2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

SDS-extraction of flour, combined with ultra-centrifugation yields a gel, the so-called GMP (glutenin macro polymer) fraction. The amount of GMP and its reological properties are strongly related to wheat end-use quality. It is not clear how the quantity and properties of GMP are related to the quantity and relative abundance of the various glutenin protein classes. Flour of cultivars Classic, Soissons, Camprimus and Galahad-7, differing in technological quality, was used to study GMP formation. GMP was redispersed and re-centrifuged at different initial concentrations of protein. With the weaker Camprimus and Galahad-7 a fast decrease of recoverable GMP was observed indicating de-aggregation at lower protein concentrations. This was not observed with Classic and Soissons. This de-aggregation behaviour corresponded with the viscosity vs concentration behaviour of dispersions of GMP. Also, from the intrinsic viscosity, the relative aggregate size was calculated, assuming a spherical shape: Galahad-7 : Camprimus : Soissons : Classic = 1 : 8 : 12 : 15. From the intrinsic viscosity and GMP protein concentration we were able to estimate the G' plateau values of GMP. Thus relevant differences in glutenin aggregates from different varieties were observed, aiding us in our aim to better understand the underlying mechanism of GMP formation.