

3.5.2 The function of water
Water hydrates the flour proteins to produce the visco-elastic substance known as gluten. This forms the dough skeleton and holds the gas produced by the yeast.  Part of the water is absorbed by the starch and partial starch gelatinisation takes place during baking. This helps to create the final loaf structure and adds to the eating quality of the bread. When a dough is mixed some of the water is absorbed by the flour proteins and some by the starch. The rest stays as free water and forms the so-called water phase of the dough.  It is this water phase that soluble products such as salt, sugar, soluble proteins etc. are dissolved and in which the yeast cells are dispersed.  Yeast and enzymes can only work when dispersed in water and yeast can only absorb food which is in solution. The correct water content in a dough, combined with correct development, ensures that the dough has the correct consistency and plasticity to withstand moulding and to form easily to the desired shape.
Oven bottom bread dough and shapes which are not supported by a tin, require less water to give a dough which will keep its shape during proving and baking.  Water confers softness to the finished bread.  Within limits the more water a dough contains, the softer will be the resultant bread. The limits are of course, that crumb softness is only one of the quality factors to be considered and many other factors determine the amount of water that a particular dough will take, i.e. flour quality, bread type and shape, breadmaking process, processing equipment etc. It is important to notice that the addition of more water will give more loaves out of the same amount of flour.
In stiff dough there is little free water so the carbon dioxide production by yeast is slow. In a weak dough there is a lot of free water and therefore too little binding between the dough constituents. The carbon dioxide production is fast. A lot of water (weak dough) will give an increased enzyme activity. Less water will reduce the enzyme activity.
By changing the water temperature we are able to adjust the dough temperature.
Free water takes care of:
1.  the transport of yeast food and waste matter;
2.  a fast enzyme activity, through which insoluble yeast food is changed into soluble, which can be used by the yeast;
3.  a smooth dough and the formation of the gluten network.
Too much water gives a weak dough with a too fast fermentation process; too little water gives a stiff  dough with a too slow fermentation process;
4.  temperature control of the dough.

3.5.3 Water absorbtion- approx. 6%.

External characteristics

Volume
High absorption: Collapsed, low volume due to:
1.      weakening of gluten structure (over extension of gluten caused by excess gas production caused by excess water accelerating yeast activity,
2.      dilution effect on gluten caused by excess of water,
3.      possible high volume if protein strength is still good, along with excess gas production.

Low absorption: Low volume due to:
1.      slower gas production (lack of water for optimum yeast activity),
2.      poor gas retention (cells rupture due to decreased dough extensibility (due to less free water content of dough - decreased dough mobility. 

Colour of crust
High absorption. Lighter crust colour due to:
1.      higher residual sugars and higher Ph (more fermentation because increase in water speeds yeast activity) causing decreased caramelization and browning reactions,
2.      Delayed caramelisation and browning (excess water delays surface temperature build-up).

Low absorption.  Darker and duller crust colour due to:
1.      higher residual sugars and higher Ph (less fermentation because decrease in water slows yeast activity) causing increased caramelisation and browning reactions,
2.      accelerated caramelisation and browning( lack of water accelarates surface temperature build-up).

Symmetry of shape
High absorption: Sharp corners, flat top due to excessive pan flow caused by higher free water.
Low absorption: Poorer symmetry showing low ends, rounded corners, usually a well defined seam, rounded top due to poor pan flow caused by lack of free water. Possible capping caused by premature dry crust.

Break and shred
High absorption: No break on low volume loaves because of  weakness in protein giving poor gas retention. Excessive break with a smooth shred on high volume loaves because of adequate protein strength, easier dough expansion and excess gas production.
Low absorption: Wild break with rough shred and possible capping. This is due to poor dough extensibility.

Eveness of  bake
High absorption: Lighter side walls and botton due to excess moisture which will delay caramelisation and browning.
Low absorption:  Darker side walls and bottomm due to less moisture which will speed caramelisation and browning. Possible light areas where product was not making contact with the pan surface, poor heat transfer.

Character of crust.
High absorption: Thin and soft crust due to high moisture content and poor bake out, low surface area. Higher volume loaves will have closer to normal crust characteristics.
Low absorption: Thick, tough and rough crust due to low moisture content and denseness of cell structure of crust.

Internal characteristics

Texture
High absorption: Moist and soft due to high moisture content.
Low absorption: Harsh and soft and firm due to dryness of crumb and denseness of the grain.

Colour of crumb
High absorption: Darker- grey caused by high moisture content and shadowing effect.
Low absorption: Tan due to compact texture with possible thick cell walls.

