脂類理化性質(zhì)

1、LIPID PHYSICAL AND CHEMICAL CHARACTERISTIC,Zhang Dequan,物理性質(zhì),氣味和色澤 芝麻油香氣：乙酰吡嗪 椰子油香氣：壬基甲酮 菜子油氣味：黑芥子苷分解 熔點和沸點 油脂熔點最高40-55 熔點溫度低于37，消化率達(dá)到96% 熔點高于37，不容易消化,煙點、閃點和著火點 smoking point：發(fā)煙的溫度 flash point：被點燃但不能燃燒的溫度 fire point：持續(xù)燃燒5s以上的溫度 精練油脂煙點在240左右 折射率 分子量大分子量小的飽和脂肪酸 飽和脂肪酸不飽和脂肪酸 油脂鑒別,結(jié)晶特性 Polymorphism 轉(zhuǎn)變 -2

2、排列(DCL) -3排列(TCL) 簡單甘油酯容易形成穩(wěn)定的結(jié)晶,DCL排列 混合甘油酯容易形成結(jié)晶,TCL排列,結(jié)晶：大豆油、玉米油、花生油、椰子油、橄欖油、可可脂油、豬油 結(jié)晶：棉子油、棕櫚油、菜子油、乳脂、牛脂、改性豬油 “調(diào)溫”獲得某種結(jié)晶產(chǎn)品 可可脂生產(chǎn) Sn-StOSt、Sn-POSt,熔融特性 融化 SFI（Solid Fat Index） SFI測定方法： 差示掃描量熱儀（DSC） NMR 脈沖NMR為AOCS的官方方法,油脂塑性 塑性是指在一定的外力下，表觀固體脂肪具有的抗變形的能力，油脂塑性取決于： SFI、脂肪晶型、熔化溫度范圍 Shortening oil 油脂的液晶態(tài)

3、（介晶相） 層狀： 六方 立方,乳化與乳化劑 分散相（01-50微米的小滴）分散在連續(xù)相中 乳濁液的制備：油脂、水、乳化劑、能量 乳濁液不穩(wěn)定的因素：分層、絮凝、聚結(jié) 乳化劑選擇方法：HLB值,一些常見乳化劑的HLB值,化學(xué)性質(zhì),水解 氧化,1. Hydrolysis and saponification,動物脂肪 不利 有利 植物油 魚脂 水解性質(zhì)的應(yīng)用構(gòu)造脂質(zhì),2、氧化(酸敗,自動氧化 光敏氧化 酶促氧化 熱氧化 輻射氧化,Flavor Quality Loss Rancid flavor Changes of color and texture Consumer Acceptance E

4、conomic loss Nutritional Quality LossEssential Fatty Acids Vitamins Health Risks Growth Retardation Heart Diseases,2.1 氧化機(jī)制,酶與非酶氧化兩種機(jī)制 自催化機(jī)制的與分子氧的反應(yīng)是脂類氧化變質(zhì)的主要反應(yīng) 光敏氧化觸發(fā)了自動氧化,2.1.1 自動氧化的一般特性,遵循自由基機(jī)制，具有5個特點 干擾自由基反應(yīng)的化學(xué)物質(zhì)能顯著抑制自動氧化 光和產(chǎn)生自由基的物質(zhì)能促進(jìn)自動氧化 產(chǎn)生大量的氫過氧化物 由光引發(fā)的氧化反應(yīng)量子產(chǎn)額超過1 當(dāng)原始物質(zhì)為純物質(zhì)時存在一個相當(dāng)長的誘導(dǎo)期,2.1.2M

5、echanisms of Lipid Oxidation,Reactions Activation Energy Protein Denaturation 100 kcal/mol Nonenzymatic Browning Reaction 50 Enzyme Catalyzed Reaction 10-15 Lipid Oxidation 10-15,Activation Energy for Chemical Reaction,History of Oxygen,Oxygen - Scheele and Priestly in 1772. Triplet oxygen - Millika

6、n in 1928. Singlet oxygen - Herzberg in 1934,Triplet Oxygen Oxidation,C,H,C,H,C,H,2,C,H,C,H,C,H,2,C,H,2,6,C,O,O,H,C,H,2,C,H,2,3,C,H,3,100,75,50,Bond Energy of Carbon and Hydrogen,kcal/mol,Stearic acid Oleic acid Linoleic acid Linolenic acid,C,H,3,C,H,2,14,C,O,O,H,C,H,3,C,H,2,6,C,H,C,H,C,H,2,7,C,O,O,

