Preparation Of Phenolic Acids From Maize Bran And Sugarcane Bagasse

Sodium hydroxide was used to release phenolic acids from maize bran and sugarcane bagasse respectively.For releasing ferulic acid from maize bran, de-starched and deproteined maize bran was suspended in ten volume of 50% of ethanol solution (v/w) containing 1% NaOH and reacted at 85℃ for 2h; and 50mg /100ml of sodium sulfite was added to the extraction solution to prevent oxidation of released ferulic acid. The extracts were concentrated, pH adjusted to 3.0 and extracted three times with two volume of ethyl acetate. HPLC analysis showed that the purity of ferulic acid is 82.69%; the yield of ferulic acid is 148.92mg/10g maize bran. Active charcoal was also investigated to separate ferulic acid in the solution. The results showed that powdered active charcoal had high capacity for adsorbing ferulic acid. Its maximum adsorption capacity was 325~340mg/g and its lowest adsorbing concentration for ferulic acid was less than 5mg/100ml under pH 2.0～9.0. 2.0% of NaOH desorbed almost 100% of adsorbed ferulic acid, however, alcohol and ethyl acetate desorbed less than 30% of the adsorbed ferulic acid. The result of TLC showed that ferulic acid separated by active charcoal from alkali-hydrolyzed products had high purity.Phenolic acids could be fully released from sugarcane bagasse by suspending sugarcane bagasse in ten volume of 1% NaOH(w/v) and reacted at 30℃ for 4h under constant stirring. The phenolic acids in alkaline extracts were purified by NKA-9 macroporous resin after anion chromatography using 717-anion resin. The adsorption condition for anion chromatography was pH 9.0 and the flow rate kept at 1 mL/min; the phenolic acids were desorbed with ethanol:water: HCl 60:36:4 (v:v:v) at elution rate 1mL/min. The eluents were vacuum-evaporated and the crystals were dissolved in deionized water (pH= 5.0) and adsorbed by NKA-9 macroporous resin in a flask for 1h. The mixture was loaded onto a column and desorbed using 30% ethanol at 1 mL/min. After purification, the purity of products reached 93.57%.Preparative liquid chromatography was used to separate the main component of alkali-released products, and HPLC, HPLC/MS, IR and UV analysis showed that the main component was p-coumaric acid rather than ferulic acid in sugarcane bagasse.The antioxidant activity of alkali-released products from sugarcane bagasse for their protection against peroxidation of linoleic acid was also investigated. The results showed that the product had equivalent antioxidant activity to ferulic acid at the same concentration. Moreover, the alkali-released products could effectively scavenge free...