What is dough method?

Breadmaking

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 45h. 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. (See WHEAT.)

The dough undergoes a series of mechanical operations (divided into pieces, rounded, and moulded) 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 (slicing, wrapping) and distribution. (See BREAD | Breadmaking Processes.)

CRACKERS

Saltine crackers are made from a sponge-dough mixing operation (Fig.8.8). The fermentation of the stiff, low-moisture sponge is unique in that it is generally very long (i.e., about 16h). Both yeast and bacterial fermentations are important to the success of the product. The final dough is further fermented for about 6h and then allowed to relax. To achieve the desired flakiness, the dough is sheeted, folded, and turned 90° to achieve a final dough sheet that has about eight very thin layers and has been sheeted in both directions. The dough sheet is then cut, docked, and transported through a high-temperature (250°C, ~450°F), direct-fired oven on a mesh band for a short time (about 23min). The crackers are then cooled slowly to avoid cracking.

Fig.8.8. Steps in the processing of a saltine cracker dough. A=dough hopper, B=forming roll, C=dough web, D=reduction rolls, E=lapper, F=final reduction rolls, G=relaxing curl, H=cutting and docking.

(Courtesy Werner and Pfleiderer, Stuttgart, Germany)

Snack cracker processing is less complicated. A straight-dough mixing process is employed. The mixed dough is then sheeted with little or no fermentation, laminated (if flakiness is desired), cut, docked, and baked. Often, these crackers are cut into circles or other shapes that create a large amount of scrap dough that must be recycled to the mixer.

Fortified bread production and evaluation

Breads were produced following the straight or sponge dough procedures. The first procedure (method 10-10B; American Association of Cereal Chemists (AACC), 2000) was used in order to detect possible deleterious effects of the ω-3 oil sources and estimate optimum water absorption and mix times. The formulation included 100 g commercial bread flour, 5.5 g sugar, 3 g vegetable shortening, 1.5 g salt, and 2 g dry yeast (Saccharomyces cerevisiae). Bake absorption, mixing time, proof height, loaf height, oven spring, loaf weight, loaf volume, loaf apparent density, and crumb grain texture were determined (Serna Saldivar et al., 2006).

Sponge dough breads were manufactured to obtain commercial loaves for sensory and texture analyses throughout 14 days of storage at room temperature. Sponges were produced from 604 g flour (14% mb), 356 ml water, and 14 g dry yeast. Sponges were fermented for 4.5 h in a proof cabinet set at 29oC and 85% relative humidity. Resulting sponges were mixed with the dough-stage ingredients (326 g flour, 56 g sugar, 28 g shortening, 28 g nonfat dry milk, 18.6 g salt, 9.3 g vital gluten, 1.86 g diastatic malt, 1.86 g lecithin, 0.94 g sodium stearoyl-2-lactylate (SSL), 55.8 mg sodium ascorbate, and 18.6 mg potassium bromate) and 258 ml of water until optimum dough development was obtained. Resulting doughs were weighed and cut into two identical parts before punching, final proofing, baking (28 min at 225oC), cooling, and slicing. One slice per loaf from 16 different loaves was submitted for determination of its full FA profile using a gas chromatograph flame ionization detector.

Bread was cut into 1-inch-thick slices for determination of texture, color, and sensory properties. Bread firmness throughout 14 days of storage at room temperature was objectively evaluated according to AACC (2000) method 74-09 with a texture analyzer equipped with a cylindrical probe. Crumb color was determined with a Minolta color meter. L, a, and b were obtained and color index E was determined by the following equation: E = (L2 + a2 + b2)1/2. Between 25 and 30 untrained panelists evaluated the color, flavor, texture, and overall acceptability of the control bread and breads enriched with 25 or 50 mg DHA/slice throughout 14 days of storage. Breads were evaluated using a 9-point hedonic scale (Serna-Saldivar et al., 2006).