Aroma
High absorption: Lacking due to decreased browning reaction caused by high moisture content. Also moisture dilutes aroma.
Low absorption: Stronger due to increased browning reaction caused by lower moisture content.

Eating qualities
High absorption: Gummy, compresses easily due to poor moisture bake out.
Low absorption: Denser and drier, this is due to tight texture and lower moisture content.

Taste
High absorption: Lack of taste due to:
1.      decrease in browning reaction and
2.      high moisture content dilutes flavours. More fermentation was carried out due to excess   water effect on yeast but other factors were greater.

Low absorption: More taste due to:
1.      increase in browning reaction and
2.      low moisture content which concentrates flavours. Less fermentation is carried out due to lack of water, slowing yeast activity, but the other factors were greater.

3.6 The function of milk and milkpowder

3.6.1 Introduction
To improve a standard loaf we can add secondary ingredients. Milk and milk powder are secondary ingredients because the improve the loaf but are not essential. It is possible to use milk or milkpowder for the same purpose. The advantages of milk powder:
- long shelf life because it is dry;
- the price, it is cheaper;
- the powder takes less room than the equivalent in milk;
- it is very easy to use, e.g. scaling.

3.6.2 The effect of milk powder on dough and bread
The main matters in milk and milk powder are:
- milk proteins;
- milk sugar;
- milk fat.
and will affect the dough and bread.

Milkprotein

The milk proteins will decrease the extensibility of the wheat gluten and also the volume.  So it means that if nothing is changed the loaves will be small and the structure coarse. We can reduce the negative influence of milk protein on the bread volume by:
- addition of more water;
- more yeast;
- longer fermentation times;
- the use of heated milk or high heated milk powder. 

Milk sugar
Milk sugar is a double sugar and built up out of the single sugars galactose and glucose.  Lactose or milk sugar does not have a very sweet taste.  The sweetness of normal sugar is 100 and the sweetness of lactose is 39.
Milk sugar is no yeast food.
Lactose cannot be broken down into simple sugars by the yeast cell during the bread manufacturing into simple sugars.  Lactose will be broken down by the enzyme lactose into glucose and galactose.  There is too little lactase present to break down the lactose.  So the lactose remains in the free water.
Milk sugar as a colour maker
With an increase in temperature milksugar gives a browner colour than other sugars.  So milk bread has a browner colour/crust.
The crust colouring is not only caused by caramelisation: it is also a reaction between amino acids and simple sugars which causes the brown colouring.  It is known as the Maillard reaction.  If there is more lactose present in the dough or bread the Maillard reaction will be stronger.  To keep it from getting too dark a colour, milk bread must be baked at a lower temperature.  The more milkpowder (lactose) added the lower the baking temperature should be.
Milk sugar is hygroscopic.
Hygroscopic means it will attract moisture during the storage of milkpower but also after baking milk bread.  It means that the crispy crust after baking will disappear very fast.  It is not clear if lactose will also affect the crumb softness because of the attraction of water.

Milkfats
Milk fats appear to be small balls in milk and milkpowder.  The melting point is between 23^oC - 32^oC.  During dough kneading part of the milk fats will melt while another part is present as a solid fat.  The solid fats will grease the gluten strands which will improve the extensibility of the gluten and increase the volume.  Part of the negative influence of milk proteins is decreased by the positive effect of milk fats on the gluten strands.
It is the combination of milk fat, milk protein and milk sugar and the brown colouring of the crust which will give the special taste to the bread.

Summary
Milk powder delays the increase of the volume of the dough. This is compensated by:
- a softer dough, more moisture;
- more yeast;
- longer fermentation times;
- addition of malt.
Milk powder gives to milk bread:
- a better taste;
- a longer softness;
- a tougher crust;
- a stronger brown colouring;
- a finer crumb structure.         

3.7 The function of bread improvers

3.7.1 Introduction
Bread improvers are secondary ingredients. They have  an improving effect on the loaves. The following ingredients are used as bread improvers.
1.      oils/fats;
2.      emulsifiers;
3.      sugar/sugar syrup;
4.      milk, powders as malt, cysteine;
5.      colours and flavours.

3.7.2 The function of bread improvers
Bread improvers will improve:
1.      bread volume;
2.      crust colour;
3.      crumb colour;
4.      increase fermentation speed;
5.      longer softness;
6.      fine structure.

