lactose

(lăk`tōs) or

milk sugar,

white crystalline disaccharide (see carbohydratecarbohydrate,
any member of a large class of chemical compounds that includes sugars, starches, cellulose, and related compounds. These compounds are produced naturally by green plants from carbon dioxide and water (see photosynthesis).
..... Click the link for more information. ). It has the same empirical formula (C₁₂H₂₂O₁₁) as sucrose (cane sugar) and maltose but differs from both in structure (see isomerisomer
, in chemistry, one of two or more compounds having the same molecular formula but different structures (arrangements of atoms in the molecule). Isomerism is the occurrence of such compounds. Isomerism was first recognized by J. J. Berzelius in 1827.
..... Click the link for more information. ). It yields the simple sugarssugar,
compound of carbon, hydrogen, and oxygen belonging to a class of substances called carbohydrates. Sugars fall into three groups: the monosaccharides, disaccharides, and trisaccharides. The monosaccharides are the simple sugars; they include fructose and glucose.
..... Click the link for more information. D-glucose and D-galactose on hydrolysishydrolysis
, chemical reaction of a compound with water, usually resulting in the formation of one or more new compounds. The most common hydrolysis occurs when a salt of a weak acid or weak base (or both) is dissolved in water.
..... Click the link for more information. , which is catalyzed by lactase, an enzyme found in gastric juice. People who lack this enzyme after childhood cannot digest milkmilk,
liquid secreted by the mammary glands of female mammals as food for their young. The milk of the cow is most widely used by humans, but the milk of the mare, goat, ewe, buffalo, camel, ass, zebra, reindeer, llama, and yak is also used.
..... Click the link for more information. and are said to be lactose intolerant. Lactose is formed in the mammary glands of all lactating animals and is present in their milk. It is produced commercially as a byproduct of milk processing. When milk sours, the lactose in it is converted by bacteria to lactic acid. Lactose is less sweet-tasting than sucrose and is not found in plants.

Lactose

Milk sugar or 4-O-β- d -galactopyranosyl- d -glucose. This reducing disaccharide is obtained as the α- d anomer (see formula, where the asterisk indicates a reducing group); the melting point is 202^°C (396^°F). Lactose is found in the milk of (1) mammals to the extent of approximately 2–8%. It is usually prepared from whey, which is obtained by a by-product in the manufacture of cheese. Upon concentration of the whey, crystalline lactose is deposited.

Lactose

(milk sugar), C₁₂H₂₂O₁₁, a disaccharide, formed from D-galactose and D-glucose radicals; it exists in the a- and β- forms. Crystalline lactose is obtained in three modifications: α-form (melting point, 223°C), β-form (melting point, 252°C), and the α-form monohydrate (melting point, 202°C). Lactose is soluble in water, diluted ethyl alcohol, and pyridine and insoluble in ether and absolute alcohol; it separates into galactose and glucose during acidic hydrolysis.

Lactose occurs in free form (2–8.5 percent) in the milk of all mammals and is included in the composition of oligosaccharides, glycolipides, and glycoproteins. It has also been found in the pollen tubes of some plants. Lactose biosynthesis is effected by the enzyme galactosyl transferase, which catalyzes the transfer of the galactose radical from uridine diphosphate galactose to D-glucose. The enzymatic hydrolysis of lactose proceeds upon action of β-galactosidase. The absence of galactosidase in the mucous membrane of a newborn’s intestines is a hereditary disease that may lead to death if lactose is not excluded from the diet.

