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|Section2= }} 3-Methylbutanoic acid, or more commonly isovaleric acid, is an organic compound with the formula (CH3)2CHCH2CO2H. It is sometimes classified as a fatty acid. It is a colourless liquid that is sparingly soluble in water, but highly soluble in most common organic solvents. The compound occurs naturally, including in essential oils. Isovaleric acid has a strong pungent cheesy or sweaty smell, but its volatile esters have pleasing scents and are used widely in perfumery. It has been proposed that it is the anticonvulsant agent in valerian. It is a major component of the cause of unpleasant foot odor, as it is produced by skin bacteria metabolizing leucine. Isovaleric acid is seen as the primary cause of the flavors added to wine caused by ''Brettanomyces'' yeasts. Other compounds produced by ''Brettanomyces'' yeasts include 4-ethylphenol, 4-vinylphenol, and 4-ethylguaiacol. An excess of isovaleric acid in wine is generally seen as a defect,〔 as it can smell sweaty, leathery, or like a barnyard, but in small amounts it can smell smokey, spicy, or medicinal.〔 These phenomena may be prevented by killing any ''Brettanomyces'' yeasts, such as by sterile filtration, by the addition of relatively large quantities of sulfur dioxide and sometimes sorbic acid, by mixing in alcoholic spirit to give a fortified wine of sufficient strength to kill all yeast and bacteria, or by pasteurization. Isovaleric acid can also be found in beer, and, excepting some English–style ales, is usually considered a flaw. It can be produced by the oxidation of hop resins, or by ''Brettanomyces'' yeasts present.〔 == See also == * Isovaleric acidemia * Valeric acid, an isomer 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「3-Methylbutanoic acid」の詳細全文を読む スポンサード リンク
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