1.Alcoholicbeveragesareproducedfromarangeofrawmaterialsbutespeciallyfromcereals,fruitsandsugarcrops.Theyincludenon-distilledbeveragessuchasbeers,wines,ciders,andsake.Distilledbeveragessuchaswhiskyandrumareproducedfromfermentedcerealsandmolasses,respectively,whilebrandyisproducedbydistillationofwine.Otherdistilledbeverages,suchasvodkaandgin,areproducedfromneutralspiritsobtainedbydistillationoffermentedmolasses,grain,potatoorwhey.Avarietyoffortifiedwinesareproducedbyadditionofdistilledspirittowinestoraisethealcoholcontentto15-20%.Notableproductsincludesherries,PortandMadeirawines.含酒精的飲料是由一系列的原料,尤其是由谷物,水果和糖作物包括non-distilled鈧的飲料,如:啤酒、葡萄酒、杯蘋果酒,酒的。如威士忌蒸餾飲料、朗姆酒制造谷物和糖蜜發(fā)酵,分別站在白蘭地是由蒸餾的酒。其他蒸餾飲料,如伏特加和杜松子酒,制造了中性酒精蒸餾發(fā)酵糖蜜,谷物,馬鈴薯或乳清。各種各樣的堅(jiān)固的葡萄酒生產(chǎn)的增加白酒酒的酒精含量,提高15-20%。顯著的產(chǎn)品包括釀,港口和馬德拉葡萄酒。2Theyeastcellenvelopecontainsaplasmamembrane,aperiplasmicspaceandacellwallconsistingmainlyofpolysaccharideswithasmallamountofpeptidematerial.Thewallcomponentisasemi-rigidbutsolutepermeablestructurewhichprovidesconsiderablycompressionalandtensilestrengthtoyeasts.Carboxylgroupsofcell-wallpeptidesconferimportantflocculatingcharacteristicsonbrewingyeasts,facilitatingpost-fermentationsolid-liquidseparation.Flocculationisthoughttoresultfromsalt-bridgeformationbetweencalciumionsandthesecell-wallcarboxylgroups.酵母細(xì)胞的細(xì)胞膜,信封里包含一個periplasmic空間和細(xì)胞壁多糖的主要組成,它含有少量的多肽物質(zhì)。墻上零件結(jié)構(gòu)半剛性但溶質(zhì)滲透提供了大大擠壓和拉伸強(qiáng)度的酵母。細(xì)胞壁肽組與羧基釀造酵母絮凝特性對重要,便于post-fermentation固液分離。絮凝法被認(rèn)為由于salt-bridge之間形成鈣離子和這些細(xì)胞壁羧基組。3Brewer?swort,producedfrombarleymaltcontains19aminoacidsandarangeofothernutrients,Theseaminoacidsareassimilatedatdifferentratesduringfermentation.Ageneralaminoacidpermease(GAPcantransportallbasicandneutralaminoacidsexceptproline.Atlease11othermorespecificaminoscidtransportsystemsexistinyeastinyeast.Prolinepermeaseisrepressedbyotheraminoacidsandammonia.Brewer?s麥汁,由麥芽含有19氨基酸和一系列其他營養(yǎng)素的吸收,這些氨基酸在發(fā)酵過程中,以不同的比率。一般氨基酸permease(缺口運(yùn)輸?shù)乃谢竞椭行园被岢彼帷Ｖ辽?1其他更特定的胺基scid運(yùn)輸系統(tǒng)存在于酵母在酵母。permease脯氨酸是被其它氨基酸和氨。