Thermal generation of Maillard flavor

Effect of Amide Content on Thermal Generation of Maillard Flavor in EnzymaticaUy Hydrolyzed Wheat Protein... 

CHEN HO Amide Content Thermal Generation of Maillard Flavor 93... 

Alkylpyrazines, effect of amide content on thermal generation of Maillard flavor, 90,92/... 

Maillard reaction is known to occur in foods and biological systems (Eriksson, 1981 Waller and Feather, 1983 Fujimaki et aL, 1986 Baynes et al, 1989 Finot, 1990 Finot et al, 1990 Labuza et aL, 1994 Lee and Kim, 1996 Ikan, 1996). Recently, food browning and its prevention (Friedman, 1996) and the thermal generation of Maillard aromas (Ho, 1996) have been reviewed. Therefore, this overview, will concentrate on application aspects of the Maillard reaction relating to the generation of flavor, antioxidant properties, desmutagenic effects, protein-polysaccharide conjugates and other major reaction products. 

In addition to simple model systems, more complex systems which are closer to actual foodstuffs have been used to investigate the formation of flavor chemicals in the Maillard reaction. Sixty-three volatile chemicals were isolated and identified from starch heated with glycine (4). When beef fat was used as a carbonyl compound precursor in a Maillard model system with glycine, 143 volatile chemicals were identified (6). These included fifteen n-alkanes, twelve n-alkenes, thirteen n-aldehydes, thirteen 2-ketones, twelve n-alcohols, and eleven n-alkylcyclohexanes. Recently, the effect of lipids and carbohydrates on the thermal generation of volatiles from commercial zein was studied (7). 

The thermal reaction of cystine and 2,3-dimethyl-4-hydroxy-3 (2H)-furanone (DMHF), a modified Maillard reaction is important for the generation of meat flavors. The reaction products, their flavor compounds, aroma character and yield vary, according to the reaction parameters. These parameters include the reaction medium, duration, water content, temperature, pH and presence or absence of oxygen. 

Mottram, D.S., Salter, L.J. Flavor formation in meat-related Maillard systems containing phospholipids. In Thermal generation of aromas, ParUment, T.H., McGorrin, R.J., Ho, C.T. (Eds.), American Chemical Society, Washington, DC, 1989, 442-451. 

Ouweland, G.A.M., Demole, E.P., and Enggist, P, Process meat flavor development and the Maillard reaction, in Thermal Generation of Aromas, Parliment, H., McGorrin, J.M., and Ho, C.T., Eds., American Chemical Society, Los Angeles, 1988, p. 433. 

K. Eichner, M. Reutter, and R. Wittmann, Detection of Amadori compounds in heated foods, in Thermally Generated Flavors Maillard, Microwave, and Extrusion Process, T. H. Parliment, M. J. Morello, R. J. McGorrin (eds), American Chemical Society, Washington, DC, 1994, 42-54. 

Severe heating of proteinaceous foods leads not only to generation of flavor compounds due to the Maillard reaction, but also to thermal degradation of Met and Cys residues in proteins, as well as of different low-molecular-weight compounds. These reactions are discussed in Chapter 10 of this volume. 

The major precursors in meat flavors are die water-soluble components such as carbohydrates, nucleotides, thiamine, peptides, amino acids, and the lipids, and Maillard reaction and lipid oxidation are the main reactions that convert these precursors in aroma volatiles. The thermal decomposition of amino acids and peptides, and the caramelization of sugars normally require temperatures over 150C for aroma generation. Such temperatures are higher than those normally encountered in meat cooking. During cooking of meat, thermal oxidation of lipids results in the formation of many volatile compounds. The oxidative breakdown of acyl lipids involve a free radical mechanism and the formation of... 

Bailey, M. E. In Flavor of Meat, Meat Products and Seafoods, Sh idi, F., ed. Blackie Academic Professional New York, NY, 1998, pp. 267-289. Mottram, D. S. In Thermally Generated Flavors Maillard, Microwave and Extrusion Processes, Parliament, T. H., Morello, M. J. and McGorrin, R. J., eds. ACS Symposium Series 543 American Chemical Society Washington, DC, 1994, pp. 104-141. 

Flavor can be produced by thermal reactions between naturally occurring compounds in foods, such as the creation of meat flavor by the thermal reactions of certain amino acids and sugars (the so-called Maillard reactions). These types of materials have been used by the industry for more than 100 years in savory applications [4]. Flavors generated during heating or processing by enzymatic reactions or by fermentation are generally considered to be natural flavors [45]. 

Meat flavor is due to a great number of volatiles from different chemical classes. However, most of the odorants described as meaty aroma contain sulfur. The two most important reactions which generate meaty aroma compounds are the reactions between sulfur containing amino acids and reducing sugars (Maillard reaction) and the thermal degradation of thiamin [35], Sulfur-containing furans are the basic chemicals responsible for the aroma of thermally treated meat. 

Bailey, M.E. Gutheil, R.A. Hsieh, F.H. Cheng, C.W. Gerhardt, K.O. Maillard reaction volatile compounds and color quality of a whey protein concentrate - corn meal extruded product. In Thermally Generated Flavors Maillard, Microwave, and Extrusion Processes, Parliment, T.H., Morello, M.J., McGorrin, R.J., Eds. American Chemical Society Washington, D.C., 1994 pp. 315-327. 

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