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

The role of glutathione in determing wheat baking quality is of considerable interest. Using HPLC methodology established recently in our laboratory, the amounts of glutathione (gamma-glutamylcysteinylglycine) and related compounds (gamma-glutamyl-cysteine, cysteinyl-glycine and cysteine) in the form of protein mixed disulphides were determined for gliadin and glutenin prepared by Osborne extraction, as well as for subfractions of those preparations isolated by gel filtration. The moderately strong breadmaking cultivar, Hereward, and the weak biscuitmaking cultivar, Riband, were used. Small amounts of the protein bound compounds were present in gel filtration purified monomeric gliadins. Gliadins therefore do contain some protein bound glutathione. Considerably larger amounts were present in glutenin polymers. Higher levels were found in glutenin polymers from cv. Riband than from cv. Hereward. For both cultivars, the level of PSSG appeared to be related inversely to the molecular weight of the glutenin polymers. These results suggest that protein bound glutathione and related compounds may act as chain terminators and, thus, contribute importantly to controlling the polymerisation of glutenin, which may, in turn, be important in relation to flour quality.