18.3.3 Fermentation

Independent of the kind of fermentation (e.g. straight dough, sponge and dough or liquid ferment process), the objectives of fermentation are to bring the dough to an optimum condition for baking. As with most of the processing steps an optimum level of fermentation depends on many factors, which include flour strength, enzymatic activity of the flour, formulation, yeast activity and the type of product desired. Regular bread doughs contain 1.52.0% of compressed yeast on flour basis. Too little yeast results in slow fermentation, sticky dough, and poor crumb grain and texture; too much yeast results in an overly porous dough and a bread that stales rapidly (Pomeranz, 1987a). During fermentation the yeast converts fermentable sugar into CO2 and ethanol. Both dissolve in the aqueous phase of the dough. When the aqueous phase is saturated with CO2, the gas evaporates from there to the gas cells. Ethanol, which is more soluble in water than is CO2, hardly evaporates during fermentation. Yeast does not create new bubbles in a dough system, and therefore air must be incorporated during mixing to provide preexisting bubbles. The gas cells in the dough become larger, as more gas is produced and growth of gas cells changes from slow to rapid after ca. 25min of fermentation. The viscoelastic dough will flow to equalise the pressure created by the additional gas and as a result the dough will expand. The oxygen in dough is rapidly consumed by the yeast as fermentation starts. Thereafter, the fermentation is anaerobic unless oxygen is added to the system (i.e. by remixing). As CO2 is dissolved in the aqueous phase, the pH decreases from about 6.0 to 5.0.

During fermentation dough development is continued, that is the dough becomes drier, less sticky and much more elastic, and gas retention is improved (Hoseney and Rogers, 1990). Fermentation with yeast causes the dough to go from having a large viscous-flow component to one that is elastic. This trend is the same that can be found when oxidants are added to dough; thus, yeast has clearly an oxidising effect. Yeast contains considerable amounts of GSH. In freshly compressed yeast, GSH is retained in the intact cells and only such minute amounts are liberated into the dough that do not influence dough rheology. Water extracts from dried yeast, however, have been shown to contain relatively high amounts of GSH (1124μmol per g dry mass) (Hahn et al., 2000). Studies on dough rheology have demonstrated that the maximum resistance is strongly lowered by the addition of water extracts from dried yeast.

5.2.2 Pretzel knots, by sheeting and cutting

The enrichment of pretzel recipes in given in Fig.5.3.

5.3. Enrichment of pretzel recipes shown.

22.2 Mixing and fermentation of cream cracker doughs

A successful cream cracker structure depends ultimately on the ability to form a pile of thin layers of dough in each dough piece which separate in the oven. The dough must be soft and extensible enough to form a good sheet which can be reduced in thickness to the laminating stage. Between the layers a fat flour mixture known as cracker dust is distributed and this dust must be soft, plastic and of more or less uniform particle size. After laminating, the extensibility of the dough must be such that further gauging prior to cutting does not rupture the gluten strands causing the laminar structure to be lost. In fact this is a very tall order and some loss of the laminar structure is probably inevitable.

Cracker dust may be used at the rate of up to 1 part of filling dust to 5.6 of dough = 17.8%. However, 9% has been shown to be adequate to produce a good structure.

The total fat content of the baked cracker is the principal factor affecting the hardness. It is possible to achieve the typical total fat percentages which lie between 10 and 16% by adjusting the amount of fat in the dough and/or the amount of centre filling used. This technique also allows some adjustment of the effect of fermentation on the gluten modification if there is some doubt about the quality of the flour. A serious problem is that the performance of filling dust applicators at lamination leaves much to be desired in terms of consistency, and it is difficult to monitor exactly how much filling dust is being fed!

The type of flour for the centre fill is not critical but it is important that the fat is in a plastic form. A harder type of fat, with less good shortening properties than dough fat, is to be preferred. The fat is mixed into the flour until a fine uniform powdery mixture is formed. This is then kept in a cool room at about 10°C until it is required. If the temperature is too high, the fat will melt and the whole will tend to become sticky and lumpy. It is wise to sieve the dust prior to use, using a sieve of about 3mm aperture.

Returning to the dough, fermentation times vary greatly. There is, of course, a similarity between cracker and bread dough fermentation but the final requirements are not the same and this should be clearly remembered. During fermentation the gluten is stretched and at the same time it mellows both physically and chemically. Enzymatic action breaks down some of the starch and most of the sugars present. There is some increase in acidity which may have an effect on the baked biscuit flavour. Typical cream cracker doughs are at approximately pH6.0.

Work done at the Flour Milling and Baking Research Association, Chorleywood by Elton and Wade [1] resulted in a process patent which described the significant reduction of the fermentation time to as little as 30 minutes. They claimed that the effect on flavour difference was minimal and the physical size and texture of the crackers was unimpaired. The reduction in time was achieved by replacing the gluten modification during fermentation by a greater amount of work in the mixer.

