lactic acid
noun
: a hygroscopic organic acid C3H6O3 present normally especially in muscle tissue as a by-product of anaerobic glycolysis, produced in carbohydrate matter usually by bacterial fermentation, and used especially in food and medicine and in industry
Examples of lactic acid in a Sentence
Recent Examples on the Web
Most of the sourdough breads on store shelves, however, include various other ingredients, most commonly yeast to speed up the rise and vinegar or lactic acid to boost sour flavor and also to stabilize the dough and lengthen its shelf life.
—
Jolene Thym,
Mercury News,
6 July 2026
More anaerobic metabolism leads to more build up of more lactic acid in your muscles.
—
Bruce Y. Lee,
Forbes.com,
5 July 2026
The same active ingredients found in face peels, including glycolic and lactic acid, also appear in body formulas at gentler concentrations suited for larger surface areas.
—
Lauren Jarvis-Gibson,
Charlotte Observer,
30 June 2026
Fermentation also changes the bread chemically, Messer notes, as beneficial bacteria known as lactic acid help break down some starches and proteins in the dough, including small amounts of gluten.
—
Daryl Austin,
USA Today,
28 June 2026
See All Example Sentences for lactic acid
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Jolene Thym,
Mercury News,
6 July 2026
More anaerobic metabolism leads to more build up of more lactic acid in your muscles.
—
Bruce Y. Lee,
Forbes.com,
5 July 2026
The same active ingredients found in face peels, including glycolic and lactic acid, also appear in body formulas at gentler concentrations suited for larger surface areas.
—
Lauren Jarvis-Gibson,
Charlotte Observer,
30 June 2026
Fermentation also changes the bread chemically, Messer notes, as beneficial bacteria known as lactic acid help break down some starches and proteins in the dough, including small amounts of gluten.
—
Daryl Austin,
USA Today,
28 June 2026
See All Example Sentences for lactic acid
Cite this Entry
“Lactic acid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lactic%20acid. Accessed 7 Jul. 2026.
Copy CitationMedical Definition
lactic acid
noun
: a hygroscopic organic acid C3H6O3 that is known in three optically isomeric forms:
a
or D-lactic acid
: the dextrorotatory form present normally in blood and muscle tissue as a product of the anaerobic metabolism of glucose and glycogen
b
or L-lactic acid
: the levorotatory form obtained by biological fermentation of sucrose
c
or DL-lactic acid
: the racemic form present in food products and made usually by bacterial fermentation (as of whey or raw sugar) but also synthetically, and used chiefly in foods and beverages, in medicine, in tanning and dyeing, and in making esters for use as solvents and plasticizers
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