Optimization of rice bread formulation by mixture design and relationship of bread quality to flour and dough attributes

The bread making aptitude of five rice flours (native and gelatinized) and five gluten substitutes (GS) were prior tested and the best ingredients for mixture design were set. Native flour with a wide distribution of particle size, xanthan gum (XG), guar gum (GG) and sodium alginate (SA) were selected due to their good performance. The effect of formulation on bread volume (BV), cell area fraction (CAF) of breadcrumb and dough rheology was determined by using a simplex centroid mixture design with constrain (2.1 g of GS/100 g of flour). A significant effect of formulation on viscoelasticity of dough was observed. A non-linear relationship between BV and dough viscosity was found with maximum BV at 60000 Pa.s. The optimum formulation, from XG to GG mass ratio of 0.71, yields maximum values of BV (4.07 ml/g of flour) and CAF (29%); optimum bread presented good textural attributes and a slightly toasted crust.