Valeric acid or pentanoic acid is a straight-chain alkylcarboxylic acid with the chemical formula . Like other low-molecular-weight carboxylic acids, it has an unpleasant odor. It is found in the perennial flowering plant Valeriana officinalis, from which it gets its name. Its primary use is in the synthesis of its esters. Salts and esters of valeric acid are known as valerates or pentanoates. Volatile esters of valeric acid tend to have pleasant odors and are used in perfumes and cosmetics. Several, including ethyl valerate and pentyl valerate are used as food additives because of their fruity flavors.
Valeric acid is a minor constituent of the perennial flowering plant valerian (Valeriana officinalis), from which it gets its name. The dried root of this plant has been used medicinally since antiquity. The related isovaleric acid shares its unpleasant odor and their chemical identity was investigated by oxidation of the components of fusel alcohol, which includes the five-carbon amyl alcohols.
Valeric acid is one volatile component in swine manure. Other components include other carboxylic acids, skatole, trimethyl amine, and isovaleric acid. It is also a flavor component in some foods.
Valeric acid occurs naturally in some foods but is also used as a food additive. Its safety in this application was reviewed by an FAO and WHO panel, who concluded that there were no safety concerns at the likely levels of intake. The compound is used for the preparation of derivatives, notably its volatile esters which, unlike the parent acid, have pleasant odors and fruity flavors and hence find applications in perfumes, cosmetics and foodstuffs. Typical examples are the methyl, ethyl, and pentyl valerates.
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