3.7.3 How do they improve bread

Oils and fats
Fats have a physical rather than a chemical effect on dough. As fat is a shortening agent, that is, it reduces toughness, thus conferring a mellowness, it is particularly valuable for use with strong flours with a tough harsh gluten. Fat is also considered to have a lubricating effect on the fine gluten strands which, together with its shortening action, results in an increase volume. The crust is rendered more thin and biscuit like. Neutral fats and oils having no flavour only improve the bread physically. Fermentation is retarded according to the amount of fat used so that an increase of yeast may be necessary.  Fat can be added by rubbing it into the dough in the form of an emulsion. By using an emulsion, a greater degree of fat dispersion is effected. Fat is generally used from 1 to 3%.  Too much fat will result in a loaf with a small volume and a close "cheesey" crumb.  The crumb will be soft and short with very little colour; in addition, both crust and crumb will have a certain greasy feel.
Summary of the effects of fat on bread:
1.      Reduces elasticity, softens the crust and crumb, thus making the bread more easily digestible;
2.      Confers moistness on bread, thus retarding staling;
3.      In normal amounts it increases volume.  Used excessively, volume is seriously reduced because the extensibility of the gluten is largely destroyed.  In larger amounts fat retards fermentation.  (Increase food value.)

Emulsifiers
Fats have a lubricating effect on the fine gluten strands and lock in the dough cells.  By using emulsifiers the lubricating effect of a fat will be greater and will improve the quality of the bread.  When an emulsifier is used the % of fat (2 1/2% fat + 1/2% GMS instead of 3% fat) can be decreased. In some bakeries GMS (Glycerol Mono-stearate) is used.

Sugar-sugar syrup
Sugars, except lactose, are fermentable by yeast. Lactose is only sparingly fermentable. Flour contains natural sugar (sucrose) in varying amounts; normally it is about 2.5 - 3%.
This is sufficient, during controlled fermentation over a reasonable period, to provide a steady source of sugar for gassing purposes. Low maltose flour will ferment normally for a time and then begins to fail towards the end, during the final proof, producing a small volumed loaf with little or no crust colour.  High maltose flour will gas excessively, partly because of the high sugar content, but also because of the increased diastatic activity, which still further adds to the sugar content by the production of maltose from the breakdown of starch.  The result is a loaf of large volume and with a high crust colour; the structure of the crumb is weak causing, in tin bread, a collapse of the sides, and because of the dextrin and the excessive sugar present, the crumb is dark, showing streaks, and the loaf is difficult to bake out. 
In low maltose flour the addition of sugar on malt is necessary.  The sugar % has also an effect on the fermentation.  At a level of 4 - 5 % it will decrease yeast activity.

Fat, low and high ratio´s

External characteristics 

Volume
High fat. Lower volume, poorer gas retention. Over lubrication (gas leakage) and dilution effect on protein.
Low fat. Lower volume, poorer gluten expansion lack of lubrication). Sponge and dough process may show good volume from overmixing. 

Colour of crust
High fat. Light and shiny, delayed caramelization and browning (better moisture retention, slow heat build-up). Longer bake will produce a deep, dark colour(frying effect).
Low fat. Dark and dull, accelerated caramelization and browning (less moisture retention, faster bake out, higher surface temperature)..

Symmetry of shape
High fat. Sharp or corners and flatter top, good pan flow. Sidewalls may collapse due to improper moisture bake out and dilution effect on protein.
Low fat. Rounded corners and round top, less flow pan.

Break and shred
High fat. Smaller break with smooth shred, over lubrication (gas leakage) and dilution of protein content.
No fat. Small break with rough shred, good gas production but poor expansion capabilities. sponge and dough may produce excessive break.

Eveness of bake
High fat. Light side wall, delayed caramelization and browning (slower bake out) and excessive pan flow, possible dark areas. Frying effect may be observed with longer bake producing darker colour.
Low fat. Dark side wall, accelerated caramelization and browning (faster bake out, higher surface temperature) and poor pan flow.

Character of crust
High fat. Thin and tender, higher moisture and fat content.
Low fat. Thick, crisp and tough, lower moisture content and lack of tenderising effect from fat. 

External characteristics

Texture
High fat. Soft but rough, less moisture bake out, tenderness from high fat and thick cell walls.
Low fat. Firm and rough, better moisture bake out and thick     cell walls.

Colour of colour
High fat. Tan, thick cell walls, shadowing effect.
Low fat. Tan, thick cell walls. Grey, holes (shadowing effect).

Aroma
High fat. More fermentation aroma, less bake out properties and increased moisture barrier.
Low fat. Less fermentation aroma, better bake out properties and decreased moisture barrier.

Eating qualities
High fat. Moister and more tender, less bake out and more fat. Possible greasy feel in the mouth.
Low fat. Dryer and tougher, better bake out and lack of fat.

