Extraction of ferulic acid from wheat bran by alkaline hydrolysis

Wheat bran is a low-cost by-product of the milling industry. Traditionally, it is used as livestock feed, but nowadays intention of wheat flour industry is to find a new value-added applications for a wheat bran. Wheat is a good source of phenolic compounds, from which the ferulic acid is the most abundant one. Ferulic acid exhibits lots of beneficial effects so it is widely used in food, health and cosmetic industries. In this paper, the optimization of extraction process of ferulic acid from wheat bran is presented. Ferulic acid was extracted by alkaline-hydrolysis using NaOH and later purified by precipitating hemicelluloses and glucomannans with ethanol. To optimize the extraction process for laboratory conditions, three initial weights of wheat bran, four concentrations of NaOH and three hydrolysis temperatures were examined. Obtained extracts were analysed by HPLC and amount of ferulic and other phenolic acids were determined. It was found out that only initial weight of ferulic acid had statistically significant effect on ferulic acid yields, however effects of concentration of NaOH and hydrolysis temperature were not so statistically significant. Besides ferulic acid, other phenolic compounds were also found to be present in wheat bran extracts such as sinapic, caffeic and coumaric acid, but they were found only in minor amounts.