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1、LIPID PHYSICAL AND CHEMICAL CHARACTERISTIC Zhang Dequan物理性质物理性质气味和色泽 芝麻油香气：乙酰吡嗪 椰子油香气：壬基甲酮 菜子油气味：黑芥子苷分解 熔点和沸点 油脂熔点最高40-55 熔点温度低于37，消化率达到96% 熔点高于37，不容易消化脂肪脂肪熔点熔点/ /消化率消化率/%/%大豆油大豆油-18-8-18-897.597.5花生油花生油030398.398.3向日葵油向日葵油-619-61996.596.5棉子油棉子油34349898奶油奶油283628369898猪油猪油365036509494牛脂牛脂42504250898
2、9羊脂羊脂445544558181烟点、闪点和着火点 smoking point：发烟的温度 flash point：被点燃但不能燃烧的温度 fire point：持续燃烧5s以上的温度 精练油脂烟点在240左右 折射率 分子量大分子量小的饱和脂肪酸 饱和脂肪酸不饱和脂肪酸 油脂鉴别l l结晶特性结晶特性 PolymorphismPolymorphism 转变转变 -2-2排列排列(DCL)(DCL) -3-3排列排列(TCL)(TCL) 简单甘油酯容易形成稳定的简单甘油酯容易形成稳定的 结晶结晶,DCL,DCL排列排列 混合甘油酯容易形成混合甘油酯容易形成结晶结晶,TCL,TCL排列排列特性
3、特性 堆积方式堆积方式正六方正六方正交正交三斜三斜熔点熔点密度密度有序程度有序程度结晶：大豆油、玉米油、花生油、椰子油、橄榄油、可可脂油、猪油结晶：棉子油、棕榈油、菜子油、乳脂、牛脂、改性猪油“调温”获得某种结晶产品 可可脂生产 Sn-StOSt、Sn-POStl l熔融特性熔融特性 融化融化 SFISFI（Solid Fat IndexSolid Fat Index） SFISFI测定方法：测定方法： 差示扫描量热仪（差示扫描量热仪（DSCDSC） NMRNMR 脉冲脉冲NMRNMR为为AOCSAOCS的官方方法的官方方法l l油脂塑性油脂塑性 塑性是指在一定的外力下，表观固体脂肪塑性是指在
4、一定的外力下，表观固体脂肪具有的抗变形的能力，油脂塑性取决于：具有的抗变形的能力，油脂塑性取决于： SFISFI、脂肪晶型、熔化温度范围、脂肪晶型、熔化温度范围Shortening oilShortening oill l油脂的液晶态（介晶相）油脂的液晶态（介晶相） 层状：层状： 六方六方 立方立方l l乳化与乳化剂乳化与乳化剂 分散相（分散相（01-5001-50微米的小滴）分散在连续相中微米的小滴）分散在连续相中 乳浊液的制备：油脂、水、乳化剂、能量乳浊液的制备：油脂、水、乳化剂、能量 乳浊液不稳定的因素：分层、絮凝、聚结乳浊液不稳定的因素：分层、絮凝、聚结乳化剂选择方法：乳化剂选择方法：
5、HLBHLB值值HLBHLB作用作用HLBHLB作用作用1.5-31.5-3消泡剂消泡剂8-188-18O/WO/W乳化剂乳化剂3.5-63.5-6W/OW/O型乳化型乳化剂剂13-1513-15洗涤剂洗涤剂7-97-9湿润剂湿润剂15-1815-18溶化剂溶化剂一些常见乳化剂的HLB值化学性质水解氧化1. Hydrolysis and saponification动物脂肪 不利 有利植物油鱼脂水解性质的应用构造脂质2、氧化(酸败)自动氧化自动氧化光敏氧化光敏氧化酶促氧化酶促氧化热氧化热氧化辐射氧化辐射氧化FlavorQualityLossRancidflavorChangesofcolora
6、ndtextureConsumerAcceptanceEconomiclossNutritionalQualityLossEssentialFattyAcidsVitaminsHealthRisks GrowthRetardationHeartDiseases2.1 氧化机制酶与非酶氧化两种机制自催化机制的与分子氧的反应是脂类氧化变质的主要反应光敏氧化触发了自动氧化2.1.1 自动氧化的一般特性遵循自由基机制，具有5个特点干扰自由基反应的化学物质能显著抑制自动氧化干扰自由基反应的化学物质能显著抑制自动氧化光和产生自由基的物质能促进自动氧化光和产生自由基的物质能促进自动氧化产生大量的氢过氧化物产
7、生大量的氢过氧化物由光引发的氧化反应量子产额超过由光引发的氧化反应量子产额超过1 1当原始物质为纯物质时存在一个相当长的诱导期当原始物质为纯物质时存在一个相当长的诱导期 2.1.2MechanismsofLipidOxidation ReactionsActivationEnergyProteinDenaturation100kcal/molNonenzymaticBrowningReaction50EnzymeCatalyzedReaction10-15LipidOxidation10-15Activation Energy for Chemical ReactionHistoryofOxy
8、genOxygen-ScheeleandPriestlyin1772.Tripletoxygen-Millikanin1928.Singletoxygen-Herzbergin1934.TripletOxygenOxidationCH CH CH2CH CH CH2(CH2)6COOHCH2(CH2)3CH31007550BondEnergyofCarbonandHydrogenkcal/molStearicacidOleicacidLinoleicacidLinolenicacidCH3(CH2)14COOHCH3(CH2)6CH CH(CH2)7COOHCH3(CH2)4CH CH CH2
