碳水化合物Carbohydrate

ImportantConceptsaboutCarbohydrates(CHO)有关碳水化合物的重要概念,CHOaremadebyplantsandaretheprimarysourceofenergyinanimaldiets碳水化合物主要来源于植物，是动物饲粮的主要能量来源CHOinthecellwallofplantsarecalledfiber,andarelessdigestiblethanCHOinsidethecell植物细胞壁中的碳水化合物称为纤维，比细胞内的碳水化合物消化性差,ImportantConceptsaboutCarbohydrates(CHO),Thereare13monosaccharidesthatarephysiologicallyimportantbutnonearedietaryessential有13种生理学上很重要的单糖，但都不是饲料必需的Ruminantsandhorsesneedminimumlevelsoffiberinthedietforhealth.反刍动物和马保持健康，饲粮必须提供最低限量的纤维,CARBOHYDRATES碳水化合物,Monosaccharides单糖Monosaccharidesarethesimplestcarbohydrates(simplesugars)单糖是最简单的碳水化合物Allothercarbohydratesaremadeupof2ormoremonosaccharides.所有其它的碳水化合物都是由两个或两个以上的单糖组成Hydratedcarbons;foreachCatomthereisonewater一个碳原子有一分子水CXH2XOXX=numberofcarbonsExample:glucose:C6H12O6,CARBOHYDRATES碳水化合物,Monosaccharides单糖are:polyhydroxyaldehydesandketones多羟醛多羟酮Thosethatarealdehydesarecalledaldoses有多羟醛的单糖称为醛糖Thosethatareketonesarecalledketoses多羟醛的单糖称为酮糖,醛糖,酮糖,甘油醛,核糖,葡萄糖,半乳糖,二羟基丙酮,核酮糖,果糖,CARBOHYDRATES碳水化合物,Amonosaccharidewiththelettersulinitsnameisaketose;单糖名称中有字母“ul”是酮糖However,notallketoseshaveulintheirname但并不是所有酮糖在名称中都有字母“ul”Example:Aldose醛糖Ketose酮糖ribose核糖ribulose核酮糖xylose木糖xylulose木酮糖,CARBOHYDRATES碳水化合物,Monosaccharides单糖Varyinthenumberofcarbonatoms(chainlength)碳原子数的变化（链长）3C=triose三糖4C=tetrose四糖5C=pentose五糖6C=hexose六糖7C=heptose庚糖Therefore,itispossibletohavealdotriose丙醛糖,ketotriose酮丙糖,aldohexose己醛糖,ketohexose己酮糖,etc.,醛糖,酮糖,甘油醛,核糖,葡萄糖,半乳糖,二羟基丙酮,核酮糖,果糖,MonosaccharidesExhibitVariousFormsofIsomerism,Stereoisomers立体异构体compoundswithsamestructuralformulabutdifferentspatialconfigurations具体相同结构式的化合物，由于不同的立体结构duetopresenceofasymmetricalCatoms(anyCatomattachedtofourdifferentatomsorgroups)导致非对称的碳原子存在numberofisomers同分异构体is2nwhenn=no.ofasymmetricalcarbons非对称碳原子数量,DandLIsomerism异构现象,DandLisomersaremirrorimagesofeachother.Theyrotatepolarizedlighttotheleft(L)ortheright(D)D和L异构体是镜像的。DesignationofDandLbasedonspatialrelationshiptoparentcompoundglyceraldehyde甘油醛.Formonosaccharideswithtwoormoreasymmetriccarbons,theprefixesDandLrefertotheconfigurationfortheasymmetriccarbonfurtherestfromthecarbonylcarbon.由于单糖含有两个或两个以上的不对称碳原子，DL是指最远羰基上的不对称碳原子结构。,甘油醛,葡萄糖,DandLIsomerism异构现像,MostmonosaccharidesinnatureareintheDform,andenzymesresponsibleformetabolismofmonosaccharidesarespecificfortheDform.自然中绝大多数的单糖是D型，酶只对D型有作用效果。ThismeansthatanimalscanutilizetheDisomers,butnottheLisomers.动物只能利用D型异构体，不能利用L型。,D-Isomersofthealdoses醛糖的D型异构体,Physiologicalornutritionalimportance,赤藓糖,甘油醛,阿苏糖,核糖,树胶醛糖,木糖,来苏糖,阿洛糖,阿卓糖,葡萄糖,甘露糖,古洛糖,艾杜糖,半乳糖,糖,D-Isomersoftheketoses酮糖D型异构体,二羟基丙酮,赤藓酮糖,核酮糖,木酮糖,阿洛酮糖,果糖,山梨糖,塔格糖,PyranoseandFuranoseRings六环糖和五环糖,Themoststableformofaldohexosesisa6-memberringsimilartoapyran.最稳定的己醛糖是与吡喃相似的六环结构Foranaldose,theringstructureisahemiacetal(combinationofaaldehydeandalcoholgroup.)醛糖的环结构是半缩醛DuetoisomerismonC1(thecarbonyloranomericcarbonatom),thisleadstotwoformsoftheDisomer,theand-form.由于异构体在第一个碳原子上，导致D型异构体有和两种形式ForD-glucose,theseare-D-glucopyranoseand-Dglucopyranose吡喃葡萄糖,AlphaandBetaAnomersofGlucose葡萄糖的和反构体,果糖,核糖,葡萄糖,-吡喃葡萄糖,-吡喃葡萄糖,呋喃核糖,呋喃果糖,AlphaandBetaGlucoseLinkedby1-4Bonds1-4糖苷键连接的和葡萄糖,淀粉,纤维素,PyranoseandFuranoserings六环糖和五环糖,Forketohexoses,a5-memberring,similartoafuran,isfound.存在五环的己酮糖，相似呋喃Forfructose,themostcommonformis-D-fructofuranose.