7、H,C,H,3,C,H,2,4,C,H,C,H,C,H,2,C,H,C,H,C,H,2,7,C,O,O,H,C,H,3,C,H,2,C,H,C,H,C,H,2,C,H,C,H,C,H,2,C,H,C,H,C,H,2,7,C,O,O,H,C,H,2,C,H,2,C,H,2,Initiation of Triplet Oxygen Oxidation,RH+引發(fā)劑,R,H,Initiation of autoxidation occurs when hydrogen atom at -methylene group in double bonds of unsaturated fatty acid

8、s is removed to form an alkyl radical (R,Propagation,ROO,RH,ROOH,R,ROOH,OH,RO,RH,RO,ROH,R,R,3O2,ROO,Termination,2RO,ROOR,ROOR,RO,ROR,ROO,ROOR,R,R-R,R,ROO,R,R,ROO,O2,Linoleic Acid Oxidation by Triplet Oxygen,14,13 12 11 10 9,12 11 10 9,H,O,2,12 11 10 9,H,C,H,2,C,H,C,H,C,H,2,C,H,C,H,C,H,2,R,C,H,2,3,C,

9、H,3,INITIATION,METAL,C,H,2,4,C,H,3,C,H,C,H,C,H,C,H,C,H,2,R,C,H,C,H,2,4,C,H,3,C,H,C,H,C,H,C,H,C,H,2,R,C,H,O,O,PROPAGATION,R = (CH2)6-COOH,12 11 10 9,HYDROPEROXIDE,DECOMPOSION,OH,H,12 11 10 9,TERMINATION,PENTANE,C,H,C,H,C,H,C,H,C,H,C,H,2,R,C,H,2,4,C,H,3,O,O,H,C,H,2,4,C,H,3,C,H,C,H,C,H,C,H,C,H,2,R,C,H,

10、O,C,H,3,C,H,2,3,C,H,2,C,H,3,C,H,2,3,C,H,3,O,C,H,C,H,C,H,C,H,C,H,C,H,2,R,R = (CH2)6-COOH,Singlet and Triplet Oxygen,Molecular Orbital of Triplet Oxygen,RH+O2自由基 35kcal/mol,Molecular Orbital of Singlet Oxygen,Singlet Oxygen Formation,3O2 + Sensitizer,H2O2 + OCI,H2O2 + O2,Ozone,Endoperoxides,OH- + O2,E

11、nzymes,O2 - + Y,1O2,O2,O2 - + O2,H2O2+ HO2,RCOO + RCOO,C,H,3,C,H,2,C,H,C,H,C,H,2,C,H,C,H,C,H,2,C,H,C,O,O,H,C,H,2,6,C,H,2,C,H,O,C,H,3,C,H,2,C,H,C,H,C,H,2,C,H,C,H,C,H,2,C,H,O,C,H,3,C,H,2,C,H,C,H,C,H,2,C,H,O,O,C,H,C,H,2,C,H,1O2,1O2,O,氫過氧化物形成：Reversion Flavor from Linolenic Acid by Singlet Oxygen Oxidat

12、ion,O,2-(2-pentenyl)-furan,H2O,C,H,3,C,H,2,C,H,C,H,C,H,2,C,H,O,O,C,H,C,H,2,C,H,C,H,3,C,H,2,C,H,C,H,C,H,2,C,C,H,2,O,C,H,2,C,H,O,C,H,3,C,H,2,C,H,C,H,C,H,2,C,C,H,C,H,C,H,O,H,O,H,C,H,3,C,H,2,C,H,C,H,C,H,2,O,C,H,3,C,H,2,C,H,C,H,C,H,2,C,H,O,O,C,H,C,H,2,C,H,O,H,OH,氫過氧化物裂解： Reversion Flavor Compounds from S

13、oybean Oil,2-(2-pentenyl)-furan,C,H,3,C,H,2,C,H,C,H,C,H,2,O,C,H,3,C,H,2,C,H,C,H,C,H,O,2,2-(1-pentenyl)-furan,Reaction of 3O2 and 1O2 with Linoleic Acid,R,R,R,R,O,O,H,3O2,Conjugated,Conjugated,R,R,R,R,R,R,HOO,3O2,H,R,R,R,R,O,O,H,O,O,H,R,R,1O2,R,R,H,O,O,R,R,H,O,O,Conjugated,Nonconjugated,Reaction Rate