9、CH CH (CH2)7COOHCH3CH2CH CH CH2CH CH CH2CH CH(CH2)7COOHCH2CH2CH2InitiationofTripletOxygenOxidationRH+引发剂RH+Initiationofautoxidationoccurswhenhydrogenatomat-methylenegroupindoublebondsofunsaturatedfattyacidsisremovedtoformanalkylradical(R).PropagationROO+RHROOH+R+ROOH+OHRORHROROHRR+3O2ROOTermination2
10、ROROOR+ROORRORORROOROORR+R-RRROO+RRROOO2LinoleicAcidLinoleicAcidOxidationOxidationbyTripletOxygenbyTripletOxygen141312111091211109-H+O21211109+HCH2CHCH CH2CHCHCH2R(CH2)3CH3INITIATION(METAL)(CH2)4CH3CH CHCHCH CH2RCH(CH2)4CH3CHCHCHCHCH2RCHOOPROPAGATIONR=(CH2)6-COOH1211109HYDROPEROXIDEDECOMPOSION-OH+H1
11、211109TERMINATION(PENTANE)CHCHCHCHCHCH2R(CH2)4CH3OOH(CH2)4CH3CHCHCHCHCH2RCHOCH3(CH2)3CH2CH3(CH2)3CH3OCHCHCHCHCHCH2R+R=(CH2)6-COOHSinglet and Triplet OxygenMolecular Orbital of Triplet OxygenEnergy*2S2S2Px2Py2Pz2Pz2Py2Px*MolecularAtomicAtomic*1S1SRH+O2自由基自由基35kcal/molMolecularOrbitalofSingletOxygenEn
12、ergy*2S2S2Px2Py2Pz2Pz2Py2Px*MolecularAtomicAtomic*1S1S Singlet Oxygen Formation 3O2+SensitizerH2O2+OCI-H2O2+O2-OzoneEndoperoxidesOH-+O2-EnzymesO2-+Y+1O2O2-O2-+O2-H2O2+HO2-RCOO+RCOOCH3CH2CH CH CH2CH CH CH2CH CH CH2(CH2)6COOHCH3CH2CH CH CH2CH CH CH2CHOCOOH(CH2)6CH2CHOCH3CH2CH CH CH2CH CH CH2CHCOOH(CH2
13、)6CH2CHOCH3CH2CH CH CH2CH CH CH2CHOCH3CH2CH CH CH2CHOOCHCH2CH1O21O2O氢过氧化物形成：Reversion Flavor from Linolenic Acid by Singlet Oxygen OxidationO2-(2-pentenyl)-furan-H2OCH3CH2CH CH CH2CHOOCHCH2CHCH3CH2CH CH CH2C CH2OCH2CHOCH3CH2CH CH CH2C CHCH CHOHOHCH3CH2CH CH CH2OCH3CH2CH CH CH2CHOOCHCH2CHOH-OH氢过氧化物裂解
14、： Reversion Flavor Compounds from Soybean Oil2-(2-pentenyl)-furanCH3CH2CH CH CH2OCH3CH2CH CH CHO22-(1-pentenyl)-furanReaction of Reaction of 3 3OO2 2 and and 1 1OO2 2 with Linoleic Acid with Linoleic AcidRRRROOH3O2ConjugatedConjugatedRRRRRRHOO3O2-HRRRROOHOOHRR1O2RRHOORRHOOConjugatedNonconjugatedReac
15、tion Rates of Lipid OxidationR+3O2K=109M-1sec-1ROO+OleicAcidK=1M-1sec-1ROO+LinoleicAcidK=60M-1sec-1ROO+LinolenicAcidK=120M-1sec-1ROO+ROOK=105-107M-1sec-1R+AntioxidantsK=107M-1sec-1RH+1O2K=105M-1sec-1Relative Reaction Rates of 3 3O2 2 and 1 1O2 2 with Oleic, Linoleic, and Linolenic AcidsTripletoxygen
16、 310441047104Singletoxygen 12777OleicLinoleicLinolenicAcidAcidAcidFormation of 1 1O2 2 by SensitizersGroundStateExcitedStatehvFluorescenceK=2108/sec1Sen1Sen*K=1-20108/secISCPhosphorescenceK=10-104/secSingletOxygen,1O2K=1-3109/sec3Sen*3O2光敏氧化LipidFreeRadical型型Photosensitizers in FoodsChlorophyllProto
