139 Changes in SDS solubility of glutenin polymers during dough mixing and resting.

T. AUSSENAC and J.-L. CARCELLER. Dept. of Plant Physiology, E.S.A.P., 75 voie du TOEC, 31076 Toulouse cedex 03, France.

Differences in breadmaking quality among flours are to a large extent determined by differences in the polymeric protein fractions. Moreover, it has been confirmed in a number of studies that the SDS insolubility of glutenin polymers is directly related to dough strengh. To improve the insight in this structure-function relationships, we studied the changes in SDS solubility of the glutenin polymers during dough mixing and resting in relation with the changes in glutenin subunit composition and size distribution of these polymeric proteins. Glutenin polymers were extracted and purified by differential solubility in aqueous 50 and 70% 1-propanol and solubilized with aqueous 2% SDS in combination with sonication. A on-line coupling of HPSEC-MALLS (Multiangle Laser Light Scattering) was used for the size characterization of the glutenin polymers. Even if changes in SDS solubility of the glutenin polymers have been related in a number of studies to a depolymerisation phenomenon, our results reveal no changes in size distribution suggesting rather changes in molecular conformation of these polymers.