CARBOHYDRATES - CARBOHYDRATES Carbohydrates are called...

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CARBOHYDRATES Carbohydrates are called carbohydrates because they are essentially hydrates of carbon (i.e. they are composed of carbon and water and have a composition of (CH 2 O) n The major nutritional role of carbohydrates is to provide energy. Digestible carbohydrates provide 4 kilocalories per gram. No single carbohydrate is essestial, but carbohydrates do participate in many required functions in the body. Carbohydrates include: Monosaccharides Disaccharides Oligosaccharides Polysaccharides:Starches, Cellulose, Gums Most people equate sugar with sucrose. Sucrose is a disaccharide made up of glucose and fructose and is found in most plant products. Common table sugar is just the juice of either sugar cane or sugar beets that has had all of the impurities removed resulting in crystalline sucrose. It is probably the purest food product we consume. Recently some of the sucrose that was used in food production has been replaced by high fructose corn syrup. Corn syrup is made from the digestion of corn starch to produce glucose. This can be accomplished either by acid or enzymatic digestion. Most corn syrup in the US is produced by combined acid enzymatic digestion and proceeds much like the digestion of starch in the body. High fructose corn syrup uses additional enzymes that are able to convert some of the glucose into fructose. This results in a mixture of glucose and fructose that is similar to what would occur if sucrose were digested. High fructose corn syrup is sweeter than either glucose or sucrose (see below) and thus less can be used to achieve greater sweetness per calorie. Consumption of all nutritive sweeteners (mostly sucrose, high fructose corn syrup and glucose) in the United States is about 150 pounds per person per year. This comes out to about 190 grams or 760 K calories per day. Thirty years ago the numbers were closer to 100 grams and 400 calories per day. Sugar is easily digested and most cells are better suited to obtain energy from glucose than from any other source. The human brain strongly prefers glucose as a source of energy and consumes an estimated 20% of a person's total energy. This would be approximately 400 K calories for a person consuming 2000 K calories per day Carbohydrates include simple sugars : 6 carbon sugars 5 carbon sugars
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glucose ribose fructose deoxyribose galactose Monosaccharides may have 6 carbons and are called hexoses or they may have 5 carbons and are called pentoses. Glucose (sometimes called dextrose), fructose and galactose are three common hexoses. Ribose and deoxyribose are two common pentoses. The smallest unit of a carbohydrate is a saccharide. The most common monosaccharides contain 6 carbons. Glucose, fructose and galactose are probably the ones you have heard of. Some sugars containing 5 carbons are very important as components of nucleic acids. Ribose and deoxyribose are the two you probably have talked about. Disaccharides
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This note was uploaded on 06/22/2011 for the course FDSCTE 201 taught by Professor Magino during the Spring '11 term at Ohio State.

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CARBOHYDRATES - CARBOHYDRATES Carbohydrates are called...

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