Hydrocolloids Structure and Properties - STEP ITN

1 18 month Meeting, Unilever Vlaardingen, March 29 31, 2010 Hydrocolloids Structure and PropertiesThe building blocks for structureTimothy J. FosterNatural MaterialsThis shows a layer of onion (Allium) cells. Manufactured MaterialsFoams Emulsions Targeting Hydrocolloids For Specific Applications:ApproachIngredientMicrostru ctureProcessOral ResponseMaterial PropertiesIngredient(enzymes)DECONSTRUCT IONC ontrolled oral response(taste, flavour, texture)In body functionalityProcess(mouth/gut)Packaging DistributionStorageProcess Ingredient CONSTRUCTIONC ontrolling StructureDesigned texture/appearance/behaviourReconstructi onReconstructionInteraction with body mucins(associative and new phase separation)

2 Microstructure changes as a function of enzyme actionRe-assembly of structures as a function of digestion breakdown products and body secretions(micelle formation, delivery vehicles)Impact on / of starting materials / structuresSingle Biopolymer systemsHydrocolloid Structure / FunctionNeed:-define biopolymer primary Structure -understand the nature of the interaction / rates-understand the solvent effects-measure material Properties -test influence of primary Structure variation and changes in environmental conditions on mechanical gumXanthanEmulsification Gelatin Milk proteins Egg proteins Soya proteins Pea proteins Gum ArabicHydrocolloid Materials & FunctionGellingPectinAlginateStarchAgarC arrageenanGellanGelatinMilk proteinsEgg proteinsGelling Pectin Alginate Starch Agar Carrageenan Gellan

3 Curdlan Celluosics Succinoglycan Scleroglucan MixturesThickening Pectin Alginate Starch LBG Guar Gum Xanthan lamda Carrageenan Cellulosics Beta GlucanEmulsification Gum Arabic Propylene glycol Alginate Sugarbeet pectin OSA starchHydrocolloid Materials & FunctionA protein is a polymerof amino acids Primary Structure amino acid sequence Secondary Structure spatial Structure through interactions between amino acids that are nearalong the amino acid chain ( helix, sheet) Tertiary Structure spatial Structure through interactions between amino acids that are far awayalong the amino acid chain Quaternary Structure association of different amino acid sequences ( haemoglobin)Protein structureProteinProtein Structure :Backbonerandom coilsbeta sheetalpha helixChargeDetermines Properties :Interfacial propertiesfoamsemulsionsGel formingColor caption.

4 -Helix -SheetsCysteinesStructure of globular proteins lactalbumin ( la) lactoglobulin ( lg)dimeric form at neutral pHbovine serum albumin(BSA)Turbid Gels How do they differ? do they look like?123456CH2 OHOOHOHOHOHHHHHHCH2 OHOOHOHOHOHHHHHHG lucoseOHCH2 OHOOHOHOHHHHHHM annoseCH2 OHOOHOHOHOHHHHHHG alactoseGuloseSugar Interactions Glycosidic linkageOHOHOHOHCH2 OHOHHHHHOHCH2 OHOHHHOHOHOHOHOHOHOCH2 OHOHHHHHHOHCH2 OHOHHOHOH+H20 Polysaccharide Structure / FunctionalitySources of hydrocolloidsBotanicalstarch, cellulose, galactomannans, pectin, gum arabic, karaya, tragacanth, beta glucanSeaweedsagar, carrageenan, alginateAnimalgelatin, chitosan, hyaluronanBacterialxanthan, gellan.

