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MAJOR CHEMICAL PROCESSES

MAJOR CHEMICAL PROCESSES. 1. The chemical processes in the food chemistry and food technology could be classified in the following groups :. Carbonyl – amine interactions (Maillard reaction) ; Thermal transformations of  - aminoacids, proteins, vitamins, carbohydrates (caramelization) etc. ;

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MAJOR CHEMICAL PROCESSES

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  1. MAJOR CHEMICAL PROCESSES 1 The chemical processes in the food chemistry and food technology could be classified in the following groups: • Carbonyl – amine interactions (Maillard reaction); • Thermal transformations of -aminoacids, proteins, vitamins, carbohydrates (caramelization) etc.; • Thermal – oxidative destruction and autoxidation of food lipids; • Polyphenol coloring of the foodstuffs; • Changes of the food components by food irradiation and other treatments.

  2. MAILLARD REACTION 2 OBJECTIVES 1. Importance of Maillard reaction for food chemistry; 2. Major steps and some reactions; 3. Study the kinetics and parameters influencing the Maillard reaction; 4. Control and inhibition of Maillard reaction.

  3. MAILLARD REACTION 2 Maillard reaction – color and flavor formation

  4. MAILLARD REACTION 3 Maillard reaction - history 1912г. Louis Camille Maillard a French physician and chemist - 3 scientific papers: C.R. Acad. Sci., France, 54, 66 - 68, 1912; C.R. Soc. Biol., 72, 559 - 561, 1912; Ann. Chem., 9 (5), 258 - 317, 1916. Major conclusions: • All reducing sugars (aldoses, ketoses;penthoses and hexoses) could react with amino acids; • Reaction takes place in broad temperature range – 150-200оС; • Reaction has autocatalytic character and the color is changed with accelerating speed and finally reach dark brown color; • During the reaction the amino acid undergo decarboxylation (lost of CO2) – a sign that Strecker degradation takes place; • The participating in the reaction carbohydrates and amino acids can not be hydrolyzed (i.e. restored) by the known methods; • The melanoidins and the humic acids (building the humus) have similar nature;

  5. MAILLARD REACTION 4 Maillard reaction - significance - important (major) in the food chemistry and technology; - formation of humus(decay of the wastes, biomaterials etc.); - in the medicine – formation of cataracts, cancerogenic compounds; mutagens – aromatic amines; acrylamide, etc.) heterocyclic aromatic amines (HAAs) - >20 acrylamide 2-Amino-3,4-dimethylimidazo[4,5-f] quinoline M. Nagao, M. Honda, Y. Seino, T. Yahagi, and T. Sugimura, Mutagenicities of smoke condensates and the charred surface of fish and meat, Cancer Lett., 1977, 2, 221–226. T. Sugimura, T. Kawachi, M. Nagao, T. Yahagi, Y. Seino, T. Okamoto, K. Shudo, T. Kosuge, K. Tsuji, K. Wakabayashi, Y. Iitaka, and A. Itai, Mutagenic principle(s) in tryptophan and phenylalanine pyrolysis products, Proc. Japan Acad., 1977, 53, 58–61.

  6. MAILLARD REACTION 4a Maillard reaction - significance

  7. MAILLARD REACTION 5 AGEs – advanced glycation end-products N-(carboxymethyl) lysine - CML Crosslines Pyraline Pentosidine The Maillard reaction (Ed. R.Ikan), John Wiley & Sons Ltd. Chichester, 1996, p.62.

  8. MAILLARD REACTION 6 Maillard reaction – general schema Preconditions and participating compounds • complexity: glucose-glycine – more than 24 products found; xylose-glycine – more than 50 products found. According to: J. E. Hodge, Chemistry of browning reactions in model systems, J. Agric. Food Chem.,1953, 1, 928–943.

  9. MAILLARD REACTION 7 ! Maillard reaction - stages

  10. MAILLARD REACTION 8 ! Maillard reaction - mechanism 1. Formation of imines and N-glycosides N-glycosides : • In the medicine – as substances with pharmaco-logical and biological activity. • In the textile industry – as softeners and detergents. • For production of rubber (caoutchouc) – as antioxidants. • N-glycosilation takes place in the human constitution and is among the most resent investigations of the field of the Maillard reaction.

  11. MAILLARD REACTION 9 Maillard reaction - mechanism 2. Amadori’s rearrangement

  12. MAILLARD REACTION 10 Maillard reaction - mechanism 3. Lobri’s rearrangement

  13. MAILLARD REACTION 12 Maillard reaction - mechanism 5. Enolisation – obtaining of osones and reductones

  14. MAILLARD REACTION 13 Maillard reaction - mechanism 5. Enolisation – obtaining of osones and their dehydration

  15. MAILLARD REACTION 14 Maillard reaction - mechanism 6. Heterocyclisation processes The pyrazines are used as artificial flavorings – some have potato, pineapple odor; some have ‘green’ odor R. Scarpellino and R. J. Soukup, Key flavors from heat reactions of food ingredients, in Flavor Science: Sensible Principles and Techniques, T. E. Acree and R. Teranishi (eds), American Chemical Society, Washington, DC, 1993, 309–335.

  16. MAILLARD REACTION 15 Maillard reaction - mechanism 6. Heterocyclisation processes isomaltol Obtaining of maltol from 1-deoxydiketose

  17. MAILLARD REACTION 16 Maillard reaction - mechanism 7. Retro aldol and aldol reactions aldol R = H ketol R = alkyl, aryl

  18. MAILLARD REACTION 18 Maillard reaction - mechanism 8. Free radical reactions Takes place when green coffee seeds are roasted

  19. MAILLARD REACTION 19 Maillard reaction - mechanism 9. Strecker degradation alloxane 1862 – reaction of alanine with alloxane !