Taste
High fat. Improved fermentation taste, less bake out (fat acts as a moisture barrier).
Low fat. Less fermentation taste, better bake out properties most fats are bland, no flavour except butter, margarine, and possibly lard.

3.8  Sugars and malt products in bread

3.8.1 Introduction
From the chapter: The function of bread improvers, you know that sugars and malt products are bread improvers. In this chapter we will have a closer look at the function of sugar and malt products.

3.82 What kind of sugar
Not every sugar is suitable for bread making. Brown sugar makes the dough brown, vanilla sugar gives a vanilla taste, etc. The most common sugar which is used in the bakery is crystal sugar. When sugar is added for extra colour, a less sweet sugar can be used.

3.8.3 Why do we always use sugars in dough?
Sugars have an effect on:
1.      the speed with which the yeast produces carbon dioxide and alcohol;
2.      the colour of the crust of the baked products;
3.      the crumb structure.

3.8.4 Influence on the fermentation speed
Yeast absorbs soluble sugars from the dough and produces carbon dioxide.  The gas bubbles increase their volume through which the dough volume increases also. If tests are made with 1, 2, 4, 8 and 16% sugar the following results can be seen:
1.      the fermentation speed increases with 4% if 1% of sugar  is added;
2.      if 2% sugar is added, the fermentation speed increases up to 6% compared to 0% sugar addition;
3.      if 4% sugar is added the carbon dioxide production  decreases.
If 1 or 2% sugar is added the concentration of ingredients in the free water is at a level whereby the yeast cell still absorbs water with dissolved ingredients to produce carbon dioxide, alcohol and organic acids (osmosis).
If 4% or more sugar is added the concentration in the water     is higher than the concentration in the yeast cell.  The transfer of yeast food from the free water to the yeast cell is much slower, through which the fermentation speed decreases.

3.8.5 Influence on the crust colour
When sugar is heated it will melt first and then caramelize.  In the free dough moisture, sugars are dissolved. During baking the moisture from the crust will evaporate. If the moisture in the crust has evaporated the temperature of the crust will become more than 100^oC. The sugars will caramelize or become brown. Protein is also very important for the crust colour. The sugars sucrose and fructose will react with protein during the process; this reaction is called the Maillard reaction.  A different example is the frying of meat in oil or butter. Milksugar is present in the butter and will react with the protein of the meat. Frying in oil will give less brown meat because of the absence of protein in oil.

3.8.6 Influence on the crumb structure
A small amount of sugar will soften the crumb because of water retention.  Ordinary bread is not supposed to be sweet.  Additions of up 2 1/2% of sugar will not affect the sweetness of the bread.

3.8.7 Malt and malt products
The active part of malt and malt products consists of enzymes.  Enzymes are living organic matters which are capable of breaking down large quantities of materials.  Enzymes bring about chemical changes without being changed themselves as a result of the chemical reaction.
For example:

Starch, with certain          Starch      Insoluble                               dextrine

characteristics                           not sweet

maltose

Glucose, different                                        glucose,     soluble

substance with different                             light sweet

characteristics

Each enzyme is designed for one reaction only.  In bread making, two groups of enzymes are important:
1.  diastatic enzymes, they convert insoluble sugars into  soluble sugars;
2.  proteolytic enzymes, they convert insoluble proteins into soluble proteins.
The most important yeast enzymes in terms of a fermenting dough are invertase, maltase and zymase complex.
a. invertase
sucrose + water          glucose + fructose
b. maltase
maltose + water          glucose + glucose
c. zymase
simple sugars            carbon dioxide + ethyl alcohol
(glucose and fructose)

3.8.8. The activity of enzymes
The speed of the enzyme activity in a dough is dependent on:
1.  the temperature;
2.  the amount of enzymes;
3.  the pH;
4.  the amount of materials to be converted;
5.  the amount of moisture present.

1. The temperature.
The activity of the enzymes is affected by the temperature. The optimum temperature is the temperature whereby the enzymes have the maximum activity.  The maximum temperature is the highest temperature whereby the enzymes are active. At the minimum temperature the enzymes stop every activity.
2.  The amount of enzymes.
The more enzymes the more insoluble matters will be converted into soluble matters.
3.  pH
Yeast fermentation is stable over a pH - range of 4.4 - 6. Each enzyme has a different optimum pH level.  Outside this range the gassing rate decreases.
4.  The amount of materials to be converted
If a lot of sugar and protein have to be converted then more enzymes are necessary.
5.  The amount of moisture.
Enzymes are active in a watery surrounding. In a dough with a lot of moisture the enzyme activity is high. In a dough with a low moisture content the activity is low.

