2.8 Fats

Oil and fats
■ Fats and oils

	►	The high-ester (large molecules) family, which occurs naturally in animal fats and plant oils.
	►	At room conditions, the fat may exist in the solid or liquid state. ○ Fat usually represent fat in the solid state. ○ Fat that exists in the liquid state was named oil.

■ Formation of fats and oils

	►	Fats are esters derived from the esterification reaction between one molecule of glycerol with three fatty acid molecules. ○ Fatty acid + Glycerol → Fats or oils
	►	The following animation shows the formation of fats and oils.
	►	The hydrocarbon chain may contain double bond(~CH=CH~) or only single bond( ~CH3-CH3~)

The importance of oils and fats for the body processes
■ The importance of oils and fats for the body processes

	►	Fat stored in the body as energy savings.
	►	Fat acts as a carrier solvent of vitamins A, D, E and K. These vitamins are only soluble in fat.
	►	The layer of fat under the skin protects the body from the cold.
	►	Fat tissue around the internal organs of the human protects organs from injury.

■ Sources of oils and fats

►

The common sources of fats are butter, ghee, cheese, meat, egg yolk, milk, nuts, etc.

■ The uses of Oils and Fats

	►	Fats are the main energy storer of the body.
	►	When hydrolysed animal fats by steam under pressure, it gives a mixture of stearic acid and palmitic that can be used to make candles.
	►	Vegetable oil can be used to make soap through the saponification process.
	►	Certain type of oil can be used to make paint, fabric, oil and linoleum.

■ This video contains information on the differences between oils and fats

■ Oils and fats differs from unsaturated fats in some aspects:

►

Differences Oils Fats Sources Mainly animals Mainly plants State at room temperature Liquid Solid or semi-solid Melting point Lower Higher Number of hydrogen atom Less More Present of double covalent bond Yes (most are unsaturated compounds) No (most are saturated compounds) Example Vegetable oils Animals fats

Saturated and unsaturated fats
■ Classification of fats

	►	Saturated
	►	Unsaturated fats

■ Saturated fats

	►	Saturated fat is fat that contains saturated fatty acids. ○ Saturated fatty acid + glycerol → saturated fat
	►	Saturated fats do not have double bonds and are solids at room temperature.
	►	Example: Glyceryl tripalmitate Glyceryl tristeaate
	►	Animal fats contain high saturated fat content.
	►	The percentage of saturated fatty acids in animals fats are normally higher compared with the percentage of unsaturated fatty acids.

■ Unsaturated fats

	►	Unsaturated fat is fat containing unsaturated fatty acid. ○ Unsaturated fatty acid + glycerol → unsaturated fat
	►	Unsaturated fats have one or more double bonds and are liquids at room temperature. The presence of double bonding causes unsaturated fats have a lower melting point.
	►	Example: Glyceryl trilinoleatee Glyceryl trioleate
	►	Vegetable oils such as palm oil, soybean oil, sunflower seed and olive contains high unsaturated fat.

■ Similarity of saturated fats and unsaturated fats:

►

Both have 1 molecule of glycerol and 3 molecules of fatty acid.

■ Saturated fats differs from unsaturated fats in some aspects:

►

Differences Saturated fats Unsaturated fats Sources Mainly animals Mainly plants Fatty acid Saturated Unsaturated Bonding No double bond Have double bond Hydrogen content Maximum Can be increased Cholesterol content High Low Melting point High Low

■ Conversion of unsaturated fats to saturated fats

	►	The presence of double bond in unsaturated fats allows unsaturated fats undergo addition reaction.
	►	Hydrogenation is the addition reaction with hydrogen. ○ Convert unsaturated fats to saturated fats with the addition of hydrogen to the double bond. ○ Fats in liquid state change to solid. ○ Example: Vegetable oil (unsaturated fat) is converted to a solid (saturated fat). $\text{Palm oil (unsaturated fats)}+\text{hydrogen}\begin{array}{c}\to \\ \text{hydrogenation process}\end{array}\text{margarine (saturted fat)}$ Temperature of 200°C and pressure 2 to 5 atmosphere in the presence of nickel powder catalyst

Effects of eating food with high fat content
■ Effects of Eating Food with High Fat Content

	►	Butter, ghee, etc. are saturated fats and oils are unsaturated fats.
	►	High intake of saturated fats increases blood cholesterol levels that can lead to coronary disorders and high blood pressure.
	►	Thus people who have a sedentary lifestyle such as old people should reduce the intake of saturated fats.
	►	However, people involved in heavy labour, fat intake should be more, as their energy requirement is high.