4ManystrainsofS.cerevisiaecanattainethanolconcentrationsof12-14%.Interesthasdevelopedintheuseofhighalcoholtolerantyeastsinhigh-gravitybrewingprocessesandinalcoholproductionfordistillationwithaviewtoincreasingplantproductivityanddecreasingdistillationcosts,Selectedstrainsareabletoproduce18-20%alcoholalthoughfermentationrateisgenerallygreatlyreducedasethanolconcentrationincreases.GrapejuiceswithveryhighsugarconcentrationsareonlyfermentedbyosmophilicyeastssuchasSaccharomycesrouxiiandSaccharomycesbailliwhichhaveahighcapacitytofermentfructose.Plasmamembranephospholipidcompositionisimportantforethanoltolerance.Increasedethanoltoleranceisobservedwhenmembraneunsaturatedfattyacidcontentisincreased.Alcoholtolerancemaybeenhancedbysupplementingthegrowthmediumwithunsaturatedfattyacids,vitaminsandproteinsandproteins.Physiologicalfactorssuchasthemethodofsubstratefeeding,intracellularethanolaccumulation,osmoticbressureandtemperatureallcontributetoyeastethanoltolerance.Yeastglycolyticenzymeshexokinase,gluceraldehydes-3-puosphatedehydrogenaseandpyruvatedecarboxylasehavebeenshowntobesensitivetoethanolconcentration.許多株釀酒酵母乙醇的濃度可以達(dá)到12-14%。興趣發(fā)展了在使用高的酒精寬容地進(jìn)行高濃度釀造酵母在酒精生產(chǎn)過程和在蒸餾,以達(dá)到提高植物的生產(chǎn)力和降低成本,選擇蒸餾可以產(chǎn)生菌發(fā)酵率-20%酒精雖然一般大大降低為乙醇濃度增加.Grape果汁糖濃度具有非常高的osmophilic只是酵母菌發(fā)酵型和baillirouxii型具有高容量的發(fā)酵果糖。細(xì)胞膜磷脂成分是一種重要的乙醇寬容。乙醇寬容是遵循增加膜的不飽和脂肪酸含量增加。會增強(qiáng)耐酒精度純培養(yǎng)基與不飽和脂肪酸、維生素和蛋白質(zhì)和蛋白質(zhì)。等生理因素的方法、胞內(nèi)乙醇積累基質(zhì)料、滲透bressure和溫度都有助于酵母乙醇寬容。酵母無氧乳酸脫氫酶,gluceraldehydes-3-puosphate己糖激酶和丙酮酸脫已被證實(shí)是敏感的乙醇濃度。5Foryeasts,PHvaluesbetween3and6aremostfavourableforgrowthandfermentationactivity.FermentationactivityishigherathigherPHvaluesandthereisanoticeablelaginfermentationactivityatPH3-4.PHaffectsformationofby-products.HighPHvaluesincreaseglycerolformation.ThePHofgrapemustisusuallyintherange3-3.9becauseofitshighacidcontent(5-15g/l,mainlytartaricandmalicacids.Sincemostbacteria,withtheexceptionofaceticacidandlacticacidbacteria,prefermoreneutralPHvaluesthesusceptibilityofwinemuststoinfectionisgreatlyreduced.酵母,酸堿值為6和3之間最優(yōu)惠活動,為經(jīng)濟(jì)增長和發(fā)酵.Fermentation活動是在更高的酸堿值較高,并有一個明顯的視覺滯后都在發(fā)酵活動對PH3-4。PH影響形成酸堿值增加,高潔的副產(chǎn)品甘油的形成。葡萄的酸度范圍必須通常在3-3.9因其高酸含量(5-15g/l和蘋果酸,主要信息。由于大多數(shù)細(xì)菌,除了乙酸、乳酸細(xì)菌,喜歡比較中性的價(jià)值觀的易感性感染酒必須大大減少。6Fermentablesugarswhichnormallyconstitute70-80%ofthewortcarbohydratesareconvertedtoethanolduringfermentation.Theresidual20-30%carbohydrateconsistsmainlyofhigherdextrinsorlimitdextrinswhicharenotsusceptibletoattackbymaltamylaesbecauseofthepresenceofα-1,6-glycosidislinkages.Intheproductionoflowcarbohydratebeer,theselimitdextrinsmaybehydrolysedtofermentablesugarbymicrobialamyloglucosidase.Ideally,thisenzymeshouldbeincubatedwithwortpriortowortboilingsothatitisinactivatedbytheboilingprocess.Whileamyloglucosidaseisalsoeffectiveinhydrolysinglimitdextrinsduringthefermentationstage,theenzymeisnotinactivatedbysubsequentpasteurizationandmayremaininthefinalproduct.