Flavor Bites: 2-Methyl-4-propyl-1,3-oxathiane

Catty notes have a proud history of use in flavors, especially in fruit flavors. Buchu oil (FEMA# 2169, CAS# 68650-46-4) was for many years the dominant note in blackcurrant flavors and an important note in many others.

Unfortunately, buchu oil had some practical disadvantages. It contained a significant level of isomenthone (FEMA# 3460, CAS#491-07-6) and menthone (FEMA# 2667, CAS# 89-80-5). This gave it a noticeable peppermint note that was often unwelcome in fruit flavor profiles. This problem was soon resolved by using the single ingredient responsible for the catty note, p-mentha-8-thiol-3-one (FEMA# 3177, CAS# 38462-22-5). This leads us to a second problem. p-Mentha-8-thiol-3-one, either from buchu oil or synthesized, decomposed quite readily, and the catty note tended to fade on storage.

The third disadvantage was the fact that many flavor types where is was used required a hint of metallic character in addition to the catty note in order to be judged authentic. This was especially true of grapefruit and passion fruit flavors. The problem could be solved by adding small quantities of alternative catty notes that were much more metallic in nature, such as 1-hexanethiol (FEMA# 3842, CAS# 111-31-9) and 1-heptanethiol (FEMA# 4259, CAS# 1639-09-4). Unfortunately, these sulfur compounds were more stable thant p-mentha-8-thiol-3-one, and the end result became unplesantly metallic on storage.


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