Fermentation is the result of the growth of microorganisms in the dough. The added yeast dominates but research by Sieler [2] at Chorleywood has shown how rich the flour microflora is normally and how this varies depending upon the source of the wheat and the length of time it has been in store. The effect of this microflora during fermentation has been very imperfectly studied but it would seem obvious that it is important to the dough quality particularly during long fermentations. It may be a source of cracker flavour but it will be very important in its action on the gluten. It is suggested that this action, combined with the differences in gluten quality and quantity in different flours, is of fundamental importance in cream cracker fermentation. To eliminate the unpredictable effects of the flour microflora, the fermentation time should be short or the microflora should be dominated by bacteria which are added to the dough. Such is the case in a continuous liquid fermentation method now available, which is described in Section22.2.4.

Excessive fermentation or excessive reaction with enzymes will give an unmanageable and short dough. It is necessary to engineer the dough modification system so that having achieved the desired level of change in a batch of dough, only a minimal further effect takes place from the commencement of using that batch until the end. Developments of continuous dough mixing can solve the problems associated with variable dough age. In fact the fermentation time is such, even under a short fermentation system, that there is a large mass of dough to handle in any continuous system and this complicates processing arrangements.

Having outlined the mechanisms of cracker dough fermentation and ways in which it may be controlled, it is perhaps important to outline the principal procedures utilised.

Processes to Combine Sourdough Fermentation with Baker's Yeast

Fermentation combining sourdough fermentation with leavening by baker's yeast eliminates the need to maintain metabolic activity of sourdough microbiota at a level that generates sufficient CO2 to leaven the dough. Metabolism of sourdough lactic acid bacteria and yeasts, however, remains sufficient to produce dough acidification and to attain other beneficial effects of sourdough on bread quality. Sourdough propagation is derived from traditional procedures but with a reduced number of refreshments one or two refreshments per day is commonly used in combination with baker's yeast. Sponge dough or poolish are a second example. In sponge dough fermentations, 1020% of the flour used in the bread dough is fermented with addition of baker's yeast for several hours or overnight. If fermentation times exceed 812h, lactic acid bacteria grow to high cell counts and the pH drops to values of less than 4.5 while the leavening activity is entirely attributable to baker's yeast. Large-scale and in some cases continuous fermentation systems rely on long fermentation times 12h to several days to achieve high levels of acidity and to obtain sourdough that remains stable for several hours or days of refrigerated storage. Dried or pasteurized sourdoughs are produced on the basis of the same principle; the defining difference is the stabilization step to allow shipment from the sourdough producer to the bakery.

Bread Making Process

The process of bread preparation can be divided into three main steps that are mixing, fermentation, and baking (Fig.1). Baking process modifies the taste, aroma, texture, and sensory properties of goods made of raw materials (Abdullah, 2008). Therefore, baking process started a chain of biochemical, chemical, and physical reactions in the product, which includes water evaporation, expansion of volume, denaturation of protein, gelatinization of starch, crust and porous structure formation, and browning reaction (Sablani etal., 2002). Bread is made of elastic, unstable, solid structure made of continuous elastic network of crossly linked molecules of gluten protein and of leached molecules of starch polymer, mainly amylose (Gray and Bemiller, 2003). The properties of final product are affected by mechanical and physical mixing, enzyme catalyzed chemical reactions, and by thermal effects, including baking time and temperature.

Figure1. Whole process of bread making.

DOUGH PROCESSING

Straight Dough Process. The straight-dough process (Fig.7.4) is the simplest breadmaking procedure. It is used for hearth breads such as baguettes as well as for common pan breads. All ingredients are scaled and added to the mixer. The dough is mixed to optimum, which can be determined by interpreting a wattmeter curve if the mixer is so equipped. This is a curve of power versus time that resembles the curve of a recording dough mixer. The peak of the curve is the point of optimum development and the point at which the dough is best able to retain gas. After mixing, the dough is loaded into a trough and allowed to ferment in bulk for about 2h, during which the dough expands dramatically and the gas cells in it become larger. Large cells in the dough yield large cells and a very coarse texture in the final bread crumb. Therefore, to decrease the size and increase the number of these cells, the dough is punched or deflated one or more times during the bulk fermentation. Then the dough is divided into pieces of the appropriate size and weight, rounded into a spherical shape, sheeted, molded (i.e., rolled into a cylinder), and deposited into baking pans. It is then allowed to proof again in the pan, and when it reaches the desired height in the pan, it is baked.

Fig.7.4. Outline of a straight-dough process.

