What Is Lactic Acid?
Lactic acid, a hydroxy acid with both carboxyl and hydroxy groups, is a colorless to pale yellow viscous liquid known as 2-hydroxypropanoic acid. It serves as a raw material for biodegradable plastics like polylactic acid and polyester polyol and finds uses in pharmaceuticals, the food industry as an acidifier, cosmetics, agrochemicals, dyeing, and leather processing.
Uses of Lactic Acid
Employed in producing methanol, and ammonia, and as a reducing agent, lactic acid also reacts with transition metals under catalyzed conditions to form important compounds like nickel carbonyl and cobalt carbonyl, used in synthetic organic chemistry.
Properties of Lactic Acid
Lactic acid is odorless, acidic, and has a molecular weight of 90.08. It is soluble in water, alcohol, and ether, and is the end product of the glycolytic metabolic pathway, found in animal tissues, and fermented milk products, and does not directly cause muscle pain post-exercise as previously believed.
Types of Lactic Acid
Due to its chiral carbon atom, lactic acid exists as L-lactic acid, D-lactic acid, and DL-lactic acid, each with distinct melting points and properties. L-lactic acid is the most abundant in nature.
Other Information on Lactic Acid
1. Production Methods of Lactic Acid
Lactic acid is produced either by fermentation using lactic acid bacteria or by chemical synthesis. The fermentation method involves malt juice and lactic acid bacteria, while the synthetic method uses acetaldehyde and cyanide for synthesis.
2. About Lactic Acid Bacteria
Lactic acid bacteria, used in the production of yogurt, and cheese, and during wine and sake brewing processes, produce lactic acid from carbohydrates. Malolactic fermentation enhances acidity and flavor in red wine, while in sake brewing, lactic acid helps prevent bacterial growth and adds subtle flavors and aromas.