呋喃果糖,MonosaccharidesofNutritionalImportance单糖营养重要作用,MonosaccharidesofNutritionalImportance单糖营养重要作用,Howmanyareketoses,123456,Howmanyarepentoses?,123456,Howmanyareketoses,123456,Howmanyarepentoses?,123456,Disaccharides-Twomonosaccharideslinkedbyglycosidicbond二糖,Maltose麦芽糖(2glucose;1-4bond)Notfoundinnature;resultsfromthedigestionorchemicalbreakdownofstarch.自然界不存在，由淀粉消化而得Maltoseisthebasicunitofstarchandglycogen.麦芽糖是淀粉和糖原的基本单位,Disaccharides二糖,Sucrose(glucoseandfructose)蔗糖Occursinthefreeforminmostplants;givesfruitstheirsweettaste在多数植物存在Sugarcaneandsugarbeetsareprocessedtoproducethetablesugarweconsume.甘蔗和甜菜生产食用的糖Sucraseisthedigestiveenzymeneededtodigestsucroseintoglucoseandfructose蔗糖酶Humansandpigssynthesizesucrase;人和猪可合成Ruminantsdonot.反刍动物不能合成蔗糖酶,Disaccharides,Lactose(glucoseandgalactose)乳糖Primarycarbohydrateinmilk;foundinmilk;commonlycalledmilksugar乳糖Lactase乳糖酶istheenzymeneededtodigestlactoseEasilyandcompletelydigestedbyyounganimalsLactoseintoleranceinhumansisduetolowlevelsorabsenceoflactase.乳糖不耐受性是由于体内乳糖酶不足或缺乏引起的,UsesandSourcesofLactose,Oligosaccharides寡糖,Carbohydratestypically2to12monosaccharideslong2-12个单糖（2-10）Raffinose(galactose+glucose+fructose)棉子糖Stachyose(galactose+galactose+glucose+水苏糖fructose)Indigestiblebymammals,buthighlyfermentablebymicrofloraofdigestivesystem哺乳动物可以消化Highcontentinsoybeansandcottonseed大豆和棉籽中含量高,WhichstatementisFALSE?,SucroseisthesweetestofthedisaccharidesLactoseistheonlydisaccharidecontainingglucoseMaltoseisnotfedtofarmanimalsMostofthedisaccharidesaremadebyplants,Polysaccharides多糖,Starch淀粉,1.Synthesizedbyplantsandusedtostoreenergyinseedsandtubers.块茎2.Starchisdepositedingranules颗粒insidethecellsoftubersandseeds,Starch,3.Starchtypes:a.Amylose直链淀粉(10to30%ofstarch)(1.)Linearhelicalchainofglucoselinkedby1-4linkage线性螺旋(2.)Molecularweight10,000-500,000(3.)Solubleinwater,Starch,b.Amylopectin支链淀粉(70to90%ofstarch)(1.)Branchedchainsofglucoselinkedby1-4and1-6bonds(2.)Branchesoccurevery12to30glucosemolecules(3.)Molecularweight:upto100million(4.)Largestmoleculeinnature,Cerealgrainsareprimarilystarch,CrossSectionofaSorghumKernel高粱横切面,Endosperm胚乳(LocationofStarch),Germ胚芽,Pericarp果皮,Endosperm胚乳,Endosperm,StarchGranule淀粉颗粒andProteinMatrix蛋白基质,Granule,Matrix,ProteinMatrix(Starchdigestedaway),Starch,Almostcompletelydigestedbyanimalsandfermentedbybacteria.,Glycogen,1.Branchedchainsofglucoselinkedbya1-4and1-6bonds2.Branchesoccurevery8to12glucosemolecules3.Molecularweightis50,000-200,0004.Sometimescalled“animalstarch”becauseitissimilarinstructuretoamylopectin支链淀粉,Glycogen,线粒体,Glycogen,5.Foundinliverandmuscle6.Notstoredinlargequantitiesinthebody7.Duringfastingorexercise,glycogenisbrokendowntoglucosewhichisusedasanimmediatesourceofenergy.,FiberisFoundinPlantCellWalls,Cellulose,1.Mostabundantsubstanceinplantkingdom2.Structuralcomponentofcellwalls3.Longstraightchainsofglucoselinkedby1-4bonds4.Notdigestedbymammalsbecauseanimalsdonothavecelluloseenzymes;digestedbybacteriainthegastrointestinaltract5.Cottonisalmostpurecellulose.,CelluloseMicrofibrilsinAppleSkin苹果皮中素微纤维,1X1Micron微米,Hemicellulose半纤维素,Heterogeneousgroupofpolysaccharides异质多糖associatedwithcelluloseandligninincellwall,Hemicellulose,2.Compositiona.Shortchainpolysaccharidesconsistingofabackbonechainofxylose,mannoseandgalactosewithsidebranchingchainsofarabinose,glucuronicacidandgalactose.