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The relationship between gluten proteins and baking quality
117-122Views:268Wheat, one of the most important cereals, is grown on the largest area in Hungary. During hydration of storage proteins of wheat – gliadin and glutenin – the gluten complex is evolved. The gliadin is responsible for the extensibility of gluten complex as well as the glutenin for the strength of gluten. The structure, composition and rheological properties of gluten proteins influence significantly the baking quality. The gliadin/glutenin ratio and the quality and structure of glutenin fraction play the most important role in evolving gluten complex. Changes in the steps of breadmaking technology also have effect on the quality of product. Several tests proved that the higher glutenin content increases the strength of dough while the higher gliadin content increases the extensibility of dough and decreases maximum resistance to extension. The monomer gliadins play a great part in plasticity of glutenin polymer. The quality of glutenin fraction significantly influences the evolving gluten complex, because of the spiral structure of glutenin which deforms under stress conditions, then the β-spiral structure resumes their original conformation by releasing from stress.
The final quality of product evolves as a result of complex characteristics of wheat proteins, so detailed knowledge on the roles of different protein compounds is the base of the quality oriented product development. -
The composition of gluten proteins and their effect on the rheological properties of gluten
124-129Views:201Wheat is the major cereal component of bread in the world and is grown worldwide. Of the cereals only the bread wheats – and less the triticale – includes storage proteins that play an important role in the performance of gluten. Proteins of gluten complex may be present in two classes:
− low molecular weight (gliadin-) components, and
− high molecular weight (glutenin-) components.
Gliadins shown appreciable heterogenity and can be separated into 40-50 components with gel electrophoresis. The composition of gliadins is employable for the identification the wheat varieties and to investigate the varieties. In the decreasing electrophoretic mobility sequence may be distinguish α-, β-, γ- and ω-gliadins. A glutenin subunits may be include in two classes:
− high molecular weight glutenin subunits (HMW-GS),
− low molecular weight glutenin subunits (LMW-GS).
Wheat varieties can be identified by glutenin and their quality selection is also possible. The gliadin’s polypeptides encoding genes are located on the short arm of chromosomes 1A, 1B and 1D, 6A, 6B and 6D. Genetic coding for HMW subunits is located on the long arms of chromosomes 1A, 1B and 1D, the LMW-GS are also located on chromosomes 1A, 1B and 1D (Glu-3 loci) near the gliadin-coding loci.
Storage proteins affect the rheological properties of gluten by two factors:
1. The quality and quantity of the protein components of the gluten complex,
2. The interactions between the protein fractions. -
Effect of agrotechnological treatment on nutritive value of common millet
65-69Views:165The cultivation of common millet shows an increasing tendency due to its adaptability to extreme poor circumstances. In addition, millet do not contain gluten forming proteins such as gliadin and glutenin, therefore people with gluten intolerance could consume it. The vitamin B and mineral content increase the importance of millet. The aim of our experiment was to measure the quality of flour of two millet varieties treated with different nitrogen fertilizer doses.
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Comparison of alveohraph and extensigraph properties of winter wheat samples
27-30Views:154The rheological properties of dough are determined by the amount and proportion of gliadin and glutenin proteins. Extensibility and resistance to the extension of doughs which can be measured using the extensigraph or alveograph allow good assesment of the baking behavior under realistic conditions. In our study, we compared the extensigraph and alveograph parameters of 87 flour samples. The results showed that the alveograph parameters were different from the extensigraph parameters. The classification of wheat varieties was different, and the order of varieties, as well. The alveograph properties were affected by other factors than the extensigraph properties, except the W value. The two rheological tests did not give similar results, therefor neither test are replaceable.