RELATIONSHIP BETWEEN FLOUR PROTEIN-COMPOSITION DETERMINED BY SIZE-EXCLUSION HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY AND DOUGH RHEOLOGICAL PARAMETERS

The relationship between protein composition, measured by size-exclusi on high-performance liquid chromatography (SE-HPLC), and rheological d ough properties, evaluated by alveographic test, were investigated in bread wheat cultivars grown at two locations in North and Central Ital y. Total polymeric proteins were separated into two size groups on the basis of their solubility in 2% sodium dodecyl sulfate-phosphate buff er with and without reducing agents. Relative and absolute amounts of total polymeric proteins, determined by SE-HPLC after sonication, show ed variable (nonsignificant to significant) relationships with rheolog ical properties, particularly dough tenacity (alveographic index P) an d strength (alveographic index W). On the other hand, absolute or rela tive amounts of insoluble polymeric proteins correlated positively wit h dough strength and tenacity and accounted for up to 30-40% more vari ation in these parameters than did total polymeric proteins. Correlati ons of both absolute and relative amounts of soluble polymeric protein s with dough strength and tenacity were not significant and significan tly negative, respectively, whereas the correlation with dough extensi bility (alveographic index L) was significantly positive.