ca·​sein | \ ˈkā-ˌsēn How to pronounce casein (audio) , kā-ˈsēn \

Definition of casein

: a phosphoprotein of milk: such as
a : one that is precipitated from milk by heating with an acid or by the action of lactic acid in souring and is used in making paints and adhesives
b : one that is produced when milk is curdled by rennet, is the chief constituent of cheese, and is used in making plastics

Examples of casein in a Sentence

Recent Examples on the Web Occasionally, bottles are fined, or clarified, with animal products like egg whites, milk casein or isinglass, which comes from fish. New York Times, "Unlocking the Secrets of Your Pantry," 15 Jan. 2021 These solids can be washed and dried to create casein protein powders. Carsen Joenk, Popular Science, "Best protein powder: Better nutrition in a bottle," 11 Jan. 2021 Common fining agents including gelatin, which is an animal product, and casein, which is a protein from milk. Tirion Morris, The Arizona Republic, "4 questions answered about kosher wine and where to find it for Hanukkah in metro Phoenix," 8 Dec. 2020 Once its pH hits 4.6, that’s when casein (milk protein) clumps. J. Kenji López-alt, New York Times, "The Food Expiration Dates You Should Actually Follow," 14 Apr. 2020 Breast milk is of course far, far more complex than just casein and lactose. Sarah Zhang, The Atlantic, "A Bold and Controversial Idea for Making Breast Milk," 27 Feb. 2020 Wheat products or anything else with gluten were out, as were dairy foods containing the milk protein casein. Jacqueline Stenson, NBC News, "Why the focus of autism research is shifting away from searching for a 'cure'," 22 Sep. 2019 Gluten is one of a couple of hot button foodstuffs (casein, dairy, GMOs, wheat, amongst others), that have become scapegoats for all kinds of health situations, often without formal diagnoses. Yvette D'entremont, SELF, "8 Simple Ways to Spot a Bogus Health Fad," 4 Oct. 2019 The company’s protein product is made by altering sections of the DNA sequence of food-grade yeast such that the microorganisms, once fed with certain nutrients, produce several key proteins found in milk, including casein and whey. Chase Purdy, Quartz, "The next big ice cream aisle addition will be dairy-free…kind of," 11 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'casein.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of casein

1823, in the meaning defined above

History and Etymology for casein

probably from French caséine, from Latin caseus cheese

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Last Updated

28 Jan 2021

Cite this Entry

“Casein.” Dictionary, Merriam-Webster, Accessed 4 Mar. 2021.

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More Definitions for casein


ca·​sein | \ kā-ˈsēn How to pronounce casein (audio) \

Kids Definition of casein

: a whitish to yellowish protein that is found in milk and cheese and is used in making paints, plastics, and adhesives


ca·​sein | \ ˈkā-ˌsēn, ka-ˈsēn How to pronounce casein (audio) \

Medical Definition of casein

: any of several phosphoproteins of milk: as
a : one that occurs as a colloidal suspension in milk

called also caseinogen

b : one that is produced when milk is curdled by rennet, is the chief constituent of cheese, and is used in making plastics

called also paracasein

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