17、porphyrineRiboflavinRedNo.3Enzymatic Oxidation（lipoxygenase,Lox）Hydropeorxideatthe-6positionofunsaturatedfattyacidPolyunsaturatedfattyacids(acis,cis-1,4-pentadieneunit)Lipoxygenase热氧化热分解热聚合热缩合辐射氧化过氧化脂质几乎可以与食品中的任何成分反应，降低品质氢过氧化物几乎与人体内所有分子或细胞反应，破坏和细胞结构脂质在常温或高温下氧化均产生有害物质油脂氧化的安全性影响自动氧化的因素脂肪酸性质脂肪酸性质氧与氧分压氧
18、与氧分压温度温度表面积表面积水分水分过渡金属元素过渡金属元素光和射线光和射线抗氧化剂抗氧化剂乳化乳化Control of Lipid OxidationApplicationofantioxidantsEliminationofoxygenbynitrogenflushingorvacuumpackagingEliminationofphotosensitizersDenaturationoflipoxygenaseLowtemperatureanddarkstorageCharacteristicsofFreeRadicalsinOxidationH:HydrogenatomThesimpl
19、estfreeradicalO2-:SuperoxideanionAnoxygen-centeredradical.LimitedreactivityHO:HydroxylAhighlyreactiveoxygen-centeredradical.IndeedattacksallmoleculesinhumanbodyRO2:PeroxylOxygencenteredradicalsformedduringtheRO:AlkoxybreakdownoforganicperoxidesFunctionofAntioxidantonLipidOxidationInhibitsorslowsthef
20、ormationoffreealkylradicalsintheinitiationstepInterruptsthepropagationoffreeradicalchainDelaysthestartorslowsthechemicalreactionrateoflipidoxidation.TypesofAntioxidants HydrogendonatingcompoundsSingletoxygenquenchersMetalchelatorsEnzymesOxygenscavengersandReducingagentsHydrogen Donating Antioxidants
21、StandardOne-ElectronReductionPotentialCompoundsE(mV)HO,H+/H2O2310RO,H+/ROH1600ROO,H+/ROOH1000PUFA,H+/PUFA600Catechol,H+/Catechol530-Tocopheroxyl,H+/-Tocopherol500Ascorbate-,H+/Ascorbate282CharacteristicsofHydrogenDonatingAntioxidantsThemajorhydrogendonatingantioxidantsaremonohydroxyorpolyhydroxyphen
22、oliccompoundswithvariousringsubstitutions.Theantioxidantfreeradicaldoesnotinitiateanotherfreeradicalduetothestabilizationofdelocalizationofradical.ReactionofAntioxidantswithRadicalsR+AHRH +ARO+AHROH+AROO+AHROOH+AReactionofAntioxidantswithRadicalsR+ ARARO + AROAROO+ AROOAEffectivenessofAntioxidantsTh
23、edifferenceofone-electronreductionpotentialbetween lipid radical and antioxidant radical. Thestabilityofantioxidantradicals-Theresonancedelocalization-FurtheroxidationofantioxidantradicalsResonanceofAntioxidantRadicalsOHC(CH3)3OCH3C(CH3)3OCH3O.OCH3C(CH3)3O.C(CH3)3OCH3O.OCH3C(CH3)3O.R,RO,ROORH,ROH,RO
24、OHStabilityofAntioxidantRadicalOCCH3CH3CH3OCH3TargetsofAntioxidantAntioxidantscanreactwithperoxylradicalsratherthanalkoxylradicals.Themostprevalentradicalisperoxyl(ROO)radical.Peroxylradicalhastheloweststandardoneelectronreductionpotentialamongalkyl,alkoxylandperoxylradicalsOHC(CH3)3OCH3C(CH3)3(CH3)
