Effect of hydrocolloids on some properties of dough and quality of gluten-free bread enriched with whey protein concentrate

Introduction.The effect of hydrocolloids (xanthan gum and guar gum) on dough properties and the quality of gluten-free bread from rice and corn flour enriched with whey protein concentrate was studied.Materials and methods.For the preparation of the whey protein concentrate it was used a laboratory system with a removable flat membrane module, equipped with a 25 kDa polyacrilonitrile ultrafiltration membrane.Dough consistency was measured by degree of immersion, using automatic penetrometer.Results and discussion.Based on the preliminary experiments (with 5, 10 and 15 %) it was found that the optimal quantity of whey protein concentrate was 10 %.That is why for the further experimental tests 10 % whey protein concentrate was added to control sample bread.Addition of higher quantities of xanthan gum resulted in weak dough consistency.Concerning the dough consistency it can be concluded that the addition of xanthan gum results in release of the dough, regardless of the quantity used.The best result was obtained when 1.5 % guar gum was added.Maximum increase in bread volume was obtained with 1.5 % guar gum.The specific volume of bread significantly improved with hydrocolloids addition.It was found that the control sample had a lower specific volume.The samples containing hydrocolloids had larger volume than the control.The addition of 1 % xanthan gum resulted in an increase in H/ D index by 50 %, compared to the control sample.When 1.5 % guar gum was added, the highest results were obtainedthe increase compared to the control sample was 100 %.Guar gum had greater influence on sensory properties of gluten-free bread from rice and corn flour than xanthan gum.Addition of 1.5 % guar gum led to the best results for almost all sensory properties (without the porosity and aftertaste).The results concerning porosity and aftertaste did not differ those obtained with the addition of 1 % guar gum.Addition of 1.5 % guar gum in formulation of gluten-free bread from rice and corn flour led to the highest volume, uniform crust and crumb color, with no rust and atypical shades.The flavor was pleasant and very well pronounced, evaluated by the panelists with 8 points, while the flavor of samples with xanthan gum had 3 points.The flavor was weaker when 1 % guar gum was used (5 points).The bread samples with guar gum were appreciated as more crisp, with a very pleasant taste and aftertaste.Conclusions.For the production of gluten-free bread of rice and corn flour enriched with whey protein concentrate, the addition of 1.5 % guar gum is most appropriate.