Vegetable Oils Infused with Rosemary

Vicente, Martin, Garcia-Risco, Fornari, and Reglero (2012) examined the extraction of rosemary’s antioxidant constituents using carbon dioxide and combing them with sunflower oil, linseed oil and grapeseed oil to determine if there was any effect on the antioxidant ability of the rosemary constituents. 

They determined if ethanol is not used with the carbon dioxide extraction process, the antioxidant ability is greatly reduced. No matter which method, with or without ethanol, the linseed oil had the most carnasol and carnosic acid, increasing as the dosage increased, The grapeseed oil had the least.

The interesting part the authors noted was the linseed oil without the rosemary was the most likely to oxidize. There was a direct relationship to the amount of PUFA (polyunsaturated fatty acids) to the likelihood of susceptibility of oxidation. 

The sunflower oil had the least PUFA and was in between the other two oils in terms of absorption of the rosemary constituents. Linseed oil had the most PUFA and absorbed the most. Grapeseed oil was the middle on PUFA but the last on absorption.

The authors are now wondering if the composition of the PUFA is the cause of oxidation.  Linseed oil was 43% linolenic acid (Omega-3) and 19% linoleic acid (Omega-6). Grapeseed oil had 68% linoleic acid, and Sunflower oil had 44% linoleic acid. They also are wondering if the position of the double bonds has an effect. Constituents which are a natural part of the original oils may also play a role.
 
Have a Great Day!

Vicente, G., Martin, D., Garcia-Risco, M. R., Fornari, T., and Reglero, G. (2012). Supercritical Carbon Dioxide Extraction of Antioxidants from Rosemary (Rosmarinus officinalis) Leaves for Use in Edible Vegetable Oils. Journal of Oleo Science, 61(12):689-697.