ANSWER

The main compounds which cause rosemary extract’s efficacy as antioxidants are two phenolic diterpenes: carnosic acid (CA) and carnosol (about 90% of antioxidant activity) (Logan et al., 2015; Raadt et al., 2015).

Common commercial extract from rosemary are available in two forms which are in liquid or fine powder form. The liquid form of rosemary extract is soluble/dispersible by either oil or water. Whereas for powder form, they are generally dispersible in oils or fats, insoluble in water but soluble in organic solvents (Hudson, 2012).

Some synthetic antioxidants are not allowed to be used in certain applications for certain countries. Rosemary antioxidants are natural antioxidants that can be used in most applications and is more effective than vitamin E (synthetic), BHA, BHT, TBHQ and others. Rosemary extract may be up to four times as effective as BHA and equal to BHT as a phenolic antioxidant (Gad & Sayd, 2015).

References

Gad, A. and Sayd, A. (2015) Antioxidant Properties of Rosemary and Its Potential Uses as Natural Antioxidant in Dairy Products—A Review. Food and Nutrition Sciences, 6(1), 179-193. https://doi.org/10.4236/fns.2015.61019

Hudson, B. J. (2012). Food Antioxidants (pp. 132-135). England: Springer Science & Business Media.

Logan, A. S., Nienaber, U. & Pan, X. (2015). Lipid Oxidation: Challenges in Food Systems (pp. 417-429). Amsterdam, Netherlands: Elsevier.

Raadt, P., Wirtz, S., Vos, E. & Verhagen, H. (2015). Short Review of Extracts of Rosemary as a Food Additive. European Journal of Nutrition & Food Safety, 5(3), 126-37. https://doi.org/10.9734/EJNFS/2015/10404

Shahidi, F. (2015). Handbook of Antioxidants for Food Preservation (pp. 179-211). Cambridge: Woodhead Publishing.