Dough Making

5 Events Involved in Dough Making and Dough Strengthening 

Bread dough is prepared by mixing water and flour (70 30 w/w). Water upttike, which depends on flour type, predetermines most of the subsequent reactions. A high water upttike favors the mobility of all the constituents involved in reactions, e. g., enzymatic degradation of starch into reducing sugars (Fig. 15.43). 

Observation of wheat dough development by light or scanning electron microscopy reveals that a sequence of forceful changes occurs in the arrangement of the water-insoluble flour proteins. 

When a light microscope is used to look at a wheat flour particle under water, practically no protein structure is discernible (Fig. 15.44, la). If the particle is stretched in one direction by moving the slide cover glass against the microscope slide, numerous protein strands with inserted starch granules become visible. These strands are 

The connected gluten framework formed in this way is responsible for the gas retention capacity of wheat dough. In fact, stands which are as thick as possible but easily extensible under the pressure of the fermentation gases are of advantage for the stability of the dough. 

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Details for a manufacture of 10 ton/week are given. It was pointed out that the reaction is reversible and that an enzymatic synthesis of fat from glycerol and fatty acid was described by Welter in 1911 (Ullmann, 1914). For the chill-proofing of beer proteolytic enzymes have been used successfully since 1911 in the USA (Tauber, 1949). Lintner, as early as 1890, observed that wheat diastase interacts in dough making. This effect was extensively studied, the addition of malt extract came into practice, and American bakers in 1922 used 30 million pounds of malt extract valued 2.5 million dollars (Tauber, 1949). The production of pectinases began around 1930 for use in the fruit industiy (Schweizerische Ferment, now part of Novo Nordisk). 

Most of the data on hpid-starch interactions was derived during studies on dough making and extrusion, wherein the material studied contained, in addition to starch, proteins, also easily interacting with lipids. 

Industrial applications represent more than 80% of the global market of enzymes. A distinction should be made between those cases in which the enzymatic conversion of the raw material into the product is the key operation and those in which the enzyme is used as an additive to modify certain functional property of the product. In the first case the enzymatic reaction is carried out in a controlled environment at optimized conditions with respect to the catalytic potential of the enzyme, while in the second case conditions for enzyme action are not specified to optimize its activity and sometimes not even controlled. Examples of the first case are the production of high-fructose syrups with immobilized glucose isomerase and the production of 6-aminopenicillanic acid from penicillin G with immobilized penicillin acylase examples of the second case are the use of fungal proteases in dough making and the use of pancreatin in leather bating. Most conventional uses of enzymes refer to... 

The balance between viscosity and elasticity is close to optimum for wheat gluten protein at the water content used in dough-making. We have seen that the first requirement for a protein in dough to have viscoelastic properties is that its Tg be below the processing (usually ambient) temperature for the water content used. A second requirement for dough in an aerated product is that the molecular weight distribution (MWD) of the protein be optimal. 

The acid (pKi =4.19 pK2 = 5.63) is appfied as a plasticizer in dough making. Succinic acid monoesters with glycerol are used as emulsifiers in the baking industry. The acid is synthesized by catalytic hydrogenation of fumaric or maleic acids. 

Cereals contain about 1% of phytate [myoinositol (1,2,3,4,5,6) hexakisphosphate], which binds about 70% of the phosphorus in the grain. Since it occurs mainly in the aleurone layer, the content of phytate in flour depends on the extent of grinding (Table 15.20). A part of it is hydrolyzed in stages to myo-inositol during dough making. 

During dough making, GSH reacts very quickly undergoing disulfide interchange with the flour proteins PSSP ... 

In dough making, the Asc added to the flour oxidizes very rapidly to DHAsc (Fig. 15.32). Dia-stereomers of Asc are converted at the same rate. In contrast, the four diastereomers of Asc (stereochemistry in Fig. 15.33) as well as the corresponding DHAsc differ in their effect as flour improvers. As shown in Table 15.42,. -threo-Asc (vitamin C) has the highest dough strengthening effect. The two erythro-Asc have a wetiker effect and D-threo-Asc is almost ineffective. Since these... 

Fig. 15.32. Oxidation of ascorbic acid in dough making from wheat flour (according to Nicolas et al., 1980) o—o ascorbic acid, — dehydroascorbic acid,...

In sour dough making (lowering the pH to 4.0-4.3) rye flour acquires the aroma and taste properties so typical of rye bread (cf. 15.1.5). 

Table 15.49. Examples for kneading conditions in white bread dough making...

Table 15.61. Odorants of white bread crumb - comparison of two kinds of bread subjected to different dough making ...

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