The straight-dough process yields bread that is usually less flavorful than bread made from other processes because the fermentation times are shorter and flavor compounds are not produced in high quantities. Often, the bread can also be elastic and chewy. Yeast liberates reducing compounds and proteases in doughs during long fermentations, and both of these reduce the size of the gluten polymers. In the straight-dough process, there is not sufficient time for this to occur, so the gluten polymers are larger, and the resultant crumb is more elastic. The short fermentation times used in straight-dough processing create some time inflexibility. Unlike sponge-dough processing, which allows some variation in fermentation time, straight-dough processes require carefully maintained production schedules, or viscoelastic properties will be significantly affected.

Sponge-Dough Process. A more popular process for breadmaking is the sponge-dough process (Fig.7.5). About two-thirds of the flour and water and all of the yeast are mixed, loaded into a trough, and allowed to ferment in bulk. This is the sponge stage. Fermentation times for a sponge vary considerably throughout the industry but are usually 34.5h. The sponge and the rest of the ingredients are then added to the mixer, and the dough is mixed to its optimum point. This is the dough stage. The dough is allowed to relax for about 45min and is then divided, rounded, sheeted, molded, and baked as in the straight-dough process. A commonly employed variation of the sponge-dough process involves a liquid preferment, in which all of the water and yeast and part of the flour are fermented in a tank before the dough is mixed.

Fig.7.5. Outline of a sponge and dough process.

Additional Dough Processing. The breadmaking processes described above are used for the pan and hearth breads commonly sold in retail outlets of various types (e.g., grocery stores, retail bakeries), and elements of these processes are used in other products as well. Various other products, however, require additional unit operations. Note that work input does not end in the mixer. Additional processing often imparts significant additional work, and dough that was optimally mixed may be overmixed by the time processing is completed. For example, croissants, pastries, and other flaky products require lamination, in which dough layers are alternated with layers of butter or shortening. To laminate dough, it is sheeted through a series of rollers; a layer of butter or shortening (i.e., roll-in fat) is applied; the dough is refolded; and sheeting and folding are repeated until the desired number of layers is obtained. There is a stretching action in any sheeting process, and turbulence is created in the dough as it is forced through the gap in each roller. The work imparted to the dough in this process is significant and may affect gas-holding properties. The turbulence may affect layer integrity. Consequently, rest time is often built into a process to allow some time for the dough to relax. This provides more process tolerance, but it also creates a more time-consuming process.

Many products are filled. In this case, the dough is often sheeted and the filling is deposited on the dough, after which the dough is folded and cut into the appropriate shape. Then the product is baked, frozen, or fried. Other products are filled after being baked by injection of a filling into the core of the product.

Immersion into boiling water is required to produce the chewy crust and smooth appearance characteristic of bagels. The boiling water gelatinizes the surface starch and creates a tough, chewy crust. In pretzel processing, lye or sodium bicarbonate is added to the water that serves as the boiling water bath. The high pH fosters Maillard browning, thus producing the shiny brown surface. Additionally, it produces the unique flavor notes characteristic of pretzels.

Mass-produced pizza crusts are generally sheeted and cut, or they may be pressed. Pizza dough is elastic dough, however, and unless precautions are taken, the final crust will not be round. To avoid this, cross rollers are often installed on the sheeting line to remove some of the directionality in the gluten network. If properly done, the snap back of the dough after cutting is the same in all directions, and the crust is round. Another pizza crust problem encountered in production is excessive blistering. Large blisters are undesirable. They are caused by air pockets that form under the dough surface during sheeting, so the dough is often docked to reduce or eliminate the problem. Docking consists of running the dough under a roller with pins protruding from it. The dough is compressed at the points contacted by the pins, and the blisters that can form are smaller.

Tortillas can be produced by sheeting, dough pressing, or extrusion. The sheeting operation involves rolling rounded, proofed dough pieces, followed by hand stretching to the appropriate size and shape. The pressing operation, a more automated procedure, involves pressing the rounded and proofed dough pieces in a heated, hydraulic stamping device. Finally, tortilla dough can also be extruded in a thin continuous band, followed by sheeting and cross rolling to the correct thickness and cutting with a circular die. Depending on the elasticity of the dough, the cutter may be designed to be slightly oblong to compensate for shrinkage after cutting.

Flat bread production is similar to the sheeting process for tortillas, except that the dough is usually sheeted mechanically and not as thin. The circular dough sheets are then proofed before baking.

