食品专业英语课件5-food chemistry and nutrition

EnglishforFoodFoodQualityandSafetyYuanYuanLessonFoodNutritionalElementsofFood,clothingandshelterformthebasicneedsofman.Thenutritionalelementsoffood,whichareessentialforallthelifeprocesses,makefoodoneofourbasicneeds.[1]Thisiswhy‘food’comesfirstinthebasicnecessitiesofman!Whenwetalkoffoodbasics,weintendtoexpressthebody’srequirementoffood.LetuslookatthenutritionalelementsoffoodandtherolestheyyinmaintainingtheCarbohydrates[ˌkɑ:bəəuˈhaidreit],fats,vitamins,minerals,proteins,fiberandwaterconstitutethebasicnutritionalelementsoffood.Theyarecategorizedbasedontheamountsinwhichthebodyrequiresthem.[2]Thenutrientsrequiredinrelativelylargeramountsbythebodyareclassifiedasmacronutrients[ˌmækrəəuˈnju:triəənt].Carbohydrates,fats,proteins,waterandfiberbelongtothisclassofnutrients.VitaminsandmineralsarerequiredincomparativelysmalleramountsandhencecalledmicronutrientsNutritionalElementsofCarbohydrates,fatsandproteinsarethesourcesofenergy.Carbohydratesgivefourcaloriesofenergypergramwhileonegramoffatgivesninecaloriesofenergy.Moleculesofcarbohydratesandfatsarecomposedofcarbon,hydrogenandoxygenatoms.Proteinsadditionallycontainnitrogenatoms.Foodscontainsomeorallofthenutrientsincertainproportions.Itisthesenutritionalelementsoffoodthathelpmaintainmetabolismofthebodyandkeepushealthy.Letuslookateachofthemindetail.Carbohydrates:Basedonthenumberofsugarunitstheycontain,carbohydratesareclassifiedasmonosaccharides,disaccharides,orpolysaccharides.Theycontain1,2and3ormoresugarunitsrespectively.Carbohydratesrequirelesswatertodigestandmakeupthemostcommonsourceofenergy.Asthebodycanobtainenergyfromproteinsandfats,theyarenottheessentialnutrients.Carbohydrate-richfoodstuffsincludebread,pastas,riceandbeans.⚫Fats:Theycontainfattyacidsandglycerol.Ifamoleculeoffathasallitscarbonatomsbondedtohydrogenatoms,itisknownasasaturatedfat.Incase,someofitscarbonatomsaredoublybondedtoeachother,itisanunsaturatedfat.[3]Saturatedfatsaresolidswhileunsaturatedfatsareliquids.Fatsdisintegrateformingfattyacidsandglycerol.[4]Fattyacidsareanessentialdietaryneedwhileglycerolisusedtoproduceglucose.Thismakesfatstheenergystoresofourbody.Apartfromthis,theyactasabufferfordiseases,theymaintainbodytemperatureandassistthefunctioningofcells.[5]FatsactassolventsforvitaminsA,D,EandK.Bodycanabsorbthesevitaminsonlywiththehelpoffats.Nuts,oilandbuttercontainfats.Fatsarealsoresponsibleforhealthyskinandhair.regulatecellandtissuegrowth.Theyarevitalnutrients.Eachofthevitaminsifconsumedinamountslessthanthoserequiredbytheleadstoadeficiency

Thisevidenttheirimportancetothebody.⚫⚫VitaminA,knownasretinal,ysamajorroleineyesight.Itsdeficiencyleadstonight-blindness.Sourcesofthisvitaminincludecarrotsandcodliveroil.⚫VitaminBcomesindifferentformssuchasB1,B2,B3,B5,B6,B7,B9andB12.RicebranisamajorsourcevitaminB1whileB2isfoundineggs.Liverprovidesotherformsofthisvitamin.B6ysaroleinproteinmetabolismandformation.Itisnecessaryforthedevelopmentofahealthyimmunesystem.Itysacrucialroleinfertility.VitaminB12isimportantforproperfunctioningofthenervoustissue.B1withthechemicalnamethiamineisresponsibleforneuralfunctionandcarbohydratemetabolism.Itisnecessaryforhealthymucusmembranes.B2isinstrumentalinthemaintenanceofnormalvisionandhealthyskin.Itisacoenzymeusedinmetabolismofenergy.DeficienciesofvitaminsB6andB12mayleadtoAnemia.DeficiencyofB9inpregnantwomenleadstobirthdefectsinchildren.healthygumsandteeth.Itincreasesabsorptionofironbythebodyandhelpsfightinfections.Citrusfruits,cabbage,pineapplesandbroccoliarerichsourcesofvitaminC.