3/10/14BetaGlucan1-3, β-linkedMixed linkages(4.118)B1-3 linikago"B-glucanLoosely-JointedHCOH(4.121)C
3/10/14 6 1-3, β-linked Beta Glucan Mixed linkages Loosely-Jointed
3/10/14CH,OHHHOHOHGlucoseOHHOCH,OHD-GalactoseHCHOHOHGalactoseStronglyPleatedorRibbonType1,4 linked α-D-galactopyranosyl-uroniate units(4.116)(4.115)
3/10/14 7 Strongly Pleated or Ribbon Type 1,4 linked α-D-galactopyranosyl-uronate units
3/10/14ConformationsofHeteroglycansFigure 3.7chioimohnsennMAyrarimwoPeriodicseguencesAperiodicFig,4.14. Schematic representation of a gel settingprocess (according to Rees, 1977)Properties.Fiber.Viscosity·Gelforming.Films and Coatingb.EnergyFig.4.15. Interchain aggregation between regular.Structuralconformations.a Double helix,b doublehelixbundle,c egg-box,d ribbon-ribbon, and e doublehelix,ribboninteraction8
3/10/14 8 Conformations of Heteroglycans Properties • Fiber • Viscosity • Gel forming • Films and Coating • Energy • Structural
3/10/14SeaweedPolysaccharides? Agar·AlginateSeaweed.Carrageenans·PlantExudates.FurcellaranProblem: Alginates are heteroglycans made from:Seedgumsβ-D-mannuronic aad a-L-guluronic acids join by 1> 4 linkages.The polysaccharide is linear and consists of periods af three·PlantstructuralmaterialDistinct tepeating regions as defined below·Microbialgums[→ 4)-β-α-ManpA(1→ 4)-β-α-ManpA(1→],.Starch[→ 4)-α-L-GulpA(1.→ 4)-a-L-GulpA(1→],[→ 4)-B-b-ManpA(1 → 4)-α-t-GulpA(1 →)Asolution of alginate will gel with calcium. DrawThestracturesof thethreeregions andpredict whichregionformsThe gel with calcium crossfinking-PlantExudates.Gum Arabic.GumGhatti:GumTragacanth.KarayaGumFountt9
3/10/14 9 Polysaccharides • Seaweed • Plant Exudates • Seed gums • Plant structural material • Microbial gums • Starch Seaweed • Agar • Alginate • Carrageenans • Furcellaran Problem: Alginates are heteroglycans made from β-D-mannuronic and α-L-guluronic acids join by 1-> 4 linkages. The polysaccharide is linear and consists of periods of three Distinct repeating regions as defined below A solution of alginate will gel with calcium. Draw The structures of the three regions and predict which region forms The gel with calcium cross linking. Plant Exudates • Gum Arabic • Gum Ghatti • Gum Tragacanth • Karaya Gum
3/10/14Plant Seed Gums.LocustBeanGum·GuaranGumTamarindFlour·ArabinogalactanCHCCH,OHReuRt 41A representative segment of a galactomannan molecule.PlantStructure.Cellulose·Hemicellulose:PectindOH-OHHOH,CHOH,OOHHOHC.HONClSHOHOFigure3,15The --1)linked fnuchofinamosechuinof iulin.sacose_resihneswlty Found widhing a mowdacing terminsfor uhar wmaldorherwtsehe thenuhicing end of the chain.10
3/10/14 10 Plant Seed Gums • Locust Bean Gum • Guaran Gum • Tamarind Flour • Arabinogalactan Plant Structure • Cellulose • Hemicellulose • Pectin