Development, optimization, and critical quality characteristics of new wheat-flour dough formulations fortified with hydrothermally-treated rice bran

Abstract

Although rice bran (RB) as a healthy-functional ingredient can be utilized to develop newly texturized foods, the phytic acid (PA) present in this bioactive constituent can significantly reduce the digestibility and quality of the final products. RB was hydrothermally processed at different operational conditions (i.e., temperature (Tp, 45–90 °C), time (Ti, 50–110 min), pH (3.0–6.0) and solid/solvent (So/St, 3–6 w/v) and optimized to attain the lowest PA content and color changes (ΔE) by response surface methodology-central composite design (RSM-CCD). The optimal hydrothermally RB (3.0–9.0% flour) was mixed and the dough rheology (e.g., farinographic (i.e., water absorption (WA); development time, stability time (ST), and softening degree (SD)), and extensographic (extension resistance (ER), extensibility, and energy) factors) was assessed. The second-order polynomial model (R2 = 0.987) was adequately fitted to the PA experimental data. The optimization results revealed that the least response variables (PA of 788 mg/kg and ΔE of 22) were obtained at 43.37 °C Tp, 94.38 min Ti, pH 7.0, and So/St of 8.0. An increase in the RB concentration led to a significant decrease in ER, ST, and extensibility (p < 0.05), whereas the WA, ER, and energy were increased remarkably. Moreover, the SD value (171.0 BU) was maximized by adding 3% treated-RB, while the incorporation peak level resulted in the minimum level (146.0 BU) of SD (p < 0.05). An integration of optimized hydrothermal processing and formulation enrichment might improve the nutritional and rheological quality of structured wheat flour-based doughs.