Improvement of bread dough quality byBacillus subtilisSPB1 biosurfactant addition: optimized extraction using response surface methodology

Abstract

Statistically based experimental designs were applied to Bacillus subtilis SPB1 biosurfactant extraction. The extracted biosurfactant was tested as an additive in dough formulation. The Plackett-Burman screening method showed that methanol volume, agitation speed and operating temperature affect biosurfactant extraction. The effect was studied and adjusted using response surface methodology. The optimal values were identified as 5 mL methanol, 180 rpm and 25 °C, yielding predicted responses of 2.1 ± 0.06 for the purification factor and 87.47% ± 1.58 for the retention yield. Study of the incorporation of purified lipopeptide powder into the dough preparation in comparison with a commercial surfactant - soya lecithin - reveal that SPB1 biosurfactant significantly improves the textural properties of dough (hardness, springiness, cohesion and adhesion) especially at 0.5 g kg⁻¹. At the same concentration (0.5 g kg⁻¹), the effect of SPB1 biosurfactant was more pronounced than that of soya lecithin. Also, this biosurfactant considerably enhanced the gas retention capacity in the course of fermentation. These results show that SPB1 biosurfactant could be of great interest in the bread-making industry. A method for preparative extraction of lipopeptide biosurfactant with methanol as the extraction solvent has been effectively established.