食品营养价值分析.ppt

WeinaTian,食品营养价值分析,proteinlipidsmacronutrientscarbohydrate(dietaryfiber)nutrientswatervitaminmicronutrientsmacroelementsminerals核酸nucleicacid?microelements,含量-16%19%.更新：动态平衡，不断更新，每天约3%，肠和骨髓最快。,Section1Protein(蛋白质),一、蛋白质,（一）人体中蛋白质：,（二）功能：,机体构成成分构成各种生理活性物质和重要的生理功能提供热能,1.种类：20种(1)必需AA（EAA）(2)非必需氨基酸（NEAA）(3)半必需氨基酸(semi-EAAorconditionalEAA)半胱酸（Cysteine）蛋氨酸（Methionine）酪氨酸（Tyrosine）苯丙氨（Phenylalanine）2.必需氨基酸：人体不能合成或合成速度不能满足机体需要，必需从食物中直接获得的AA。Aminoacidsthatthebodycannotsynthesizeinamountsufficienttomeetphysiologicalneedsandhastoobtainthemfromfoods.,二、氨基酸和必需AA(essentialaminoacid,EAA),表1-1人体内的氨基酸,*组氨酸为婴儿必需氨基酸，成人需要量可能较少。摘自ModernNutritioninHealthandDisease,第9版,第14页,1999。,1.氨基酸模式(AAPattern)：蛋白质中各种必需氨基酸的构成比例。,氨基酸模式(AAPattern)和限制氨基酸(limitingAA),表1-2几种食物和人体蛋白质氨基酸模式,数据摘自营养与食品卫生学，第3版，第9页。,2.限制氨基酸（limitingaminoacid）：,与人体蛋白质模式比较，食物蛋白质中含量相对较低的必需AA。Theessentialaminoacidfoundintheshortestsupplyrelativetotheamountneededforproteinsynthesisinthebody.,3.参考蛋白、完全蛋白和蛋白质的互补作用,参考蛋白,用于测定食物蛋白质质量的标准蛋白。ReferenceProtein:Astandardagainstwhichtomeasurethequalityofotherproteins.,完全蛋白,必需氨基酸模式与人体蛋白质相对一致，能满足机体蛋白质合成需要的食物蛋白质。CompleteProtein:Adietaryproteincontainingalltheessentialaminoacidsinrelativelythesameamountsthathumanbeingrequired.(includinganimalproteinandsoyprotein)Incompleteprotein,蛋白质互补,将两种或两种以上的食物蛋白质混合事用，使不同食物中必需氨基酸以多补少，从而提高膳食蛋白质的营养价值。ComplementaryProtein:Twoormoreproteinswhoseaminoacidsassortmentscomplementeachotherinsuchawaythattheessentialaminoacidsmissingfromonearesuppliedbytheother.,几种食物混合后蛋白质的生物价,三、蛋白质的消化、吸收和代谢,（一）消化和吸收（digestionandabsorption）,1.代谢,图1-1蛋白质代谢及氮平衡,代谢与氮平衡(metabolismandnitrogenbalance,氮平衡（Nitrogenbalance）,(1)必要的氮损失（obligatorynitrogenlosses）(2)氮平衡：BI（UFS）,食物蛋白质营养学评价,(1)真消化率（true-）,(一)蛋白质含量(content）,(2)表观消化率（apparent-）,(二)蛋白质消化率(digestibility),蛋白质利用率（utilization）,1.Biologicalvalue,BV:生物价,Theamountofproteinnitrogenthatisretainedforgrowthandmaintenance,expressedasapercentageoftheproteinnitrogenthathasbeendigestedandabsorbed.Todeterminetheactualvalueofanabsorbedproteinasitisusedbythebody.,NetProteinUtilization,NPU蛋白质净利用率,Theamountofproteinnitrogenthatisretainedfromagivenamountofproteinnitrogeneaten.Todeterminetheaminoacidcompositionanddigestibilityofatestprotein.,ProteinEfficiencyRatio,PER:蛋白质功效比值,Ameasureofproteinqualityassessedbydetermininghowwellagivenproteinsupportsweightgainingrowingrats.Usedtoestablishtheproteinqualityforinfantformulasandbabyfoods.,AminoAcidScore,AAS氨基酸评分,ThelowestscoreisthescoreoflimitingAAwhichistheAASoftheprotein.Amethodofevaluatingproteinqualitybycomparingatestproteinsaminoacidpatternwiththatofareferenceprotein;sometimescalledchemicalscoring.,表1-4几种食物和不同人群需要的氨基酸评分模式,摘自WTOTechnicalReportSeries724,第12页,1985年。,表1-5常见几种食物蛋白质质量,摘自“营养与食品卫生学”，第3版，第11页。,ProteinDigestibilitycorrectedAAS,PDCAAS:（经消化率校正的氨基酸评分）,AmeasureofproteinqualityassessedbycomparingtheaminoacidscoreofafoodproteinWiththeaminoacidrequirementsofpreschool-ageChildrenandthencorrectingforthetruedigestibilityoftheprotein;RecommendedbytheFAO/WHOandusedtoestablishproteinqualityoffoodsfordailyvaluepercentageonfoodlabels.,表1-6几种食物蛋白质的PDCAAS,摘自UnderstandingNutrition,第7版，第215页，1996年。