25、3CCH3OHSyntheticAntioxidantsButylatedhydroxyanisole(BHA)Butylatedhydroxytoluene(BHT)O HO HO HC O O C3H7PropylgallateO HC (C H3)3O HTertiarybutylhydroquionone(TBHQ)NaturalAntioxidantsBenefitsHealthimplicationStabilityinfoodsystemLimitsCharacteristicflavorSafetytestrequiredTocotrienolsOHOR1R2R3CH3CH3C
26、H3CH3TrivialName ChemicalNameR1R2R3-Tocotrienol5,7,8-TrimethyltocotrienolCH3CH3CH3-Tocotrienol5,8-DimethyltocotrienolCH3HCH3-Tocotrienol7,8-DimethyltocotrienolHCH3CH3-Tocotrienol8-MethyltocotrienolHHCH3AntioxidantMechanismofTocopherolTransferofphenolichydrogenScavengingofsingletoxygenRegenerationoft
27、ocopherolinthepresenceofascorbateTocopherolAchainbreakingantioxidantcompeteswithpolyunsaturatedlipidforthelipidperoxylradicals.-Tocopherol-TocopherylsemiquinoneLipidradicalsLipidradicals-TocopherylquinoneResonance of - Tocopherol RadicalsOOCH3H3CCH3C16H33CH3R,RO,orROO-TocopherolOHOCH3H3CCH3CH3CH3CH3
28、CH3OCH3CH3H3CCH3C16H33OOCH3H3COC16H33CH3CH3OCH3H3COC16H33CH3CH3RH,ROH,ROOHR,RO,orROOEffects of Diet Tocopherol on the Content of Tocopherol in Egg YolkEffects of Tocopherol on the Stability of Egg YorkEffects of Tocopherol on the Stability of Egg York05101520253035404502468Time (Days)Total Headspace
29、 Volatiles ( 1000)25g Tocopherol / g yolk45 g Tocopherol / g yolk50 g Tocopherol / g yolk75 g Tocopherol / g yolkControlAscorbic AcidHydrogendonationtolipidradicalsQuenchingofsingletoxygenRemovalofmolecularoxygenRegeneratetocopherolradicalsProoxidantReduceferricirontoferrousironAscorbic AcidOOOHOHCH
30、CH2OHOHOOOOHCHCH2OHOHL-AscorbicacidDehydroascorbicacid-H-HOOHOHOHCHCH2OHOHR,RO,ROOR,RO,ROOAscorbic Acid and Related CompoundsL-AscorbicAcidOOHOHCHOCH2OHHOHErythorbicAcidAscorbicPalmitateOOHOHOHCHCH2OHOHOOOHOHOHCHCH2OC(CH2)14CH3OHSynergistic Effectof Tocopherol & Ascorbic AcidOOCH3H3CCH3C16H33CH3OOCH
31、3H3CCH3C16H33CH3HROO + ROOH-TocopherolOOCH3H3CCH3C16H33CH3AscorbicAcidOOCH3H3CCH3C16H33CH3H-TocopherolAscorbicradicalOOHOHCHOCH2OHHOHOOHOHCHOCH2OHHO+Singlet Oxygen QuencherSinglet Oxygen Quenching MechanismISC3O2A1Sen1Sen*3Sen*1O2AO2KqKox-QQO2KdQQ1Sen1Sen3O23O2hvCarotenoidsCHO - CaroteneApo-8-carote
32、nalOCanthaxanthinO - PeroxideValue(meq/kgoil)StorageTime(hr)Effects ofEffects of -Apo-8-Carotenal, -Apo-8-Carotenal, -Carotene or -Carotene or Canthaxanthin on the Soybean Oil Oxidative QualityCanthaxanthin on the Soybean Oil Oxidative QualityQuenching Mechanism of -Carotene on Singlet Oxygen Oxidat