Proteolytic enzymes
The advantages of proteolytic enzymes are:
1.  they will weaken the gluten;
2.  the dough will become more extensible;
3.  the bread volume will increase;
4.  they will improve the structure.

1.  Weakening of the gluten.
During the fermentation process the insoluble protein will be converted into soluble protein. The broken - down protein will release moisture, which will soften the dough.
2.  The dough will become more extensible
After kneading the gluten network is very elastic and not very extensible.  Due to the activity of proteolytic enzymes part of the hard gluten will be broken down, increasing the extensibility.  Now it will be easier for the carbon dioxide produced to blow up the gluten.  The volume will increase. With hard gluten the increase of the volume will cause cracks. The produced carbon dioxide cannot retain the gluten.

3.8.9 Malt products
Malt products used in the bakery are:
1.  malt flour;
2.  malt extract. 

1. Malt flour contains 2 types of enzymes:
a. diastatic enzymes
b. proteolytic enzymes
The advantage of malt flour is that it is easy to scale. The disadvantage is that it will give a light grey colour to the bread produced.

2. Malt extract looks like a syrup.
Two types are used:
a. one containing diastatic and proteolytic enzymes
b. one containing only diastatic enzymes
The disadvantage of malt extract is its stickness when scaling. It is often used in advanced bread improver. The addition of the flour weight is + 1% malt flour and 0.2 - 0.5% malt extract.

When are malt products used
Diastatic malt is used with a low diastatic flour; this means that the flour has a low capacity to produce soluble sugars. Hard wheats have a low diastatic power, so a malt addition is useful.  Proteolytic malt is used with a flour with very elastic protein. The development of the dough will take too long. Very high quality flours often have very elastic gluten; the use of proteolytic malt is necessary . 

Effects on the bread.
A correct use of malt will confer the following qualities on bread.
1.      Increase volume
2.      Improved crust colour
3.      Better bloom
4.      Brighter and softer crumb
5.      Better flavour
6.      Better keeping qualities
7. Increased food value (calorific value). 

3.8.10 Sugar, high and low levels

External characteristics.

 Volume
High sugar. Low volume, poor gas production (high sugar concentration increases osmotic pressure) 5% sugar level, slower yeast activity (gassing).
Low sugar. Low volume, poor gas production (limited food supply).

Colour of crust
High sugar. Darker crust colour,  more residual sugars available for caramelization and browning.
Low sugar. Lighter crust colour, less residual sugars     available for caramelization and browning.

Symmetry of shape
High sugar. Smooth, flat top and sharp corners, good pan flow caused by increased free water content.
Low sugar. Round top and round corners, poor pan flow caused by increased hydration of flour (less free water).

Break and shred
High sugar. Small to large break with smooth shred, possible capping. poor gas production due to increased osmotic pressure effect on slowing fermentation (high pH), but may expand easly due to higher free water content in dough.
Low sugar. Capping to a small break with rough shred. Capping may be caused by underfermentation, low volume and/or drying of the crust in the final prover.

Eveness of bake
High sugar. Dark and even colour with shiny side walls, more residual sugars available for caramalisation and browning.
Low sugar. Light and even colour, less residual sugars available for caramelisation and browning.

Character of crust
High sugar. Thick and tender crust, poor bake out properties, low volume and high residual sugars content (hygroscopic effect).
Low sugar. Thin and crisp crust, good bake out properties. Less residual sugars.

Internal characteristics.

Texture
High sugar. Soft, smooth texture.
Soft  = high moisture content (hygroscopic effect)
Smooth= thin call walls (not too underfermentated)
Rough = thick cell wallls (underfermented)
Low sugar. Firm and rough texture, broken cells, thick cell walls and better bake out properties. 

Colour of crumb
High sugar. Cream to tan, thich cell walls, shadowing effect.
Low sugar. Cream to grey, thick cell walls and broken cells shadowing effect.

Aroma
High sugar. Lack of fermentation aroma, decreased fermentation, lower acid and alcohol content, high degree of caramelization and browning (crust aroma).
Low sugar. Stronger fermentation aroma, increased fermentation, high acid and alcohol content due to decreased osmotic pressure.

Eating qualities
High sugar. Moist and easy to bite, high residual sugar content, less bake out (hygroscopic effect).
Low sugar. Tough and dry, better bake out properties, and no dilution effect on protein.

Taste
High sugar. Sweeter taste, higher residual sugar content. Less fermentation taste due to osmotic pressure decreasing yeast activity.
Low sugar. Less sweet, more fermentation flavour, increased fermentation, higher acid and alcohol content and less caramelization and browning due to decreased residual sugars.