Stanley P. Cauvain, in Breadmaking , 2020
Subdivision of the dough mass after mixing into unit pieces.
Breadmaking is a centuries-old traditional craft, practiced in any country capable of growing or importing wheat. This has meant the evolution of a diverse range of breadmaking processes designed to deliver a wide range of bread products. There are a number of basic steps that are common to all breadmaking processes. They can be listed as follows:
Development of a gluten structure in the dough through the application of energy during mixing.
C. Wrigley, I. Batey, in Bread Making , 2003
T. Deák, in Encyclopedia of Food Sciences and Nutrition , 2003
In Technology of Breadmaking Cauvain states that for no-time dough-making processes that “About 90% of final bread quality is decided by what bakers chose to do in the mixer.” This aspect of quality embraces the choice of raw materials and formulation, as well as decisions on how to mix and develop the gluten structure in the dough. The relationship between mixing and dough development is still not fully understood but it provides the foundations on which breadmaking quality is built . This theme is visited in many of the chapters in this book. It is well known that simply blending the bread recipe ingredients is not enough to initiate the development of a fully developed gluten structure. If you want convincing of the relative importance of mixing and dough development, try mixing your own bread dough by hand. The harder you work the dough , the greater will be the gas retention in the dough, the larger the loaf and the softer its crumb. However, the mixing times concerned may last for 30 min or even longer, so be prepared for some hard work and a significant rise in your personal temperature which confirms the fundamental relationship between work and heat!
Martin G. Scanlon, … John H. Page, in Bubbles in Food 2 , 2008
The concept of bread flavour is perhaps the most contentious of all the quality issues associated with bread. The formation of bread flavour arises in part from fermentation processes and in part from the complex interactions between the heat of the oven and the recipe ingredients. Factors that influence bread aroma are discussed in Chapter 21 , and readers are left to form their own opinions on this highly individual subject.
In Technology of Breadmaking it has been stated of no-time dough-making processes that ‘About 90% of final bread quality is decided by what bakers chose to do in the mixer’. This aspect of quality embraces the choice of raw materials and formulation as well as decisions on how to mix and develop the gluten structure in the dough. The relationship between mixing and dough development is still not fully understood. This theme is visited in many of the chapters in this book. It is well known that simply blending the bread recipe ingredients is not enough to initiate the development of the gluten structure. The technological aspects associated with gluten development and their place in the different breadmaking processes are discussed in Chapters 2 and 12 . If you want convincing of the relative importance of mixing and dough development, try mixing your own bread dough by hand. The harder you work the dough , the greater will be the gas retention in the dough, the larger the loaf and the softer its crumb. However, the mixing times concerned may last for 30 minutes so be prepared for some hard work and a significant rise in your personal temperature which confirms the fundamental relationship between work and heat!
The dough undergoes a series of mechanical operations while being allowed to rest between these procedures for short periods. During these proofing periods, fermentation proceeds, and leavening continues. After the final proof, loaves are placed into a hot oven for baking. Within the loaf, gas expands, steam and alcohol evaporate to form holes in the coagulated matrix of gluten, and the characteristic structure of the crumb sets. While the temperature in the center of the loaf remains below 100 °C, the surface reaches 140 °C, to form a hard, brown-colored crust. The baked bread is left to cool before the finishing operations and distribution.
E. Betoret, C.M. Rosell, in Breadmaking , 2020
Preliminary modification of the shape of the divided piece.
M. Seguchi, M. Abe, in Using Cereal Science and Technology for the Benefit of Consumers , 2005
Mixing of wheat flour and water, together with yeast and salt, and other specified ingredients in appropriate ratios.
Breadmaking bread making article
Add to Mendeley Download as PDF Set alert About this page Bread: Chemistry of Baking C.M. Rosell, in Encyclopedia of Food and Health , 2016
Additionally, the nature and extent of the chemical alterations produced during breadmaking are greatly dependent on the specific characteristics of each cereal flour. Since wheat flour is the most common flour used in making bread specialties, this article will be focussed on changes occurring in wheat flour during breadmaking.
Improvement of breadmaking properties by blending flour with Allium powder such as Welsh onion , scallion , and leek may be caused by naturally occurring disulphides in Allium through sulphydryldisulphide- exchange reactions in wheat proteins. The Allium is generally known to have beneficial effects on human health, and the improvement of breadmaking properties by Allium suggests that it may have a possible use in breadmaking. Regarding using Allium in bread, the unpleasant smell of raw Allium was lost and the fresh taste of the bread treated with Allium powder was rather desirable.
