Ingredient Profile—Sorbic Acid/Potassium Sorbate

By: Michael J. Fevola, PhD, Johnson & Johnson

Posted: November 1, 2012, from the November 2012 issue of Cosmetics & Toiletries.

Sorbic acid (SorbH) and its potassium salt, potassium sorbate (KSorb), are well-known food preservative ingredients that are also employed for the preservation of cosmetic and personal care formulations. As the safety of commonly used preservatives such as parabens continues to be questioned by consumers and nongovernmental organizations, formulators are motivated to seek preservatives that are perceived more favorably yet still safe and effective against microbial contamination. Accordingly, SorbH and KSorb have become increasingly popular options due to their worldwide status as Generally Recognized As Safe (GRAS) food ingredients and their long and successful use history.^1–2

Chemistry and Manufacture

SorbH, also known as 2,4-hexa-dieneoic acid, is a straight-chain fatty acid with molecular formula C₆H₈O₂, corresponding to molecular weight of 112.13 g/mol.³ As shown in Figure 1, there are two conjugated trans double bonds located at the C2 and C4 positions, which render SorbH highly unsaturated for a six-carbon fatty acid. Its potassium salt, KSorb, has a molecular weight of 150.22 g/mol, of which 26% is attributed to the potassium ion.⁴

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