Ingredient Information

Function

Lactic acid, also called sour milk, is found in fermented milk products like lassi, koumiss, kefir, yogurt, laban and cottage cheese. The casein in the milk is coagulated by the lactic acid. Lactic acid may also be present in wine as a result of a specific malolactic fermentation process to help impart a sharp taste to wine. In winemaking, a bacteria is used to convert malic acid to lactic acid. Lactic acid may also be added to boiled sweets, and can be added to sourdough bread to impart a sour taste. It is also added to beer to lower the pH and impart a tart taste to the finished product. Lactic acid is also present in pickled dishes like sauerkraut and kimchi. Lactic acid is also a preservative and prevents growth of bacteria in preserved foods.

Other Use and Industries

Lactic acid is used as a starting material to make polylactic acid which is a biodegradable plastic material. Lactic acid can penetrate skin and is hence used in cosmetic and skin care preparations. In pharmaceuticals, lactic acid is used to solubilize insoluble active ingredients in the form of lactates.

Health Effects

Lactic acid is a safe ingredient to eat. Lactic acid is also produced by our muscles following intense exercise and by gut bacteria. It is well tolerated and completely digested. Also, foods containing lactic acid can be preserved at ambient temperature and can keep well for a few days. Additionally, fermented foods that are made by fermentation with Lactobacilli also have the enzyme lactase which helps in digesting residual lactose.

Origins

Lactic acid is produced by Lactobacilli and Streptococcus thermophilus bacteria by fermenting carbohydrates under anaerobic conditions. It was refined for the first time by the Swedish chemist Carl Scheele in 1780 when he obtained it from sour milk. In 1856, Louis Pasteur discovered Lactobacilli and its role in making lactic acid. It was first produced commercially by a German pharmacy in the 1890s. In 2006, global production of lactic acid reached 275,000 tons per year. Lactic acid is approved for food use in Europe, the United States, Australia, and New Zealand.