RESUMO
Bánkúti 1201, an old Hungarian wheat variety with special quality traits, was analysed to determine the relationships between its storage protein composition and superior quality-attributes for breadmaking. Based on the storage protein composition, the variety appears to have the nature of a population, containing several genotypes with different gluten protein alleles. Using molecular markers, a new mutant x-type HMW glutenin allele was identified, containing an extra cysteine residue and showing a moderate, positive-effect on gluten properties. In lines possessing subunits Bx7+By8 the overexpression of the Bx-type subunit could be detected, resulting in a higher unextractable polymeric protein (UPP) content and increased dough strength. It was found that the presence or absence of subunit Bx7 has an equilibrating effect on the dough extensibility, which is generally characteristic of the Bánkúti 1201 population. The complex good bread-making quality of the variety, which has strong but highly extensible dough, is probably due to the balance between lines which express subunit Bx7 and those which do not.
Assuntos
Glutens/análogos & derivados , Proteínas de Plantas/análise , Triticum/química , Alelos , Sequência de Bases , Pão , Cruzamento , DNA de Plantas/genética , Tecnologia de Alimentos , Genes de Plantas , Variação Genética , Gliadina/análise , Gliadina/química , Gliadina/genética , Glutens/análise , Glutens/química , Glutens/genética , Hungria , Peso Molecular , Mutação , Proteínas de Plantas/química , Proteínas de Plantas/genética , Subunidades Proteicas , Triticum/genéticaRESUMO
The electrophoretic analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE; reduced and unreduced) of fractions, collected from a size exclusion-high performance liquid chromatography (SE-HPLC) separation of gluten proteins using a column with pore size of around 400A, showed clear resolution for the seven elution ranges studied in two Australian bread wheat lines. Polymeric proteins - high molecular weight (HMW) glutenin subunits, low molecular weight (LMW) glutenin subunits, HMW albumins and some modified omega-gliadins - appeared exclusively in the region within the first peak of the chromatogram (fractions 1 to 5), the limit being a region that resolved as a small peak before the large peak of gliadins and where some omega-gliadins eluted. A larger proportion of HMW glutenin subunits and B subunits contributed to polymer formation of higher molecular weight. The polymer size decreased as the proportion of the other protein components increased.