可發(fā)酵的糖分一般構(gòu)成70-80%的麥汁的碳水化合物被轉(zhuǎn)化成乙醇發(fā)酵過程。殘余的20-30%碳水化合物的主要成分是高等dextrins或者限制dextrins不是由麥芽amylaes極易受到攻擊,因?yàn)榇嬖诘那闆r下,6-glycosidisα-1連接。生產(chǎn)低碳水化合物啤酒,這些限制可能hydrolyseddextrins表達(dá)由微生物amyloglucosidase糖。理想情況下,這個酶應(yīng)與前孵化麥汁煮沸的做法,這樣就可殺死沸騰的過程。而在hydrolysingamyloglucosidase同樣有效7Afterlageringthebeercontainsmicrobialcells,proteinaceousprecipitatesandcolloidalmatter,whichareseparatedoutbyavarietyofprocessesincludingflocculation,centrifugationandfiltration.Microbiologicalstabilityisachievedbysterilefiltrationand/orbypasteurization.TheoverallbrewingprocessissummarizedinFig.2.lagering后啤酒含有微生物細(xì)胞、蛋白質(zhì)沉淀和膠體物質(zhì)中分離出來,它是由多種流程,包括絮凝法、離心分離、過濾.Microbiological穩(wěn)定性可通過無菌過濾和/或巴斯德殺菌法,全面總結(jié)了釀造工藝量程。8Wineismadebythefermentationofalmostanyripefruitjuiceorofextractsfromcertainvegetableproducts,suchasdandelions.Becausethesestartingmaterialscontainahighconcentrationofsugar,asmuchas15%alcoholmaybeobtainedwithcertainyeaststrains.Thegrapesusedforwineusuallyrangeinsugarcontentfrom12%to30%andinwatercontentfrom70%to85%.Theotherconstituentsingrapes,includingacidsandminerals,accountforthedifferentcolor,taste,andsometimesbouquetofvariouswines.酒是由發(fā)酵成熟的幾乎所有的果汁或提取物對某些蔬菜產(chǎn)品,如蒲公英。因?yàn)檫@些原料含有高濃度的糖,多達(dá)15%的酒精會取得一定的酵母株。通常用于酒葡萄的范圍內(nèi)糖含量從12%降至30%,而水分含量從70%增加到85%。其他成分,包括酸葡萄和礦物質(zhì),說明不同的顏色、味道,有時束各種葡萄酒。9Assoonastheskinofthegrapeisbroken,thefermentationbegins.Commercially,thefruitiscrushedandpressedmechanically.Theresultingpressedgrapejuice,calledmust,canbefermentednaturally,asisdoneinEurope,bytheenzymaticactivityofwildyeaststhatgrowonthegrapes.IntheUnitedStates,ontheotherhand,grapesjuiceandotherfermentablesubstancesareusuallyeithersterilizedortreatedwithsulfurdioxidetopreventthegrowthofundesirablemicroorganisms.Specificyeastcultures,strainsofSaccharomycesellipsoideus,arethenintroduced,andthemixtureoffruitjuiceandmicroorganismsisaeratedinordertopromoteyeastgrowth.Anaerobicconditionsresultwhenyeastsarepresentinsufficientnumberstocarryoutthefermentation.一旦皮膚的葡萄被打破,發(fā)酵過程的開始。商業(yè),果實(shí)粉碎和按機(jī)械式的反應(yīng)。