■ Cholesterol

	►	Cholesterol is a type of complex organic compounds commonly found in fat.
	►	This is because cholesterol is a fat-soluble, transported to fat and stored in fat.
	►	In fact, cholesterol can be synthesized in our body itself. Cholesterol is essential for the formation of cell membranes, bile salts, reproductive hormones and vitamins.
	►	However, scientific studies show that consumption of foods with high cholesterol can affect human health.
	►	There are two types of cholesterol, the low-density cholesterol (LDL) and high density cholesterol (HDL).
	►	Research shows that low-density cholesterol (LDL) deposited in the arteries.
	►	High density cholesterol (HDL) could be useful to our body.

■ Based on these studies, high levels of cholesterol in the blood can cause a variety of diseases.

	►	High cholesterol can lead to a disease of arteries, called arteriosclerosis.
	►	Arteriosclerosis caused by the accumulation and deposition of lipids, particularly cholesterol (a type of steroid) in combination with fatty acids and proteins, as thick layers on the surface of the wall in blood arteries.
	►	This situation, if allowed to continue can cause clogged arteries cavities and thus restricting normal blood flow.
	►	Blood clots will cause heart attacks and cause a stroke.

Industrial extraction of palm oil
■ Structure of oil palm fruit

	►
	►	Mesocarp(husk) : ○ Thick fleshy layer, orange when ripe ○ Contain a lot of oil
	►	Kernel: ○ White fleshy piece ○ Produces kernel oil
	►	Shell: ○ Hard protective layer

■ Stages in palm oil extraction from the mesocarp

	►	Sterilisation (fresh fruit bunch is heated with pressurized steam to:) ○ soften the fruits. ○ kill bacteria and other micro-organisms. ○ stop the decomposition of oil. ○ loosen the fruit from its bunches.
	►	Threshing ○ To separate fruit from its bunches.
	►	Digestion ○ The heat of the steam is used to separate mesocarp from the shell.
	►	Pressing ○ Oil is squeezed from the mesocarp with a hydraulic press.
	►	Filtration ○ To remove the foreign substances from oil.
	►	Purification ○ Palm oil is treated with phosphoric acid. ○ Steam passes through the oil to separate acid. ○ Pure palm oil is obtained.

■ Stages in palm oil extraction from the mesocarp

	►	Extraction ○ The fruits obtained from the crushing process are boiled at high pressures and cooked to remove the kernel from its shell. ○ The shell is broken, and the kernel is separate from the shell. ○ The kernel is dried at a high temperature and squeezed to obtain its oil.
	►	Purification ○ Oil from kernel is purified.

■ This video shows how sterilisation and threshing process in palm oil extraction.

The use of palm oil in food production
■ There are many uses of palm oil and palm kernel oil:

►

Cooking oil Margarine Candle Lotion Condensed milk Soap

■ Palm oil has many advantages as compared to other vegetables oils.

	►	Palm oil is a nutritious oil because it supplies fatty acids as well as important fat-soluble micronutrients like Carotenoids (including pro-vitamin A), vitamins D, E and K. ○ Beta-carotene/Vitamins A: an effective antioxidant that helps strengthen the body's immune system and reduces the risk of cancer, heart disease and cataract. Lack of Vitamin A can lead to blindness and a variety of serious medical conditions. ○ Vitamin E is a powerful anti-oxidant, capable of reducing the harmful types of oxygen molecules in the body. This means they may help to protect from certain chronic diseases, while delaying the body's ageing process. ○ Fatty acids are the raw materials for building the membranes of every cell in your body, including your bones, nerves and brain! The micronutrients keep body cells healthy and functioning properly.
	►	Palm oil is cholesterol free.
	►	The extraction cost of palm oil is lower compare to most of the vegetable oil.

⇲ For exercise(objective and subjective), download for free on Android OS.