What is a Fat
Fats are a type of macronutrient that are a major source of energy in food. They are also known as lipids or fatty acids. Lipids are organic compounds that are fatty acids or derivatives of fatty acids, which are insoluble in water but soluble in organic solvents.
Fat has many functions
Energy: Fat provides energy to the body, similar to carbohydrates.
Insulation: Fat insulates the body from cold and heat.Fat is a poor conductor of heat and forms thick layers of fatty tissues inside the body. This makes fat a good thermal insulator.
Protection: Fat protects vital organs and cushions soft organs.
Regulation: Fat regulates hunger and satiety, glucose and cholesterol, and insulin sensitivity. Leptin is a hormone your adipose tissue (body fat) releases that helps your body maintain your normal weight on a long-term basis.
Storage: Fat stores energy in the form of triglycerides.
Absorption: Fat helps the body absorb vital nutrients and produce hormones.
Signaling: Fat plays important roles in regulating and signaling.
Parts of Fat
Fats are composed of a glycerol molecule and three fatty acid molecules. Fat molecules can store a very high amount of energy for their size which is important for animals because animals require more energy.
Glycerol is the backbone of fat molecules, also known as triglycerides. Glycerol is a three-carbon chain that connects one, two, or three fatty acids together.
Generally, a fatty acid consists of a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain and at one end of the chain and a carboxyl group (―COOH) at the other end. It is that carboxyl group that makes it an acid (carboxylic acid).
Tests for fats:
Solubility test - This preliminary test detects the presence of lipids by checking their solubility in different solvents.
Translucent spot test - A sample is pressed into the folds of filter paper. If a greasy spot appears, it indicates the presence of fats or oils. The spot will grow larger when the filter paper is heated and dried.
Acrolein test - This test gives off a pungent smell to confirm the presence of fats and oils.
Baudouin test - This test detects the presence of sesame oil. Sesame oil reacts with concentrated hydrochloric acid and furfural solution to produce a characteristic rose red color.
Huble's test - This test detects the degree of unsaturation in oil or fat. Huble's reagent reacts with an alcoholic solution of iodine that contains mercuric chloride. During the reaction, the violet color of iodine fades away.