Maillard reaction pyrolysis

G. Vernin, Mechanism of Formation of Heterocyclic Compounds in Maillard and Pyrolysis Reactions, Chem. Heterocycl. Compd. Flavours Aromas 1982, 151-207. 

Thus, by the Maillard reaction in different browning systems of sugars and amino compounds, some mutagenic substances were formed, although their activities are quite weak compared with those formed by pyrolysis of amino acids. They were confirmed as intermediates and some of them were identified as furan, pyrrole, or thiazolidine derivatives formed from glucose and amino acids... 

N, S and 0 heterocyclic compounds, along with noncyclic sulfur compounds and hydrocarbons, are predominant in "meaty" flavor volatiles. The mechanisms of heterocyclic formation by Maillard and pyrolysis reactions have been reviewed by Vemin and Parkanyi (57) and the Maillard reaction itself is a recurring subject of review (58). Since other speakers contributing to this volume will discuss these aspects of meat flavor, they will not be repeated in this presentation. 

Heterocyclic aroma compounds found in meat primarily arise from interactions between mono- and dicarbonyl compounds, H2S and ammonia. The carbonyl compounds are derived from the Maillard reaction, including Strecker degradation of amino acids, oxidation of lipids and aldolization reactions. H2S is produced by thermal degradation of sulfur amino acids and ammonia by amino acid pyrolysis. 

G. Vernin and C. Parkanyi, Mechanisms of formation of heterocyclic compounds in Maillard and pyrolysis reactions, in Chemistry of Fleterocyclic Compounds in Flavours and Aromas, G. Vemin (ed), Ellis Horwood, Chichester, 1982, 151-207. 

The furanic aldehydes 5-(hydroxy-methyl)furfural and 2-furaldehyde, systematically present in the toasted wood, can be formed by the thermal degradation of 3-deoxyosone during sugar pyrolysis or Maillard reactions (27). They could also be formed from glyceraldehyde, coming from degradation of DDMP, by condensation with subsequent elimination of water or formaldehyde (24). 

The association of Maillard polymer pyrolysis with the formation of these compounds is based on the correlation of the level of sugars and amino acids with the level of mutagen formation. Also, it was shown that the presence of creatinine (common in animals) may play an important role in the formation of these compounds, and a reaction path as shown below was proposed [19] ... 

Reactions between reducing sugars and amino acids (G18, H12, H13, R6) precede the browning (Maillard) reaction that may occur in food products, especially milks. Such adducts, subjected to acid pyrolysis are hydrolyzed to... 

The main compounds yielded by flash pyrolysis are transformation or degradation products of biogenic precursors. Next to the amino acid glycine I most of the identified compounds are structurally related to carbohydrates, amino acids and condensed molecules of both components resulting from Maillard reactions. Examples include furfural 2, methylfurfural 3 and pyrrol-2-carboxaldehyde 4 (see Fig. 3). 

Formed in the pyrolysis of isoleucine (Merritt et al., 1970) and from isoleucine by polyphenol oxidase (Motoda, 1979). For Ho et al. (1993) it is also, generated by a Maillard reaction. 

Other possible mechanisms for the formation of pyrazines during smoking are possible. For instance, leaf carbohydrates could be degraded either through pyrolysis or Maillard reactions to form a-dicarbonyl compounds, which could, in turn, react with amino acids to undergo a Strecker degradation forming... 

Caramelization is the breakdown of sugar molecules with heat (pyrolysis), while the Maillard reaction requires amino acids (proteins). Caramelization, like the Maillard reaction, is a term for hundreds of different chemical reactions taking place at the same time. 

In view of their chemical structure, they can be classified into two main groups called thermic HCAs, IQ-type or amino-imidazoazaarenes and pyrolytic HCAs, non-lQ-type or amino-carbolines. Those of the first type are produced by Maillard reaction when mixtures of creat(ni)ne, amino acids, and sugars are heated at temperatures between 100°C and 300°C [32]. Those of the second type are mainly formed by the pyrolysis of amino acids and proteins at higher temperatures, above 300°C... 

Vernin G, Parkdnyi C (1982) Mechanisms of formation of heterocyclic compounds in Maillard and pyrolysis reactions. In Vernin G (ed) Chemistry of heterocyclic compounds in flavours and aromas. Ellis Horwood, Chichester, pp 151-207 Versini G, Dalla Serra A, DelPEva M, Scienza A, Rapp A (1988) Evidence of some glycosidically bound new monoterpenes and norisoprenoids in grapes. In Schreier P (eds) Bioflavor 87. de Gruyter, Berlin, pp 161-170... 

An alternative source of characteristic heated flavor compounds is via the Maillard pathway, the thermally induced reaction between amino acids and reducing sugars. Aroma constituents in chocolate, coffee, toasted bread, and popcorn are products of Maillard reactions, in addition to flavors in roasted nuts and meats, which are discussed in Sec. II.E and 11.E. Guaiacols occur as pyrolysis products of carbohydrates or lipids in smoked or char-broiled meats. 

The intent of this chapter is to summarize naturally occurring flavor compounds in aromatic foods, and the formation of flavor during processing of foods including the Maillard, lipid oxidation, microbial, and enzymatic reactions. A brief discussion on the impact of interactions between these components on food flavor and off-flavor formation is also included. At the end of chapter, the manufacturing of flavor compounds by the utilization of biotechnology and pyrolysis techniques is further explained. 

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