Maillard reaction 2,3-butanedione

Many other compounds have been identified as products of the sugar-amino acid reaction. Amongst these are 2,3-butanedione,195 formaldehyde,196 pyruvaldehyde,20,195, 247, 248 3-hydroxy-2-butanone,248 hydroxy-2-propanone,248 and acetaldehyde.73 Imidazoles,196, 249-251 especially 4(5)-methylimidazole, have also been isolated from the reaction under mild conditions, and could have been formed from a-hydroxy ketones or aldehydes plus amino compounds. Following the early identification247 of pyru-valdehyde as a product of the Maillard reaction, much work was done in an attempt to show that this reactive compound plays a major role in the reaction,249 262 254 but, that this is so is by no means certain.7... 

The Maillard reaction between reducing sngars and amino acids under specific conditions (pH, water activity, and temperature) is primarily responsible for the production of heterocyclic volatile compounds such as pyrazines, pyridines, pyrroles, furans, and the Strecker aldehydes. Maillard reactions produce many potent aroma compounds identified in some roasted tree nuts, including 3-methylbutanal, 2,3-butanedione, methional, phenylacetaldehyde, 2-ethyl-3,5-dimethylpyrazine, and 2,5-dimethyl-4-hydroxy-3(2//)-furanone, among others. 

The work also demonstrates that IMP in meat is a precursor for 2-methyl-3-furanthiol and mercaptoketones, although it does not seem to be as important in the formation of 2-furylmethanethiol. The roles of IMP and ribose as sources of these thiols have been discussed previously (12,19). The mechanism involves the Maillard reaction and could require the intermediate formation of 4-hydroxy-5-methyl-3(2H)-furanone and dicarbonyls, such as butanedione and pentanedione, which is then followed by their reaction with hydrogen sulfide or cysteine. The concentrations of IMP in meat vary considerably between different animals and different muscles, and are affected by production conditions both pre- and post-slaughter. The present results indicate that the amount of IMP in the meat at the time of cooking may be an important factor in determining the amount of meaty flavor. 

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