Modelling the effects of psyllium and water in gluten-free bread: An approach to improve the bread quality and glycemic response

[Display omitted] •Psyllium addition levels in a gluten-free bread (GFB) formulation were studied.•Fibre-enriched, well-accepted GFBs were produced.•Optimum GFB formulation presented acceptability scores like those of wheat bread.•Psyllium decreased the glycemic response of the GFB. A 22 factorial design with three centre points was used to study psyllium (P) and water (W) addition level effects on gluten-free bread (GFB) physical properties and sensory acceptability. The P levels ranged from 2.86 to 17.14% and W levels from 82.14 to 117.86% on a flour basis. The results show that the P and W interactions improve the bread quality by yielding a better loaf volume, softer crumbs, and improved bread appearance and enhancing the sensory acceptability scores. The optimum formulation (desirability of 0.89) was prepared with 2.86% P and 82.14% W, increasing the dietary fibre content from 2.5% in the control formulation to 4.0%. The results also show that it is possible to add 17.14% P and 117.86% W to obtain an acceptable GFB with nearly a four-fold increase in the fibre content and a 33% decrease in the glycemic response compared to that of the control formulation.