Ferulic acid and diferulic acids as components of sugar-beet pectins and maize bran heteroxylans

✍ Scribed by Saulnier, Luc; Thibault, Jean-Fran�ois

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 160 KB
• Volume: 79
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(19990301)79:3<396::aid-jsfa262>3.0.co;2-b

✦ Synopsis

Enzymatic hydrolysis of sugar-beet pulp, and subsequent isolation of feruloylated oligosaccharides, has shown that ferulic acid groups are ester-linked mainly on O-2 of arabinose residues and on O-6 of galactose residues in the pectin side-chains. After saponiücation of sugar-beet pulp enzymatic digests, dehydrodiferulic acids (0.14% , w/w) have also been identiüed and characterised as 8-5º, 5-5º, 8-8º and 8-O-4º isomers, suggesting that covalent cross-linking of pectic polysaccharides through diferulic bridges occurs in sugar-beet pulp. Feruloylated oligosaccharides from the side-chains of heteroxylans have been isolated from maize bran by acid hydrolysis. Ferulic acid is esteriüed on O-5 of arabinofuranose residues. 8-8º, 8-5º, 8-O-4º and 5-5º coupled dimers, which represent 2.5% (w/w) of the bran, have also been detected. It has been calculated that, in the cell wall, each heteroxylan macromolecule bore ¿75 esteriüed ferulic acid groups and could be cross-linked through ¿30 diferulic bridges. This result suggests a high degree of cross-linking of heteroxylans chains through ferulic acid in maize bran cell walls.