14、s of Lipid Oxidation,R+3O2K=109 M-1sec-1 ROO+Oleic AcidK=1 M-1sec-1 ROO+Linoleic AcidK=60 M-1sec-1 ROO+Linolenic AcidK=120 M-1sec-1 ROO+ROO K=105-107 M-1sec-1 R+AntioxidantsK= 107 M-1sec-1 RH+1O2K=105 M-1sec-1,Relative Reaction Rates of 3O2 and 1O2 with Oleic, Linoleic, and Linolenic Acids,Triplet o

15、xygen 3 104 4 104 7 104,Singlet oxygen 12777,Oleic Linoleic Linolenic Acid Acid Acid,Formation of 1O2 by Sensitizers,Ground State,Excited State,hv,Fluorescence K= 2108/sec,1Sen,1Sen,K=1- 20108/sec ISC,Phosphorescence,K=10- 104/sec,Singlet Oxygen, 1O2,K=1- 3109/sec,3Sen,3O2,光敏氧化,Lipid,Free Radical,型,

16、型,Photosensitizers in Foods,Chlorophyll Protoporphyrine Riboflavin Red No. 3,Enzymatic Oxidation（lipoxygenase,Lox,Hydropeorxide at the -6 position of unsaturated fatty acid,Poly unsaturated fatty acids (a cis, cis-1,4-pentadiene unit,Lipoxygenase,熱氧化,熱分解 熱聚合 熱縮合,輻射氧化,過氧化脂質(zhì)幾乎可以與食品中的任何成分反應(yīng)，降低品質(zhì) 氫過氧化物幾

17、乎與人體內(nèi)所有分子或細(xì)胞反應(yīng)，破壞和細(xì)胞結(jié)構(gòu) 脂質(zhì)在常溫或高溫下氧化均產(chǎn)生有害物質(zhì),油脂氧化的安全性,影響自動氧化的因素,脂肪酸性質(zhì) 氧與氧分壓 溫度 表面積 水分 過渡金屬元素 光和射線 抗氧化劑 乳化,Control of Lipid Oxidation,Application of antioxidants Elimination of oxygen by nitrogen flushing or vacuum packaging Elimination of photosensitizers Denaturation of lipoxygenase Low temperature an

18、d dark storage,Characteristics of Free Radicals in Oxidation,H : Hydrogen atom The simplest free radical O2 - : SuperoxideanionAn oxygen-centered radical. Limited reactivity HO : HydroxylA highly reactive oxygen-centered radical. Indeed attacks all molecules in human body RO2: PeroxylOxygencentered

19、radicals formed during the RO : Alkoxy breakdown of organic peroxides,Function of Antioxidant on Lipid Oxidation,Inhibits or slows the formation of free alkyl radicals in the initiation step Interrupts the propagation of free radical chain Delays the start or slows the chemical reaction rate of lipi

20、d oxidation,Types of Antioxidants,Hydrogen donating compounds Singlet oxygen quenchers Metal chelators Enzymes Oxygen scavengers and Reducing agents,Hydrogen Donating Antioxidants,Standard One-Electron Reduction Potential,Compounds E (mV,HO , H+ / H2O 2310 RO , H+ / ROH1600 ROO , H+ / ROOH1000 PUFA

21、, H+ / PUFA600 Catechol , H+ / Catechol530 - Tocopheroxyl , H+ / - Tocopherol500 Ascorbate- , H+ / Ascorbate282,Characteristics of Hydrogen Donating Antioxidants,The major hydrogen donating antioxidants are monohydroxy or polyhydroxy phenolic compounds with various ring substitutions. The antioxidan

22、t free radical does not initiate another free radical due to the stabilization of delocalization of radical,Reaction of Antioxidants with Radicals,R + AHRH +A,RO + AHROH+ A,ROO + AHROOH + A,Reaction of Antioxidants with Radicals,Effectiveness of Antioxidants,The difference of one-electron reduction

23、potential between lipid radical and antioxidant radical. The stability of antioxidant radicals - The resonance delocalization - Further oxidation of antioxidant radicals,Resonance of Antioxidant Radicals,O,H,C,C,H,3,3,O,C,H,3,C,C,H,3,3,O,C,H,3,O,O,C,H,3,C,C,H,3,3,O,C,C,H,3,3,O,C,H,3,O,O,C,H,3,C,C,H,

