CARBOHYDRATES
What are Carbohydrates?
Carbohydrates are a macronutrient which means that they are increasingly difficult to breakdown, therefore preventing ease of digestion and absorption for the body.
Carbohydrates are the starches, sugars and fibres which is found in various types of produce i.e vegetables, fruits and milk products (Szalay, 2015).
It is one of the three main macronutrients needed to provide energy to an animals diet and is the most important for providing a readily energy source. A carbohydrate is a form of molecule which consists of three chemical elements, these include; carbon, hydrogen and oxygen (CHO) (Petfood nutrition, 2012). These three chemical compounds will continue to appear constantly on a 1:2:1 ratio as this is what defines as why it is a carbohydrate. All carbohydrates have the general formula of (CH2O)n.
Carbohydrates are the preferred source of energy for most of the tissues within the body, which includes the nervous system and the heart. When carbohydrates are consumed from food they are converted into glucose which can then be used as a source of energy or kept stored in the body as glycogen (Cloe, 2015).
Did you know?
"Carbohydrates consist mainly of glucose and glycogen which makes up less than 1% of the weight of an animal" (Pond et al,. 2005).
Uses and functions of carbohydrates
What are carbohydrates required for in animals;
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Energy - glucose is the prefered energy source for the brain, nervous tissue and both red and white blood cells
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Producing lactose during lactation
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Maintains blood glucose levels
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Aids in lipid digestion
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It is stored as glycogen, energy source for the muscles
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it is converted to and stored as fat when excess amounts are eaten (Agar, 2001).
Chemical properties..
The main function of carbohydrates is to provide energy for the brain and body of an animal.
The correct amount of carbohydrates spare protein, once carbohydrates are consumed and digested they are broken down into smaller units of sugar, in which are then absorbed out of the digestive tract and into the blood steam to flow around the body.
An adequate intake of carbohydrates also spares protein, meaning that in the absence carbohydrates, protein and fats will therefore undertake the function and act as an energy source themselves (Gillaspy, 2015).
Carbohydrates are also a function necessary for fat oxidation, although carbs are converted and stored as fats if not burned, they still need them in order to begin the process. They also help with cellular recognition processes - meaning they are important for the bodies immune system and how it works in conjunction with protein (Functions of carbohydrates, 2015).
In the basic format, carbohydrates in their basic form are simple sugars , also known as monosaccharides. When the digestion of food occurs in an animal, the presence of simple sugars can combine with one another to form more complex carbohydrates, in which two simple sugars will then be named as disaccharides.Carbohydrates that contain two to ten simple sugars are called oligosaccharides, and those with a larger number are called polysaccharides (Scientificphysic, 2015).
Monosaccharides are the simplest form of carbohydrates and are also known as simple sugars. This is because simple sugars are quick and easy to breakdown to enable a supply of enegy (Chemistry: carbohydrates, 2015). These are compound, which posseses a free aldehyde or ketone group. Aldehyde and ketone groups are organic compounds which combine a carbonyl functional group e.g. C=O. Depending on the bond will dertermine whether or not the substituents is hydrogen, meaning the compound will be aldehyde but if neither is hydrogen, then the compound is ketone (Carbonyl reactivity, 2015).
Aldehydes and ketones are similar with many of their reactions, owing to the presence of the carbonyl functional group in both.
They do differ, however, in one most important type of reaction: oxidation. Aldehydes are readily oxidized to carboxylic acids, whereas ketones resist oxidation (Commons, 2015).
Chemical Bonding
In relation to bonding there are two types of atomic bonds, these are ionic and covalent bonds, however they do differ in structure and properties (Covalent bonds vs ionic bonds, 2015).
Covalent bond = A bond in which one or more pairs of electrons are shared by two atoms
Ionic bond = A bond in which one or more electrons are from one atom are removed and then attached to another atom which results in the negative and postive ions which attract each other (Chemical bonds, 2015).
The chemical properties of carbohydrates help them to be easily used by cells within the body, in order for them to perform work. A diet without carbohydrates can force the body to break down proteins and fats for energy which can be dangerous (Payseur, 2015).
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Monosaccharides = are simple sugars which are easily absorbed by the body e.g. glucose and fructose
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Disaccharides are two sugars formed by a combination of any other two simple sugars e.g. glucose + fructose =sucrose / glucose + galactose = lactose
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Oligosaccharides are short chains of the monosaccharides which are hydrolysed (broken down) into simple sugars but act similar to dietary fibres
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Polysaccharides are complex sugars which may be bonded in one of two ways due to them being extremely hard to digest e.g. cellulose - sweetcorn (Agar, 2001)
The difference between the saccharides / physical properties
The image above shows the same molecular formula of three monosaccharides (simple sugars) - glucose, galactose and fructose. As previously mentioned the chemical compound of them are on a 1:2:1 ratio - C6, H12, O6 (Carbohydrates, 2015), these molecule formulas are known as hexoses which is a monosaccharide identified by having six carbon atoms where as pentoses only include five carbon atoms. The classification of carbohydrates is identified basing on the number of carbon atoms per molecule of carboydrates and also the number of molecules of sugar within the compound (Pond et al., 2005)
Dietary sources:
Main sources of carbohydrates found within an animal’s diet may include;
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Fruits
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Vegetables
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Cereal grains (e.g. barley, maze, oats or wheat)
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Rice
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Potatoes (Topness, 2015)
Complex carbohydrates also cover fiber within the diet. Fiber is hard to digest and resists the breakdown by enzymes in the small intestine, however some fiber is fermented in the large intestine which helps regulate bacteria in the colon (PetMD, 2015).
The digestion of feed sources can sometimes be difficult for animals and therefore requires preparation methods to be put in place to help aid the process of digestion. examples of this may include; heating, crushing or liquidising the food.
As previously mentioned about complex carbohydrates, they are what fall into the polysaccharide category. polysacchardies (homoglycans) may have a molecular structure that is either linear (straight) or branched (different segments) (Britannica, 2015).
The majority of them are high molecular weight which are composed of large numbers of pentose or hexose residues. Homoglycans do not give the various sugar reactions characteristic of the aldose and ketose groups. Most of them occur in plants either as reserve food materials such as starch or as structural materials which includes the ingredient cellulose (McDonald et al., 2001).