Fatty AcidsPresented by: Bitali Islam

Mohammad Nabil Hossain Mohtashim Mohammad Zahin

Md. Shabab Mehebub

Introduction of Fatty acids • Fatty acids are basic building blocks of lipids(simplest lipids) & they are amphipathic.

Fatty acids are naturally occurring carboxylic acids with an unbranched carbon chain and an even number of carbon atoms. *Long-chain fatty acids (12 to 26 carbon atoms) are found in meats and fish. *Medium-chain fatty acids (6 to 10 carbon atoms) are found in Coconut oil.*Short-chain fatty acids (fewer than 6 carbon atoms) occur primarily in dairy products.

Structure of Fatty Acids

3

• Oils and fats are liquids or solids having a greasy feel. When pure, they are colorless, odorless and tasteless.

• They are insoluble in water but soluble in organic solvents such as ether, chloroform, benzene and hot alcohol.

• They have lower specific gravity than water and consequently will float on the surface when mixed with it.

Physical properties of Fatty Acids

Classification of Fatty Acids

• Another type of fatty acids is Trans Fatty Acids.

Fatty acids

saturated unsaturated

monounsaturated polyunsaturated

Saturated Fatty Acids• Fatty acid chains that contain only carbon-carbon single bonds are referred to as

saturated.

Unsaturated Fatty Acids• Those molecules that contain one or more double bonds are said to be unsaturated.• There are mono- and poly unsaturated fatty acids.

- Monounsaturated fatty acids have one double bond.

- Polyunsaturated fatty acids have two or more double bonds.Trans Fatty Acids are a type of unsaturated fats that are uncommon in nature but became commonly produced industrially from vegetable fats

for use in margarine, snack food, packaged baked goods and frying fast food

Monounsaturated fatty acids and Polyunsaturated fatty acidsMonounsaturated fatty acids: - Help to decrease LDL and increase HDL. - Examples: Palmitoleic acid, Oleic acid etc. - Natural sources: red meat, nut, olive oil etc.

Polyunsaturated fatty acids: - Help to decrease total cholesterol level. -Examples: Linoleic acid,Arachidonic acid etc. - Natural resources: corn oil, soybean oil etc.

Chemical Properties• Hydrolysis: - Fatty acids are readily hydrolyzed by heating with acids or alkyls or superheated steam. When boiled with sodium or potassium hydroxide solution, the hydrolysis products are sodium or potassium salts of long chain fatty acids. The latter are called soaps and alkaline hydrolysis is referred to as saponification.

HC

H2C

H2C

O C (CH2)14CH3

O

O C

O

(CH2)14CH3

O C (CH2)14CH3

OHC

H2C

H2C

OH

OH

OH

+ O C (CH2)14CH3

O

3NaOH

Na

(Soap)

Chemical Properties Some facts about hydrolysis of fatty acids:• Fatty acids with 4,6 & 8 carbon atoms are released when the fats in

milk & butter are hydrolysed.• Plmitic, stearic & oleic acids are produced during the hydrolysis of

chocolate & give it an oily/fatty flavor.• Hydrolysis also happens during deep fat frying.

Chemical Properties• Hydrogenetion: - On catalytic hydrogenation at low pressure, hydrogen adds across the C=C of the acid components of the triglyceride. This results in the formation of saturated glycerides which are solids fats at room temperature. This hydrogenation precess is called hardening.

CH

CH2

O C

O

(CH2)7CH CH(CH2)7CH3

O C

O

(CH2)7CH CH(CH2)7CH3

CH2 O C

O

(CH2)7CH CH(CH2)7CH3

Chemical Properties• Rancidification: - When fats are oils are left exposed to moist air, they develop foul-smell and sour taste. They are said to have become rancid. The rancidification is caused by two types of reaction: Oxidation and hydrolysis.Oxidative rancidification: It involves the oxidation of C=C in fats and oils to produce volatile

carboxylic acids.Hydrolytic rancidification: It involves the hydrolysis of one or more ester linkages in fats and

oils to produce the original acid.

• Drying: - When highly unsaturated oils are exposed to air, they undergo oxidation and polymerization to form a thin waterproof film. Such oils are called drying oils and the reaction is referred to as drying. Linseed oil, which is rich in linolenic acid, is common drying oil used in oil based paints. Non drying oils are either saturated or only moderately unsaturated.

Biological Importance of Fatty Acids• Unsaturated fatty acids are found in membranes as phosphoglycerides (also known as phospholipids).

• Without Fatty acids the Phospholipids can’t formed. So the bilayer can’t be construct. Fatty acid composition results more fluids in a cell membrane but also one that is "leakier" to various ions (H+ & Na+). However polyunsaturation of cell membranes occur in response to chronic cold temperatures. In fish increasingly cold environments lead to increasingly high cell membrane content of both monounsaturated and polyunsaturated fatty acids, to maintain greater membrane fluidity (and functionality) at the lower temperatures.

Biological Importance of Fatty Acids• Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good

health but cannot synthesize them.

Only two fatty acids are known to be essential for humans: alpha-linolenic acid (an omega-3 fatty acid) and linoleic acid (an omega-6 fatty acid).

Omega 3 Fatty acid-

Omega 6 Fatty acid-

They act on DNA (activating or inhibiting transcription factors such as NF-κB, which is linked to pro-inflammatory cytokine production)

High intakes of omega-3 fatty acids are linked to decreased rates of major depression.

Without omega 3 and omega 6 human or animal will suffer in sick.

Omega-3 fatty acids in algal oil, fish oil, fish and seafood have been shown to lower the risk of heart attacks.

Omega-6 fatty acids in sunflower oil and safflower oil may also reduce the risk of cardiovascular disease.

One gram of fat gives you nine calories of energy, which is over twice that provided by carbohydrates or protein. Fat enables your body to transport, store and absorb the fat-soluble vitamins A, D, E and K.

Biological Importance of Fatty Acids• Cell Membranes: Require (50%) fatty acids to be “waterproof” and function properly.• Heart: Prefers saturated long chain 16-carbon palmitic and 18-c stearic acid (over

carbohydrates) for energy.• Bones: Need fats to assimilate calcium effectively.• Liver: They protect it from the adverse effects of alcohol and medications like

acetaminophen.• Lungs: Lung surfactant, which prevents asthma and other breathing disorders, is

composed entirely of 16-c palmitic acids.• Hormones: They function as signaling messengers for hormone production.• Immune system: Saturated fatty acids play an important role here. They prime white

blood cells to destroy invading bacteria, viruses and fungi and to fight tumors. Medium chain 12-c lauric acids and 14-c myristic acid(in butter) kill bacteria and candida in the gut.

Dangerous Fact of Fatty Acids• High Fat, low fiber in diet can create “Bowel, Pancreas, Prostate and Breast” CANCER. It is the largest amount

of cancer case in the United States. • Polyunsaturated fatty acid can lead to greater risk of decreased accretion of brain DHA in offspring.• Consumption of omega-3 fatty acids during pregnancy is critical to fetal development. • Consumption of trans fats has shown to increase the risk of coronary heart disease in part by raising levels of

the lipoprotein LDL (so-called "bad cholesterol"), lowering levels of the lipoprotein HDL ("good cholesterol").• The intake of both trans fats and saturated fats promote the development of Alzheimer disease.• Type 2 diabetes, Liver Dysfunction, Infertility in women etc are caused by trans fatty acids.

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