D. M. BELEN’KII

lactose

[′lak‚tōs] (biochemistry) C₁₂H₂₂O₁₁ A disaccharide composed ofD-glucose andD-galactose which occurs in milk. Also known as lactin; milk sugar.

lactose

a white crystalline disaccharide occurring in milk and used in the manufacture of pharmaceuticals and baby foods. Formula: C₁₂H₂₂O₁₁

lactose

[lak´tōs] a sugar derived from the milk of mammals, which on hydrolysis yields glucose and galactose; used as a tablet and capsule diluent, a powder bulking agent, and as a component of infant feeding formulas. Many persons are intolerant to lactose as a result of hereditary deficiency of lactase.

lac·tose

(lak'tōs), A reducing disaccharide present in mammalian milk and consisting of a galactosyl residue linked B1,4 to a glucopyranose; obtained from cow's milk and used in modified milk preparation, in food for infants and convalescents, and in pharmaceutical preparations; in large doses, acts as an osmotic diuretic and as a laxative. Human milk contains 6.7% lactose. Synonym(s): milk sugar, saccharum lactis

lactose

(lăk′tōs′)n. A white crystalline disaccharide, C₁₂H₂₂O₁₁, found in milk, that may be hydrolyzed to yield glucose and galactose. Refined lactose obtained from whey is used in infant foods, bakery products, confections, and pharmaceuticals as a diluent and excipient. Also called milk sugar.

lactose

A reducing disaccharide that is hydrolysed by beta-galactosidase into d-galactose and d-glucose; it is synthesised by mammalian mammaries, and causes intolerance to milk products that occurs in some adults.

lac·tose

(lak'tōs) A disaccharide present in cow's milk and used in food for infants and convalescents and in pharmaceutical preparations; large doses act as an osmotic diuretic and as a laxative.
Synonym(s): milk sugar.

lactose

The main sugar in milk. It is broken down by the digestive enzyme lactase (beta-galactosidase) to galactose and glucose.

Fig. 203 Lactose . The condensation reaction between galactose and glucose.

lactose

milk sugar

a DISACCHARIDE carbohydrate found in the milk of mammals. Lactose is produced by a CONDENSATION REACTION between galactose and glucose. See Fig. 203 .

The sugar can be broken into its component monosaccharides by LACTASE. Souring of milk is due to the conversion of lactose to LACTIC ACID by microorganisms present in the milk.

Lactose

A sugar found in milk and milk products. Some people are lactose intolerant, meaning they have trouble digesting lactose. Lactose intolerance can produce symptoms resembling those of IBS.Mentioned in: Galactosemia, Irritable Bowel Syndrome, Lactose Intolerance

lac·tose

(lak'tōs) A disaccharide present in cow's milk and used in food for infants and convalescents and in pharmaceutical preparations.
Synonym(s): milk sugar.

Patient discussion about lactose

Q. can you be lactose intolerant just in the morning? if i drink milk or eat a dairy product in the morning i get nausous, vomit and have diarehha. but i eat dairy products in the evening and im fine. is it possible to be lactose intolerant just in the morning?A. Not that I'm aware of.. You are either lactose intolerant or you're not. However, it depends on how much dairy products you eat, and perhaps you consume more dairy products in the morning, on an empty stomach, where it all absorbs, where as in the evening you might eat less and combine it with other food. I would suggest you dicrease the total amount of dairy you eat, in order to get rid of these symptms.

Q. lactose intolerant If you are lactose intolerant and you consume a dairy related product can it cause a fever?A. No
Lactose Intolerance means you lack the enzyme to digest milk.
You get diarrhea NOT fever
DrMDK

Q. I am lactose intolerant. Can I have any other dairy food? A. If you are lactose intolerant then you must avoid all lactose containing foods like milk, yoghurt & cheese. You can consume these dairy products If your intolerance is less or else you can have cultured yoghurt and lactobacillus milk as a better dairy option.

More discussions about lactose

lactose

lac·tose

lactose

lac•tose

lac·tose

lactose

lactose

milk sugar,

Lactose

Lactose

lactose

lactose

lactose

lactose

lac·tose

lactose

lactose

lac·tose

lactose

lactose

milk sugar

Lactose

lac·tose

Patient discussion about lactose

lactose

Synonyms for lactose

noun a sugar comprising one glucose molecule linked to a galactose molecule

Synonyms

Related Words