Dough development is a poorly defined term that covers a number of complex changes that begin when the ingredients first become mixed. These changes are associated with the formation of gluten, which requires both the hydration of the proteins in the flour and, as noted earlier, the transfer of energy through the process of kneading. The role of energy in the formation of gluten is not always fully appreciated but it is a significant contributor to the breadmaking process. There is more to dough development than a simple kneading process. The process of developing bread dough brings about changes in the physical properties of the dough and in particular, an improvement in its ability to retain the carbon dioxide gas subsequently generated by yeast fermentation. This improvement in gas retention ability is particularly important when the dough pieces reach the oven. In the early stages of baking before the dough has set, yeast activity is at its greatest so that large quantities of carbon dioxide gas are being released from solution in the aqueous phase of the dough, along with expansion of the trapped gases. If the dough pieces are to continue to expand at this time, then the dough must be able to retain a large quantity of that gas being generated and it can do this only if we have created a gluten structure with the appropriate physical properties, not least of which is significant extensibility.
In-depth considerations of the molecular changes during dough mixing will be encountered in several chapters. The molecular interactions involved depend very significantly on the key quality traits of the proteins in wheat, and as discussed in Chapters 13 and 15 we can see how the genetic puzzle that is wheat protein is slowly being solved. The role of water in gluten development is commonly taken for granted with water being seen simply as an ingredient that varies in level of addition with flour properties so that bakers can achieve a given consistency. It is true that the quantity of water added to bread flour is critical in providing a dough rheology which is suitable for subsequent processing but as discussed in Chapters 14 and 16 it is also part of the underpinning essential molecular changes which occur during the mixing/development process. Experiments with powdered ice or pre-hydrated flours reveal the complex relationship between hydration and development. Water plays a key role all through the breadmaking process starting with mixing and ending with contributions to end product eating and keeping quality. These pivotal roles are described in Chapter 20 . Critical reference to dough rheology, its control and contribution to final product quality is made in many chapters. Techniques for assessing dough rheology have changed , and some of the latest developments are described in discussions that follow.
Creation and modification of particular flavor compounds in the dough, which remain in the baked product.
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A short delay in processing to further modify the rheological properties of the dough pieces.
Conventional breadmaking technology involves sponge dough. This dough comprises about two-thirds of the total flour mixed with water, salt, and yeast, and is left for a fermentation period of 4–5 h. The sponge is then added to the balance of flour, water, and all remaining ingredients and thoroughly mixed mechanically until it is transformed into a smooth dough. The characteristic rheological properties of the dough are due to the structure of gluten, a cross-linked network formed from wheat proteins and lipids. This allows the elasticity of dough to retain gas evolved by yeast and thus to leaven.
Expansion of the dough pieces and fixation of the final bread structure during baking.
Continued “development” of the gluten structure initially created in order to modify the rheological properties of the dough and improve its ability to expand when gas pressures increase during fermentation.
Cooling and storage of the final product before consumption.
Table 2 . Schematic comparison of breadmaking processes
The Extensograph, another type of dough-testing equipment, shows the results of stretching dough, in terms of the resistance to this stretching and the extensibility of the dough . In this case, the dough is mixed in a Farinograph , which provides a different mixing action from the pin-mixing mechanism of the Mixograph.
The vitamin content is also affected during the breadmaking process. The yeasted breadmaking process leads to a 48% loss of thiamine and a 47% loss of pyridoxine in white bread, although higher levels of those vitamins could be obtained with longer fermentations . Native or endogenous folates show good stability in the baking process, and an increase in endogenous folate content in dough and bread compared with the bread flour was even observed by Osseyi et al. . Nevertheless, in the breadmaking process with wholemeal wheat flour, yeast fermentation is beneficial for reducing the phytate content, which subsequently results in increases in magnesium and phosphorus bioavailability . The extent of phytase activity during breadmaking depends on the wheat flour extraction rate, the proofing temperature and time, dough pH, and the amount of yeast . Even the type of breadmaking process affects the phytate content . Therefore it would be possible to control phytase activity, and thus the resulting phytate content by modifying the process conditions . Lately, specific strains of bifidobacterial species with phytate degrading activity have been proposed as starters for the fermentation of wholemeal wheat bread to reduce the phytate content . During fermentation in the presence of different bifidobacterial strains, the concentration of phytic acid showed a progressive decrease, leading to the release of hydrolysis products, bread making article within a short fermentation time. The species B. breve and B. longum induced greater hydrolysis of phytic acid, producing inositol phosphates.
Fermentation and expansion of the shaped dough pieces during proof.
Table 21.2 . Effect of different breadmaking conditions on both the phytase activity and phytate content of whole wheat dough.
