title: Impact of redox agents on the extractability of gluten proteins during bread making.
abstract: The gluten proteins gliadin and glutenin are important for dough and bread characteristics. In the present work, redox agents were used to impact gluten properties and to study gliadin-glutenin interactions in bread making. In control bread making, mixing increased the extractability of glutenin. The level of SDS-extractable glutenin decreased during fermentation and then further in the oven. The levels of extractable alpha- and gamma-gliadin also decreased during bread baking due to gliadin-glutenin polymerization. Neither oxidizing nor reducing agents had an impact on glutenin extractabilities after mixing. The redox additives did not affect omega-gliadin extractabilities during bread making due to their lack of cysteine residues. Potassium iodate (0.82-2.47 micromol/g of protein) and potassium bromate (1.07-3.17 micromol/g of protein) increased both alpha- and gamma-gliadin extractabilities during baking. Increasing concentrations of glutathione (1.15-3.45 micromol/g of protein) decreased levels of extractable alpha- and gamma-gliadins during baking. The work not only demonstrated that, during baking, glutenin and gliadin polymerize through heat-induced sulfhydryl-disulfide exchange reactions, but also demonstrated for the first time that oxidizing agents, besides their effect on dough rheology and hence bread volume, hinder gliadin-glutenin linking during baking, while glutathione increases the degree of covalent gliadin to glutenin linking.
authors.affiliation: Laboratory of Food Chemistry and Biochemistry, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Leuven, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Lagrain
authors.forename: Bert G
authors.initials: BG
authors.lastname: Thewissen
authors.forename: Kristof
authors.initials: K
authors.lastname: Brijs
authors.forename: Jan A
authors.initials: JA
authors.lastname: Delcour
mesh_terms: D001939:Bread / Q000032:analysis*; D005285:Fermentation; D005903:Gliadin / Q000737:chemistry / Q000302:isolation & purification; D005978:Glutathione / Q000494:pharmacology; D005983:Glutens / Q000737:chemistry / Q000302:isolation & purification*; D010084:Oxidation-Reduction
chemical_list: D005983:Glutens; D005903:Gliadin; C037302:glutenin; D005978:Glutathione