,Kwishiorkor(浮肿型):AGhanaianwordmeaning“theevilspiritthatinfectsthefirstchildwhenthesecondchildisborn”.Thesecondchildsuddenlyswitchedfromnutrientdense,protein-richbreastmilktoastarchy,protein-poorcereal,soonbeginstosickenanddie.,Marasmus（消瘦型）:Aseveredeprivationoffoodoveralongtime(chronicPEM)andthereforeiscausedbyaninadequateenergyandproteinintake(andbyinadequateessentialfattyacids,vitamins,andmineralsaswell).,蛋白质营养不良（protein-energymalnutritio）,蛋白质营养不良,Kwashiorkor,Marasmus,Marasmus,Kwashiorkor,Infancy(lessthan2yr),olderinfants(1-3yr),Developsslowly;chronicPEM,rapidonset;acutePEM,Severeweightloss,someweightloss,Severemusclewasting,withfat,Somemusclewasting,withretentionofsomebodyfat,Growth:60%weight-for-age,growth:60%-80%weight-for-age,Nodetectableedema,edema,Nofattyliver,enlargedfattyliver,Anxiety焦急,apathy淡漠,apathy,misery痛苦,irritability易怒,sadness,Goodappetitepossible,lossofappetite,Hairissparse,thinanddry;Easilypulledout,hairisdryandbrittle;easilypullout;changescolor;becomesstraight,Skinisdry,thin,andeasilywrinkles,skindevelopslesion,高蛋白质膳食过多的危害（problemsofexcessprotein）,AdultBoneLoss(Osteoporosis骨质疏松):Calciumexcretionrisesasproteinintakeincreases.Recommen-dationofcalcium-to-proteinismorethan20(mg)to1(g).,Cancer:populationstudiessuggestacorrelationbetweenhighintakesofanimalproteinandsometypecancer(cancerofcolon,breast,kidneys,pancreas,andprostate),GainWeight:Protein-richfoodsareoftenfat-richfoods.Others.,HeartDisease:Foodsrichinanimalproteintendtoberichinsaturatedfatsandcholesterol;homocystei（高半胱氨酸）maybeanindependentriskfactorforheartdisease.,RNI:1)数量2）质量(优质蛋白质)Assessmentofproteinnutritioninhumanbody(1)Serumalbumin:35-50g/L(2)Serumtransferritin:2.2-4g/L(3)Retinol-bindingprotein:26-76mg/L(4)Thyroxine-binding-albumin:280-350mg/L3.FoodSource:animalandplantfoods.MilkandSoybeen,蛋白质供给量和食物来源（DRIsandFoodsource）,中国居民膳食蛋白质的推荐摄入量:RNI与RDA,RNI与RDA：续表,Section2Lipids(脂类),固醇类,sterols：,脂类,甘油三脂,triglycerides：,磷脂,phospholipids,一、脂类的分类Classification,一、脂类的功能(function),Structure：1glycerol3fattyacidsFunction,（一）triglycerides,甘油三脂(TG),(3).riskofhigh-fatdiet,Heartdisease:Foodsaturatedfat(especially12,14,16carbons)raisesbloodcholesteroldramatically,whichcausesheartattackorstroke.Obesity:High-fatdiettendtostorebodyfatefficiently.(3)Cancer:Prostatecancerisastrongassociationwithfat;Breastcancerisalittleornoassociationwithdietfat.(4)Riskfromtrans-fattyacids:TheyraiseLDLandlowerHDL.,(二)fattyacids,脂肪酸(FA),chainlength:long-chain(1014carbonsormore)medium-chain(6or8-)short-chain(24or26)Saturation:saturatedFA(SFA)monounsaturatedFA(MUFA)polyunsaturatedFA(PUFA)positionofdoublebond:“n”or“”“n-3”:theinitialdoublebondsituatedbetweenthethirdand4thcarbonatomsfromthemethylend.