2-Methyl butyric acid (FEMA# 2695, CAS# 116-53-0) (F-1) is notably different in character from the closely related unbranched aliphatic fatty acid valeric acid (FEMA# 3101, CAS# 109-52-4) and also from the even more closely related isovaleric acid (FEMA# 3102, CAS# 503-74-2). It has a mild, soft, dried fruit character, whereas the related fatty acids are stronger, but much more one-dimensional and cheesy in character. 2-Methyl butyric acid is very widely distributed in nature and has an unusually wide spectrum of use in flavors.
The characters of several other 2-methyl substituted fatty acids show marked similarities. They may be less useful overall than 2-methyl butyric acid, but they can be very interesting in specific applications. 2-Methyl pentanoic acid (FEMA# 2754, CAS# 97-61-0) is also soft and reminiscent of dried fruit, and it is particularly useful in nut flavors. 2-Methyl hexanoic acid (FEMA# 3191, CAS# 4536-23-6) has a similar character and blends well with chocolate flavors. 2-Methyl heptanoic acid (FEMA# 2706, CAS# 1188-02-9) is the last member of the series to find widespread use and is particularly effective in vanilla and beef flavors.
The dose rates given below are the levels of 2-methyl butyric acid to be used in flavors that are intended to be dosed at 0.05% in a ready-todrink taster, beverage or bouillon. They all assume the chemical is used alone, without other members of the same family.