Use of Response Surface Methodology to Optimize Gluten-Free Bread Fortified with Soy Flour and Dry Milk

The percentages of soy flour (X1) and dry milk (X2) were varied for the production of gluten-free bread to optimize batter softness (Y1), specific volume (Y2), crumb grain score (Y3), bread score (Y4) and bread protein content (Y5). A central composite design was used and second-order models for Y1 were employed to generate response surfaces. When bread protein content was decreased from 10 to 3%, specific volume increased from 3.2 to 4.6 cm3/g and bread score increased too. Nevertheless, the highest crumb grain score was obtained at 7.3% of bread protein content. The results demonstrated that a gluten-free bread can be prepared by adding 7.5% soy flour and 7.8% dry milk to a previously developed formulation, increasing its protein content from 1 to 7.3% and modifying in a small degree, its sensory quality.