⚫⚫SunlightistherichestsourceofvitaminD.Cheese,liverandsalmonareothers.Thisvitaminhelpsintheabsorptionofcalciumandphosphateandysavitalroleinthehealthofbonesandteeth.⚫⚫Functionsofvitaminsaresomuchinter-related.VitaminEhelpspreventdestructionofvitaminsAandC.WheatgermandgreenleafyvegetablesarerichinvitaminE.synthesisofproteinsinsma,bonesandkidneysisbroughtaboutbyvitaminK.Itisalsonecessaryfornormalclottingofblood.Spinach,lettuce,cabbageandcaulifloweraresourcesofvitaminK.⚫⚫Minerals:Oystersisanaturalsourceofminerals.Iodizedsaltisanexampleofmineraladdedasasupplement.Calcium,magnesiumandphosphorous,helpfulinthegrowthandhealthofbonesareafewoftheessentialminerals.Sodium,potassium,iodineasalsoironandzincareotherusefuldietaryminerals.⚫⚫Proteins:Proteinsareoftenknownasthebuildingblocksofthebody.Theaminoacidsthattheycontainformthestructuralelementsofthebody.Proteinsareparticularlyneededduringthegrowthperiodofanyanimal.Meat,grains,eggsandmilkarerichinprotein. provide the body

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majorroleintheprocessofWholegrainfood,branandceleryareWeallknowthat70%ofthebodyiswater.Thisfactissufficienttoillustratetheimportanceofwaterasabasicnutrient.Humanbodyneedsaround1-7litersofwatereveryday.Needofwaterdependsonthephysicalactivityofeveryindividual.Waterpreventsthedehydrationofthebody.⚫⚫Nutritionisascience.Itisakeymaintainanoptimalstateofhealth.Wedon’t‘livetoeat’butwedefini y‘eattolive’.Rightfoodconsumedinrighttieshelpsusleadahealthyandahappy返回幻灯【1】Thenutritionalelementsoffood,whichareessentialforallthelifeprocesses,makefoodoneofourbasicneeds.主语Thenutritionalelementsoffood与谓语makefoodoneofourbasicneeds之间插入了一个非限制性定语从句whichareessentialforallthelifeprocesses造成了主谓分割。谓语部分的make是使动词，oneofourbasicneeds个句子是因果逻辑关系，因此全句的通顺译文可以返回幻灯【2】Theyarecategorizedbasedontheamountsinwhichthebodyrequiresthem.本句讲基本营养素分类的依据是对它们的需求量，下文的说法是：Thebodyrequiressomenutrientsinrelativelylargeramountsandtheotheronesincomparativelysmalleramounts.因此定语从句中出现了inwhich。【2】Theyarecategorizedbasedontheamountsinwhichthebodyrequiresthem.本句讲基本营养素分类的依据是对它们的需求量，下文的说法是：Thebodyrequiressomenutrientsinrelativelylargeramountsandtheotheronesincomparativelysmalleramounts.因此定语从句中出现了in返回幻灯【3】Incase,someofitscarbonatomsaredoublybondedtoeachother,itisanunsaturatedfat.所谓carbonatomsaredoublybondedtoeachother，就是—C=C—双键，因此中返回幻灯【4】Fatsdisintegrateformingfattyacidsandglycerol.伴随情况的状语，即“脂肪时产【5】Apartfromthis,theyactasabufferfordiseases,theymaintainbodytemperatureandassistthefunctioningofcells.肪。Apartfromthis,theyactasabufferfordiseases,中，this一定是下指，即theyactasabufferfordiseases“脂肪的功能是对疾病产生缓冲作用”，返回幻灯【6】Eachofthevitaminsifconsumedinamountslessthanthoserequiredbythebody,leadstoadeficiencydisease.主语Eachofthevitamins后面跟了个if条件从句把其与谓语部分leads deficiencydisease分 。if条件从句是一个省略句，说全了应该是ifitisconsumedinamountslessthanthoserequiredbythebody.全句的译文可 【7】Thismakesevidenttheirimportancetothebody.和宾补的顺序颠倒了。主语：this，使动词makes，宾语是theirimportancetothebody，宾补是形容词evident。全句汉译“这充分显示了维生素对于的重要TheNutritionSourceFoodPyramids:WhatShouldYouReallyEat?Morethanadecadeandahalfago,theU.S.DepartmentofAgriculture(USDA)createdapowerfulandenduringicon:theFoodGuidePyramid.ThissimpleillustrationconveyedinaflashwhattheUSDAsaidweretheelementsofahealthydiet.