CLASSIFICATION AND PROPERTIES OF FATS AND THEIR FUNCTIONS ANIMAL NUTRITION LIPIDS

1. Submitted to: Submitted by:
Dr. M. R. CHAVDA TATHAGAT P. KHOBRAGADE
Assistant Professor MVSc (Ani. Nutrition)
Animal Nutrition I yr
Polytechnic In A.H COVSAH
KU, Junagadh KU, Junagadh
ANN - 601 NUTRITIONAL BIOCHEMISTRY 1+0
M.V.Sc
DEPARTMENT OF ANIMAL NUTRITION
COLLEGE OF VETERINARY SCIENCE AND ANIMAL HUSBANDARY,
KAMDHENU UNIVERSITY, JUNAGADH
CLASSIFICATION AND PROPERTIES
OF FATS AND THEIR FUNCTIONS

2. Learning Objectives:-
 INTRODUCTION
 LIPIDS AND THEIR CLASSIFICATION
 FATS
 FATTY ACIDS
 STRUCTURE OF FATS
 PROPERTIES OF FATS
 FUNCTION OF FATS
 OTHER LIPIDS

3. INTRODUCTION
 Food is that which nourishes the body. Food may also be defined as anything eaten or
drunk, which meets the needs for energy, building, regulation and protection of the animal
body.
 Nutrition is the process of providing or obtaining the food necessary for health and growth.
 Nutrition includes everything that happens to food from the time it is eaten until it is used
for various functions in the body.
 Nutrients are components of food that are needed by the body in adequate amounts in
order to grow, reproduce and lead a normal, healthy life.
 Nutrients include Water, Proteins, Fats, Carbohydrates, Minerals And Vitamins.

5. LIPIDS
 Lipids (Greek: lipos–fat) are of great importance to the body as the chief concentrated
storage form of energy, besides their role in cellular structure and various other
biochemical functions.
 As such, lipids are a heterogeneous group of compounds and, therefore, it is difficult
to define them precisely.
 Lipids may be regarded as organic substances relatively insoluble in water, soluble in
organic solvents (benzene, ether etc.), actually or potentially related to fatty acids and
they are utilized by the living cells.
 In animals, Lipids are the major form of energy storage, mainly as FAT, which
may constitute up to 97 % of the adipose tissue of obese animals.

6. CLASSIFICATION OF THE LIPIDS

7. FATS
 In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a
mixture of such compounds, most commonly those that occur in living beings or in food.
 The term ‘fat’ is frequently used in a general sense to include both groups i.e vegetable
oils and animal fat , Both have the same general structure but have different physical and
chemical properties.
 Solid fats :- solid at room temperature like butter or lard , mainly come from animal
foods, Solid fats contain more saturated fats.
 Oils :- liquid at room temperature like olive oil , have lower melting point than solid fat.
 Fats major function is to supply energy and stored fat is important as a thermal insulator.

8.  Fats are esters of fatty acids with the trihydric alcohol glycerol, and are also referred
to as glycerides or acylglycerols.
 When all three alcohol groups are esterified by fatty acids, the compound is a
triacylglycerol (triglyceride).
STRUCTURE OF FATS
Here R represents the residue of fatty acid, if
all the 3 residue are same they are called
simple triglyceride.
 R1, R2 and R3 represent the chains
of different fatty acids, so they are
called as mixed triglyceride.

9.  Saturated fatty acids do not contain double bonds, while unsaturated fatty acids
contain one or more double bonds.
 The unsaturated acids contain either one (monoenoic), two (dienoic), three
(trienoic) or many (polyenoic) double bonds.
 Fatty acids with more than one double bond are frequently referred to as
polyunsaturated fatty acids (PUFA).
 The unsaturated acids possess different physical and chemical properties from the
saturated: they have lower melting points and are more chemically reactive.
FATTY ACID
 Fatty acids are carboxylic acids with hydrocarbon
side chain.
 They are the simplest form of lipids.

11.  SATURATED FATTY ACIDS
 Saturated fatty acids do not contain double bonds.
 High melting point
 Solid state in room temperature
 Foods sources of saturated fats are whole milk, butter, cheese, coconut oil, vegetable oil,
meat fat, peanut, fried foods, etc.
Palmitic acid n-Hexadecanoic acid 16C CH3(CH2)14COOH
Stearic acid n-Octadecanoic acid 18C CH3(CH2)16COOH
Arachidic acid n-Eicosanoic acid 20C CH3(CH2)18COOH
 UNSATURATED FATTY ACIDS
 The unsaturated acids contain either one (monoenoic), two (dienoic), three (trienoic)
or many (polyenoic) double bonds.
 Good for consumption (Leads to formation of HDL Cholesterol)
 Low melting point
 Liquid state in room temperature
 Foods sources of unsaturated fats are walnuts, flax, avocado, sunflower oil, soybean oil,
fish oil, red meat fat, etc.

