《食品生物化学》课件-7-2重要的维生素

ImportantvitaminsFoodBiochemistry食品生物化学CONTENTS目录12Fat-solublevitaminsWater-solublevitaminsFat-solublevitamins01Importantvitamins7.2vitaminAAlsoknownasanti-dryeyevitamin,itincludesvitaminA1andA2.Whencaroteneentersthebody,itcanbeconvertedintovitaminA1,whichisaprecursortovitaminA.FoodbiochemistrystructureVitaminsA1andA2arebothunsaturatedmonoolscontainingβ-ioninrings.Thebranchedchainontheringconsistsoftwo2-methylbutadiene(1,3)andanalcoholgroup.Importantvitamins7.2FoodbiochemistryqualityStabletoalkali;Itisresistanttoheatintheabsenceofoxygen,andcanbedamagedbyoxidationbyair,oxidizingagentsandultravioletrays.Importantvitamins7.2FoodbiochemistryMaintainthehealthofepithelialcelltissueandmaintainnormalvision.VitaminAdeficiencycanleadtonightblindness,keratinizationofcornealepithelialcellsinthedigestivetractandeyes,andevendryeyedisease.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFoodsourcesVitaminA1ismainlyfoundintheliver,bloodandmarinefishofanimals,andvitaminA2ismainlyfoundinfreshwaterfish.Carrotoidsarerelativelyhighinvegetables.Importantvitamins7.2FoodbiochemistryvitamindAlsoknownasanti-ricketsvitamin.VitaminsD2,D3,D4,D5,D6andD7areknown.Amongthem,vitaminsD2andD3arethemostimportant.Importantvitamins7.2FoodbiochemistrystructureVitaminDisasterolsubstancewithacyclopentanepolyhydrophenanthrenestructure.ThevariousvitaminDvitaminsarestructurallyverysimilar,withonlybranched-chainRdifferences.Importantvitamins7.2FoodbiochemistryqualityItisquitestableinnature,noteasytobedamagedbyacid,alkalioroxygen,andhasheatresistance,butcanbedamagedbylightandexcessiveheating.Importantvitamins7.2FoodbiochemistryRegulatecalciumandphosphorusmetabolismandmaintainnormalbloodcalciumandphosphorusconcentrations.VitaminDdeficiencycancausericketsinchildren;Inadults,itcausesbonedecalcificationandosteomalacia.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFoodsourcesFishfatandanimalliverarerichinvitaminD,amongwhichseafoodcodliveroilisthemostabundant,followedbyeggyolk,milkandcream.Importantvitamins7.2FoodbiochemistryvitaminEVitaminE,alsoknownastocopherol,iswidelyfoundinseeds,seedoils,cereals,fruits,vegetables,andanimalproducts.Importantvitamins7.2FoodbiochemistrystructureAllkindsofvitaminEarederivativesofbenzotrihydropyran,butthedifferenceisthatthenumberandpositionofmethylgroupsonthephenylenenucleusaredifferent.Importantvitamins7.2FoodbiochemistryqualityItisnoteasytobedamagedbyacid,alkaliandheat,andisalsostablewhenheatedto200°Cintheabsenceofoxygen,butitisveryeasytobeoxidizedandcanbeusedasanantioxidant.Importantvitamins7.2FoodbiochemistryRelatedtoreproductivefunction,whenvitaminEisdeficient,thereproductiveorgansaredamagedandinfertility.Maleshaveatrophictesticlesandareunabletoproducesperm,whilefemalesarestillabletoconceivebutarepronetoearlymiscarriage.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionvitaminkAlsoknownasabloodclottingvitamin.TherearetwotypesofnaturalvitaminK:vitaminK1,whichisextractedfromalfalfa,andvitaminK2,whichisobtainedfromspoiledfish.Importantvitamins7.2FoodbiochemistrystructureVitaminsK1andK2arebothderivativesof2-methyl-1,4-naphthoquinone,differingonlyonthesidechains.Importantvitamins7.2FoodbiochemistryqualityBothvitaminK1andK2areheat-tolerant,buttheyareeasilydestroyedbyalkaliandlight,andvitaminK2ismoreeasilyoxidizedthanvitaminK1.Importantvitamins7.2FoodbiochemistryAcceleratebloodclotting,promotethelivertosynthesizethefactorsnecessaryforprothrombin,andparticipateintheredoxreactioninthebody.Deficiencycanleadtolowerlevelsofprothrombinandlongerbloodclotting.