Influence of Disulfide Bond Formation Via Recombinant PDI‐Ero 1 Processing of Proteins and Baking Quality

Abstract

　Disulfide (SS) bond formation in dough is an important factor in bread making. In this paper, we examine the effects of recombinant protein disulfide isomerase (PDI) and endoplasmic reticulum oxidoreductase 1 (ERO1) on SS bonds in dough. The oxidation regeneration ability of ERO1 for PDI, which results in the formation of SS bonds in proteins, was analyzed. ERO1 obtained from wheat also had oxidation regeneration ability for PDI. In addition, the ability of SS bond formation to reduce ovomucoid degeneration increased about 3-fold with coexistent ERO1 and FAD compared with PDI alone. TaPDI, TaERO1, and FAD were reacted with acid-soluble wheat proteins prepared from hard flour and analyzed by diagonal electrophoresis. PDI has been suggested to form SS bonds in gliadin. Further, in bread-making tests using medium flour with poor suitability for bread making, the specific volume of 4.69cm³/g without TaPDI increased to 5.34cm³/g with addition of PDI, ERO1, and FAD, similar to that of hard wheat flour bread. From this result, it was possible to confirm the effect of using PDI in poor wheat flour on improving bread quality.