24、3,3,O,R , RO , ROO,RH , ROH , ROOH,Stability of Antioxidant Radical,O,C,C,H,3,C,H,3,C,H,3,O,C,H,3,Targets of Antioxidant,Antioxidants can react with peroxyl radicals rather than alkoxyl radicals. The most prevalent radical is peroxyl (ROO) radical. Peroxyl radical has the lowest standard one electro

25、n reduction potential among alkyl, alkoxyl and peroxyl radicals,Synthetic Antioxidants,Butylatedhydroxyanisole (BHA,Butylatedhydroxytoluene (BHT,Propyl gallate,Tertiary butylhydroquionone (TBHQ,Natural Antioxidants,Benefits Health implication Stability in food system Limits Characteristic flavor Saf

26、ety test required,Tocotrienols,O,H,O,R,1,R,2,R,3,C,H,3,C,H,3,C,H,3,C,H,3,Trivial NameChemical NameR1R2R3 -Tocotrienol5,7,8-TrimethyltocotrienolCH3CH3CH3 -Tocotrienol5,8-DimethyltocotrienolCH3HCH3 -Tocotrienol7,8-DimethyltocotrienolHCH3CH3 -Tocotrienol8-MethyltocotrienolHHCH3,Antioxidant Mechanism of

27、 Tocopherol,Transfer of phenolic hydrogen Scavenging of singlet oxygen Regeneration of tocopherol in the presence of ascorbate,Tocopherol,A chain breaking antioxidant competes with polyunsaturated lipid for the lipid peroxyl radicals,Tocopherol -Tocopheryl semiquinone,Lipid radicals,Lipid radicals,T

28、ocopheryl quinone,Resonance of - Tocopherol Radicals,O,O,C,H,3,H,3,C,C,H,3,C,16,H,33,C,H,3,R, RO , or ROO,Tocopherol,O,H,O,C,H,3,H,3,C,C,H,3,C,H,3,C,H,3,C,H,3,C,H,3,O,C,H,3,C,H,3,H,3,C,C,H,3,C,16,H,33,O,O,C,H,3,H,3,C,O,C,16,H,33,C,H,3,C,H,3,O,C,H,3,H,3,C,O,C,16,H,33,C,H,3,C,H,3,RH , ROH , ROOH,R, RO

29、 , or ROO,Effects of Diet Tocopherol on the Content of Tocopherol in Egg Yolk,Effects of Tocopherol on the Stability of Egg York,0,5,10,15,20,25,30,35,40,45,0,2,4,6,8,Time (Days,Total Headspace Volatiles ( 1000,25g Tocopherol / g yolk,45 g Tocopherol / g yolk,50 g Tocopherol / g yolk,75 g Tocopherol

30、 / g yolk,Control,Ascorbic Acid,Hydrogen donation to lipid radicals Quenching of singlet oxygen Removal of molecular oxygen Regenerate tocopherol radicals Prooxidant Reduce ferric iron to ferrous iron,Ascorbic Acid,O,O,O,H,O,H,C,H,C,H,2,O,H,O,H,O,O,O,O,H,C,H,C,H,2,O,H,O,H,L-Ascorbic acid,Dehydroasco

31、rbic acid,H,H,R, RO , ROO,R , RO , ROO,Ascorbic Acid and Related Compounds,L-Ascorbic Acid,O,O,H,O,H,C,H,O,C,H,2,O,H,H,O,H,Erythorbic Acid,Ascorbic Palmitate,O,O,H,O,H,O,H,C,H,C,H,2,O,H,O,H,O,O,O,H,O,H,O,H,C,H,C,H,2,O,C,C,H,2,14,C,H,3,O,H,Synergistic Effectof Tocopherol & Ascorbic Acid,Singlet Oxyge

32、n Quencher,Singlet Oxygen Quenching Mechanism,ISC,3O2,A,1Sen,1Sen,3Sen,1O2,AO2,Kq,Kox-Q,QO2,Kd,Q,Q,1Sen,1Sen,3O2,3O2,hv,Carotenoids,C,H,O,b,Carotene,Apo - 8- carotenal,O,Canthaxanthin,O,b,Peroxide Value (meq/kg oil,Storage Time (hr,Effects of -Apo-8-Carotenal, -Carotene or Canthaxanthin on the Soybe

33、an Oil Oxidative Quality,Quenching Mechanism of b-Carotene on Singlet Oxygen Oxidation,1/ Soybean Oil (1/ M,1/ Peroxide (1/ M,Singlet Oxygen Quenching Rates of Carotenoids,Carotenoids Number of Conjugated Quenching Rate Double Bonds Constants (M-1sec-1) -Apo-8- carotenal 10 2.86 109 - Carotene 11 4.