33、ion1/SoybeanOil(1/M)1/Peroxide(1/M)Singlet Oxygen Quenching Rates of CarotenoidsCarotenoidsNumberofConjugatedQuenchingRateDoubleBondsConstants(M-1sec-1)-Apo-8-carotenal102.86109-Carotene114.60109Canthaxanthin131.121010Singlet Oxygen Quenching Rate of CarotenoidsCarotenoidsNumberofConjugatedRateConst
34、antsDoubleBonds(109M-1sec-1)Astaxanthin139.88Isozeaxanthin117.31Zeaxanthin117.03Lycopene116.89Lutein105.86Singlet Oxygen Quenching Rates of TocopherolsSingletoxygenquenchingability:-Tocopherol-Tocopherol:2.70107(M-1sec-1)Singlet Oxygen QuenchersSingletOxygenQuencher QuenchingRate(M-1sec-1)-Carotene4
35、.60109Ascorbicacid1.08108-Tocopherol2.70107MetalChelatorsProoxidantMechanismsofMetalsHydroperoxide decomposition to form peroxyl radical and alkoxyl radical Fe3+ROOHFe2+ROO+H+Fe2+ROOHFe3+RO+OH-Formations of alkyl free radical by direct reactionFe3+RHFe2+R+H+Activation of oxygen for singlet oxygen fo
36、rmationFe2+3O2Fe3+O-21O2FormationofhydroxylradicalFe2+H2O2Fe3+OH-+OHk1k2k2k1=105ReactionbetweenMetalandHydroperoxideRapid Exponential increase in oxidation during propagation stepRapid Exponential increase in oxidation during propagation step -Scission of alkoxyl radical to low molecular weight -Sci
37、ssion of alkoxyl radical to low molecular weight compoundscompoundsCopper is 50 faster than ferrous ion in decomposing hydrogen Copper is 50 faster than ferrous ion in decomposing hydrogen peroxide peroxide Ferrous is 100 faster than ferric iron in decomposing hydrogen Ferrous is 100 faster than fer
38、ric iron in decomposing hydrogen peroxideperoxideFerrous is 10Ferrous is 1015 15 times more soluble than ferric irontimes more soluble than ferric ironMetalChelatorsPhosphoricacidCitricacidAscorbicacidEthyleneDiamineTetraAcetate.(EDTA)ProteinssuchasTransferrin,OvotransferrinAminoacidsandPeptidesMech
39、anismofMetalChelatorsFormationofcomplexionsorcoordinationcompoundswithmetalsPreventionofmetalredoxcyclingOccupationofallmetalcoordinationsitesFormationofinsolublemetalcomplexesSterichindranceofinteractionsbetweenmetalsandlipidintermediatesPhospholipidsPhosphatidylethanolamineCH2O COR1CHOCOR2CH2O POO
40、O CH2CH2NH2-Phosphaticacid-CH2O COR1CHOCOR2CH2O POOO-MOCOC H2OCOC H2NC H2C H2OONCOC H2COC H2EthyleneDiamineTetraAcetate(EDTA)InteractionofChealatorandMetalEnzymaticAntioxidants2Glucose+2O2+2H2O2Gluconicacid+2H2O2GlucoseOxidase/Catalase2Glucose+O22Gluconicacid2H2O22H2O+O2GlucoseOxidase CatalaseCatala
