Fractionation and structural characterization of six purified rhamnogalacturonans type I from flaxseed mucilage. (January 2017)

• Record Type: Journal Article
• Authors: Elboutachfaiti, Redouan; Delattre, Cédric; Quéro, Anthony; Roulard, Romain; Duchêne, Julie; Mesnard, François; Petit, Emmanuel
• Is Part Of: Food hydrocolloids. Volume 62(2017)
• Page Start: 273
• Page End: 279
• Publication Date: 2017-01
• Subjects: Flaxseed -- Chromatography -- Mucilage -- Separation -- Arabinoxylan -- Rhamnogalacturonan; AX arabinoxylan -- RG-I rhamnogalacturonan type I -- Xylp xylopyranose -- Araf arabinofuranose -- Glcp glucopyronose -- Fucp fucopyranose -- Galp galactopyranose -- Rhap rhamnopyranose -- GalpA galactopyranuronic acid; Hydrocolloids -- Periodicals; Food additives -- Periodicals; Colloïdes -- Périodiques; Aliments -- Additifs -- Périodiques; Colloids; Food additives; Periodicals; Electronic journals; 664.06
• DOI: 10.1016/j.foodhyd.2016.08.005
• Languages: English
• ISSNs: 0268-005X

Abstract

Abstract: An improved method for the qualitative fractionation of water-soluble mucilage (WSM) polysaccharides isolated from flaxseed ( Linum usitatissimum ) comprising ion-exchange chromatography coupled with an evaporative light scattering detector was developed. One neutral fraction (NWSM) and six acidic fractions (AWSM-1 to AWSM-6) were purified. The molecular weights of NWSM, AWSM-1 - AWSM-6, determined using SEC/MALLS, were 1300 kDa, 756.4 kDa, 718.8 kDa, 505.6 kDa, 457.5 kDa, 354.8 kDa and 593.2 kDa, respectively. Monosaccharide composition and linkage analysis confirmed that NWSM was an arabinoxylan with a (1 → 4)-xylan backbone to which terminal arabinose residues and putative short-chain monosaccharides were attached at positions 2 and/or 3. On the other hand, it was shown that the six acidic fractions had similar rhamnogalacturonan I (RG-I) blocks that can be monosubstituted at O -3 position of rhamnose, mostly by terminal galactose or terminal fucose and occasionally by short side-chains of neutral monosaccharides. The calculated rhamnose/galacturonic acid ratio was from 1.22 to 0.85, which remained virtually unchanged and close to 1. The degree of branching of the isolated RG-I fractions was estimated at 0.33 to 0.65. The structural variability of the acidic fractions appeared not to be related to the RG-I backbone but possibly to the type and degree of substitution. These results might serve as a basis for developing chromatography conditions to contribute towards a better separation of mucilage polysaccharides. Graphical abstract: Highlights: Chromatography conditions towards a better separation of flaxseed mucilage. Q Sepharose Big Beads columns coupled to an evaporative light scattering detector. Fractionation into one arabinoxylan and six RhamnoGalacturonan of type I fractions. Variability of the RGI fractions given by the type and degree of substitution.