Effect of phenolic acids on the rheological properties and proteins of hard wheat flour dough and bread

BACKGROUND: The effects of different phenolic acids on the rheological properties and gluten proteins of hard wheat flour dough and bread were investigated. Caffeic, ferulic, syringic and gallic acids were each blended with hard wheat flour at a concentration of 4.44 µmol L(-1) g(-1) flour. RESULTS: Mixing time and tolerance were reduced with the addition of phenolic acids. The phenolic acids reduced the maximum resistance to extension (R(max)) and increased the extensibility of dough, with effects in the following order: gallic < syringic < ferulic < caffeic acid. The effect on R(max) was more pronounced in overmixed dough. Loaf volume was most significantly decreased with the addition of caffeic acid. Extraction of sodium dodecyl sulfate-soluble high-molecular-weight proteins was increased in both mixed and fermented doughs by the addition of ferulic and caffeic acids. The order of influence of the phenolic acids on the rheological properties and protein structure of dough and bread was consistent with that of their antioxidant activity. CONCLUSION: The addition of caffeic and ferulic acids reduced R(max) and increased the extensibility of hard wheat flour dough by modifying the high-molecular-weight gluten, which resulted in decreased bread volume.