Bread and the technology of bread production

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Bread is made from wheat flour, water, yeast and salt : with these four "simple" raw materials we succeed in making many thousands of different types of bread. Apart from the quality of the raw materials, the process itself has an enormous influence on the final quality of the bread.

1. The raw materials

1.1. Wheat flour

In this chapter we talk about the wheat kernel and wheat flour. Which methods are used to determine the quality of the flour: Chopin, amylograph, falling number, moisture content etc. What are flour improvers? What kind of enzymes are present in the flour and what is enzymatic activity in the flour? What is the relationship between the quality of the flour and the quality of bread? What other types of cereals are used in the bakery?

1.2. Water

Water plays an important role in the production of bread. However bakers normally don't think about the water. It comes out of the tap and that's it. And why is water the best bread improver (and the cheapest) you can get?

1.3. Yeast and sourdough

What is yeast and what is sourdough? General description of yeast and its characteristics. What are lactic acid bacteria? How is sourdough made, what different technologies are used in the different countries of Europe (France, Germany, Italy etc.). What is the difference between a poolish and a sourdough? Why has bread made with sourdough a longer shelf life and why does it tastes better? What is the importance of the temperature, the pH, the quantity of water used etc.? Which aromatic compounds are formed during the sourdough fermentation and how can the ratio between acetic acid and lactic acid be influenced?

1.4. Other raw materials: emulsifiers, sugar, malt

Emulsifiers are important ingredients of bread improvers. Why do they improve the bread and what does improvement mean? What role plays sugar and what is the influence of salt? Everybody has heard about enzymes but what are they and which enzymes play an important part in the production of bread?

1.5. Other raw materials: fruits, nuts, eggs etc.

Quite some different ingredients can be added to dough either to make a savoury product or to obtain a luxury product with nuts and raisins for instance. These ingredients also need to be of the highest quality and there are quite some possible issues linked to their use.

1.6. Enzymes

Enzymes are naturally occurring components of many bakery ingredients. If an enzyme is added, it often is destroyed by the heat of the baking process. In both cases, product designers can obtain the functional benefits of the enzyme while maintaining a "clean label" image for the finished product. Enzymes also are specific to a particular function, eliminating concerns about undesired effects.

1.7. Gums and hydrocolloids

Gums and hydrocolloids are used to create texture. These are substances that are added to foods to emulsify and create interesting mouth feel and diversity in texture. They can be used for shelf life extension of cakes and bread for instance, to control batter consistency, as partial fat replacers etc. This chapter gives an overview of the hydrocolloids used in the bakery industry. If you read carefully the label of your bread improver or your cake's stabilising system you might discover some gums and hydrocolloids in the ingredient declaration.

1.8. Salt and salt reduction

Recently there has been quite some pressure on the bakery sector to reduce the salt content in bread, cakes, muffins etc. Salt has a positive effect on taste, microbiological shelf life, rheology of the dough etc. So it is quite a challenge to replace salt, but there are a number of possibilities.

2. The technology

We will limit us to the 3 most important phases of the production process. Finally we will take a look at the freezing of dough and parbaked bread.

2.1. Mixing

It cannot be stressed enough that the mixing is the most important stage of the entire process. If you do it wrong, there is no possibility to correct it later. Mixing is the only discontinuous step in an otherwise continuous process. Therefore discipline is required. I know it is not easy to repeat exactly every 12 or 15 minutes exactly the same process however it is necessary and of the utmost importance. Someone who wants to be proud of quality of the product he made, must also be proud of the fact that he is capable of repeating over and over again the same process. And that really is a challenge.

2.2. Moulding, make-up and proofing

The early use of yeasts for bread making was dependent upon wild yeast cells from the surrounding environment falling into a batch of dough. Such fermentation was highly variable due to the unknown quantity, type of organisms present and the conditions to which the dough was subjected. Eventually it was seen that when a piece of this dough was saved for the next batch, the subsequent dough was more consistent and fermented fasted. Hence, the birth of the starter dough. To leaven bread became an "art" and remained as such for thousands of years. Even today some sours are handled as in generations past.

2.3. Baking

The final step in bread making is the baking process in which the dough piece is transformed into a light readily digestible and flavourful product under the influence of heat. Within this baking process, the natural structures of the major dough constituents are altered irreversibly by a series of physical, chemical and biochemical interactions. In this chapter the concepts and knowledge of baking processes are discussed.

2.4. Cooling & Freezing

The quality of fresh bread is often related to its crust (thickness, crispiness, colour and taste) and to the structure of the crumb (flavour, softness, cell wall thickness and cell size). Unfortunately fresh bread is a product with a short shelf life and a number of chemical and physical changes, known as staling, take place during storage. As a result of these changes the bread gradually loses its freshness and crispiness while the crumb firmness and rigidity increase. The pleasant aroma vanishes and off tastes can be detected. So the basic challenge for the baker is to get is product as fresh as possible to the market. This can be done by making sure that the moment of baking is as close as possible to the moment of consumption. For this reason frozen dough and bake-and-serve products were developed.

