LIPID

LIPIDS

Lipids are organic compounds that are insoluble in water but can be extracted with non polar solvents such as chloroform, ether, benzene, alcohol, acetone, and karbondisulfid. These organic compounds are present in all cells and function as:

1. Energy storage and transport

2. Membrane structure

3. Leather protector, cell wall components

4. Chemical transmitter

Some lipid compounds have important biological activity in the body, including vitamins and hormones. Viewed from the angle of nutrients, fat is an important source of calories in addition to acting as a solvent in vitamins.  Lipids can be classified according to chemical and physical properties.

Bloor dividing the lipids as follows:

1. Simple lipids

This group also called homolipida that is an ester form containing carbon, hydrogen, and oxygen. If hydrolysis, lipids are included in this fatty acid and alcohol. This simple lipids can be divided into three categories, namely:

a. Fat, fatty acids and glycerol ester

b. Wax, fatty acid esters  

2. Lipide Compound

This group of fatty acid esters with alcohols containing other clusters, for example phospholipide, serebrosida (glikolipida), sulfolipida, amino acids, lipids, and lipoproteins.

3. Lipid derivatives

Lipids is a result of hydrolysis derivatives group that had called earlier. Included in this group is fatty acids, glycerol, steroids, alcohols, aldehydes, and ketones.

Many physical properties of lipids that have amfipatik. Amfipatik term originally used by Hartley in 1936, giving derivatives of hydrocarbons which have one section (polar) "sympathetic" to the atmosphere of water and one part of the hydrocarbon (hydrophobic) that do not sympathize with the atmosphere of water.

Fatty acids are rarely found free in nature but exist as esters in combination with alcohol function. We can make some generalization about fatty acids, although there are exceptions as we shall see.

1. Fatty acids in general is a straight chain monocarboxylic acids.

2. Fatty acids typically have an even number of carbon atoms.

3. Fatty acids can be saturated or can have one or more double bonds.

Based on the absence of double bonds, fatty acids are divided into saturated fatty acids and unsaturated fatty acids. The animals at a higher level can be entered biosynthesis of saturated fatty acids and the mono-unsaturated from other sources such as carbohydrates. Acid-linoleic acid and linolenic acid and poly-unsaturated fatty acids higher-rise can not be produced in animals rise higher and therefore termed essential fatty acids.

Fatty acid salts are usually called soap. Cleaning power of soap resting on amfipatrik properties of soap molecules. Ions with Ca + + and Mg + + soap can form salts precipitated Ca or Mg. Therefore, if there is water or ions is called hard water. Soap has the properties can decrease the surface tension of water. This is evident from the emergence of bubbles when soap is dissolved in water and stirred.

Unsaturated fatty acid reaction on the bond easily entered rangkapnya. With hydrogen gas and catalytic hydrogenation reactions of Ni can occur, ie solving a single bond double bond. This hydrogenation process is of significant importance because it can alter fatty acid fatty acid liquid into solid. This is one of the margarine-making process at the head of palm oil.

Neutral fat is also called acyl glycerol or glyceride. Fat is a major component of fatty deposits in animal cells and plants, especially in adipose tissue of vertebrates.

Physical properties reflect the composition of neutral lipid fatty acids from fat. As a general proposition is the melting point of fatty acids decreases with increasing molecular weight and reduced ketidakjenuhan.

Fat composition of animals and plants having fatty acids contained therein is measured by the number of iodine. Iodine number is the number of grams of iodine, which can react with 100 grams of fatty acids. So, the more double bonds, the greater the number of iodine.

With fat hydrolysis process will break down into glycerol fatty acids. This process can be run by using acid, alkaline, or certain enzymes. Which uses alkaline hydrolysis process produces glycerol and fatty acid salt or soap. Therefore, the hydrolysis process that uses a base is called saponification process.

Oxidation of unsaturated fatty acids will generate peroxides and aldehydes will be formed. This is what causes the smell and taste unpleasant or rancid. The humidity, light, high temperatures and the presence of destructive bacteria are factors that menyebabkanterjadinya ketengikan fat. 

Candles are esters of long chain fatty acids with monohydric alcohol. There are as pelidung skin and feathers, leaves danbuah protector, or as a secretion of insects. Candles insoluble in water. 

Phospholipide is a glyceride containing phosphorus in the form of phosphoric acid ester. Phospholipide widely available in bacteria, plants and animal tissue. Fosfatidil fosfolipida called choline is usually found in the membrane and very little fat phospholipide have on deposit.

Sfingolipida is a lipid that did not contain glycerol amfipatik, especially abundant in brain and nerve tissue. These lipids are derived from sfingosin. Sfingolipida sfingomyelin most abundant is contained in the brain and nerve tissue and lipids in the blood.

Terpene and steroid is a lipid that can not be disaponifikasikan which means that the alkaline hydrolysis did not produce the soap. General structure which is common to all steroid framework perhidro siklompentano penantren. Steroids are widely available in nature. Among them in limited amounts but have important biological activity of bile acids, male and female sex hormones, hormones adreval cortex steroids and some poison contained in the class more number of sterols. Examples of cholesterol, lanosterol, phytosterol, and mikosterol.