Types of Carbohydrates
Although each gram of carbohydrates contains the same amount of energy, the different types of carbohydrates act differently on metabolism. This is directly related to the amount of secreted hormone insulin after their intake, its metabolic functions and effects on other hormones.
Carbohydrates are separated into two major groups: Simple and Complex.
Simple Carbohydrates – they are divided into 3 groups: monosaccharides, disaccharides and oligosaccharides.
Oligosaccharides are located on the surface of cell membranes and have a signaling function, but they do not matter as a foodstuff, so we will accentuate on the first two groups.
Monosaccharides are a large class of compounds containing carbonyl and hydroxyl group. They differ by the type of carbonyl group, the number of carbon atoms in the molecule, number and spatial location of the asymmetric carbon atoms. We will examine the main monosaccharides which are included in the composition of many foodstuffs.
In the human body, all taken carbohydrates can be metabolized to glucose. In the pure form, it is produced by enzymatic hydrolysis of farina (corn, rice, potatoes, wheat) and is mainly used in the confectionery industry. Many fruits are natural sources of glucose and among them record holder is the grapes. Glucose is the quickest absorbing of all carbohydrates, and this process depends on the presence of the hormone insulin.
Fructose or fruit sugar is an ingredient in sweet fruits and honey, and also it is about 73% sweeter than sucrose (simple sugar). The process of absorbing fructose is twice more slowly than glucose and does not require insulin because of which it is known as sugar for diabetics. Another fact for the fructose is that it is easily convertible into fats. The reason is that muscles can not use it directly and instead the body stores it in the liver as glycogen. Average there can be stored 100 grams of carbohydrates and when this maximal quantity is reached then the excess fructose goes directly into the fat cells. However, its ability to not increase the insulin is important and used wisely it can find its place in each diet. Moreover, its main source – fruit and honey contains and other valuable nutrients.
Galactose enters the body mainly as a component of the disaccharide lactose which is contained in milk and some dairy products. It can be used as energy only after its converting in glucose.
Disaccharides are composed of two monosaccharides.
Sucrose is simple sugar obtained from sugar beet or sugarcane. It is consisting of one molecule of glucose and one fructose.
Lactoseismilksugar foundinmilkand somedairy products. It contains one molecule of glucose and one galactose. The lactose is of large importance for infants and less for adults. Some people develop lactose intolerant because they have low levels of the enzyme which breaks down it. These people can not easily consume milk and unfermented milk products but some of them can eat yogurt, cheese, cottage cheese.
Maltose is composed of two glucose molecules, which break down during its digestion.
Complex carbohydrates – Complex carbohydrates are composed of hundreds or thousands of monosaccharides.
Depending on the type of monosaccharides included in them, they are divided into homopolysaccharides (composed of the same monosaccharides) and heteropolysaccharides (composed of different monosaccharides).
Starch is the main carbohydrate supplying energy for our body.It is a polymer of glucose and in the digestive tract it is hydrolyzed to glucose. From the energetic point of view 100 g starch are converting into 105 grams glucose. This is because of included molecule water during link’s hydrolysis.
Main foods containing starch are cereals – barley, wheat, buckwheat, rice, oats, millet, rye, corn (and received of them flour and bakery products), potatoes and beans.
Glycogen is a reserve saccharide stored in our body. It actually is the storage form of glucose. Each cell contains small amounts of glycogen. Large accumulations there are only in two places in the body – muscle tissue and liver. Because of significantly greater mass muscles contains more glycogen (300-600 grams) compared with weighing about a kilo liver containing (60-100 grams).
Muscle glycogen supplies glucose only for muscular work.
Liver glycogen supplies glucose for all tissues and organs.
Cellulose is an element of the cell walls in plants. It also is a polymer of glucose but because of the difference in building links between glucose molecules it is completely indigestible and there is not any energetic value. Its function is to improve peristalsis of the stomach and intestines, to stimulate secretion of digestive fluid and to create a sense of satiety.
Together with plant food we take significant amounts of cellulose.
Besides the cellulose, there are other types of indigestible or partially digestible carbohydrates commonly called fibers. They are found in vegetables, fruits, legumes, whole grain flours, oat bran.
<a href="http://fitness-healthandbeauty.com/types-of-carbohydrates/" >Types of Carbohydrates</a>