Dough resistance

Extensiographic measurements demonstrate the rheological changes of bread dough the elasticity increases and the dough resistance falls by addition of increasing amounts of starter doughs. 

Mutation. For industrial appHcations, mutations are induced by x-rays, uv irradiation or chemicals (iiitrosoguanidine, EMS, MMS, etc). Mutant selections based on amino acid or nucleotide base analogue resistance or treatment with Nystatin or 2-deoxyglucose to select auxotrophs or temperature-sensitive mutations are easily carried out. Examples of useful mutants are strains of Candida membranefaciens, which produce L-threonine Hansenu/a anomala, which produces tryptophan or strains of Candida lipolytica that produce citric acid. An auxotrophic mutant of S. cerevisiae that requires leucine for growth has been produced for use in wine fermentations (see also Wine). This yeast produces only minimal quantities of isoamyl alcohol, a fusel oil fraction derived from leucine by the Ehrlich reaction (10,11). A mutant strain of bakers yeast with cold-sensitive metaboHsm shows increased stabiUty and has been marketed in Japan for use in doughs stored in the refrigerator (12). 

Cera.mic, The ceramic substrate is made from a mixture of siUcon dioxide, talc, and kaolin to make the compound cordierite [12182-53-5]. Cordierite possesses a very low coefficient of thermal expansion and is thermal-shock resistant. The manufacturing process involves extmding the starting mixture (which is mixed with water and kneaded into a sort of dough) through a complex die to form the honeycomb stmcture. The extmded piece is dried and fired in a kiln to form the cordierite. The outside or circumferential dimension is formed by the die, and the length is cut later with a ceramic saw. 

Buddie, B.M., Jowett, G., Green, R.S., Dough, P.G.C. and Risdon, P.L. (1992) Association of blood eosinophilia with the expression of resistance in Romney lambs to nematodes. InternationalJournal for Parasitology 22, 955-960. 

Wafer Flour. Wafer flour is a type of biscuit flour with the same basic specification of low protein soft wheat flour with a low starch damage. Once again the required dough property is extensibility. The only differences are that if the protein is too low the wafer will be too soft to handle, and if the protein is too high the wafer will be too hard. The other important property is a resistance to gluten separation. Wafer flours are likely to be brown. 

A complete set of measurements from the extensogram will give the energy, i.e. the area under the curve, the resistance to extension, the extensibility and the maximum, i.e. the deflection when the dough broke. The ratio of the extensibility to resistance and the ratio of extensibility to maximum are calculated. The Extensograph-E is set up to calculate these values directly. 

The most important dough property in biscuit doughs is extensibility. Resistance is undesirable. The only type of flour that can not be used to... 

The area under the curve and the ratio of resistance to extensibility provide useful information as to the elasticity of the dough. 

After the dough has been shaped, it is subjected to predrying which reduces the solvent content to 20-30%. The mass so dried becomes mechanically resistant and may therefore be cut without being deformed. Due to the presence of residual... 

As I bicycle back to my office, I think about the fact that some people eat food known to be a health hazard, because the benefits seem to outweigh the risks. This is certainly true for me. A few days ago, when I was preparing the Christollen egg-bread, I could not resist tasting the rich, buttery dough. Similarly, I cannot resist dough from my favorite cookies (recipe 7.4). 

The surface of a powdered polysaccharide equilibrated in air is hydrophobic and resistant to wetting—a condition that poses difficulty in dispersal when cereal flour, for example, is mixed with water in the preparation of doughs and batters. Dispersion usually requires a large expenditure of mechanical energy. 

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