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Classification of Carbohydrates
It ranks carbohydrates according to their glycemic index that is to say according to their hyperglycaemic effect. Indeed, if all the carbohydrate source is glucose, they do not increase blood glucose equivalent. Overall, the simple carbohydrates tend to raise blood sugar quickly, as the complex carbohydrates it varies.
The glycemic index (GI) of food used to evaluate the rate of absorption of the glucose.
To calculate a GI is given to volunteers 50 g glucose dissolved in water (glucose is the carbohydrate of reference, you can also take the starch in white bread). Blood glucose is then measured every 30 minutes for 2 to 3 hours. This operation is repeated with a portion of the test food containing 50 grams of carbohydrates. By dividing the area under the curve of blood glucose test food by the area under the curve obtained with glucose, we obtain the IG. Below 55 we talk about low GI between 55 and 70 IG moderate and over 70 high GI. More GI of a food is, the more it increases rapidly and the brutal blood sugar.
Carbohydrates What’s the Point?
The main function of carbohydrates is to provide energy. They release 4 kcal / g. The human body uses carbohydrates as glucose (all carbohydrates we eat are converted to monosaccharides during digestion to pass into the blood. Assimilated monosaccharides other than glucose are then converted into glucose by the liver).
Glucose is distributed in the body to be directly used by all cells (muscle, heart ) and especially nerve cells. Glucose is the sole source of energy in the brain (the latter can not utilize fat for this purpose). For this reason, the blood glucose (or glucose) must be maintained above a minimum level.
Glucose can also be converted into glycogen, a polysaccharide similar to starch, which is stored in the liver and muscles and provides an energy reserve immediately available.
The fibers are not treated, they do not provide energy. However they have an important role in the mechanical action of digestion. They increase the volume of stool and stimulate transit.
Sources of Carbohydrates
Carbohydrates are found in many foods. They are found mostly in foods of plant origin. There was very little in foods of animal origin except for milk which is a source of lactose.
Simple carbohydrates
Glucose is rarely encountered in this simple form in nature. Fructose is naturally present in fruits, corn, honey. Sucrose is composed of one molecule of glucose and one fructose molecule. This disaccharide is a carbohydrate reserve of plant species such as sugar beet or cane sugar. It is the white sugar, our table sugar. Lactose is composed of one glucose and one galactose molecule: the milk sugar. The maltose present in the malt combines two molecules of glucose.
Molecule of Vitamin A
In the body, it exists as Retinol from retinal, Retinoic acid and retinyl phosphate. These molecules are altered by oxygen in the air, changes accelerated by light and heat.
Foods of animal origin (meat, dairy products and especially liver) contain retinol and retinyl esters, whereas plants contain predominantly carotenes which are precursors of retinol. One molecule of beta-carotene, by hydrolysis of the 15-15 ‘under the influence of carotenoid monooxygenase (??-carotene 15,15′ monooxygenase), gives two molecules of vitamin A. For cons, the two other Carotenes (alpha and gamma) give birth to only one molecule of vitamin A.
The need for vitamin A are estimated at about 5 000 IU per day. An international unit of vitamin A equals 0.3 mg of retinol. Retinol is considered the basic unit, retinol-equivalent, which compares the vitamin activity of various derivatives of vitamin A. The most useful form of vitamin A is retinol, although it can also be found in the form of retinal or retinoic acid. Retinol is a hydrophobic molecule synthesized from isoprene. Vitamin A is involved in bone growth and synthesis of pigments of the eye. Retinol is sometimes used to treat severe acne.
Fats are Non Polar Substances
Fats, also called lipids, together with carbohydrates represent the major source of energy for the body. As in the case of proteins, fats are essential and nonessential. The essentials are those that the body can not synthesize, and are linoleic acid and linolenic acids, but typically are not absent from the body and are contained in meat, cold meats, fish, eggs. Biochemically, fats are non polar substances and are therefore insoluble in water. This is nonpolar because their molecules have many carbon and hydrogen atoms covalently bound to pure and therefore do not form dipoles that interact with water. We conclude that lipids are excellent insulators and separators. Fats consist of fatty acids. Overall call triglyceride oils of vegetable origin, and correspond to derivatives containing predominantly unsaturated fatty acids which are liquid at room temperature. (vegetable oils for cooking, and fish, see table). In the case of fats, these are composed of triglycerides consisting of animal saturated fatty acids, solid at room temperature. (butter, fat, chicken skin, in general: dairy, meat, chocolate, avocado and coconut).
Generic Term for Several Kinds of Lipids
In biochemistry, fat is a generic term for several kinds of lipids, but generally refers to the Glyceride, esters in which one, two or three fatty acids attached to a glycerol molecule to form monoglycerides, diglycerides and triglycerides respectively. Fats are present in many organisms, and have both structural and metabolic functions.
