Extraction And Purification Of Ferulic Acid From Wheat Bran

Ferulic acid is a good antioxidant that showed high scavenging activity for hydrogen peroxide, superoxide, hydroxyl radical and nitrogen dioxide free radicals. In medical industry, ferulic acid as an antioxidant has been reported to have many physiological functions, including antioxidation, antimirocbal, anti-immflammatory, anti-thrombosis, and anti-cancer activities. In food industry, ferulic acid is used as production of vanillin, a preservative and a cross-linking agent. Ferulic acid is widely used as an biological substance in functional foods.In the present study, ferulic acid in wheat bran was extracted and purified,the extraction proceeding parameters were optimized. Macroporous resin and powdered activated carbon were used to purify crude ferulic acid. The main results are listed as following:(1) According to the properties of ferulic acid in structure and character, RP-HPLC analytical method and derived spectrophotometry determination method were developed for determination of ferulic acid. Effects of column and mobile phase constitute on retention behaviors of ferulic acid were discussed. The optimal chromatographic conditions included Hyperclone ODS C18 column (150×4.6mm,5μm) and the mobile phase consisting of a mixture of methanol-1%acetic acid solution (25:75,volume ratio) at a flow rate of 1.0 mL/min at 30℃. The UV detection wavelength was 320nm. A good linear relationship was shows in the range of 0.0342-0.2397μg for ferulic acid, with correlative coeficient 0.9999. The relative standard deviation is 0.64% and the average recovery is 97.9%.For derived spectrophotometry,the detection wavelength is 720nm. There is a good linear relationship in the range of 0.00472-0.02832mg for ferulic acid, and the correlative coefficient is 0.9992, The relative standard deviation is 2.339% and the average recovery is 97.9%. These simple, rapid, sensitive and accurate methods could be used in quantitative determination of ferulic acid in wheat bran.(2) Starches and protein were removal by enzymatic hydrolysis with a-amylase and proteinas before extraction of ferulic acid from wheat bran respectively. Total content of ferulic acid extracted from wheat bran was taken as index to compare six extraction effects, including.solid/liquid ratio, NaOH concentration, alkali/ethanol ratio, the mass fraction of sodium hydrogen sulfite, extraction temperature, extraction time, and pH. Response surface methodology and orthogonal design were respectively used to evaluate the effects of NaOH concentration, alkali/ethanol ratio, extraction temperature and pH on ferulic acid extraction yield from wheat bran. The optimized conditions are as follows:solid/liquid ratio the mass fraction of sodium hydrogen sulfite 0.4g(2%),alkali/ethanol ratio2:1, NaOH concentration of 5.76%, pH of 3.2, alkali/ethanol ratio of 1.39:1, temperature of 59.75℃, the actual extraction yield in agreement with the expected yield,4.48mg.g-1 extraction rate of ferulic acid in wheat bran. The residue was preparation for dietary fiber after extraction of ferulic aicd.(3) The adsorbing and desorbing properties of ferulic acid by macroporous resin and powdered activated carbon were studied, it shows that D101 was better in static adsorption and elution. The optimal purification conditions were as follows:flow ratel ml.min-1, adsorption volume 12BV, elution volume 5BV, adsorption pH 6.2, concentration elution58.22%, elution pH7.1. Purified solution was detected through HPLC, and purity of ferulic acid was 75.65%.