34、60 109 Canthaxanthin 13 1.12 1010,Singlet Oxygen Quenching Rate of Carotenoids,Carotenoids Number of Conjugated Rate Constants Double Bonds (109 M-1sec-1) Astaxanthin 13 9.88 Isozeaxanthin 11 7.31 Zeaxanthin 11 7.03 Lycopene 11 6.89 Lutein 10 5.86,Singlet Oxygen Quenching Rates of Tocopherols,Single

35、t oxygen quenching ability: - Tocopherol,Tocopherol: 2.70 107 (M-1sec-1,Singlet Oxygen Quenchers,Singlet Oxygen Quencher Quenching Rate (M-1sec-1) -Carotene 4.60 109 Ascorbic acid 1.08 108 -Tocopherol 2.70 107,Metal Chelators,Prooxidant Mechanisms of Metals,Hydroperoxide decomposition to form peroxy

36、l radical and alkoxyl radical Fe3+ROOHFe2+ ROO + H+ Fe2+ROOHFe3+ RO + OH- Formations of alkyl free radical by direct reaction Fe3+RH Fe2+ + R + H+ Activation of oxygen for singlet oxygen formation Fe2+3O2Fe3+ + O-2 1O2 Formation of hydroxyl radical Fe2+H2O2Fe3+ + OH- + OH,k1,k2,k2 k1 = 105,Reaction

37、between Metal and Hydroperoxide,Rapid Exponential increase in oxidation during propagation step b-Scission of alkoxyl radical to low molecular weight compounds Copper is 50 faster than ferrous ion in decomposing hydrogen peroxide Ferrous is 100 faster than ferric iron in decomposing hydrogen peroxid

38、e Ferrous is 1015 times more soluble than ferric iron,Metal Chelators,Phosphoric acid Citric acid Ascorbic acid Ethylene Diamine Tetra Acetate.(EDTA) Proteins such as Transferrin, Ovotransferrin Amino acids and Peptides,Mechanism of Metal Chelators,Formation of complex ions or coordination compounds

39、 with metals Prevention of metal redox cycling Occupation of all metal coordination sites Formation of insoluble metal complexes Steric hindrance of interactions between metals and lipid intermediates,Phospholipids,Phosphatidyl ethanolamine,C,H,2,O,C,O,R,1,C,H,O,C,O,R,2,C,H,2,O,P,O,O,O,C,H,2,C,H,2,N

40、,H,2,Phosphatic acid,C,H,2,O,C,O,R,1,C,H,O,C,O,R,2,C,H,2,O,P,O,O,O,M,O,C,O,C,H,2,O,C,O,C,H,2,N,C,H,2,C,H,2,O,O,N,C,O,C,H,2,C,O,C,H,2,Ethylene Diamine Tetra Acetate (EDTA,Interaction of Chealator and Metal,Enzymatic Antioxidants,2 Glucose + 2O2 + 2H2O 2 Gluconic acid + 2H2O2,Glucose Oxidase/Catalase,

41、2 Glucose + O2 2 Gluconic acid,2H2O2 2H2O + O2,Glucose Oxidase Catalase,Catalase,Glucose Oxidase,Oxygen Scavenging,Superoxide Dismutase,2O,2,O,2,2H,Superoxide anion participates in oxidative reactions Maintaining transition metals in their reduced, active state Promoting the release of metals bound

42、to proteins Producing singlet oxygen,Superoxide Dismutase,Catalase,2H,2,O,2,O,2,2H,2,O,3,Glutathione Peroxidase,H2O2 + 2GSH 2H2O + GSSG LOOH + 2GSH LOH + H2O + GSSG,GSH: Reduced glutathione GSSH: Oxidized glutathione,Oxygen Scavengers,Oxygen Scavengers and Reducing Agents,Ascorbic acid Ascorbic palm

43、itate Erythorbic acid Sodium erythorbate Sulfites,Oxygen Scavenger Mechanisms,C,H,3,S,H,C,H,3,S,S,C,H,3,O,2,O,O,O,O,H,C,H,C,H,2,O,H,O,H,H O,2,O,2,H O,H,O,S,O,H,O,H,O,S,O,H,O,O,O,2,2,Superoxide Dismutase,2O,2,O,2,2H,H,2,O,2,Superoxide Dismutase,Catalase,O,2,2H,2,O,3,2H,2,O,2,Producing triplet oxygen

