Exhibiting a complex character, iso-butyric acid is
effective in a wide range of fruit and non-fruit flavors,
particularly those outside of the dairy category.
Given the very widespread use of normal butyric acid in flavors, it might seem surprising to focus on iso-butyric acid (FEMA# 2222, CAS# 79-31-2), an ingredient that is only used in a fraction of the volume of its “big brother.” Both chemicals have a strong cheesy odor, but normal
butyric acid has an obviously sharp, cheesy impact than iso-butyric acid. So
why am I enthusiastic about iso-butyric acid? My main motivation is the fact
that the more subtle profile of iso-butyric acid blends into many fruit flavors
more harmoniously than butyric acid. There is a parallel here with the comparison between 2-methyl butyric acid and its two cousins 3-methyl butyric
acid and normal valeric acid. The softer, more subtle and complex, character
of 2-methyl butyric acid also makes it a better choice for most fruit flavors.
iso-Butyric acid has a predominantly bright, cheesy character but this is
shaded by a hint of a vinegary note, similar in some respects to propionic
acid. This complex character is especially effective in a wide range of fruit
flavors but it is also interesting in many non-fruit flavors, particularly those
outside the dairy category. One unexpected property of iso-butyric acid is
the fact that it works very well in combination with normal butyric acid.
n BY JOHN WRIGHT,