5 DextranStructural Features Linear (homo- and hetero-) Linear branched (homo- and hetero-) Branched (homo- and hetero-) Ordered helices (single, double, triple)Polysaccharide thickeners The most efficient thickeners are; Linear, High molecular mass Charged Alternative HydrocolloidsAloe GumCashew GumGum GhattiGum KarayaOat gumOkra GumGum TragacanthCaramania Gum (almond)Cassia Gum Cassava StarchCherry GumChia GumChickpea FlourCocoyam FlourCombretum GumCowpea protein /starchCyclodextrinsDetarium microcarpum polysaccharideFenugreek gumFlaxseed GumGleditsia macracanthaHsian-tsao Leaf gum (Taiwan/China)Lesquerella GumLicheninLucaena galactomannanLupin ProteinManna GumMoussul Gum (Plum)

6 Opuntia FicusPortulaca OleraceaPrickly PearPsyllium gumQuince seed gumRice FlourRye bran (beta d glucan / arabinoxylan)Sassa GumSorghum flourSoy Bean PolysaccharideTamarind gumTara GumTremella Aurantia PoysaccharideTropical StarchesYamYellow Mustard GumTypical Solution PropertiesHydrocolloid Structure / FunctionNeed:-define biopolymer primary Structure -understand the nature of the interaction / rates-understand the solvent effects-measure material Properties -test influence of primary Structure variation and changes in environmental conditions on mechanical Galactomannans include guar gum, locust bean gum (carob), fenugreek, cassia and tara gum.

7 They have a high molecular mass (~ in excess of 500kDa) and consist of 1,4 linked mannose residues with galactose units linked 1,6. The M:G ratio is ~2:1 for guar, 3:1 for tara and 4:1 for locust bean gum. The galactose units are not evenly distributed along the chain. LBG can be fractionated wrt temperature of solubility. Cold soluble LBG (30C) has a higher G/ M than that soluble at high temperature (80C). LBG soluble at 80C has a galactose content of , and gels at ambient temperature. Cold soluble LBG does NOT gel even when frozen & thawed.

8 Not necessary for ice to be present, a non ionic interaction, dependent on solvent Structure / FunctionalityGelation RateGelation RateGelation Rate[LBG] (%)205065 Temperature-810- Self association is kinetically controlled as a function of the number of available junction zones- The distribution of galactose sidechains is all important in dictating of Hydrocolloids0 (%).Load (KN).3%Gelatin3%AgarTypical polymer gel propertiesDependent on Solvent quality, Polymer fine Structure , Junction zone type / quantityEffect of Shear during Gelation: Fluid gel Particle formation Composite Properties are dependent upon the number and size of particles produced.

9 This in turn is dependent upon the polymer used, the polymerconcentration and the shear ,00010,000100,0001,000,000[Agar]G'(Pa)Qu iescentShearedStorage Modulus of Agar Gels FormedQuiescently and Under ShearMeasurement Temperature = of DilutionViscosity (Pas)XanthanFluid gel Due to the colloidal nature of their Properties they providebetter dilution characteristics than their molecular BiopolymersAqueous-based two-phase systemsMicrostructureo/w emulsionwater-in-water emulsion 25 (WT%)MICELLAR CASEIN (WT%)**25% LBG / 75% PR75% LBG / 25% PR50% LBG / 50% PRPhase diagram measured at 5 CPhase Separation phenomena is used in the creation of two-phase systemsExample: Aqueous mixture of gelatin and maltodextrinTop phase: GelatinBottom phase: MaltodextrinFor charged polymers (polyelectrolytes) salt (type and concentration) as well as pH are important parameters.

10 Influence of varying polymer characteristics02468101214024681012 Isothermal Binodal Evolution Owing to Ordering [SA2] / t = % / minLH1 / SA2 No Salt20oC[LH1] / % w/w[SA2] / % w/w Schematic phase diagram showing the binodal as a function of ordering at 20 CPhase separation driven by molecular ordering of one of the effectsStructure induced phase separation. Measure of gelatin helices required to induce phase separation in a 4% LH1e:4% SA2 mixture , in water, when quenched to 20oC (top) and 25oC (bottom). Morphology when quenched to Helix% Helix% Helixt/ / cm-110203040500246810121416% Helix% Helixt/ / cm-1 Turbidity1min4min29min20oC25oCEffect of shear during cooling / gelation of the gelatinProcess effects on mixed biopolymer biopolymer forms the dispersed based on aqueous-based two-phase systemsScheme developed by Tolstoguzov**V TolstoguzovJournal of Texture Studies11, 3 (1980) 199-215 Gel particle suspensionsModification of (shear) rheology.