Glutens from poor breadmaking quality wheat, cv. Riband, had a higher SDS extractability than glutens from good quality cv. Hereward. Heating of gluten, especially above 70 degreesC, caused a reduction in the amount of SDS-extractable gluten proteins. Treatment of gluten with redox additives (ascorbic acid, potassium bromate or glutathione) affected extractability, being highest for bromate treated glutens. The SH content of gluten was lower for poor breadmaking Riband and heating resulted in greater decrease in SH content of gluten from good breadmaking Hereward. Hereward gluten had a higher SS content than Riband. The alteration of SS content on heating was not significant and may indicate the heat-induced involvement of non-covalent interactions. SDS-PAGE revealed that oxidants, especially bromate, affect polypeptide composition leading to a more heat stable/tolerant protein structure. (C) 2004 Published by Elsevier Ltd.