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

The structure of wheat polymeric proteins has been difficult to elucidate due to the large molecular size and the low charge to size ratio making it difficult to solubilize these proteins completely. Sonication is a non-chemical method of dissolving large proteins in aqueous solution by controlled breakdown of the largest molecules. This method has been used extensively in last decade to quantitate protein composition of total extracts from flour or gluten. However details of the mechanism and structural changes occurring during sonication have not been investigated. In this work sonication has been used to solubilize a purified glutenin fraction and changes during sonication have been studied. SE-HPLC has been used to check changes in molecular weight. It has been assumed that weaker intermolecular disulfide bonds break preferentially. Changes in sulfhydryl content as a function of time and power of sonication have been followed using Ellman's reagent. The decrease in SH content suggests that there may be refolding of protein with formation of new intramolecular disulfide bonds during sonication. To further clarify the question, circular dichroism and SDS-PAGE have been carried out to compare the components and subunits released during sonication and during reduction of glutenin.