Nutrition 3

VI, DIETARY CARBOHYDRATES
The primary role of dietary carbohydrate is to provide energy.
A. Classification of carbohydrates
Carbohydrates in the diet are classified as either monosaccharides ,disaccharides (simple sugars), polysaccharides (complex sugars),or fiber.
1.Monosaccharides: Glucose and fructose are the principal monosaccharides found in food. Glucose is abundant in fruits, sweet corn, corn syrup, and honey. Free fructose is found together with free glucose and sucrose in honey and fruits.
2. Disaccharides: The most abundant disaccharides are sucrose(glucose + fructose), lactose (glucose + galactose), and maltose(glucose + glucose). Sucrose is ordinary "table sugar," and is abundant in molasses and maple syrup. Lactose is the principal sugar found in milk. Maltose is a product of enzymic digestion of polysaccharides. It is also found in significant quantities in beer and malt liquors. The term "sugar" refers to monosaccharides and disaccharides. "Added sugars" are those sugars and syrups added to foods during processing or preparation.
3.Polysaccharides: Complex carbohydrates are polysaccharides(most often polymers of glucose), which do not have a sweet taste. Starch is an example of a complex carbohydrate that is found in abundance in plants. Common sources include wheat and other grains, potatoes, dried peas and beans, and vegetables.
4. Fiber: Dietary fiber is defined as the non digestible carbohydrates and lignin (a complex polymer of phenylpropanoid subunits) present in plants. Several different terms are used to describe this complex group of compounds. For example, functional fiber is the isolated, extracted, or synthetic fiber that has proven health benefits. Total fiber is the sum of dietary fiber and functional fiber. Soluble fiber refers to fibers that form a viscous gel when mixed with a liquid. Insoluble fiber passes through the digestive tract largely intact. Dietary fiber provides little energy but has several beneficial effects. First, it adds bulk to the diet. Fiber can absorb ten to fifteen times its own weight in water, drawing fluid into the lumen of the intestine and increasing bowel motility. Soluble fiber delays gastric emptying and can result in a sensation of fullness. This delayed emptying also