結(jié)果按葡萄汁,稱為必須,可以發(fā)酵當(dāng)然,作為做是在歐洲,酶活性的野生酵母生長的葡萄。在美國,另一方面,葡萄果汁和其它代謝物質(zhì)治療通常要么消毒或二氧化硫?qū)Ψ乐共涣嘉⑸锏纳L。特定文化、株酵母菌,然后ellipsoideus型,并介紹了混合果汁和微生物曝氣,以促進(jìn)酵母菌的生長。由于厭氧條件下呈現(xiàn)在足額酵母進(jìn)行發(fā)酵。10Thewiderangeofwinescurrentlyavailableistheresultofchangeinthebasicfermentationprocess.Mustfrombothredandwhitewinggrapesiswhiteandisusedtoproducewhitewine.Redwinesaremadebyallowingthefermentationtoproceedinthepresenceofredgrapeskins.Thealcohol,formedduringtheprocess,extractsthecoloringintothewine.Rosewinesarepreparedbylightlypressingtheskinsofpurplegrapesandallowingfermentationtooccurrapidlyinthepresenceofthegrapeskins.Certainwinesarealsodistinguishedfromothersonthebasisofsweetness.Indrywines,forexample,mostorallofthesugarismetabolizedduringfermentation.Insweetwines,fermentationsisstoppedwhilesomesugarstillremainsintheproduct.各種葡萄酒的現(xiàn)有的結(jié)果是改變基本發(fā)酵過程。必須從紅酒和白酒翼葡萄是白色的,被用來制造的白葡萄酒。紅酒的發(fā)酵是由允許繼續(xù)存在的紅葡萄皮。酒精,形成了在這一過程中,抽取色素在醋里。玫瑰葡萄酒準(zhǔn)備輕輕地按紫色的葡萄皮,并允許發(fā)酵發(fā)生得很快的面前葡萄皮。一些葡萄酒也區(qū)別于其他甜蜜的基礎(chǔ)上。在干燥的葡萄酒,舉例來說,大多數(shù)或所有的糖是在發(fā)酵過程中代謝。在甜葡萄酒,而一些糖極致味道停止仍然保持產(chǎn)品。11Sometypesofwinesareknownforaparticularflavor,effervescence,orhigheralcoholcontent.Theseincludesparklingwinesandfortifiedwines.Sparklingwines,suchaschampagne,undergoasecondalcoholicfermentationinsidethebottleunderpressure,SugarandyeastaddedtoanalreadyfermentedproductresultsinCO2production,whichcarbonatesthewine.某些種類的葡萄酒而聞名的泡沫,一個特定的味道,或更高的酒精含量。這些包括起泡葡萄酒和堅(jiān)固的葡萄酒。起泡葡萄酒,如香檳,進(jìn)行第二次酒精發(fā)酵瓶內(nèi)壓力、糖和酵母發(fā)酵產(chǎn)物添加到一個已經(jīng)導(dǎo)致二氧化碳的產(chǎn)生,而碳酸酒。12Sinceyeastscannotsurviveinwinesthataremorethan15%alcohol,mosttablewinescontain10%to12%.Alcoholconcentrationsofwinesmaybeincreasedthroughtheadditionofbrandyorotherspirits.SuchproductsarecalledfortifiedwinesandincludeMadeira,port,andsherry.因?yàn)闊o法生存的葡萄酒酵母在酒精超過15%,大多數(shù)葡萄佐餐酒含有10%至12%。的葡萄酒的酒精濃度可以增加通過增加白蘭地或其他烈酒。這樣的產(chǎn)品被稱為堅(jiān)固的葡萄酒,包括馬德拉、港口、和雪莉酒。13Mostindustrialenzymesareproducedbymicroorganisms,thelargestgroupbeingproteolyticenzymesfrombacteriafollowedbycarbohydrases.Animalenzymesincluderennetsandpancreaticproteasesandlipases;theproteasesareusedprimarilyinleatherprocessing.Amongtheplantenzymes,papainisthelargestsingleindustrialproduct.Industrialenzymesareusuallymixturesofdifferentenzymes.Commercialproductsarestandardizedwithdiluents.