Isolation and characterization of ferulic acid carbohydrate esters from corn hull (Zea mays)

Refined corn hulls (bran) were hydrolyzed with 30 mM oxalic acid in order to release carbohydrate fragments containing ferulic acid. The fragments which were high in ferulic acid also contained high levels of arabinose, xylose, and galactose, which are characteristic of sugars comprising corn hull hemicellulose side chains. Corn hull hydrolysate fragments were fractionated by chromatography to obtain purified feruloyl oligosaccharides. A The structure of the major feruloyl compounds were characterized by analysis of the products of acid, alkali, and enzyme hydrolysis, in combination with carbon-13 and 2D proton NMR spectroscopy. Three feruloyl oligosaccharides were identified as 5-0-(trans)-feruloyl-L-arabinofuranose (FA), 2-0-β-xylopyranosyl-(5-0-trans-feruloyl arabinofuranose) (FXA), and 0-(6-0-trans-feruloyl-α-D-galactopyranosyl)-(1-4) -O-β-D-xylopyranosyl-(1-2)-L-arabinofuranose (FGXA).