Effect of hydrocolloids on selected properties of gluten-free dough and bread.

Addition of hydrocolloids (H/C) in gluten-free (GF) bread formulation is necessary in order to act as polymeric substances that should mimic the viscoelastic properties of gluten and increase the dough's gas-retaining ability. The properties of H/C vary depending on their origin and chemical structure. Addition of H/C (hydroxypropylmethylcellulose (HPMC), xanthan, κ-carrageenan and guar gum) of different origins at 1%, 1.5% and 2% (w/w) in GF formulations based on corn starch and rice flour was carried out to investigate the effects on dough rheology and bread quality. The consistency, viscosity and thermal properties of doughs were evaluated. According to results, 1% and 1.5% addition of H/C (except from xanthan) contributed to bread with higher loaf volume and better color compared to control GF bread as well as to increased shelf life due to its moisture-absorption ability. Sensory evaluation by a trained panel revealed a preference for bread containing 1.5% HPMC because of its loaf volume, appearance and firmness characteristics. The micrographs of the dough showed a continuous matrix between starch and HPMC obtaining a more aerated structure.