41、seGlucoseOxidaseOxygenScavengingSuperoxideDismutase2O2O2-+2H+SuperoxideanionparticipatesinoxidativereactionsMaintainingtransitionmetalsintheirreduced,activestatePromotingthereleaseofmetalsboundtoproteinsProducingsingletoxygenSuperoxideDismutase+Catalase2H2O2O22H2O3GlutathionePeroxidaseH2O2+2GSH2H2O+
42、GSSGLOOH+2GSHLOH+H2O+GSSGGSH:ReducedglutathioneGSSH:Oxidizedglutathione OxygenScavengers OxygenScavengersandReducingAgentsAscorbicacidAscorbicpalmitateErythorbicacidSodiumerythorbateSulfitesOxygenScavengerMechanismsCH3SHCH3SSCH3O2+OOHOHOHCHCH2OHOHOOOOHCHCH2OHOHHO2+O2+HO+HOSOHOHO SOHOOO22Superoxide D
43、ismutase2O2O2-+2H+H2O2SuperoxideDismutase+CatalaseO22H2O32H2O2Producingtripletoxygenfromsuperoxideanion3Multifunctional AntioxidantsTocopherolAscorbicacidAntioxidant InteractionsCombinationofmetalchelatorandfreeradicalscavengingantioxidantsCombinationofdifferentantioxidantslike-tocopherolandascorbic
44、acidAntioxidant SourcesFlavonoidsOHOHOHOOOHHOQuercetinFlavonolsOOHOOHHOGlucosideOHCyanidin-3-glucosideAnthocyaninsFlavonoidsSecondaryproductsofplantmetabolismMetalchelatingabilitySuperoxideanionscavengersAnthocyanines,catechins,flavones,flavonols,isoflavone,andproanthocyanidins VegetablesCacaobeans,
45、Potato,Tomato,Spinach,Legumes,Garlic,andSeaweedPolyphenoliccompounds FruitsWines:AnthocyaninPolyphenoliccompoundsTeaHOOHOOHOHOHEpicatechinHOOHOOHOHOHOHEpigallocatechinSesame SeedSesamolOOOHSesamolinolOOOOOOCH3OHHerb and SpiceSage,Ginger,Greenpepper,LavenderandRosemaryCH3HOOHCH3CH3H3CHOOCCarnosoicAci
46、dCOH3CCH3HOOHCH3CH3OCarnosolOHOHHOOHOOHOOCRosemarinicAcidReaction Rates of Carnosol and Carnosic AcidOHHOHHOOCOHOHHOOC+LOOLOOH+CarnosicacidCarnosicacid3 3 10107 7 MM-1-1s s-1-1OHHOCHOOOHOCHOO+CarnosolCarnosol2 2 10106 6 MM-1-1s s-1-1LOOLOOHSoybeanChlorogenicacid,caffeicacid,ferulicacid-Metalchelatio
47、nandsingletoxygenquenchingIsoflavones-phytoestrogeneffects-MetalchelationandhydrogendonationOOOHOHCOOHOHHOHOChlorogenicacidOROOHGenisteinOHOHDaidzeinHOHIsoflavones R1R212SoybeanRGinsengFerulicacidCaffeicacidGinsengHOOCH3COOHVanillicacidOHOOHOHOOHKaempferolHOOCH3CHCH COOHHOOHCH CH COOHGinsengSingleto
48、xygenquenchers:CaffeicacidKaempferolVanillicacidSalicylicacidFerulicacidLinoleicacidinaqueoussystemunderdark:KaempferolMaltolVanillicacidSaponinSalicylicacidFerulicacidMetalchelationactivity:KaempferolMaltolVanillicacidFerulicacidCaffeicacidAmino Acid, Peptide and Protein Glycine,methionine,andlysin
