Author: Site Editor Publish Time: 2022-02-28 Origin: Site
Lactic acid is an organic acid. It has a molecular formula CH3CH(OH)CO2H. It is white in solid state and it is miscible with water.While in liquid state (dissolved state) it is a colorless solution. Production includes both artificial synthesis as well as natural sources. Lactic acid is an alpha-hydroxy acid (AHA) due to the presence of carboxyl group adjacent to the hydroxyl group. It is used as a synthetic intermediate in many organic synthesis industries and in various biochemical industries. The conjugate base of lactic acid is called lactate.
Lactic acid with a chiral carbon atom has two optical isomers, L (+) - lactic acid and D (-) - lactic acid, and the mixture is DL - lactic acid. Only L-lactic acid can be metabolized in human body because only L-lactic acid enzyme exits in animal body.
Lactic acid is an important organic acid, wildly used in fields of Food, beverage, medicine, plastic, feed, pesticides, packaging materials, daily chemicals, cosmetics, paper and electronic industry.
Lactic acid is found primarily in sour milk products, such as koumiss, laban, yogurt, kefir, and some cottage cheeses. The casein in fermented milk is coagulated (curdled) by lactic acid. Lactic acid is also responsible for the sour flavor of sourdoughbread.
In lists of nutritional information lactic acid might be included under the term "carbohydrate" (or "carbohydrate by difference") because this often includes everything other than water, protein, fat, ash, and ethanol. If this is the case then the calculated food energy may use the standard 4 kilocalories (17 kJ) per gram that is often used for all carbohydrates. But in some cases lactic acid is ignored in the calculation.The energy density of lactic acid is 362 kilocalories (1,510 kJ) per 100 g.
Some beers (sour beer) purposely contain lactic acid, one such being Belgian Lambics. Most commonly, this is produced naturally by various strains of bacteria. These bacteria ferment sugars into acids, unlike the yeast that ferment sugar into ethanol. After cooling the wort, yeast and bacteria are allowed to “fall” into the open fermenters. Brewers of more common beer styles would ensure that no such bacteria are allowed to enter the fermenter. Other sour styles of beer include Berliner weisse, Flanders red and American wild ale.
In winemaking, a bacterial process, natural or controlled, is often used to convert the naturally present malic acid to lactic acid, to reduce the sharpness and for other flavor-related reasons. This malolactic fermentation is undertaken by lactic acid bacteria.
Lactic acid is also employed in pharmaceutical technology to produce water-soluble lactates from otherwise-insoluble active ingredients. It finds further use in topical preparations and cosmetics to adjust acidity and for its disinfectant and keratolyticproperties.