propanoaatin

Propanoaatin refers to the propanoate ion derived from propanoic acid (propionic acid) and, more broadly, to the salts and esters of this carboxylic acid. The propanoate ion is a negatively charged carboxylate (R-COO−). In solution it exists in equilibrium with propionic acid, depending on pH.

Common propanoates include sodium propanoate, potassium propanoate, and calcium propanoate. These salts are typically water-soluble; many propanoate esters (such as propyl propanoate) are used as flavorings or solvents. Propionic acid itself is a short-chain fatty acid with three carbon atoms; its conjugate base forms the propanoate ion.

In biology, propionate is produced in the human gut by bacterial fermentation of dietary fiber and other substrates. After absorption, propanoate can be converted to propionyl-CoA and entered into metabolism as succinyl-CoA via the enzymes propionyl-CoA carboxylase and methylmalonyl-CoA mutase. Defects in this pathway cause propionic acidemia, a rare metabolic disorder.

Uses include as a preservative in bread and other baked goods, where calcium propanoate and sodium propanoate inhibit mold and bacterial growth. Propanoate esters are used as flavorings or fragrance ingredients and as solvents in various products.

Safety: Propanoates used as food additives within regulatory limits are generally regarded as safe. Concentrated solutions can cause irritation to skin, eyes, and mucous membranes. In medical or metabolic contexts, excessive propionate accumulation can be harmful, especially in people with propionic acidemia.