Optimization of extraction of antioxidants from wheat bran (Triticum spp.) using response surface methodology

In this study, the optimal conditions for the extraction of antioxidants from hard winter wheat bran (WH711) were determined using response surface methodology (RSM). A central composite face centred design was used to investigate the effects of three independent variables, namely solvent composition (%v/v), extraction temperature (°C) and time (minutes) on the responses; free phenolic content (FPC), total flavonoid content (TFC), total antioxidant activity (TAA), ferric reducing power (FRP), hydrogen peroxide scavenging activity (HPSA). Regression analysis showed that more than 90% of the variation was explained by the models of different responses. The optimal conditions for the antioxidantss extraction were found to be methanol concentration of 85%v/v, extraction temperature of 75 °C, extraction time of 45 min, for wheat bran. The experimental values of FPC, TFC, TAA, FRP and HPSA were 0.921 mg GAE/g bran (B), 0.4588 mg CE/g B, 0.01408 mM AAE/g B, 2.532 mM AAE/g B and 3.193 mM TE/g B, respectively which agreed with those predicted, thus indicating suitability of the model employed and the suitability of RSM in optimizing the extraction conditions.