[1]ThePyramidwastaughtinschools,appearedincountlessmediaarticlesandbrochures,andwassteredoncerealboxesandfoodlabels.Tragically,theinformationembodiedinthispyramiddidn'tpointthewaytohealthyeating.Whynot?Itsblueprintwasbasedonshakyscientificevidence,anditbarelychangedovertheyearstoreflectmajoradvancesinourunderstandingoftheconnectionbetweendietandhealth.Withmuchfanfare,in2005,theUSDAretiredtheoldFoodGuidePyramidandreceditwithMyPyramid,anewsymboland"inctivefoodguidancesystem."ThenewsymbolisbasicallytheoldPyramidturnedonitsside.ThegoodnewsisthatthisdismantlesandburiestheflawedPyramid.Thebadnewsisthatthenewsymboldoesn'tconveyenoughinformationtohelpyoumakeinformedchoicesaboutyourdietandlong-termhealth.Anditcontinuestomendfoodsthataren'tessentialtogoodhealth,andmayevenbedetrimentalinthe tiesincludedin flawed[flɔːd]有瑕疵的detrimental[ˌdetriˈmentl]AsanalternativetotheUSDA'sflawedpyramid,facultymembersattheHarvardSchoolofPublicHealthbuilttheHealthyEatingPyramid.ItresemblestheUSDA'sin Healthy

Eating

consideration,andputsinto ,thewealthofresearchconductedduringthelast15yearsthathasreshapedthedefinitionofhealthyeating.[2]PyramidInthechildren'sbookWhoBuiltthePyramid?differentpeopletakecreditforbuildingtheonce-grandpyramidofSenwosret.KingSenwosret,ofcourse,claimsthehonor.Butsodoeshisarchitect,thequarrymaster,thestonecutters,slaves,andtheboyswhocarriedwatertotheworkers.[3]TheUSDA'sMyPyramidalsohadmanybuilders.Someareobvious—USDAnutrition experts,

staff members, and effortsfromavarietyoffoodindustriesalsohelpedshapethepyramid.lobbyIntheory,theUSDApyramidshouldreflectthenutritionadviceassembledintheDietaryGuidelinesforAmericans.AccordingtotheUSDA,theguidelines"provideauthoritativeadviceforpeopletwoyearsandolderabouthowgooddietaryhabitscanpromotehealthandreduceriskformajorchronicdiseases."[ ,whichbylawmustberevisedeveryfiveyears,aimstooffersoundnutritionadvicethatcorrespondstothelatestscientificresearch;indeed,onApril10,2008,theUSDAandtheU.S.DepartmentofHealthandHumanServicesannouncednstoformtheadvisorycommitteeforthe2010versionoftheguidelines.Thepanelassembledtocreatetheguidelinesusuallygenerates100orsopagesofdense istranslatedintoareaderfriendlybrochureaimedatheltheaverage chooseabalancedandhealthydiet.Offargreaterimportance,theDietaryGuidelinesforAmericanssetthestandardsforallfederalnutritionprograms,includingtheschoollunchprogram,andhelpsdeterminewhatfoodproductsAmericansbuy.Inotherwords,theguidelinesinfluencehowbillionsofdollarsarespenteachyear.Soevenminorchangescanhurtorhelpafoodindustry.Accordingtofederalregulations,thepanelthatwritesthedietaryguidelinesmustincludenutritionexpertswhoareleadersinpediatrics,obesity,cardiovasculardisease,andpublichealth.Selectingthepanelistsisnoeasytask,andissubjecttointenselobbyingfromorganizationssuchastheNationalDairyCouncil,UnitedFreshFruitandVegetableAssociation,SoftDrinkAssociation,AmericanMeatInstitute,NationalCattlemen'sBeefAssociation,andWheatFoodsCouncil.[4]pediatrics[ˌpi:di‘ætriks]DietaryGuidelinesTwoStepsForward,OneStepReleasedinearlyJanuary2005,theDietaryGuidelinesforAmericans2005continuestoreflectthetenseinter yofscienceandthepowerfulfoodindustry.Severalof mendationsinthecurrentversionrepresentimportantstepsintherightdirection:Thecurrentguidelinesemphasizetheimportanceofcontrollingweight,whichwasnotadequa yaddressedinpreviousversions.Andtheycontinuetostresstheimportanceofphysicalactivity. Themendationondietaryfatsmakesaclearbreakfromthepast,whenallfatswereconsideredbad.Theguidelinesnowemphasizethatintakeoftransfatsshouldbeaslowaspossibleandthatsaturatedfatshouldbelimited.Thereisnolongeranartificiallylowcaponfatintake.