Study on preparation of ferulic acid from corn bran by ultra- and nano-filtration

Ferulic acid was released from corn bran by alkaline-ethanol aqueous solution, thus significantly decreased the viscosity of extracts and mad it easy for further purification by membrane separation. The optimal extraction technology was:one weight of corn bran was suspended in 10 volume of extraction solution (0.25mol/L NaOH dissolved in 50% ethanol solution) and extracted at 75℃ for 2h under constant stirring at 120r/min. Ferulic acid in the extract was concentrated and purified using ultrafiltration and nanofiltration successively. 86.4% of ferulic acid was recovered in the permeats when extracts were ultrafiltrated using the membrane with 5000u molecular cutoff. These permeats after ultrafiltration was then nanofiltrated using a membrane with 150u molecular cutoff, when the concentration factor reached 4.3, 94.3% of ferulic acid was maintained in the retentate, in which, the pH value was adjusted to 2.0 and the crystal of ferulic acid was obtained. After the extraction and separation processes, it was yielded 16.5g/kg of ferulic acid powder with the purity of 55.8%.