Today I’d like to introduce a new series of articles entitled as aroma chemistry. As you know I’m a chemist and when I was creating Chemist in the Bottle I had a concept in my mind that it would be great if you could find some interesting information from my field of studies here and so the idea of aroma chemistrywriting appeared. In this series I will be writing about chemical molecules used in perfumery and cosmetics, about their sources, properties and eventual effects on us. I hope you’ll find those articles educative and fun! Our first guest is a molecule of limonene!
Limonene is a chemical substance which is build of 10 carbon atoms and 16 hydrogen atoms, so it’s formula is C10H16. It has an annular structure based on 6 carbon atoms, so it’s a cyclohexane derivative. It also belongs to the group of alkenes as it possesses one double C=C bond. Where you can find limonene? There’s plenty of it in lemons, oranges, limes, mandarines and many other citrus fruits. The name of the molecule actually comes from the word “lime.” Did you ever experienced the situation when you wanted to peel the orange and some juice got into your eye making it red and itchy? Yup, that’s limonene doing. The greatest amounts are in outer, coloured part of the rind. There’s almost no limonene in the white part of the peel, in the pulp there are only small amounts.
That won’t be a surprise for you that limonene has a nice smell of bittersweet citruses. But you might be curious what does it have to do with cosmetics and perfume. Well, it has to do quite a lot. Check out the boxes of your face creams and favourite perfume. Most of you will find limonene listed in the ingrediens list, somewhere by the end of it probably. This substance is used there in several purposes. Purpose one: it can be a part of fragrance composition of your cream or perfume (especially a citrus one). Purpose two: it has mild antibacterial properties so that your cream would live longer after opening. Purpose three: in both cosmetics and perfume it is added to preserve the product.
Now you know where to find limonene, how does it smell, how does it look like and why is it used in your products. Limonene is one of those chemicals that are prone to oxidation. It’s probably oxidized limonene that causes perfume to change it’s smell after many years of storing it (and it applies not only for wrong storing). Products of limonene oxydation can cause a contact dermatitis on your skin in bigger amounts. But you don’t need to worry much. Your knowledge about perfume is on a high level and I’m sure you know that expired cosmetics and perfume that changed their aroma shouldn’t be used for one’s own sake!
There are also some good sides of having limonene in your everyday diet. Small amounts of limonene and it’s derivatives like carveol and carvone protect our body tissues from bad mutations and cancer. So eat citrus fruits and your body will be thankful to you! I think that will be it when it comes to speaking about limonene. Of course numerous studies on this molecule are being conducted but they’re advanced chemistry things that generally don’t apply to perfume and cosmetics industry. Lemons want to than you for your attention!