[5]Thelatestadvicemendsgettingbetween20and35percentofdailycaloriesfromfatsandrecognizesthepotentialhealthbenefitsofmonounsaturatedandpolyunsaturatedfats.Insteadofemphasizing"complexcarbohydrates,"atermusedinthepastthathaslittlebiologicalmeaning,thenewguidelinesurgeAmericanstolimitsugarintakeandtheystressthebenefitsofwholegrains.Othersremainmiredinthe⚫Theguidelinessuggestthatitisfinetoconsumehalfofourgrainsasrefinedstarch.That'sashame,sincerefinedstarches,suchaswhitebreadandwhiterice,behavelikesugar.Theyaddemptycalories,haveadversemetaboliceffects,andincreasetherisksofdiabetesandheartdisease.mired[‘maired]⚫Intermsofprotein,theguidelinescontinuetolumptogetherredmeat,poultry,fish,andbeans(includingsoyproducts).Theyaskustojudgetheseproteinsourcesbytheirtotalfatcontent,and"makechoicesthatarelean,low-fat,orfat-."Thisignorestheevidencethatthesefoodshavedifferenttypesoffats.Italsooverlooksmountingevidencethatrecingredmeatwithacombinationoffish,poultry,beans,andnutsoffersnumeroushealthbenefits. nokesftkrtesfrys rpneg.f⚫e t⚫ kaysoen0asa.ssa⚫eresfsoWhat’smore,millionsofAmericansarelactoseintolerant,andevensmallamountsofmilkordairyproductsgivethemstomachaches,gas,orotherproblems.Thismendationignoresthelackofevidenceforalinkbetweenconsumptionofdairyproductsandpreventionofosteoporosis.Italsoignoresthepossibleincreasesinriskofovariancancerandprostatecancerassociatedwithdairyproducts. [əəu‘vɛəəriəən]的prostateWhatisonthehorizonforthenextversionoftheDietaryGuidelinesforAmericans,dueoutlaterin2010?[6]Thescientificadvisorycommitteeforthe2010guidelinesreleaseditsreportonJune15,2010.Thecommittee mendedthatthenextitionoftheguidelinescallforreducingoverallcalorieintakeacrosstheU.S.populationandincreasingition[ˌitəəˈreiʃəən]重复，循环physicalactivitytoreducethenumberofAmericanswhoareoverweightorobese;shiftingtoamore diet;andreducingtheintakeoffoodscontainingaddedsugarsandsolidfats(whichdelivercaloriesbutfew remainstobeseenhowthese mendationswillbedistilledintothefinalguidelines.TheUSDAPyramid,BrickbyDistillingnutritionadviceintoapyramidwasastrokeofgenius.Theshapeimmediaysuggeststhatsomefoodsaregoodandshouldbeeatenoften,andthatothersaren'tsogoodandshouldbeeatenonlyoccasionally.Thelayersrepresentmajorfoodgroupsthatcontributetothetotaldiet.MyPyramidtriestodothisinan way,andfails.SixswathsofcolorsweepfromtheapexofMyPyramidtothebase:orangeforgrains,greenforvegetables,redforfruits,ateenybandofyellowforoils,blueformilk,andpurpleformeatandbeans.Eachstripestartsoutasthesamesize,buttheydon'tendthatwayatthebase.Thewidthssuggesthowmuchfoodshouldchoosefromeachgroup.AbandofstairsrunningupthesideofthePyramid,withalittlestickfigurechuggingupit,servesasareminderoftheimportanceofphysicalactivity.[7]MyPyramidcontainsnotext.AccordingtotheUSDA,itwas"designedtobesimple,"anddetailsareatMyPyramid..Unlessyou'vetakenthetimeto efamiliarwiththePyramid,though,youhavenoideawhatitmeans.RelyingontheWebsitetoprovidekeyinformation—likewhatthecolorstripesstandforandwhatthebestchoicesareineachfoodgroup—guaranteesthatthemillionsofAmericanswithoutaccesstoacomputerortheInternetwillhavetroublegettingtheseessentialfacts.[8]TheUSDAalsochosenottoputmendednumbersofservingsonthenewPyramidbecausethesedifferfromindividualtoindividualaccordingtoweight,gender,activitylevelandage.Instead,italizedPyramidsatMyPyramid.BuildingaBetterIftheonlygoalofMyPyramidistogiveusthebestpossibleadviceforhealthyeating,thenitshouldbegroundedintheevidenceandbeindependentofInsteadofwaitingforthistohappen,nutritionexpertsfromtheHarvardSchoolofPublicHealthcreatedtheHealthyEatingPyramid,andupdateditin2008.TheHealthyEatingPyramidisbasedonthebestavailablescientificevidenceaboutthelinksbetweendietandhealth.ThisnewpyramidfixesfundamentalflawsintheUSDApyramidandofferssoundinformationtohelppeoplemakebetterchoicesaboutwhattoeat.TheHealthyEatingPyramidsitson