  20. MAILLARD REACTION 20 Maillard reaction - mechanism 9. Strecker degradation Of cysteine and methionine dimethyl disulphide methanethiol acrolein

  21. MAILLARD REACTION 22 Maillard reaction - mechanism Premelanoidins formation

  22. MAILLARD REACTION 23 Premelanoidins formation The structures of some low-molecular-mass coloured compounds formed in model Maillard systems

  23. MAILLARD REACTION 25 Melanoidins formation Melanoidins – gives the color of thermally treated products, fluorescence, flavor;serve as matrix for low-molecular substances;do not fermented in the stomach; have foam forming properties – important for making coffee

  24. MAILLARD REACTION 26 Maillard reaction - mechanism Melanoidins formation melanoidins

  25. MAILLARD REACTION 28 Maillard reaction – analysis and isolation of melanoidins Model systems and standard melanoidins • Glucose (Sigma; min 99.5%, Cat. No. G8270) • Glycine (Sigma; min 99%, Cat. No. G7126) 0.05 mol from each in 100mlH2O; 2 hrs/ 125 ºС. Dialysisof the mixture – 24 h, 4°С; lyophilization

  26. MAILLARD REACTION 29 Maillard reaction – analysis and isolation of melanoidins Meat Roasting, grinding Grinded brown meat extraction (methanol: chloroform=1:2) filtration filtrate solid residue extraction water filtration Ion-exchange chromatography dialysis brown filtrate solution solid residue colorless eluate brown eluate Neutralization; Dialysis; Concentration Melanoidins

  27. MAILLARD REACTION 30 Maillard reaction – analysis and isolation of melanoidins Coffee (instant or roasted) Sequential extraction (ether, acetone, CCl3H, ethanol), Time – 3 h each) extract solid residue Concentration – distilation Flavor substances for instant coffee for roasted coffee Water extraction Gel Filtration Chromatography (GFC) Evaporation (< 30 °C) Evaporation (< 30 °C) Crude extract Melanoidins GFC Evaporation (< 30 °C) Melanoidins

  28. MAILLARD REACTION 31 Kinetics and influence of different parameters on the reaction C. M. Brands and M. A. J. S. van Boekel, Kinetic modelling of Maillard reaction browning: effect of heating temperature, in Melanoidins in Food and Health, Vol. 2, J. M. Ames (ed), European Communities, Luxembourg, 2001, 143–144.

  29. MAILLARD REACTION 32 Kinetics and influence of different parameters on the reaction 1. Type of the carbohydrate pentoses > hexoses ribose – the most reactive sugar (pentoses) ! galactose – the most reactive sugar (hexoses) ribose : xylose: galactose = 100 : 6 : 1 lactose – the most reactive disaccharides 2. Type of the amino compound ! Lysine – the most reactive amino acid

  30. MAILLARD REACTION 33 Kinetics and influence of different parameters on the reaction Determination of the nutritionally blocked lysine

  31. MAILLARD REACTION 34 Kinetics and influence of different parameters on the reaction Determination of the nutritionally blocked lysine

  32. MAILLARD REACTION 35 Kinetics and influence of different parameters on the reaction 3. Molar ratio 4. pH – optimal is 6.5-7 2-furaldehyde furanone

  33. MAILLARD REACTION 36 Kinetics and influence of different parameters on the reaction 5. Water and water activity – during the reaction water is produced (according to T.P. Labuza, Sorption phenomena in foods: Theoretical and practical aspects. In “Theory, determination and control of physical properties of food materials”, C. K. RHA ed., p.197, Riedel, Dordreht, 1975)

  34. MAILLARD REACTION 37 Kinetics and influence of different parameters on the reaction 6. Temperature - 180-220ºС 7. Metal cations – Cu, Fe – catalyzers (speeding); Mn, Sn – inhitors; 8. Other compounds – lipids, chitosan, phospholipids

  35. MAILLARD REACTION 38 Kinetics and influence of different parameters on the reaction 9. Pressure – influencing the flavor compounds

  36. MAILLARD REACTION 39 ! Kinetics and influence of different parameters on the reaction 10. Inhibition of Maillard reaction 10.1. Storage at lower temperatures – most foodstuffs do not brown at -10ºС (when stored one year) 10.2. Addition ofSO2 (E220; sulphites – Е221-224, 226-228) - allowed limits (EU / mg.kg-1, mg.L-1)

  37. MAILLARD REACTION 40 ! Kinetics and influence of different parameters on the reaction 10. Inhibition of Maillard reaction 10.2. Addition ofSO2 (E220; sulphites – Е221-224, 226-228)

  38. MAILLARD REACTION 41 ! Kinetics and influence of different parameters on the reaction 10. Inhibition of Maillard reaction 3. Lowering the рН 4. Dehydration – example: fruit juices (with combination with addition of SO2 5. Removal of some of the foods’ components 5.1. Carbohydrates dried Chinese egg white – removal of glucose by fermentation (!Microbial contamination) potato chips – dipping in the solution with glucose oxidase removal of lactose from milk

  39. MAILLARD REACTION 42 ! Kinetics and influence of different parameters on the reaction 10. Inhibition of Maillard reaction 5. Removal of some of the foods’ components 5.2. Amino acids - precipitation by thermal treatment and filtration - adsorption 5.3. Changes of the amino acids (mainly lysine)

  40. MAILLARD REACTION 43 NO!

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