Carbohydrate in fruit and vegetables

Fruits and vegetables are consumed at all times, and due to their convenient size; they are an excellent between-meal snack. They are relatively low in calories and fat (avocado and olives being the exceptions), they have no cholesterol, they are rich in carbohydrates and fiber, they contain vitamin C and carotene, and some are a good source of vitamin B 6.

The empirical composition of carbohydrates may be expressed by the formula CnH2nOn. With regard to their specific chemical properties, carbohydrates may contain a potential aldehyde, -CHO, or ketone, C=O, group. Carbohydrates are part of a healthful diet.

Vegetables are composed chiefly of carbohydrates, mainly simple sugars and complex carbohydrates (starch and dietary fiber). The content ranges from 1-2% in the leaf and stem vegetables to 27% in sweet potato. Root vegetables have the highest carbohydrate content. Dietary fiber content ranges from 0.8% in cucumber to 8.0% in artichoke.

Carbohydrate functions include, among others, the storage of energy reserves and the make-up of much of the structural framework of cells. Simple carbohydrates, which are also the immediate products of photosynthesis, are important components of sensorial quality attributes.

Fruit vary widely in their carbohydrate content (between 1.5% and 26%). Ripe fruit contain no starch; the main sugars are fructose and glucose which are often present in equal proportions. Apple and pear, contain more fructose, while apricot and peach also contain sucrose. Like vegetables, fruit also contain dietary fiber. Various organic acids in unripe fruit produce the typical sour taste. During ripening concentration of these acids falls and that of sugars rises.

Glucose, fructose and sucrose are water-soluble and together they comprise most of the sugars associated with the sweet taste of fruits and vegetables. In many fruits (e.g. apple, pear, strawberry, grape) glucose and fructose are present in greater amounts than sucrose, but in certain vegetables, such as parsnip, beetroot, carrot, onion, sweet corn, pea and sweet potato, and in some ripe fruits such as banana, pineapple, peach and melon, the sucrose content is higher.

Free xylose, in trace amounts, has been reported in onion, strawberries, prunes, apples, pears, grapes, juniper berries, barley malts, brewhouse worts, maple syrup, asparagus, the white and the yolk of eggs, corn, tomatoes, apricots, bamboo shoots, potatoes, beans, alfalfa, beer, and mangoes.

Dietary fiber is composed of non-digestible carbohydrates and lignin intrinsic and intact in plants. Diets rich in dietary fiber have been shown to have a number of beneficial effects, including decreased risk of coronary heart disease and improvement in laxation.

The recommended dietary fiber intake is 14 grams per1,000 calories consumed. The majority of servings from the fruit group should come from whole fruit (fresh, frozen, canned, dried) rather than juice. Increasing the proportion of fruit that is eaten in the form of whole fruit rather than juice is desirable to increase fiber intake.

Carbohydrate in fruit and vegetables

What are the functions of glycogen?

The excess carbohydrates will be converted to fat and stored in body as fat.  The main stores of glycogen in the body are found in skeletal muscle and liver, although most other cells store small amounts of glycogen for their own use.

Stored glycogen is synthesized during a high carbohydrate meal due to hyperglycemia and an increase in the insulin: glucagon ratio.

Muscle glycogen 
The function of muscle glycogen is to serve as a fuel reserve for the synthesis of adenosine triphosphate (ATP) during muscle contraction.

The production of energy from glucose involves oxidation of sugar with the release of water and carbon dioxide, which are easily removed from the body.

Liver glycogen
Liver glycogen function is to maintain the blood glucose levels, particularly during the early stages of a fast.

The liver releases glucose from the breakdown of glycogen and from gluconeogenesis for utilization by peripheral tissues mainly the brain cells and red blood cells.
What are the functions of glycogen?

Disaccharide sugar of lactose

In disaccharides, pairs of single sugars are linked together. Three disaccharides are important in nutrition: maltose, sucrose and lactose.

All three have glucose as one of the single sugars.

Lactose is the principle carbohydrate of milk. Lactose gives milk and other dairy products a slightly sweet taste. Most human infants are born with the digestive enzymes necessary to split lactose into its two monosaccharide parts, glucose and galactose so as to absorb it.

Lactose

Lactose is the only disaccharide that has a beta glycosidic bond between the monosaccharides. It is often referred to as milk sugar and is sometimes added to processed foods.

During lactation, enzymes in the mammary glands combine glucose and galactose to produce lactose. 

Lactose can exist in a number of different physical forms depending on the method of production.

In aqueous solution, lactose exists as an anomeric mixture of alpha and beta forms. In the solid for, lactose usually crystallizes in its alpha form as a monohydrate.
Disaccharide sugar of lactose

Carbohydrate

In order to carry out its day to day physiological functions and maintain a constant body temperature (due to invariably in an environment of changing temperatures), the body requires a constant source of energy.

Carbohydrates are an important energy source in the human diet. They generally supply about 45% of the energy requirement in developed countries and up to 85% in developing countries.

Carbohydrate are the cheapest, most efficient and most readily available source of food energy in the world, since they are the main constituents of the foods that are the easiest to produce and that can be obtained throughout the world, namely, grains, legumes and potatoes.

Carbohydrate are the most widely distributed, naturally occurring organic compounds on earth.

Carbohydrates have been considered a fundamental source of nourishment and inexpensive and versatile staple of the diet.

The carbohydrates are a class of chemical compounds that consists of carbon, oxygen and hydrogen. The carbohydrates that are important in nutrition include the sugars, the starches, the dextrin and glycogen.

The functional properties of carbohydrates in food include:

*Nutrition

*flavour and color production

*Sweetening

*Texturing

*Plasticizing action and humectancy

Dietary guidance for consumption of carbohydrates has resemble laboratory analysis of carbohydrates: take way fat and protein and the remainder must to be carbohydrate.

Nutritionist generally accept the fact that humans don’t need more than 10-12% kilocalories from protein, and less than 30% of kilocalories from fat.

Subsequently, intake of carbohydrate should be 55% of kilocalories or more.

Human diets historically have contained 40-80% of their energy as carbohydrate although as income increase, so does the fat content of the diet while carbohydrate content of the diet, especially the starch, decreases.

Starch is the major plant polysaccharide that is readily digested in the intestine and thus serves as a source of carbohydrates.

The major portion of energy requirements of human is met by starch of cereal grains and tubers such as potatoes.

What exactly is a carbohydrate? As the names implies, an empirical formula of CH2O (or CH2O) was often encountered, with molecular formulae of C5H10O5 and C6H12O6 being most common.

It was founded in the nineteenth century that carbohydrates in general have a formula Cn(H2O)n. They were therefore thought to be hydrates of carbon and hence were called ‘carbohydrates’.

The water solubility of these molecules was commensurate with presence of hydroxyl groups and there was always evidence for the carboxyl group of an aldehydes of ketone.

Carbohydrate