carbohydrate(redirected from Polyhydroxyketone)
Also found in: Dictionary, Thesaurus, Encyclopedia.
a compound of carbon, hydrogen, and oxygen, the latter two usually in the proportions of water (CH2O)n. They are classified into mono-, di-, tri-, poly-, and heterosaccharides. Carbohydrates in food are an important and immediate source of energy for the body; 1 g of carbohydrate yields 4 calories. They are present, at least in small quantities, in most foods, but the chief sources are the sugars and starches. Food substances that are almost pure sugar include granulated sugar, maple sugar, honey, and molasses. The monosaccharides (simple sugars) include glucose and fructose. galactose, another simple sugar, is produced by the digestion or hydrolysis of lactose. The disaccharides (double sugars) include sucrose (white sugar, found in sugar cane or sugar beets), maltose, and lactose. All ripe fruits and many vegetables contain natural sugars. The starches are present in such foods as rice, wheat, and potatoes. Carbohydrates may be stored in the body as glycogen for future use. If they are eaten in excessive amounts, however, the body changes them into fats and stores them in that form.
carbohydrate/car·bo·hy·drate/ (kahr″bo-hi´drāt) any of a class of aldehyde or ketone derivatives of polyhydric alcohols, so named because the hydrogen and oxygen are usually in the proportion of water, Cn(H2O); the most important comprise the starches, sugars, glycogens, celluloses, and gums.
1. Any of a group of organic compounds, including sugars, starches, celluloses, and gums, that contain only carbon, hydrogen, and oxygen and that originate chiefly as products of photosynthesis. Carbohydrates serve as a major energy source for living things.
2. A food, such as bread, rice, or potatoes, that is composed largely of these substances.
Etymology: L, carbo, coal; Gk, hydor, water
any of a group of organic compounds, the most important of which are the saccharides, starch, cellulose, and glycogen. They are classified according to molecular structure as mono-, di-, tri-, poly-, and heterosaccharides and soon will be classified according to the degree of polymerization. Carbohydrates constitute the main source of energy for all body functions, particularly brain functions, and are necessary for the metabolism of other nutrients. They are synthesized by all green plants and in the body are either absorbed immediately or stored in the form of glycogen. Current dietary goals of the United States recommend that carbohydrates provide 55% to 60% of total calories. Cereals, vegetables, fruits, rice, potatoes, legumes, and flour products are the major sources of carbohydrates. They can also be manufactured in the body from some amino acids and the glycerol component of fats. Symptoms of deficiency include fatigue, depression, breakdown of essential body protein, and electrolyte imbalance. Muscle protein-sparing amounts of food carbohydrates have been estimated to be 50 to 100 grams per day for most people. Excessive consumption of simple carbohydrates is associated with tooth decay and is carefully monitored in persons with diabetes. The dietary reference intake for carbohydrates is 130 grams a day.
Aldehyde or ketone derivatives of a polyhydric—especially pentahydric and hexahydric—alcohol. The name derives from ratio of hydrogen and oxygen-Cn(H2O)n; the major carbohydrates are starches, sugars, celluloses and gums, which are classified into monosaccharides (e.g., glucose), disaccharides (e.g., sucrose), trisaccharides (e.g., raffinose) and polysaccharides (e.g., starch, cellulose and glycogen).
An abundant organic compound, it is one of the three main classes of foods and a principal source of energy. Ingested carbohydrates are sugars and starches, which are metabolised into glucose or assembled into glycogen and stored in the liver and muscle for future use.
carbohydrateNutrition An abundant organic compound, which is one of the 3 main classes of foods and a principal source of energy; ingested carbohydrates are sugars and starches, which are metabolized into glucose, or assembled into glycogen, and stored in the liver and muscle for future use. See Complex. Cf Fats, Protein.
Organic compound of carbon, hydrogen, and oxygen; sugars are simple carbohydrates, starches are complex carbohydrates.
carbohydratea family of organic molecules (hydrates of carbon) with the general formula (CH2 O)x, ranging from simple sugars such as glucose and fructose to complex molecules such as starch and cellulose. All complex carbohydrates are built up from simple units called MONOSACCHARIDES which cannot be hydrolysed to a simpler structure.
The types of carbohydrate are described in detail under their own heading, but are summarized in Fig. 89.
a compound of carbon, hydrogen and oxygen, the latter two usually in the proportions of water (CH2O)n. They are classified into mono-, di-, tri-, poly- and heterosaccharides. Carbohydrates in food are an important and immediate source of energy for the body; 1 gram of carbohydrate yields 3.75 calories (16 kilojoules). They are present, at least in small quantities, in most foods, but the chief sources are the sugars and starches of plants. Herbivores are able to utilize the insoluble polysaccharides (crude fiber) because of bacterial conversion to volatile fatty acids by fermentation in the rumen and cecum.
Carbohydrates may be stored in the body as glycogen for future use. If they are eaten in excessive amounts they are converted to and stored as fat. Rapid ingestion of very large amounts in ruminants and horses causes carbohydrate engorgement.
polysaccharides containing either α- and β-type glycosidic bonds. Usually occurring in mixtures in food.
the carbohydrate components of food.
depletion/repletion means of maximally loading glycogen into type II muscle for increased power of muscle contraction.
glucose loss in urine due to diabetes mellitus or chronic renal disease.
series of related enzymic reactions involved in the synthesis and catabolism of carbohydrates.
carbohydrate tolerance test
see glucose tolerance test.
Patient discussion about carbohydrate
Q. What are carbohydrates and where they are found and what is their nutritional value?
A. You got it.More discussions about carbohydrate