12. Oleic Acid 18C 1 Double Bond
Linoleic Acid 18C 2 Double Bond
Linolenic Acid 18C 3 Double Bond
Arachidonic acid 20C 4 Double Bond
ESSENTIAL FATTY ACIDS
The fatty acids that cannot be synthesized by the body and, therefore, should be
supplied in the diet are known as essential fatty acids (EFA).
 Chemically, they are polyunsaturated fatty acids, namely linolenic acid (omega-3
fatty acid) and linoleic acid (omega-6 fatty acid). Linoleic acid and linolenic acid are
thus dietary essentials.
Omega-3 Fatty Acids - Fish and other seafood , Nuts and seeds (such as flaxseed,
and walnuts)
Omega-6 Fatty Acids – Sunflower, Peanut, Corn, Soyabean, Egg

13. PROPERTIES OF FATS
 Hydrolysis
 Fats may be hydrolysed by boiling with alkalis (like KOH) to give glycerol and soaps
 Such a hydrolysis is termed saponification since it produces soaps, which are sodium
and potassium salts of the fatty acids.
 Oxidation
 The unsaturated fatty acids readily undergo oxidation at the carbon atom adjacent to
the double bond to form hydroperoxides.
 The products of oxidation include shorter-chain fatty acids, fatty acid polymers,
aldehydes , ketones , epoxides (cyclic ethers) and hydrocarbons.
 Oxidation of saturated fatty acids results in the development of a sweet, heavy taste
and smell, commonly known as ketonic rancidity.

14.  Antioxidants
 Natural fats possess a certain degree of resistance to oxidation, due to the presence of
compounds termed antioxidants (which can be phenols, quinones, tocopherols etc).
 These antioxidants prevent the oxidation of unsaturated fats until they themselves have
been transformed into inert products.
 The most important naturally occurring antioxidant is vitamin E, which protects fat by
preferential acceptance of free radicals.
 Hydrogenation
 This is the process whereby hydrogen is added to the double bonds of the unsaturated
acids of a fat, thereby converting them to their saturated analogues.
 Use to produce saturated fat with higher melting points (Hardening) Ex. Margarine
 Dietary fats are highly unsaturated, but the body fats are highly saturated in case of
ruminants due to hydrogenation by rumen microbial activity.

15. 1. They are the
concentrated fuel reserve
of the body. Fat has about
9 calories per gram, and
protein and carbohydrate
have just 4.
2. Fat are the constituents
of membrane structure
and regulate the
membrane permeability
(phospholipids and
cholesterol).
3. They serve as a source
of fat soluble vitamins (A,
D, E and K).
4. Fat are important as
cellular metabolic
regulators (steroid
hormones and
prostaglandins).
5. Fats protect the
internal organs, serve as
insulating materials and
give shape and smooth
appearance to the body.
6. Fats contribute to the
flavor, texture, and
palatability of foods.
FUNCTIONS OF FATS
 Fats perform several important functions:-

16. COMPOUND LIPIDS
A) GLYCOLIPIDS
 In these compounds, two of the alcohol groups of the glycerol are esterified by fatty
acids and the other is linked to a sugar residue.
 Glycolipids (glycosphingolipids) are important constituents of cell membrane and
nervous tissues (particularly the brain).
 They can be Glucolipids or Galactolipids.
 Rumen microorganisms are able to break down the galactolipids to give galactose,
fatty acids and glycerol.
 This are glycerol based lipids which are ester of fatty acids containing
other groups like Sugar (Glycolipids), Phosphate (Phospholipids), etc.

17. B) PHOSPHOLIPIDS
 The role of the phospholipids is primarily as constituents of the lipoprotein complexes
of biological membranes.
 They are widely distributed, being particularly abundant in the heart, kidneys and
nervous tissues.
 The phospholipids contain phosphorus in addition to carbon, hydrogen and oxygen.
 Phosphoglycerides :- These are esters of glycerol in which only two of the alcohol
groups are esterified by fatty acids, with the third esterified by phosphoric acid.
 The most commonly occurring phosphoglycerides in higher plants and animals are
lecithins and cephalins.

18.  Lecithins : These are the most abundant group of phospholipids in the cell membranes.
 Cephalins : Ethanolamine is the nitrogenous base present in cephalins. Thus, lecithin and
cephalin differ with regard to the base. Cephalins are found in most cell membranes,
particularly in brain tissues.
NON-GLYCEROL BASED LIPIDS
 WAXES
 Waxes are simple, relatively non-polar lipids consisting of a long-chain fatty acid
combined with a monohydric alcohol of high molecular weight.
 They non nutritive , solid at ordinary temperatures , protective function.
 Waxes are widely distributed in plants which lead to overestimation of ether extract.
 Waxes are resistant to breakdown and are poorly utilized by animals.
 Natural waxes are usually mixtures of a number of esters. Ex. Beewax

19.  STEROIDS
 The steroids include such biologically important compounds as the sterols,
the bile acids, the adrenal hormones and the sex hormones.
 Cholesterol :-
 Cholesterol is a zoosterol that is present in all animal cells.
• It has a low solubility in water, and is important as a constituent of various biological
membranes.
• It is present in abundance in nervous tissues as insulating cover.
• It is precursor for Vit D, Bile acids, Sex hormones like estrogens , testosterone etc.
• Cholesterol is very insoluble, and prolonged high levels in blood result in its deposition
on the walls of the blood vessels.

20.  REFERENCES
P McDonald et al. : Animal Nutrition Book (eighth edition).
U. Satyanarayan et al. : Biochemistry Book (fourth edition).
Nalini Pandey : Fatty acids and lipids.