Monday, October 4, 2010
An aside...shea oil
What is the difference between shea butter and shea oil? Shea oil is a fractionated version of shea butter that remains liquid at 20˚C. The liquid is separated from the solid, so we get higher levels of the unsaturated fatty acids like oleic and linoleic acid, and lower levels of stearic acid. Let's compare the fatty acid profiles...
5% palmitic acid - shea butter has 4%
27% stearic acid - shea butter has 42%
57% oleic acid - shea butter has 45%
9% linoleic acid - shea butter has 6%
This means the shea oil might be more moisturizing for our skin, thanks to the oleic acid, as well as more anti-inflammatory, and the increased level of linoleic acid might help repair our skin's barrier properties faster. Both of these fatty acids are better absorbed by our skin than stearic or palmitic acid.
The difference between the two shea oils above is likely the difference in stearic acid amounts. The more stearic acid, the more viscous the oil will be.
Shea oil contains higher levels of unsaponifiables - 10% to shea butter's 8% - which is where we find the anti-inflammatory triterpenes and cinnamic acid esters, which can penetrate the skin and help with cell regeneration. It contains higher levels of Vitamin E - 150 to 200 ppm vs. 100 to 150 ppm in shea butter - but it's still considered low compared to other oils and butters.
So why use shea oil? You can get all the awesome power of shea butter into your products without worrying about graininess or crystallization and it has slightly higher levels of the fatty acids and unsaponifiables that offer more anti-inflammatory properties. Shea oil has a lighter skin feel than shea butter, so you can use it in products where heaviness isn't a good thing like facial moisturizers or spray lotions. It has a shorter shelf life than shea butter - one year as opposed to two - so you might want to include some Vitamin E in your shea oil based creations!
Join me tomorrow to try making whipped shea without shea butter!