ITALIAN BREAD

The most famous Italian durum wheat bread, made in the Apulia region and the only European bread awarded the protected designation of origin (PDO) label (EEC 2003), is the pane di Altamura. This bread is produced with remilled semolina characterized by the above-mentioned rheological parameters (Raffo et al 2003, Pasqualone et al 2004). Furthermore, the protein quantity and quality of the remilled semolina from the durum wheat cvs. Appulo, Arcangelo, and Duilio e Simeto (i.e., the PDO-mandatory cultivars, which must be grown in the area of Altamura and make up at least 80% of the total semolina) were shown to affect the dough properties, hydration level during breadmaking, and water loss rate during bread storage, all phenomena having a strong influence on bread shelf life. The production protocol of pane di Altamura specifies all the breadmaking steps in detail. The official recipe, reported by Pagani et al (2006), is a sponge-dough breadmaking method, with 20 parts of full sourdough, 100 parts of remilled semolina, two parts of salt, and 60 parts of water. The full sourdough is prepared by adding ingredients at least three times (refreshment step). The final kneading takes 20 min, and the mass is then covered with a thick cloth to maintain a constant temperature and rested for 90 min. The final shape is obtained via three distinct molding phases, each coupled with a rest phase (intermediate proof) of established length. The baking operation must be performed under controlled conditions, in ovens heated with oak wood, in order to obtain bread loaves with a characteristic thick crust (at least 3 mm) and an atypical flavor, both due to the presence of remilled semolina and the sourdough process. The traditional shape of pane di Altamura is like a hat with a wide brim; it is also produced in the form of a large loaf, which can weight up to 2 kg (Fig. 10.8).

Fig. 10.8. Altamura bread.

The main characteristic of this specialty bread, in addition to the typical yellow color of the crumb, is its long shelf life, reaching at least one week (Raffo et al 2002, 2003).

Another typical Italian durum wheat bread, named carasau, is the most important bread of the Sardinian tradition (Fig. 10.9). It is also known as carta musica (music paper) because of the particular sound it produces during chewing. Carasau is a round-shaped bread, about 40 cm in diameter and 2 mm thick, with no crumb, made of a blend of semolina and other by-products obtained from durum wheat milling. The very long shelf life of this bread is due to its low moisture content (about 6%), a consequence of the double cooking process. In the past, this long shelf life made carasau the most important food for shepherds, who lived away from the their family for up to five to six months without being able to acquire fresh bread (Bordo and Surrasca 2002).

Fig. 10.9. Carasau bread.

This product is obtained from a straight-dough process in which semolina (100 kg), water (45 L), natural yeast (1 kg), and salt (2 kg) are mixed using a low-speed wishbone mixer; the resulting dough is used directly for breadmaking. Presently, industrial yeast is used for better standardization of the fermentation time. When the dough is ready, usually after a mixing time of a few min, it is divided, rested for about 60 min at 2832°C, and sheeted by being passed through two rolling cylinders to obtain the traditional round shape. The layers of dough are put on cotton or flax sheets, piled up, covered, and rested for about 2 hr. Then they are baked at 560580°C for a few seconds in an electric oven (or in a wood-burning oven, when homemade). The baked sheets, swollen by fermentation and high temperature, are taken out and cut through the middle to obtain two symmetrical sheets that are baked and toasted for 1520 sec at 400410°C. The few existing studies on this breadmaking process emphasize that carasau bread needs semolina with intermediate protein content and a relatively high gluten index (Dettori et al 2002).

Durum wheat is used in Italy to produce many different types of bread, whose characteristics are reported in two books entitled Atlante dei Prodotti Tipici: Il Pane, edited by the Istituto Nazionale di Sociologia Rurale (1995), and Atlante del Pane di Sicilia, edited by the Consorzio Gian Petro Ballatore (2001). Some of these breads, such as pane di matera and pagnotta del dittaino, have protected geographical indication (PGI), which expresses the link between the product and its area of origin. However, this link is not absolute because it is not mandatory that all steps of the transformation process be performed in a particular geographical area. Nevertheless, PGI bread complies with strict regulations established for the production process. An inspection agency ensures compliance with the regulations. The sponge-dough breadmaking method is a common characteristic of all Italian durum breads, as well as those from other countries. This reduces the negative effects on loaf volume of both the extra-strong gluten properties and the low α-amylase activity of the milling products of durum wheat grain.