大多數(shù)工業(yè)酶、微生物產(chǎn)生的最大群體被蛋白水解酶細(xì)菌的酶,緊隨其后的是carbohydrases.Animal包括蛋白酶和脂肪酶和胰rennets;蛋白酶主要用于皮革加工。在植物酶、木瓜酶是最大的單一工業(yè)產(chǎn)品。工業(yè)酶混合物通常是不同的酶。商業(yè)產(chǎn)品標(biāo)準(zhǔn)化與稀釋劑。14Bacterialα-amylasesaredividedintostandardamylasesandheat-stableamylases,dependingonthenstabilitytoheat.Standardbacterialα-amylasesfrom枯草芽孢桿菌orB.amyloliquefaciensrequirestemperaturesof70-85foroptimalactivity.Heat-stablebacterialα-amylasefrom,e.g.,地衣芽孢桿菌，hasatemperatureoptimumbetween90and105.However,thisoptimumdependsonthePH,theconcentrationofcalciumions,andthesubstrateconcentration.Atypicalreactioniscarriedoutona30%starchsuspensionatPH7and103-105for7-11mininthepresenceof70mg/lofcalcium.TheenzymeisinactivatedbyloweringthePHto3.5-4.5andthetemperatureto80-90foraperiodof5-30min.細(xì)菌α-amylases分為標(biāo)準(zhǔn)amylases和熱穩(wěn)定amylases然后穩(wěn)定性,根據(jù)升溫。從枯草芽孢桿菌細(xì)菌α-amylases標(biāo)準(zhǔn)或B.amyloliquefaciens需要溫度的優(yōu)化70-85活動.Heat-stable細(xì)菌α-amylase,例如,從地衣芽孢桿菌溫度優(yōu)化,90年和105年之間。然而,這取決于PH值,優(yōu)化鈣離子的濃度、底物濃度。一個典型的反應(yīng)是執(zhí)行30%的淀粉懸架在PH7和103-105為7-11min存在鈣70毫克/升。這個酶活性降低,PH值為3.5~-4.5和溫度80-905-30min的一段時期。15Proteasesandlipasesareusedincleaninganimalhides,anecessarystepinleatherproduction.Proteasesarealsousedcommercillyformeattenderizing,astheyarecapableofbreakingdownsomeofbreakingdownsomeofthetoughmeatprotein.蛋白酶和脂肪酶用于清洗獸皮,皮革生產(chǎn)的必要步驟。也用commercilly蛋白酶對肉類tenderizing,因?yàn)樗麄冇心芰Υ蚱埔恍┐蚱埔恍┢D難的肉類蛋白。16Varioustechniquesareusedtodeterminethenumbersandkindsofmicroorganismsandtheirproductsinfoods.Thesemethodsincludesdirectmicroscopiccountsforbothlivinganddeadcells,standardplatecounts,specificstainingprocedures,immunologicaltestsforenzymesandothermicrobialproducts,isolationandbiochemicalidentification,andstatisticaldeterminationsforlivingcells.Table1listsbacteriathatareconsideredtobeindicatorsofpotentialhumanorfecalcontaminationandalsobacteriathatareconsideredtobeindicatorsofpost-heat-processingcontamination.各種不同的技術(shù)用于確定編號和微生物及其產(chǎn)品在食品。這些方法包括直接顯微計(jì)數(shù)都活著的和死去的細(xì)胞,標(biāo)準(zhǔn)板計(jì)數(shù),具體染色程序、免疫學(xué)檢查為酶與其它微生物的產(chǎn)物,分離和測定生化鑒定、數(shù)理統(tǒng)計(jì)對活細(xì)胞組成。表1列出細(xì)菌被認(rèn)為是潛在的人類的指標(biāo)或排泄物污染細(xì)菌,也被認(rèn)為是post-heat-processing污染的指標(biāo)。