Teasing out the underlying aromas of complex flavors

One of the most interesting things about flavor science is the fact that certain aromas and flavors are so complex that no single compound can replicate the experience. Even flavors which are represented fairly well by a single compound (like the isoamyl acetate in bananas, or the methylanthranilate in concord grapes) are more of a simulacrum to their natural inspirations, often times having a slight “artificial” quality. While this “marquee” compound may make up the bulk of that particular flavor, there are probably a half-dozen or more other compounds at or below threshold levels which are contributing to the overall impression of the flavor, adding to its complexity and depth. In some cases, these compounds may have aromas in the same category as the main flavor, but sometimes they seem to come out of left-field…

Chocolate, maybe not surprisingly, is one of those flavors that is made up of a strange hodge-podge of flavor compounds which, taken on their own, have no relation or similarity to the flavor of chocolate. Research from the Technical University of Munich is starting to show just how complex chocolate flavors are. They’ve found that there are up to 600 different aromatic compounds in cocoa beans, but you really only need about 25 of them to make a decent chocolate flavor. Twenty-five is still a big number for a single flavor and the ones on that list come from a wide-range of flavor categories, many having no obvious connection to chocolate: potato chips, cooked meat, peaches, raw beef fat, cooked cabbage, human sweat, earth, cucumber, honey… etc etc. Certainly not the types of flavors you contemplate as that decadent Swiss chocolate melts in your mouth, are they?

While not part of the research mentioned in this latest press release (for an ACS meeting), here is a table from a book about ‘chocolate science’ which includes data from the same researcher (Schieberle) which shows a large list of compounds found in the aroma of chocolate (milk chocolate, pg 67; dark chocolate, pg. 69). Since chocolate also undergoes Maillard reactions and is fermented as well (like beer in both regards), a number of these flavors are also found in beer: maltol, phenylacetaldehyde, diacetyl, dimethyl trisulphide (ew!), gamma-nonalactone, butanoic acid, various furans and pyrazines, just to name a few. Fascinating stuff!

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