The conventional sponge dough technology requires about 8 h to finish, and several alternative methods have been developed to shorten this period . In the straight dough method, all the ingredients are mixed at the start, and one bulk fermentation period of 2–4 h is allowed for leavening. In the short-time dough process, only 15–30 min are allotted for the dough to rest, and intense mechanical working brings about the structure of the dough. Time is also saved by the continuous mix processes, in which a ferment or brew is first prepared from yeast with little or no flour , and after about 2 h of fermentation, the dough is mechanically developed in a continuous mixer. Bulk fermentation of the dough can be replaced by intense mechanical working and/or the addition of chemical improvers in other process variants. Improvements in equipment design have brought about savings in labor, better control and automation, effective sanitation, and greater processing flexibility of breadmaking technology.
The control of the pH and TTA are important in the sponge or brew so that the correct flavour is developed . This is because the optimum conditions for the activity of different microorganisms vary and if left uncontrolled then flavour development will also vary. In this context the effect of water hardness must be considered. As discussed above, the hardness of water varies according to geological and processing conditions and the presence of calcium carbonate in water will act as a buffer and restrict the degree to which pH of the brew or sponge will fall during storage. This buffering effect may be so marked that it becomes necessary to use softened water or add a suitable acid to lower the pH.
S.P. Cauvain, L.S. Young, in Breadmaking , 2012
Most breadmaking processes require a strong extensible dough to provide best bread quality. In contrast, a weaker but extensible dough is required for most types of biscuits . Provision of grain that will yield the most suitable dough properties is critical to the efficiency of the milling and baking process. Attention to the many aspects of quality that have been described above should ensure that this aim is achieved.
Incorporation of air bubbles within the dough during mixing.
Some breadmaking processes include a pre-fermentation stage in which some of the recipe ingredients other than flour are mixed together and allowed to stand. If water-based they are known as ‘brews’. Other processes have been evolved in which part of the flour and water used in dough making are mixed together as a preliminary fermentation stage, commonly referred to as a ‘sponge’. In these two-stage processes there is commonly a fermentation period before blending with the remaining dough ingredients at a second mixing stage . The initial consistency of the sponge may be made somewhat softer by adding water at levels above the determined flour water absorption level. The lower dough viscosity facilitates a more rapid expansion of the dough during fermentation and increases the water activity of the sponge.
Breadmaking is a centuries-old traditional craft, practised in any country capable of growing or importing wheat. This has meant the evolution of a diverse range of breadmaking processes designed to achieve a wide range of bread products. There are a number of central themes that are common to all bread products and breadmaking processes. They are: the mixing of wheat flour, water, yeast and other functional ingredients and the expansion of the dough mass through the generation of carbon dioxide gas.
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The breadmaking process is a dynamic process in which flour constituents are subjected to numerous physicochemical changes. Physical changes have been considered in a previous article; thus, only chemical variations in flour until bread will be considered in this article. Breadmaking is a dynamic process with continuous physicochemical, microbiological, and biochemical changes induced by the mechanical–thermal action and the activity of the yeast and lactic acid bacteria together with the activity of the endogenous enzymes. Mixing involves mechanically and hydration-induced alterations, whereas during proofing, enzymes are mainly implicated and changes related to temperature increase occur during baking. The two main flour biopolymers, starch and proteins, undergo the most dramatic changes during the breadmaking process. The gluten proteins are largely responsible for the rheology of wheat flour dough, structural formation during mixing, and gas holding, whereas the role of starch is mainly implicated in final textural properties and product stability after baking.
Nevertheless, it must be also taken into account that breadmaking has experienced numerous changes in the way of processing and raw materials used. Commercial bakeries have understood very soon the changes in consumer lifestyles and shift their production processes, products, and even distribution channels to meet the new society requirements. Different alternatives have been developed for adapting breadmaking to the consumer demands and for facilitating the baker’s work. Breadmaking stages have been extended including mixing the ingredients, dough resting, dividing and shaping, proofing, and baking, with great variation in the intermediate stages depending on the type of product. Low-temperature technology has been initially applied to bakery products to solve the economic losses associated with the bread staling problem that produces a decrease of consumer acceptance. Nowadays, the technology of frozen dough, par-baked bread, and frozen bread is being incorporated as routine processes. The partial baking consists in baking the bread dough until the structure is fixed, giving a product with structured crumb and without a crunchy crust that only requires a very short baking time in the retail bakery. Therefore, these alternative breadmaking processes promote additional chemical changes that were not considered in conventional breadmaking.
The use of different yeast strains has also been suggested for the production of enriched baked goods. A selenium-enriched yeast has been used to increase the selenium content of bread . The wheat roll obtained with this yeast can provide 25% of the recommended daily allowance in the form of selenomethionine, which is the best form of selenium for humans. Although consumers favor selenium enrichment of foods, particularly by biofortification , there is little knowledge on the role of selenium in the diet. In the same direction, Hjortmo et al. demonstrated that it is possible to increase the amount of folate in white wheat bread by using Saccharomyces cerevisiae CBS7764 cultured in a defined medium and harvested at a specific phase of growth. With this high folate-producing strain it was possible to increase three-to five-fold the level of folate in white flour breads.