17Severalchemicaladditivesareusedtopreventmicrobialspoilageoffoods.Examplesarecitricacid,usedtojams,jellies,andsoftdrinks;themoldinhibitorsodiumpropionate,usedinbakerygoodsandprocessedcheese;andthebacterialinhibitorssodiumnitrateandsodiumnitrite,usedinthecuringofmeatandfish.ThesesubstancesareclassifiedasfoodadditivesundertheFederalFood,Drug,andCosmeticAct,indicatingthattheyhavebeentestedandfoundsafeforhumanconsumptionbytheFoodandDrugAdministration.Thisagencyiscurrentlyreviewingallfoodadditivesastolevelsofsafetyandeffectivenessforfoodpreservation.Thelevelsofsubstancessuchasnitratesandnitritesmaybereducedconsiderablyinthenearfutureasaresultofsuchstudies.幾個化工助劑用于防止微生物腐壞的食物。例子是檸檬酸,用于果醬、果凍、和軟飲料,模具抑制劑,用于面包店丙酸鈉產(chǎn)品和加工奶酪;與細(xì)菌抑制劑對亞硝酸鈉和硝酸鈉,用于治療的肉和魚。這些物質(zhì)分類作為食品添加劑在食品、藥品、聯(lián)邦和化妝品法案,這表明他們已經(jīng)測試,發(fā)現(xiàn)可以安全食用了美國食品及藥物管理局認(rèn)可。該機(jī)構(gòu)正在審核所有食品添加劑以水平的安全性和有效性為食物的保存。等物質(zhì)的水平的硝酸鹽程度大大減少硝酸鹽可能在不久的將來由于這樣的研究。18Chemicalpreservativesincludebothinorganicandorganiccompounds.Thesecompoundseitherkillmicroorganismsorinhibittheirgrowth,enzymaticactivities,orreproduction.Somecompoundsarealsousedtodestroyorreducethenumberofusedintheprocessingoffoods.化學(xué)防腐劑包括無機(jī)和有機(jī)化合物。這些化合物不是殺死或抑制微生物生長、酶的活動,甚至繁殖。一些化合物也被用來破壞或降低一系列的用于加工的食物。19Likefood,waterisessentialforlife.However,watercanalsobehazardous,sinceitcancontaindiseaseagentsandpoisonousmaterials.如食物、水是生命所必需的。然而,水也可以是有害的,因?yàn)樗梢园砗陀卸静牧霞膊　?0Lifeisnourishedbyfood,andthesubstancesinfoodonwhichlifedependsarethenutrients.Theseprovidetheenergyandbuildingmaterialsforthecountlesssubstancesthatareessentialtothegrowthandsurvivaloflivingthings.Themannerinwhichnutrientsbecomeintegralpartsofthebodyandcontributetoitsfunctionisdependentonthephysiologicandbiochemicalprocessesthatgoverntheiractions.生活是由食品和營養(yǎng)物質(zhì)生活取決于食物的營養(yǎng)成分。這些提供能量和建筑材料為無數(shù)的物質(zhì),是必須的生長和生存的生物。營養(yǎng)的方式成為身體的組成部分,有利于其功能是依賴的生理、生化過程控制著他們的行動。21Mostofthemajornutrientsinfoodsareboundinlargemoleculesthatcannotbeabsorbedfromtheintestinebecauseoftheirsizeorbecausetheyarenotwatersoluble.Thedigestivesystemisresponsibleforthereductionoftheselargemoleculesintosmaller,readilyabsorbedunitsandtheconversionoftheinsolublemoleculesintosolubleforms.Properfunctionoftheabsorptiveandtransportmechanismsiscrucialtodeliveringtheproductsofdigestiontotheindividualcells.Derangementsofanyofthesesystemscanresultinmalnutritioninthepresenceofanadequatediet.大多數(shù)重要的營養(yǎng)食品捆綁在大分子,不能從小腸吸收,因?yàn)樗麄兊拇笮』蛞驗(yàn)樗麄儾皇撬苄?。消化系統(tǒng)負(fù)責(zé)減少這些大的分子分解成較小,容易被吸收的單位和的轉(zhuǎn)化成可溶不溶于水的分子形式。