Gluten Network of Dough Affected by Addition of γ-Polyglutamic Acid

  Objective  Effect of γ-polyglutamic acid on the structure of gluten network during dough-making was studied.

  Method   Amount ofγ-polyglutamic acid added to the dough was set as variable for the experiment. Moisture and structure of the dough were observed by nuclear magnetic resonance and magnetic resonance imaging techniques. Texture, tensile properties and microstructure of the dough were measured by a texture analyzer and an environmental scanning electron microscopy. Based on these parameters, the effects of γ-polyglutamic acid additions on the gluten network at different stages of dough formation were studied.

  Result   At 0.3% addition of γ-polyglutamic acid in the dough, the proton density M₂₁ and M₂₂ peaked reaching a maximum water entrapment in the protein-starch network. The proton density imaging showed a dense and uniform red portion in the dough. The texture measurements and electron microscopy imaging displayed consistent results as did the nuclear magnetic measurements. Addition of γ-polyglutamic acid prolonged the dough-making time resulting in a most stable network structure.

  Conclusion   An addition of γ-polyglutamic acid at 0.3% in the dough with 23 min for a complete network formation would improve, but excessive additions be detrimental to, the quality of the baked bread.