49、einemulsionsystem-antioxidantactivityatlowconcentrationandhighpH.Carnosineinhibitstheactivitiesofhemoglobin,lipoxygenase,iron,peroxyl,andhydroxylradical.FerritinandtranferritinproteinsbindironMaillard ReactionReducingSugarsand-aminoacidsN-glycosylamineorN-fructosylamine1-Amino-1-deoxy-2-ketose(Amado
50、riintermediate)or2-Amino-2-deoxy-1-aldose(Heynesintermediate)ReductonesanddehydroreductonesFuransThiophenesPyrrolesRetroaldolcondensationH2SNH3StreckerdegradationAminoAcidsHydroxyacetoneHydroxyacetylaldehydeAcetoinAcetylaldehydeGlyoxalPyruvaldehydeGlycerolaldehydeAldehydes+-aminoketone(Methional,NH3
51、,H2S)HeterocyclizaionPyrazinesPyridinesOxazolesThiazolesPyrrolesCH3C OC OHC OHCHOHCHOHCH2OHReductoneAntioxidants from Maillard BrowningNitrogeneouscompoundsEthylthiolCH3SHCH2Polarity of Antioxidants PolarantioxidantsaremoreactiveinbulkoilsystemsHydrophobicantioxidantsthatarelocatedontheinterfaceofli
52、pid/watercanprotectlipidbetterthanhydrophilicantioxidantsEffects of Antioxidant Polarity in Food Systems AirOilWaterOilHydrophobicantioxidantHydrophilicantioxidantWaterOilFactorsAffectingPartitioningofAntioxidantsThechemicalstructureandpolarityThetypesoflipidsubstrateThepresenceofsurfactantspHThecom
53、positionofthephasesAntioxidant Measuring MethodsFactors Affecting the Antioxidant ActivitySubstratesConditionsAnalysesConcentrationsCalculationsSubstratesSubstratesrelevanttofoodsystemsincludingtriacylglycerlsandphospholipidsVariousbulkoilandemulsionsystemTestundervariousoxidationconditionsDifferent
54、temperaturesMetalcatalystsSimulatedrealfoodsystemsConditionsAnalysesInitialproductsPeroxidevalueorconjugateddienesSecondarydecompositionproductsCarbonylsorvolatilecompoundsConcentrationsCompareantioxidantsatthesamemolarconcentrationofactivecomponentsusingstructurallyrelatedreferencecompounds.Conside
55、rtheconcentrationratioofantioxidants/substrates.CalculationsQuantifyonthebasisofInductionperiodincreasepercentageInhibitionpercentageofperoxidevaluecomparedtothecontrolsampleReductionpercentageofvolatilecompoundsConsideration of Antioxidant SelectionIdealAntioxidantsNoharmfulphysiologicaleffectsPath
56、ologicaleffectCarcinogenicpotentialInteractionswithenzymesEffectsofreproductionNatureofthemetabolismrateinmanNoobjectionableflavor,odor,orcolorEffectiveinlowconcentrationFat-solubleCarry-througheffectReadily-availableEconomicalNotabsorbablebythebodyPossibleFutureAntioxidantsAntioxidantattachedtothepackagingmaterials油脂氧化质量评价方法油脂加工化学