適當(dāng)吸收和運(yùn)輸?shù)墓δ軝C(jī)制至關(guān)重要的消化船期的單個細(xì)胞。這些系統(tǒng)紊亂的任何會導(dǎo)致營養(yǎng)不良、在耶和華面前一個適當(dāng)?shù)娘嬍场?2Nutritionmightbedefinedastheprocesswherebyweobtaintheessentialnutrientsandusethemtomakemanyothersubstancesourbodiesneed.Thisprocesswouldincludeeatinganddigestingfoodandabsorbingandusing,ormetabolizing,thenutrientsitcontains.營養(yǎng)可能被定義為一種過程,我們獲得必需的營養(yǎng)物質(zhì),用它們來做許多其他物質(zhì)我們的身體需要。這個過程包括飲食,食物的消化和吸收或代謝和使用過程中,營養(yǎng)含量。23Weneedsome50chemicalnutrientstomaintainhealth:water,carbohydrate,fat,protein,13vitamins,17minerals,severalfibersandsometraceamountsofothercomponents.Themacronutrientsarethosenutrientswemustconsumeinlargeamountstoprovideenergyforourbodies.Eachofthesenutrientscontainscarbon,hydrogen,andoxygen,whileproteinalsocontainsnitrogen,anditistheratioofcarbontohydrogentooxygenthatdeterminesthenumberofcaloriestheyprovide.Themicronutrientsarewhatweneedinrelativelysmallamounts.Allofthenutrientsexceptformineralelementsandwaterareclassifiedasorganicchemicalsbecausetheycontaintheelementcarbon.我們需要一些50化學(xué)物質(zhì)以保持健康:水、碳水化合物、脂肪、蛋白質(zhì)、維生素、礦物質(zhì)、十七13幾個纖維和一些微量的其他組件。macronutrients營養(yǎng)的是那些我們必須消耗大量能源,提供我們的身體。每種營養(yǎng)素含有碳,氫,氧,而蛋白質(zhì)也含有氮,是比氫和氧碳決定消耗的卡路里數(shù)提供。我們所需要的微量元素是相對少量的營養(yǎng)本土人除了礦質(zhì)元素和水分為有機(jī)化合物,因?yàn)樗鼈兒刑荚貥?gòu)成的。24Differentnutrientsgiveusdifferentamountsofcalories,basedontheratioofcarbontohydrogentooxygentheycontain.Ingeneral,agramofproteinsuppliesuswith4calories;agramoffat,9calories;andagramofcarbohydrates4calories.Wecanseethatagivenweightoffatsuppliesuswithmorethantwicetheenergyofthesameamountofproteinorcarbohydrates.Thisiswhyfatsareconsidered"fattening".Ifwetakeinmoreenergythanwerequire,thisenergyisstoredinthebodyasfatandintimeresultsinweightgainandobesity.不同的營養(yǎng)給了我們不同,基于大量的熱量的比例氫和氧碳他們的內(nèi)容。一般說來,一個克蛋白質(zhì)為我們提供4克脂肪卡路里;9卡路里,一克的碳水化合物4卡路里。我們可以看到,一個給定的脂肪重量為我們提供超過兩倍的能量相同數(shù)量的蛋白質(zhì)或碳水化合物。這就是為什么脂肪被認(rèn)為是“增肥”。如果我們要比我們需要更多的能量,這個能量儲存在體內(nèi)的脂肪和及時導(dǎo)致體重增加和肥胖。25Itisasimpleandeasilyrememberedfactthat3500excesscalorieswillproduce1lboffat.These3500excesscaloriestypicallyaccumulatenotin1dayor2butoveraperiodoftime.Thatis,ifyouconsume500caloriesmoreperdaythanyourbodyrequires,thenin1weekyouwillgainapound.Conversely,ifyouconsume500caloriesadaylessthanwhatyourbodyneeds,youwillloseapound.Therearesomeinterestingstudiesshowingthatthesefiguresdonotholdexactly,andindeedthee