Abstract

• Ferulic acid (4-hydroxy-3-methoxycinnamic acid) is one of the most significant natural bioactive phenolic acids generally found in the seeds as well as leaves, both in its free form and covalently conjugated with the plant cell wall materials. The extraction of ferulic acid has been found much attention nowadays due to the fact that it exhibits a wide variety of biological activities. In the present study, the extraction of ferulic acid from wheat bran was carried out by alkaline hydrolysis using NaOH and later purified by precipitating hemicellulose and glucomannans with ethanol. Optimization of antioxidant activity in ferulic acid from defatted wheat bran was conducted using response surface methodology (RSM). The conditions investigated were 0.5, 1.0 and 1.5 M of NaOH concentration (x1), 2, 4 and 6 hr of extraction time (x2), and 40, 50 and 60 ˚C for the extraction temperature (x3). Box-Behnken design indicated that the model can significantly (p < 0.05) express more than 80 % (> 0.80) of the response variation. The optimal extract condition for maximum antioxidant activity was 0.5 M of NaOH concentration, 2 hr of extraction time, and 50 ˚C for extraction temperature. The antioxidant activity of extracted ferulic acid was determined by DPPH (2, 2-diphenyl-1-picryl-hydrazyl) radical photometric scavenging method. According to these results, ferulic acid from wheat bran possesses high antioxidant activity.