Impact of Redox Agents on the Extractability of Gluten Proteins during Bread Making

• Published in: Journal of agricultural and food chemistry 2007-06, Vol.55 (13), p.5320-5325
• Main Authors: Lagrain, Bert, Thewissen, Bert G, Brijs, Kristof, Delcour, Jan A
• Format: Article
• Language: English
• Subjects: Animal, plant, fungal and microbial proteins, edible seaweeds and food yeasts; baking; Biological and medical sciences; Bread - analysis; breadmaking; Cereal and baking product industries; crosslinking; extractability; extraction; Fermentation; food additives; Food industries; Fundamental and applied biological sciences. Psychology; gliadin; Gliadin - chemistry; Gliadin - isolation & purification; glutathione; Glutathione - pharmacology; glutenins; Glutens - chemistry; Glutens - isolation & purification; oxidants; Oxidation-Reduction; polymerization; potassium bromate; potassium iodate; reducing agents; wheat flour
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf070639n

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 α- and γ-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 ω-gliadin extractabilities during bread making due to their lack of cysteine residues. Potassium iodate (0.82−2.47 μmol/g of protein) and potassium bromate (1.07−3.17 μmol/g of protein) increased both α- and γ-gliadin extractabilities during baking. Increasing concentrations of glutathione (1.15−3.45 μmol/g of protein) decreased levels of extractable α- and γ-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. Keywords: Bread making; wheat gluten; gliadin−glutenin interaction; protein extractability