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFoodsourcesGreenleafyvegetablesareparticularlyrichinvitaminK1;VitaminK2isametaboliteofmanybacteria.VitaminKcanalsobesynthesizedbyintestinalbacteriainanimals.Importantvitamins7.2FoodbiochemistryWater-solublevitamins02Importantvitamins7.2VitaminB1Thechemicalnameisthiamine,andcerealsarecurrentlythemainsourceofthiamineinChina'straditionaldiet.Asgrainsarerefined,thelossofvitaminB1increases.FoodbiochemistrystructureThemoleculeofvitaminB1containsapyrimidineringwithanaminogroupandathiazoleringcontainingsulfur,soitisalsocalledthiamine.Importantvitamins7.2FoodbiochemistryqualityItisthemostunstableoftheBvitamins.Easilydegradedunderneutraloralkalineconditions;Sensitivetoheatandlight.ItcanbeconvertedintoTPPinlivingorganismsandplaysanimportantroleinglucosemetabolism.Importantvitamins7.2FoodbiochemistryParticipatesintheoxidativedecarboxylationreactionoftheintermediateproductofmonosaccharidemetabolismα-ketoacidsintheformofcoenzymes.VitaminB1cancausenervoussystemdisorders,fatigue,indigestion,polyneuritis(beriberi).Inseverecases,itcancausedeath.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFoodsourcesYeastisthemostabundantinvitaminB1,andleanmeat,stonefruitsandeggsarealsomoreabundant.Atpresent,cerealsarestillthemainsourceofthiamineinthetraditionaldietinChina.Importantvitamins7.2FoodbiochemistryImportantvitamins7.2VitaminB2Alsoknownasriboflavin,itismainlydistributedinyeast,liver,milk,leanmeat,eggyolkandotherfoods,aswellasingreenleafyvegetables,graingrainsandgerminatedseeds.FoodbiochemistrystructureRiboflavinisacondensationofD-ribolitoland7,8-dimethylisoflurazine,whichisflavin,hencethename.Importantvitamins7.2FoodbiochemistryqualityRiboflavinisthermallystable,noteasilyaffectedbyoxygenintheair,stableinacidicsolutions,butunstableinalkalinesolutions,andeasilydecomposedbylightirradiation.Importantvitamins7.2FoodbiochemistrySubstancesthatmakeupflavonasesandcoenzymesofmanyotherdehydrogenasesintherespiratorychain.IfvitaminB2isdeficientinhumans,growthstopsinchildren,andadultsdevelopdiseasessuchas"stomatitis","angularcheilitis"and"dermatitis".Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionImportantvitamins7.2pantothenicacidAlsoknownasperpenicacid,itiswidelydistributedinnature,andhumanintestinalbacteriaandplantscansynthesizepantothenicacid,soitisrarelydeficient.FoodbiochemistrystructureThechemicalnameofpantothenicacidisN-(alpha,gammadihydroxy-β,β-dimethylbutyryl)-β-aminopropionicacid.Importantvitamins7.2FoodbiochemistryqualityItisstabletodampheat,oxidationandreductioninneutralsolutions.Acids,alkalis,anddryheatcansplititintoβ-alanineandotherproducts.Importantvitamins7.2FoodbiochemistryIntheformofacetyl-CoA,itparticipatesinthemetabolismofsugars,lipidsandproteins,playstheroleoftransferringacetylgroups,andpantothenicacidisrequiredforthegrowthofavarietyofmicroorganisms.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFoodsourcesPantothenicacidiswidelypresentinthebiologicalworld,andisrichinyeast,liver,kidney,eggs,leanmeat,skimmilk,peas,peanuts,sweetpotatoesandotherfoods.Importantvitamins7.2FoodbiochemistryImportantvitamins7.2VitaminB5AlsoknownasvitaminPPandlysporosisvitamin,itincludestwocompounds,niacin(alsoknownasniacinicacid)andniacinamide(alsoknownasniacinamide).FoodbiochemistrystructureNiacinandnicotinamidearebothpyridinederivativesthataremainlyfoundinlivingorganismsintheformofnicotinamide.Importantvitamins7.2FoodbiochemistryqualityNiacinisthemoststableofvitamins,notdestroyedbylight,air,heat,nicotinamidecanbeconvertedintoniacinwhenheatedinanacidicsolution.Importantvitamins7.2FoodbiochemistryNicotinamideisamajorcomponentofCoenzymeIandCoenzymeII,whichplaysaroleinthetransportofhydrogenduringbiologicaloxidation.Whenthebodylacksniacin,itcancauseleprosydisease.