The law of diminishing returns certainly seems to have applied to new flavor chemical research in recent years, and the trickle of new additions to the FEMA GRAS list have not all proved to be uniformly interesting. With that in mind, it was a very pleasant surprise to test a sample of ethyl 3-methyl 2-oxo-pentanoate (FEMA# 4903, CAS# 26516-27-8). To my knowledge, this chemical is not found in nature and it has quite a complex aroma. It is primarily a fruity note, with hints of succulence and dried fruit notes. Intertwined with the fruity character is a pleasant nutty note that is especially reminiscent of walnuts. Certainly, a uniquely different profile and one that is capable of adding an interesting nuance to quite a range of different flavors.
Note that the dose rates given throughout this article are the levels suggested for use in flavors intended to be dosed at 0.05% in ready-to-drink beverages or in a simple bouillon.
Almond: Most nut flavors are built around a group of unsaturated ketones, which deliver authenticity but can tend to taste a little thin and dry if they dominate a flavor. A modest addition of around 80 ppm of ethyl 3-methyl 2-oxo-pentanoate in almond flavors helps to add depth and rounds out the nutty note.
Hazelnut: A similar effect can be observed in hazelnut and praline flavors, but the ideal level of this ingredient is a little higher, around 150 ppm.
Peanut: Peanut flavors can incorporate ethyl 3-methyl 2-oxo-pentanoate at different levels, depending on their profile. A good place to start is 100 ppm.
Pistachio: In many respects, pistachio flavors are similar to almond flavors but perhaps with a more assertive nutty character. A level of 100 ppm is effective.
Walnut: Trying to judge the ideal level of this ingredient in walnut flavors is not so easy. I usually tend to favor a relatively subtle approach and 200 ppm achieves good realistic results. Alternatively, it is quite possible to build a walnut flavor pretty much around ethyl 3-methyl 2-oxo-pentanoate and force the other ingredients to fit in. With this approach, levels up to 1,000 ppm can be added and you certainly end up with a unique flavor.
Caramel: Ethyl 3-methyl 2-oxo-pentanoate, used at around 50 ppm, adds a very interesting nutty note to caramel flavors and blends in well with the natural fruity notes of this flavor category.
Chocolate and Cocoa: The effect is equally impressive in cocoa flavors and levels up to 50 ppm also work well in this category. The best level in chocolate flavors depends on the profile but 20 ppm is a good starting point for milk chocolate.
Maple: The ideal level of addition of ethyl 3-methyl 2-oxo-pentanoate to maple flavors depends on the type of flavor to an unusual degree. A realistic maple syrup flavor is probably best served by a relatively modest 30 ppm. If the goal is an overtly flavored style, then much higher levels can be used because the unusual profile of this raw material blends in very well with fenugreek notes.
Tea, Black and Red: Ethyl 3-methyl 2-oxo-pentanoate is not so useful in green tea flavors but it is readily applicable to black tea and, especially, red tea flavors. A good starting point is 50 ppm.
Toffee: The category of toffee flavors covers a multitude of sins in addition to relatively authentic profiles. A reasonable compromise here is 100 ppm.
Vanilla Bean: Vanilla bean flavors are an exercise in cramming the maximum complexity into the profile by using modest amounts of many different ingredients. An addition of 30 ppm ethyl 3-methyl 2-oxo-pentanoate makes an especially useful addition.
Bacon and Ham: It would be quite possible to use ethyl 3-methyl 2-oxo-pentanoate in a wide range of meat flavors at low levels, but it seems especially attractive in bacon and ham flavors. The best level of use in bacon flavors is 20 ppm and in ham flavors it is 30 ppm.
Mushroom, Cooked: This ingredient really comes into its own in cooked mushroom flavors and more substantial additions are possible, up to 100 ppm.
Soy Sauce: The effect of this ingredient in soy sauce flavors is also interesting. I personally find that the unique character of Kishibori Shoyu, fermented in 100-year-old casks, is vastly superior to supermarket brands and ethyl 3-methyl 2-oxo-pentanoate adds a little hint of this special character at around 50 ppm.
Apricot, Dried: Using ethyl 3-methyl 2-oxo-pentanoate in fruit flavors represents a turning of the tables. The fruity note fits in perfectly with the profile of dried apricots, but the level of addition is limited to around 20 ppm by the need to keep the nutty character in check.
Orange: This need for caution is even more true for orange juice flavors, but a modest addition of 10 ppm can add an interesting degree of juice character and naturalness.
Pineapple: Keto and hydroxyl esters are generally interesting in pineapple flavors and ethyl 3-methyl 2-oxo-pentanoate is no exception. A good starting point is 60 ppm if there is no objection to a hint of processed juice character.
Strawberry: For strawberry flavors, as with most fruit flavors, we are back to a very subtle approach but even 5 ppm can add interesting depth and realism to a category where the fruity note can often be too light and simplistic.
Brandy: Ethyl 3-methyl 2-oxo-pentanoate adds an attractive depth to all spirit flavors and here the nutty note is equally valued along with the fruity note. A level of 10 ppm works well in brandy flavors.
Rum: An addition of 10 ppm also gives an interesting effect in light rum flavors, where the effect is quite similar to that in brandy flavors. This ingredient really shines in dark rum profiles, where 50 ppm is a reasonable starting point. Much more can be used with ease to give an unusually and interesting profile.
Whiskey: Dried fruit and walnut nuances work very well in whiskey flavors and help to round out the profile very nicely. Levels of use depend on the flavor, but 20 ppm will typically work very well.