The most common type of fat is one in which three fatty acids are attached to the glycerol molecule, receiving the name of triglycerides or triacyl glycerols. Triglycerides are solid at room temperature as fats, while those who are known as liquid oils. Through a technological process called hydrogenation, the oils are processed to obtain fats or hydrogenated fats. Although currently have reduced the adverse effects of this process, the technological process still has the drawback fatty acid formation whose unsaturation (double bonds) are of trans configuration.
All fats are insoluble in water having a density significantly lower (floating in the water).
Chemically, fats are generally triesters of glycerol and fatty acids. Fats may be solid or liquid at room temperature, depending on their structure and composition. Although the words “oils”, “fat” and “lipids” are all used to refer to fats, the word “oil” is usually used to refer to lipids that are liquid at room temperature, while the word “fat” is used to refer to fats that are solids at room temperature. The word “fat” is used to refer to both liquid and solid. The word “oil” is used for any substance that does not mix with water and fat, such as oil and cooking oil, regardless of their chemical structure.
Fats form a category of lipid, distinguished from other lipids by their chemical structure and physical properties. This category of molecules is important for many forms of life, serving both structural and metabolic functions. These constitute a very important part of the diet of most heterotrophs (including humans).
Examples of edible fats are butter, margarine, butter and cream. Fats or lipids are degraded in the body by enzymes called lipases
Types of Carbohydrates
Carbohydrates (or carbohydrates) are usually divided between sugars (monosaccharidas such as glucose, galactosa or fructose) and saccharides, which are polymers of sugars (polysaccharides). Disaccharidas (Disaccharide), such as sucrose or lactose, and polysaccharides (polysaccharides or polysaccharides) are part of the latter category. Only Monosaccharidas and disacharidas have a sweetness. Polysaccharides, like starch, are insipid.
- Monosaccharidas (simple sugars) are simple molecules, nonhydrolyzable, forming crystals.
- Aldoses are carbohydrates with an aldehyde function on the first carbon.
- Ketoses are carbohydrates with a ketone function on the second carbon.
- Sacharide (complex sugars), are hydrolysable polymers of monosaccharides linked by a saccharide.
Holosidas are polymers of only dare :
- Oligoholosidas (oligosaccharidas) are an index of polymerization less than 10.
- Polysaccharides (polysaccharides) have an index of polymerization greater than 10 (eg amylose, amylopectin, cellulose, glycogen).
- Homopolyosides are carbohydrates whose hydrolysis gives only one kind of dare.
- Heteropolyosidas are carbohydrates which hydrolysis did not give a single type of monosaccharides.
Glycosides are polymers of monosaccharides and molecule (s) not the carbohydrate Aglycone:
- O-glycosides in which an alcohol (-OH) of the aglycone involved in sacharide binding.
- N-glycosides in which an amine (-N =) of the aglycone involved in sacharide binding
- S-glycosides in which a thiol (-SH) of the aglycone involved in saccharide binding.
Carbohydrate Derivative Compounds
Fructose Ketohexose, is Cyclized by reaction between carbon 1 and 4, this form is derived from furan, furan is the form (Figure 3). Glucose but also the D-glucofuranose is not stable and is rapidly becoming D-glucopyranose. The dare is cyclizing furan form (furanose) are:
- The ribose giving ribofuranose.
- The 2-deoxyribose 2-giving desoxyribofuranose.
- Fructose giving fructofuranose.
- Generally, it is Ketohexose.
The dare is cyclizing pyran form (Pyranose) are:
- Glucose giving glucopyranose.
- Galactose giving galactopyranose.
- Generally, it is Aldohexose.
How to Implement a Healthy Diet in Children
The rules of basic food are often rules of common sense.
Food and nutrition for children: dietary laws. Know the basic rules of food is helping the child manage his diet.
- Eat with pleasure.
- Eat sitting at the table.
- Eat with pleasure in calm and friendly.
- Eat slowly, chew food well.
- Follow the rhythms food, do not skip meals.
- Eating a daily diet of starchy foods, bread, product rich in protein (meat, etc. …), and many portions of fruit and vegetables (5 fruits and vegetables a day).
- Limit consumption of foods rich in sugar and fat.
- Avoid sugary drinks during meals, preferring water.
- Do not eat while watching TV.
- Do not make plans, but eat everything.
- Do not eat without hunger.
- Do not nibble.
Carbohydrate Constituent Molecules
Carbohydrates are a class of organic molecules containing a carbonyl group (aldehyde or Ketone) and several hydroxyl groups (-OH). Carbohydrates were historically called carbohydrates. Their chemical formula is based on the model Cn (H2O) p (hence the title history). However, this model is not valid for all carbohydrates, which provide for some atoms of nitrogen or phosphorus (for example). They belong, along with proteins and lipids, essential constituents of living things and their nutrition because they are a key biological intermediate storage and consumption of energy. In Autotrophic organisms, like plants, sugars are converted into starch for storage. In heterotrophic organisms, like animals, they are stored as glycogen and used as a source of energy in metabolic reactions, they are oxidized during digestion of carbohydrates providing approximately 17 kJ / g depending on the study in the bomb calorimeter .