Flavor from Maillard reactions between amino acids

Alkylpyrazines occur frequently as flavor constituents in foodstufis that imdergo heating, for example, coffee and meat. They are probably formed by a Maillard reaction between amino acids and carbohydrates. Alkylpyrazines also act as alarm pheromones in ants. Coelenterazine (35) is a bioluminiscent natural product isolated from a jellyfish [293]. 

The term processed flavor is used in different contexts to describe (a) products where the natural raw materials lack a characteristic flavor profile and the desired aromatic profile is achieved only by deliberate processing (e.g., coffee) (b) flavorings created as a result of Maillard and other related reactions between amino acids and sugars (e.g., meat-like flavors) (c) flavorings resulting from controlled enzymatic reactions (e.g., enzyme-modified dairy products) (d) products made by fermentation (e.g., wines, vinegar) and (e) products of thermal reactions of lipids (e.g. French fry flavor). 

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. 

Hodge [10] was the first to present an outline of the overall reactions involved in the Maillard reaction. Generally speaking, the Maillard reaction is a reaction between carbonyls and amines. The carbonyls in foods most often are reducing sugars, while the amines come from either amino acids or proteins. In the flavor industry, the... 

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