“n-6”:theinitialdoublebondisbetweenthe6and7isomericforms异构体:cis顺式；trans反式,(1)Classification,(2).Essentialfattyacid,必需脂肪酸(EFA),Definition:,Classification:,(1)linoleicacid(亚油酸).C18:2,n-6(2)-linolenicacid（亚麻酸）.C18:3,n-3,Fattyacidsneededbythebody,butnotmadebyittomeetphysiologicalneeds.,SynthesizeofMUFAinbody,linoleicacid(C18:2,n-6)-linolenicacid(C18:3,n-3)6去饱和酶-linolenicacid(C18:3,n-6)十八碳四烯酸(C18:4,n-3)bi-homotype-linolenic二十碳四烯酸(C20:4,n-3)acid(C18:3,n-6)5去饱和酶arachidicacid(AA)timnodonicacid(EPA)(C20:4,n-6)(C20:5,n-3)二十二碳四烯酸(C22:4,n-6)clupanodonicacid(C22:5,n-3)4去饱和酶二十二碳五烯酸(C22:5,n-6)docosahexenoicacid(DHA)(C22:5,n-3),碳链延长酶,碳链延长酶,1.Structure：,Itconsistofaglycerolbackbonewithoneortwoattachedfattyacids,plusadifferentstructurethatincludesaphosphategroupattachedtotheotherhydroxylgroup(s).Themostimportantmemberislecithins（卵磷脂）.,(三)磷脂(phospholipid),(四)固醇(Sterols),1.Structure:,Asamemultipleringwithdifferentsidegroupsattached.Cholesterolisthemostimportant.,2.Function:,Essentialtothestructureandfunctionofcells,especiallythecellmembrane(about90%oftotalbodycholesterol).Cholesterolistheoriginalmaterialforsynthesisofmanyvitallyimportantbodycompoundssuchasbile,sexhormones,adrenalhormone,andvitaminD.,3.Harmfuleffects:,Itformsdeposits(沉积物)inthearterywallswhichleadtoatherosclerosis(动脉粥样硬化)-adiseasethatcausesheartattacksandstrokes.,HDLmadeinthelivercarrycholesterolsandphospholipidsfromthecellsbacktotheliver.,TheylosetriglyceridesandgathercholesterolfromOtherlipoproteinscirculatingthroughthebloodstreamAndbecomeLDL,Metabolismofcholesterol,三、FoodsourceandRDA脂类的食物来源及供给量,Foodsource:,1).Animalfat:plentyofSFA,2).Vegetableoil:plentyofMUFA,LinoleicAcid(n-6),leafyvegetables,seeds,nuts,grains,vegetableoil(corn,safflower红花,soybean,cottonseed,sesame芝麻,sunflower),ArachidonicAcid(n-6),meats,canbesynthesizedfromlinoleicacid,linolenicacid（n-3）,fatsandoil(soybean,walnut胡桃,wheatgerm),EPAandDHA(n-3),Humanmilk,shellfishandfish(mackerel鲐鱼,tuna金枪鱼,salmon大麻哈鱼,sturgeon鲟鱼,herring鲱鱼,trout鳟鱼,sardines沙丁鱼),canbemadefromlinolenicacid.,2.DRIs:basicprinciple,percentageoftotaldietaryenergy：20%-30%SFA/totaldietaryenergyfemale(3)Age:2%ofdeclineper10yearsafterage305%ofdeclineper10yearsafterage60(4)Nutritionstate:LowenergyintakedecreasesBMRabout10%-20%(5)Physiologicalstatus:PregnancyincreasesBMR(6)Bodytemperature:FeverincreasesBMR(7)Highorlowairtemperature,hormonesystemactivity,nerveandeatingtoomuchincreaseBMR(AdaptiveThermogenesis,适应性生热作用)(8)CaffeineandtobaccoincreaseBMR,(二)PhysicalActivity,Theenergyneededduringphysicalactivitydependsonbodyleanmass,intensity(强度)andtimeofactivity.Theenergyisabout15%-30%oftotalenergyuseinsedentary(久坐的)people.,(三)Specificdynamicaction(orThermicEffectofFood,TEF)食物特殊动力作用或食物热效应,1.Definition,Theamountofextraenergyusedbybodyduringdigestion,absorption,metabolism,andstorageofenergy-yieldingnutrients.,2.Energyexpenditure,5%-6%oftotalcalorieproducedbycarbohydrates,carbohydrates,lipids,4%-5%ofthat,protein,30%ofthat,mixedfood,10%0ftotalenergyconsumed（消耗）,(一)calculation,三、热能需要量的确定Estimatingenergyrequirements,1.calculatingthetotalenergyexpenditure,basalmetabolis