3. Quality, recipes and other interesting aspects of bread

3.1. What is quality ?

3.2. Recipes from all over the world

This topic is of course endless and it would be rather impossible to describe here all types of bread. Suffice to say that, if there are in a town 5 bakers, there will be 5 different kinds of bread, because the secret of bread does not lie in the recipe but in the way the product is made. So by definition we had to limit ourselves and we made a choice of a number of products which however are distinct and well know all over the world. So, in this chapter, we describe a number of products and their production methods from a selected number of countries.

3.3. Staling of bread

The subject of bread staling is certainly not something new and studies on this particular topic go back many years. Various definitions have been given to the term "bread staling." Very broadly speaking, bread staling refers to all of the changes which occur in bread after baking and has been defined as "a term which indicates decreasing consumer acceptance of bakery products by changes in the crumb other than those resulting from action of spoilage organisms."

3.4. The nutritional value of bread

Nutritious fibres are considered to be an important element in the prevention of the typical prosperity diseases such as obesity, heart conditions and cancer of the bowels. A fibre shortage is not the cause of these diseases, but fibres will slow down the development of these diseases. Especially in the industrialized and well-developed countries, these prosperity diseases appear. Exactly in these places, the use of refined products such as white bread, white rice and white sugar is high. The image of bread as "starchy" or "fattening" is, ironically, contrary to the unique role of cereal grain foods in the history of man.

3.5. The microbiological shelf life of bread

The distribution of fresh bread is a particular problem. The consumer expects a certain microbiological shelf life of bread. Bread that has been packed in a hermetically sealed packet, will stay mould free for a couple of days. Next to the phenomenon of staling, mould will develop. It is even possible that harmful bacteria grow in the bread. This is possible because the crumb of bread has a rather high moisture content. Methods (physical as well as chemical) to extend the mould free shelf life of bread are discussed in this chapter.

3.6. The history of bread

Look at bread: it is the history of the humanity which you contemplate. Bread is the very base of our food since millennia; it is the privileged witness of the history of mankind and of its civilization. As a spiritual symbol, it has accompanied religious festivals and rites. With the whims of nature and military campaigns, the bread has been token of opulence or misery, of constraint or freedom. Lack of bread caused famine in the Middle-Ages, protests because of the bread price at the dawn of the French revolution, bread rationing during World War II, the success of white bread in the post-war period and until recently the rediscovery of tasty whole grain bread, made with sourdough.

3.7. Allergy and intolerance for bread

4. Specialties

4.1. Danish and puff pastry

The origin of puff pastry and Danish pastry is thought to be the Turkish baklava. Baklava is a rich, sweet pastry made of layers of filo pastry filled with chopped nuts and sweetened with syrup or honey. It is characteristic of the cuisines of the former Ottoman Empire. We all think that a croissant originated in France. While traditionally ascribed to the French painter and cook Claude Gelée, the origin of the croissant lies in Vienna.

It is important to understand all these types of products (puff pastry, croissant, Danish pastry) are made by creating alternating layers of dough and fat by folding and rolling the dough. There are basically 3 methods to make puff pastry and Danish pastry: French method, Dutch method and the extruder system.

4.2. Cakes and muffins

Cake is often the dessert of choice for meals at ceremonial occasions, particularly weddings, anniversaries, and birthdays. There are countless cake recipes; some are bread-like, some rich and elaborate and many are centuries old. In this chapter we talk about the raw materials needed to make a good cake and how to make it.

The definition of muffin here is the American muffin i.e. a small individual cakes baked in paper cups. An English muffin, which predates by far the American muffin, is a type of light bread leavened with yeast. The English muffin will be discussed in another chapter.

4.3. Recipes from the Middle Ages

This chapter is not available in English. It also would be a rather difficult task to translate as the original recipes are in Dutch of the 16th and 17th century.

4.4. Donuts and other fried products

You might be surprised by the presence of leavening agents in a yeast raised donut but they tenderise and benefit fermentation and the handling of the dough at make-up. It is not uncommon to use for donuts a combination of baking powder and yeast. I prefer to keep the yeast on the lower side for the better sheeting and handling of doughs. Excessive uses of yeast to hurry the doughs along only causes gassiness, less tolerance to proofing and sometimes collapse when the donuts are removed from the fryer.

4.5. Tortilla production

Tortillas have been used for many centuries in Mexico, where they are consumed year round. More recently other countries have begun producing them to serve the Mexican market and the growing demand for Mexican food, particularly in North America, Europe and Eastern Asia. Tortillas are most commonly prepared with meat to make dishes such as tacos, burritos, and enchiladas, however, there are many alternate versions without meat.

4.6. Gluten free products

The baking industry is paying increased attention to consumers seeking gluten-free products. In fact, sales of these products is on the rise. Coeliac disease is a common digestive condition where a person has an adverse reaction to gluten. Consumers with an intolerance to the wheat protein gliadin or suffer from sensitivity to gluten, are estimated at up to 5 % of the EU population. Besides the people who suffer from coeliac disease, an increasing number of consumers choose gluten free products because they are perceived as “more healthy”.


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Noël Haegens