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFoodsourcesNiacinandniacinamidearewidelydistributed,withyeast,liver,leanmeat,milk,peanuts,soybeans,etc.Cerealsarealsoabundantinthecortexandembryo.Importantvitamins7.2FoodbiochemistryImportantvitamins7.2VitaminB6VitaminB6,alsoknownaspyridoxine,hasthreecompounds:pyridoxine,pyridoxalandpyridoxamine.FoodbiochemistrystructurePyridoxine,pyridoxal,andpyridoxamineareallderivativesofpyrimidine.Importantvitamins7.2FoodbiochemistryqualityPyridoxineisstableinacid,easytodestroyinlye,stableinair,easytobedestroyedbylight,pyridoxineisheat-resistant,pyridoxalandpyridoxaminearenotresistanttohightemperatures.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionItisacoenzymeofavarietyofenzymesinaminoacidmetabolism.VitaminB6deficiencycancauseskininflammation,manifestedasseborrheicdermatitis,stomatitis,chappedlips,glossitis,irritability,depression,etc.Importantvitamins7.2FoodbiochemistryFoodsourcesVitaminB6iswidelydistributedintheanimalandplantkingdoms,andcontainsmorewheatgerm,ricebran,soybean,peanuts,yeast,liver,fish,meat,etc.Importantvitamins7.2FoodbiochemistryImportantvitamins7.2biotinAlsoknownasvitaminB7,vitaminH.TherearetwotypesofvitaminHinnature:α-vitaminHandβ-vitaminH.FoodbiochemistrystructureBiotinconsistsofureaandthiophenewithasidechainofvalericacid.Importantvitamins7.2FoodbiochemistryqualityBiotinisstabletolight,heat,andacid,buthightemperatureandoxidantscandestroyitandlosephysiologicalactivity.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionItisacoenzymeofavarietyofcarboxylases,suchaspyruvatecarboxylase,etc.Biotindeficiencycanleadtodermatitis,musclepain,hyperesthesia,lethargy,anorexia,mildanemia,etc.Importantvitamins7.2FoodbiochemistryFoodsourcesBiotiniswidelyfoundinanimalandplantfoods,andisabundantinmeat,liver,kidney,milk,eggyolk,yeast,vegetableandmushroom.Importantvitamins7.2FoodbiochemistryImportantvitamins7.2folicacidVitaminB11isfolicacid.Folicacidiswidelydistributedinnature,andpartoffolicacidcanbesynthesizedinthehumanintestine.FoodbiochemistrystructureVitaminB11ismadeupofpterine,para-aminobenzoicacidandL-glutamicacid.Importantvitamins7.2FoodbiochemistryqualityFolicacidisunstabletoheat,lightandacidicsolutions,anddecomposesattemperaturesabove100°Cinacidicsolutions.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionFolicacidisinvolvedinthesynthesisofmanysubstancesinthebody.Whenfolateisdeficient,itleadstomegaloblasticanemia.Folicaciddeficiencyinpregnantwomenduringthefirsttrimestercanleadtofetalneuraltubedefects.Importantvitamins7.2FoodbiochemistryFoodsourcesFolicacidiswidelydistributed,andthecontentofgreenleaves,liver,kidney,cauliflower,andyeastismore,followedbybeef,wheatgrains,etc.Importantvitamins7.2FoodbiochemistryImportantvitamins7.2VitaminB12Itisapolycycliccompoundcontainingtrivalentcobalt,alsoknownascobalaminorcobalamin.OnlymicroorganismssynthesizevitaminB12innature.FoodbiochemistrystructureThechemicalnameofpantothenicacidisN-(alpha,gammadihydroxy-β,β-dimethylbutyryl)-β-aminopropionicacid.Importantvitamins7.2FoodbiochemistryqualityItisquitestableatpH4.5-5.0,andiseasilydecomposedunderstrongacidsandbases,whichcanbedestroyedbysunlight,oxidantsandreducingagents.Importantvitamins7.2FoodbiochemistryPhysiologicalfunctionIntheformofcoenzymes,itparticipatesinvariousmetabolismsinthebodyandpromotesthesynthesisofnucleicacids;Maintainnormalhematopoieticfunction.Humanintestinalbacteriacanbesynthesized,anddeficiencycancauseperniciousanemia,neuritis,nerveatrophy,etc.Importantvitamins7.2FoodbiochemistryFoodsourcesThemainsourcesaremushroom