Galactomannans with Man:Gal ratios ranging from 1.1:1 to 3:1, obtained from the seeds of Mimosa scabrella, Stryphnodendron barbatiman, Schizolobium parahybum and Schizolobium amazonicum, were submitted to mild acid hydrolysis. The products were fractionated by gel permeation chromatography on BioGel P2 yielding fractions with degrees of polymerization (DP) of 1 to 6. Those with DP 2 to 6 from each species were analysed by ion-exchange high-performance liquid chromatography and characterized by 13C- and 1H-nuclear magnetic resonance (NMR) spectroscopy. The distribution of the oligosaccharides of each degree of polymerization was very similar for the products from S. parahybum and S. amazonicum, indicating the same D-galactosyl distribution on the D-mannan backbone, in agreement with the 13C-NMR splitting in the C4 region of the D-mannosyl units in the original polymers. The hydrolytic conditions adopted allowed characterization of compounds that are not generally produced by enzymatic treatments. The results show that the structures of the oligosaccharides, even if there is a preferential hydrolysis of Gal-Man linkages, reflect the composition of the parent polymer.
Oligosaccharides, galactomannans, Brazilian seeds
NCBI PubMed ID: 7772557Publication DOI: 10.1016/0141-8130(95)93512-VJournal NLM ID: 7909578Publisher: Butterworth-Heinemann
Institutions: Department of Biochemistry, Universidade Federal do Paraná, Brazil, Centre de Recherche sur les Macromolécules Végétales (CNRS), Grenoble Cédex, France
Methods: 13C NMR, GLC-MS, gel filtration, partial acid hydrolysis, acid hydrolysis, GLC, HPLC, GPC, PC
Found