甘露糖葡、萄糖醛酸b.Directbondingofhemicellulosesugarstoligninc.Intermixedwithcellulosefibers,Hemicellulose,Notwelldigestedbyanimals;morefermentablethancellulosebybacteria,Pectins果胶,HighmolecularweightcolloidalcarbohydratesfoundinthecellwallOftencalledintracellularcement细胞内接合剂;foundmainlyinmiddlelamellaofcellwalls细胞壁中胚层Composition-Chainsofgalacturonicacidwithassociatedarabans(chainsofarabinose)andgalactans(chainsofgalactose)Watersoluble,formsgelsNotdigestedbymammals;fermentedbybacteria,Pectin,LIGNIN,1.Notatruecarbohydrate;itisapolymerofphenylpropanemolecules2.Chemicallylinkedwithcelluloseandhemicellulose3.Providesrigiditytocellwall4.Highcontentinwoodypartsofplants,LigninStainedRedinWood,LIGNIN,5.Increaseswithplantmaturity6.Indigestiblebyanimalsandbacteria,WhyFiberContentofAnimalFeedsIsImportant,Fiberanalysesisonemeansofestimatingthenutritionalvalueoffeedstuffs.Asfibercontentincreases,nutritionalvaluedecreassFiberisfoundonlyinplants,primarilyinthecellwalls.,PlantCellWalls,Plantcellwalls,CrudeFiber,Sample,Boiled30min.in1.25%H2SO4,Filtered,Residue,Solubles,Boiled30min.in1.25%NaOH,Residue,Solubles,Filtered,Burned,CrudeFiber,Ash,DriedFatremovedbyExtractedwithether,CrudeFiber,Assumesmaterialnotsolubleinweakacidandbaseare“fiber”.Oldestsystemstillinuse;originallydevelopedinmid1800s.Crudefiberdoesapoorjobofquantifyingthefibercontentoffeeds,hemicellulosesarenotmeasured.Itisstillusedtoguaranteemaximumfibercontentincommercialanimalfeeds.,VanSoestMethod,Sample,Heatedinaneutraldetergentsolution(pH7.0)for1hour,Filtered,NeutralDetergentFiber(NDF)(cellwalls-cellulose,hemicellulose,legnin+ash),Cellcontentsandpectin(protein,lipids,andsolubleCHO),Heatedinaciddetergentsolution,(1NH2SO4)for1hour,Filtered,Hemicellulose,AcidDetergentFiber(ADF)(cellulose,lignin,ash),72%H2SO4,Cellulose,Lignin+ash,Lignin,Ash,Burn,VanSoestMethod,Separatescellwalls(totalfiber)fromcellcontentsthenseparatesoutthepartsoffiberMostcommonmethodofdeterminingfiberinanimalfeedsNDFisthebestindicatoroftotalfibercontentinanimalfeedsADFiscommonlyusedasapredictorfordigestibility(energycontent)offorages,becauseitcontainsthetwoleastdigestiblefractionsoffiber,DietaryFiber,Sample,Etherextraction,Lipids,Residue,Heatstableamylase,Protease,Amyloglucosidase,Theseenzymesmimicdigestioninthestomachandsmallintestineofhumans.,Ethanoltoprecipitatesolublefiber,Solublesugarsandproteins,Filter,Residue,Burnpartofresiduetodetermineash,Partofresidueisanalyzedtodetermineinsolubleprotein,Dietaryfiberisdeterminedbysubstractingashandproteincontentfromtheresidue,DietaryFiber,UsesenzymaticdigestiontomimicdigestioninhumansDietaryfibercanbesubdividedintotwocategories.,DietaryFiber,Insolublefiberprocedureidenticaltotheoneaboveexceptethanolisnotaddedtoprecipitatethefiberssolubilizedbyenzymaticdigestion.Solublefiber=Totalfiberinsolublefiber.HighintakesofsolublefiberbyhumansisassociatedwithlowerincidenceofheartdiseaseHighintakesofinsolublefiberbyhumansisassociatedwithlowerincidenceofcoloncancer.,ComparisonofMethods,Whichofthebermudagrasshayswasmostmatureatharvest?,Hay1has46%ADFHay1has38%ADFHay1has28%ADF,Whichofthebermudagrasshayswouldmostlikelybethemostfermentable?,Hay1has46%ADFHay1has38%ADFHay1has28%ADF,ImportanceofCarbohydratesinAnimalandHumanNutrition,Carbohydratesaretheprimarysourceofdietaryenergyforfarmanimalsandhumans.Farmanimalsarefedprimarilyplants;seedsthatcontainstarch,orforagesthatcontainfiber.Therearenodietaryessent