Carbohydrates Types

Not all carbohydrates have the same form, function, and health impact. The basic unit of all carbohydrates is the monosaccharide, or single-molecule carbohydrate. The common monosaccharides all have six carbons, and while they vary only slightly in hydrogen'oxygen configuration, these subtle variations account for important metabolic differences. The basic metabolic unit for human cells is the monosaccharide glucose, and the other monosaccharides have biochemical pathways that enable them to be converted to glucose. The number of monosaccharides bonded together provides the main basis for classifying carbohydrates .

Each of the three main monosaccharides (glucose, fructose, and galactose) has different characteristics of solubility, sweetness, and reactivity with the food environment in which it is found. With the exception of fructose, which is present in an increasingly wide variety of processed foods as high-fructose (corn) sweetener, most monosaccharides are delivered in the food supply as breakdown products of disaccharides, which are two-molecule carbohydrates (i.e., composed of two connected monosaccharides.)

There are three main disaccharides-sucrose, maltose, and lactose-each containing a different combination of monosaccharides. Together, the monosaccharides and disaccharides are referred to as simple carbohydrates, or sugars, while the polysaccharides are commonly referred to as complex carbohydrates. The indigestible carbohydrates are also complex carbohydrates, but they are commonly referred to as dietary fiber. The sugars (the mono- and disaccharides) have different sweetness characteristics, with fructose tasting the most sweet, followed by sucrose, glucose, and lactose (the least sweet). However, the sugars also differ in mouth feel and solubility (e.g., fructose is less soluble than sucrose), all of which influence food manufacturers in their choice of sugars in food preparation. Athletes now have a wide array of sports beverages from which to choose, with each containing different proportions of the mono- and disaccharides, and each trying to achieve the best combination of flavor, gut tolerance, gastric emptying, electrolyte replacement, and energy delivery to working muscles.