44、from superoxide anion,3,Multifunctional Antioxidants,Tocopherol Ascorbic acid,Antioxidant Interactions,Combination of metal chelator and free radical scavenging antioxidants Combination of different antioxidants like - tocopherol and ascorbic acid,Antioxidant Sources,Flavonoids,O,H,O,H,O,H,O,O,O,H,H

45、,O,Quercetin Flavonols,O,O,H,O,O,H,H,O,G,l,u,c,os,i,de,O,H,Cyanidin-3-glucoside Anthocyanins,Flavonoids,Secondary products of plant metabolism Metal chelating ability Superoxide anion scavengers Anthocyanines, catechins, flavones, flavonols, isoflavone, and proanthocyanidins,Vegetables,Cacao beans,

46、Potato, Tomato, Spinach, Legumes, Garlic, and Seaweed Polyphenolic compounds,Fruits,Wines: Anthocyanin Polyphenolic compounds,Tea,H,O,O,H,O,O,H,O,H,O,H,Epicatechin,H,O,O,H,O,O,H,O,H,O,H,O,H,Epigallocatechin,Sesame Seed,Sesamol,O,O,O,H,Sesamolinol,O,O,O,O,O,O,C,H,3,O,H,Herb and Spice,Sage, Ginger, Gr

47、een pepper, Lavender and Rosemary,Carnosoic Acid,C,O,H,3,C,C,H,3,H,O,O,H,C,H,3,C,H,3,O,Carnosol,O,H,O,H,H,O,O,H,O,O,H,O,O,C,Rosemarinic Acid,Reaction Rates of Carnosol and Carnosic Acid,O,H,H,O,H,H,O,O,C,O,H,O,H,H,O,O,C,LOO,LOOH,Carnosic acid,3 107 M-1s-1,O,H,H,O,C,H,O,O,O,H,O,C,H,O,O,Carnosol,2 106

48、 M-1s-1,LOO,LOOH,Soybean,Chlorogenic acid, caffeic acid, ferulic acid - Metal chelation and singlet oxygen quenching Isoflavones - phytoestrogen effects - Metal chelation and hydrogen donation,O,O,O,H,O,H,C,O,O,H,O,H,H,O,H,O,Chlorogenic acid,GenisteinOHOH DaidzeinHOH,IsoflavonesR1R2,1,2,Soybean,R,Gi

49、nseng,Ferulic acid,Caffeic acid,Ginseng,H,O,O,C,H,3,C,O,O,H,Vanillic acid,O,H,O,O,H,O,H,O,O,H,Kaempferol,H,O,O,C,H,3,C,H,C,H,C,O,O,H,H,O,O,H,C,H,C,H,C,O,O,H,Ginseng,Singlet oxygen quenchers: Caffeic acid Kaempferol Vanillic acid Salicylic acid Ferulic acid Linoleic acid in aqueous system under dark

50、: Kaempferol Maltol Vanillic acid Saponin Salicylic acid Ferulic acid Metal chelation activity : Kaempferol Maltol Vanillic acid Ferulic acid Caffeic acid,Amino Acid, Peptide and Protein,Glycine, methionine, and lysine in emulsion system- antioxidant activity at low concentration and high pH. Carnos

51、ine inhibits the activities of hemoglobin, lipoxygenase, iron, peroxyl, and hydroxyl radical. Ferritin and tranferritin proteins bind iron,Maillard Reaction,Reducing Sugars and -amino acids,N-glycosylamine or N-fructosylamine,1-Amino-1-deoxy-2-ketose (Amadori intermediate) or 2-Amino-2-deoxy-1-aldos

52、e (Heynes intermediate,Reductones and dehydroreductones,Furans Thiophenes Pyrroles,Retroaldol condensation,H2S NH3,Strecker degradation,Amino Acids,Hydroxyacetone Hydroxyacetylaldehyde Acetoin Acetylaldehyde,Glyoxal Pyruvaldehyde Glycerolaldehyde,Aldehydes + -aminoketone (Methional, NH3, H2S,Heteroc

53、yclizaion,Pyrazines Pyridines Oxazoles,Thiazoles Pyrroles,C,H,3,C,O,C,O,H,C,O,H,C,H,O,H,C,H,O,H,C,H,2,O,H,Reductone,Antioxidants from Maillard Browning,Nitrogeneous compounds,Ethyl thiol,C,H,3,S,H,C,H,2,Polarity of Antioxidants,Polar antioxidants are more active in bulk oil systems Hydrophobic antioxidants