stronglyinfluenceyourchancesofstayinghealthy.Theyalsoaffectwhatyoueatandhowyourfoodaffectsyou.Exerciseandweightcontrolarealsolinkedthroughthesimpleruleofenergybalance:Weightchange=caloriesin–caloriesout.Ifyouburnasmanycaloriesasyoutakeineachday,there'snothingleftoverforstorageinfatcells,andweightremainsthesame.Eatmorethanyouburn,though,andyouendupaddingfatandpounds.Regularexercisecanhelpyoucontrolyourweight,anditiskeypartofanyweight-losseffort.2015-2020Dietary Every5yearssince1980,aneweditionoftheDietaryGuidelinesforAmericanshasbeenpublished.Itsgoalistomakemendationsaboutthecomponentsofahealthyandnutritionallyadequatediettohelppromotehealthandpreventchronicdiseaseforcurrentandfuturegenerations.Althoughmanyofitsmendationshaveremainedrelativelyconsistentovertime,theDietaryGuidelineshasevolvedasscientificknowledgehasgrown.Theseadvancementshaveprovidedagreaterunderstandingof,andfocuson,theimportanceofhealthyeatingpatternsasawhole,andhowfoodsandbeveragesactsynergisticallytoaffecthealth.Therefore,healthyeatingpatternsisafocusofthe2015-2020DietaryGuidelines.TheFollowahealthyeatingpatternacrossthelifespan.Allfoodandbeveragechoicesmatter.Chooseahealthyeatingpatternatanappropriatecalorieleveltohelpachieveandmaintainahealthybodyweight,supportnutrientadequacy,andreducetheriskofchronicFocusonvariety,nutrientdensity,andamount.Tomeetnutrientneedswithincalorielimits,chooseavarietyofnutrient-densefoodsacrossandwithinallfoodgroupsin Limitcaloriesfromaddedsugarsandsaturatedfatsandreducesodiumintake.Consumeaneatingpatternlowinaddedsugars,saturatedfats,andsodium.Cutbackonfoodsandbeverageshigherinthesecomponentstoamountsthatfitwithinhealthyeatingpatterns.Shifttohealthierfoodandbeveragechoices.Choosenutrient-densefoodsandbeveragesacrossandwithinallfoodgroupsin ceoflesshealthychoices.Considerculturalandalpreferencestomaketheseshiftseasierto plishandSupporthealthyeatingpatternsforall.Everyonehasarolein tocreateandsupporthealthyeatingpatternsinmultiple Consumeahealthyeatingpatternthataccountsforallfoodsandbeverageswithinanappropriatecalorielevel.AhealthyeatingpatternAvarietyofvegetablesfromallofthesubgroups—darkgreen,redandorange,legumes(beansandpeas),starchy,andotherFruits,especiallywholeGrains,atleasthalfofwhicharewhole orlow-fatdairy,includingmilk,yogurt,cheese,and/orfortifiedsoybeveragesAvarietyofproteinfoods,includingseafood,leanmeatsandpoultry,eggs,legumes(beansandpeas),andnuts,seeds,andsoyproductsAhealthyeatingpatternSaturatedfatsandtransfats,addedsugars,and mendationsthatare tativeareprovidedforseveralcomponentsofthedietthatshouldbelimited.ThesecomponentsareofparticularpublichealthconcernintheUnitedStates,andthespecifiedlimitscanhelpindividualsachievehealthyeatingpatternswithincalorielimits:Consumelessthan10percentofcaloriesperdayfromaddedsugarsConsumelessthan10percentofcaloriesperdayfromsaturatedfatsConsumelessthan2,300milligrams(mg)perdayofsodiumIfalcoholisconsumed,itshouldbeconsumedinmoderation—uptoonedrinkperdayforwomenanduptotwodrinksperdayformen—andonlybyadults