There was a time when many bakers considered water to be a ‘free’ ingredient or at least a cheap one. Those days have gone and the only truly cheap ingredient left for the baker is air. It is ironic that a plentiful, cheap ingredient plays such a key role in the breadmaking processes. The role of air assumes equal importance with that of wheat flour, water and yeast. It has been said that gases are the neglected ingredients in breadmaking but after reading Chapter 12 you would be forgiven for thinking that this is far from true. The study of the contribution of gases goes back over 70 years and the latest research is providing a fascinating insight into the role of gas bubbles in bread doughs and how they change during breadmaking. Gases may well have been taken for granted and overlooked by the baker but that is certainly not the case for the cereal scientist.
Since breadmaking can be viewed as a set of process operations where bubble numbers and sizes in dough are controlled, it is highly desirable to have tools that can non-invasively monitor the presence of bubbles in dough, their subsequent growth and effect on dough’s mechanical properties, and the cellular structure that they create in the resulting bread. Low-intensity ultrasound is a powerful tool for meeting these objectives. To demonstrate the sensitivity of ultrasound to bubbles in dough, we use low frequency ultrasound to study lean-formula mechanically-developed bread doughs, which were mixed under different headspace pressures to entrain different concentrations of bubbles. At this frequency, the ultrasonic attenuation increases as headspace pressure is increased, while the ultrasonic velocity decreases dramatically. Large changes in the complex longitudinal modulus are associated with changes in bubble volume fraction. Examination of the frequency dependence of ultrasonic velocity and attenuation in the dough showed that at higher frequencies, velocity differences between vacuum-mixed dough and dough mixed at atmospheric pressure were small, reflecting sensitivity to dough matrix properties. A broad peak in attenuation at approximately 1.5 MHz, along with the associated changes in the phase velocity, has the potential to provide information on bubble sizes in dough, an important outcome in probing the properties of this opaque material. Changes in ultrasonic velocity and attenuation at 50 kHz were also measured as the dough fermented, using a set-up in which the dough expanded freely in a plane perpendicular to the ultrasonic propagation direction. Velocity decreased rapidly in the early stages of fermentation, although changes in attenuation were constant over most of the fermentation period of interest to bakery technologists. Ultrasonic techniques were also used to study how the size, concentration and anisotropy of gas cells created in the bread from bubbles in the dough affected the properties of freeze-dried bread crumb. Gas cell size and concentration were controlled by varying the proving time, while the anisotropy was altered by uniaxially compressing the bread. The longitudinal modulus determined from the ultrasonic velocity was found to scale with relative density of the crumb in good agreement with Gibson and Ashby’s model for open-cell cellular solids. We conclude that ultrasonic techniques provide a useful tool for studying the effects of bubbles in opaque food systems such as dough and bread, and can provide unique insights into events taking place in food processing operations.
There are several types of equipment for analysing dough properties in the laboratory. One of these is the Mixograph, the mixing curves from which are shown in Fig. 4.4 . These show the progressive rise in resistance to mixing as the dough structure forms, reaching a peak, after which there may be a slow or faster decline in resistance to mixing, depending on whether the dough is stronger or weaker, respectively.
Breadmaking is a dynamic process during which continuous physicochemical, microbiological, and biochemical changes take place, motivated by the mechanical and thermal inputs and the activity of the yeast and lactic acid bacteria together with the endogenous enzymes in wheat . Yeasts and lactic acid bacteria contain different enzymes responsible for the metabolism of microorganisms that modify dough characteristics and the technological and nutritional quality of bread . Amino acids are absorbed by yeast and lactic acid bacteria and metabolized as a nitrogen source for growth, and proteins can be hydrolyzed by the action of proteolytic enzymes from both flour and microorganisms as well as by yeast autolysis. The amino acid profile during breadmaking reveals that the total amino acid content increases by 64% during mixing and undergoes a decrease of 55% during baking, the most reactive amino acids being glutamine leucine, ornithine, arginine, lysine, and histidine . In general, wheat doughs started with lactic acid bacteria show a gradual increase in valine, leucine, and lysine during the fermentation. Proline also increases, but only during the initial hours of proofing . Additionally, the action of proteinases and peptidases from lactic acid bacteria on soluble polypeptides and proteins results in an increase in short-chain peptides that contribute to the plasticization of the dough, and make the gluten more elastic. Jiang et al. fairy bread article