title: Effect of apotransferrin, lactoferrin and ovotransferrin on the hydroxyl radical mediated degradation of beta-glucan.
abstract: Beta-glucan is a polysaccharide widely accepted and used as a functional ingredient due to its positive effects on human health. However, beta-glucan is readily degraded in aqueous systems in presence of a hydroxyl radical generating system such as ascorbic/iron(II). In the present study, we tested whether iron binding proteins; apotransferrin, lactoferrin and ovotransferrin; could prevent the hydroxyl radical mediated degradation of beta-glucan. The radical formation was investigated by ESR spectroscopy and the polysaccharide degradation was monitored by the viscosity loss of the solutions. Apo-transferrin increased the formation of hydroxyl radicals and this related with a faster degradation of beta-glucan. Lactoferrin did not have any effect on the ascorbate induced degradation of beta-glucan, whereas ovotransferrin completely inhibited the hydroxyl radical generation by a system containing ascorbic acid and iron(II). However, the presence of ovotransferrin in beta-glucan decreased the viscosity of the solution, which was accompanied by the apparition of a precipitate, indicating a potential interaction between the protein and beta-glucan. FT-IR analyses indicate the presence of beta-glucan and ovotransferrin in both precipitate and supernatant, as well as the occurrence of interactions between the two compounds. This study reveals that ovotransferrin is a promising candidate for inhibiting the formation of ascorbate/iron(II) induced hydroxyl radicals in beta-glucan solutions.
authors.affiliation: ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zurich, Switzerland.
authors.forename: Audrey M
authors.initials: AM
authors.lastname: Faure
authors.affiliation: ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zurich, Switzerland. Electronic address: laura.nystroem@hest.ethz.ch.
authors.forename: Laura
authors.initials: L
authors.lastname: Nyström
mesh_terms: D001059:Apoproteins / Q000737:chemistry*; D001205:Ascorbic Acid / Q000737:chemistry; D003207:Conalbumin / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005296:Ferrous Compounds / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry*; D007781:Lactoferrin / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014168:Transferrin / Q000737:chemistry*; D047071:beta-Glucans / Q000737:chemistry*
chemical_list: D001059:Apoproteins; D005296:Ferrous Compounds; D014168:Transferrin; C028284:apotransferrin; D047071:beta-Glucans; C051140:iron(II)-ascorbic acid complex; D003207:Conalbumin; D017665:Hydroxyl Radical; D007781:Lactoferrin; D001205:Ascorbic Acid
keywords: Beta-glucan; Hydroxyl radicals; Oxidative degradation; Transferrin proteins