lactose

/lak"tohs/, n.
1. Biochem. a disaccharide, C12H22O11, present in milk, that upon hydrolysis yields glucose and galactose.
2. a white, crystalline, sweet, water-soluble commercial form of this compound, obtained from whey and used in infant feedings, in confections and other foods, in bacteriological media, and in pharmacology as a diluent and excipient. Also called milk sugar, sugar of milk.
[1855-60; LACT- + -OSE2]

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Slightly sweet sugar (disaccharide) composed of two monosaccharides, glucose and galactose, linked together.

Lactose-intolerant adults, and more rarely infants, cannot digest lactose because they lack the enzyme (lactase) that splits it into simpler sugars and suffer diarrhea and bloating when they eat foods containing it. Lactose, which makes up 2–8% of the milk of mammals, is the only common sugar of animal origin. Commercial lactose is obtained from whey, a liquid by-product of cheese. It is used in foods, in pharmaceuticals, and in nutrient broths used to produce penicillin, yeast, and riboflavin, and other products.

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      carbohydrate containing one molecule of glucose and one of galactose linked together. Composing about 2 to 8 percent of the milk of all mammals, lactose is sometimes called milk sugar. It is the only common sugar of animal origin. Lactose can be prepared from whey, a by-product of the cheese-making process. Fermentation of lactose by microorganisms such as Lactobacillus acidophilus is part of the industrial production of lactic acid. Human lactose intolerance is indicated by diarrhea and abdominal bloating and discomfort; lactose intolerance also may be a cause of diarrhea in newborns.

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Universalium. 2010.

Look at other dictionaries:

  • Lactose — (Milk sugar) IUPAC name β D galactopyranosyl (1→4) D glucose …   Wikipedia

  • Lactose — Général Nom IUPAC β D galactopyrannosyl (1→4)β D glucopyrannose Synonymes …   Wikipédia en Français

  • lactose — [ laktoz ] n. m. • 1843, aussi fém.; de lact(o) et 1. ose ♦ Chim. Diholoside contenu dans le lait des mammifères (C12H22O11), hydrolysable en glucose et galactose. ● lactose nom masculin Sucre (molécule à 12 atomes de carbone) contenu dans le… …   Encyclopédie Universelle

  • lactose — lac tose (l[a^]k t[=o]s ), n. 1. (Physiol. Chem.) The main sugar present in milk, called also {sugar of milk} or {milk sugar}. When isolated pure it is obtained crystalline; it is separable from the whey by evaporation and crystallization. It is… …   The Collaborative International Dictionary of English

  • lactose — lactose. См. молочный сахар. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • Lactose — Lactose, der durch Säuren veränderte Milchzucker, s.d …   Pierer's Universal-Lexikon

  • Lactose — Lactose, Milchzucker, Kohlenhydrat aus der Gruppe der ⇒ Oligosaccharide; Disaccharid aus den β 1,4 glykosidisch verknüpften Monosacchariden Glucose und Galactose. L. ist in der Milch der Säuger vorhanden und wird von den Milchsäurebakterien in… …   Deutsch wörterbuch der biologie

  • Lactose — vgl. Laktose …   Das Wörterbuch medizinischer Fachausdrücke

  • lactose — sugar from milk, 1858, from French, coined by French chemist Marcelin Pierre Eugène Berthelot (1827 1907) from L. lac (gen. lactis) milk (see LACTATION (Cf. lactation)) + chemical suffix ose …   Etymology dictionary

  • lactose — |lâct| s. f. Açúcar de leite …   Dicionário da Língua Portuguesa

  • lactose — ► NOUN Chemistry ▪ a compound sugar present in milk …   English terms dictionary

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