Improved quality characteristics of Sangak bread by response surface optimisation of farinograph and extensograph traits of doughs formulated with fenugreek gum

Abstract

Fenugreek gum (FG) was evaluated as a potential material for the improvement of dough farinographic and extensographic characteristics and quality of an Iranian flat bread 'Sangak' in terms of moisture content (MC), loaf volume, textural, colour, and sensorial attributes. Response surface methodology-central composite rotatable design was used to optimise the effects of FG content and leavening time on the dough water absorption (WA), development time (DDT), stability time (ST), softening degree (SFD), resistance to extension (R50), extensibility (E), and R/E values. The significant second-order polynomial regression equations with high R2 (>0.888) were successfully fitted for all responses as function of independent variables. However, the quadratic and interaction effects were of independent variables shown to be non-significant on the R/E. The dough formulated with 5.5% w/w FG and leavened for 2.61 h yielded to the maximum WA (63.69%), DDT (2.85 min), ST (6.88 min), and E (284.58 mm) values, minimum SFD trait (46.52 Brabender Units; BU), and optimum R50 (289.13 BU) and R/E (1.00) amounts. Experimental data at the optimum conditions were very close to the amounts predicted by the constructed models. The bread baked with optimal dough significantly had higher MC, loaf volume, softness and lightness than the control bread (P<0.05). Sensory evaluation by a consumer panel showed a higher score for overall acceptability to the formulation supplemented with 5.5% FG. The levels of MC and softness for control bread due to the staling process were significantly reduced during 3-day storage.