Fats and oils.ppt

Fats and Oils ppt

1. Fats and Oils
Mr. P.S.Kore
Assistant Professor(Research Scholar)
Department of Pharmaceutical Chemistry
RCP, Kasegaon.

2. Contents
oFATTY ACIDS: REACTIONS.
oHYDROLYSIS
oHYDROGENATION
oSAPONIFICATION
oRANCIDITY OF OILS
oDRYING OF OILS
oANALYTICAL CONSTANTS:
oACID VALUE
oSAPONIFICATION VALUE
oESTER VALUE
oIODINE VALUE
oACETYL VALUE
oREICHERT MEISSL (RM) VALUE

3. Fats And Oils
oAlipidcanbedefinedasnaturallyandchemicallyoccurring
substancethatisinsolubleinwaterandsolubleinalcohol,ether,
andchloroform.
oThetypesoflipidsinvolvedincludeBilesalts,Eiosanoids,
Glycolipids,Ketonebodies,Phospholipids,Sphingolipids,Steroids
andCholesterols.
oLipidsarefatsthatareeitherabsorbedfrombloodorsynthesized
bytheliver.
oTriglyceridesandcholesterolcontributemostofdiseases.
oWaxes:Waxesareestersoflong-chainfattyacidsandlongchain
monohydricalcohols,eachcontaining16to34carbonatoms.

4. They are produced from plants and animals, also melts between
35
0
C-100
0
C.
It is insoluble in water but soluble in organic solvents like.
Various types of waxes:
1. Bees wax: obtained from honeycomb of the bee.
It melts at 62
0
C-65
0
C and used for boot polishes, cosmetic creams,
lipsticks, floor and furniture polishes and candles.
2. Carnauba Wax: derived from leaves of carnauba palm native in
brazil, melts at 80-87
0
C and used for boot polishes, coating on
mimeograph stencils and carbon papers.
3.Supermaceti Wax: obtained from head-cavity of the sperm
whale,melts at 42-50
0
C and is primarily used in emollient(skin
southner) in ointments and cosmetics. Also used in laundry wax
for lustering linen, making soap and candles.
All lipids are hydrophobic and mostly insoluble in blood, so they
require transport within hydrophilic spherical structures called
lipoproteins.

5. Fats And Oils
oFats and oils are lipids which are saponifiable(having ester
functional group)(i.e.complex lipids), while other such steroids
are non-saponifiable.
oNatural fats and oils are triesters of glycerol with long chain
carboxylic acids (12 to 20 carbons).
oThey are known as Triglycerides.CH
2
CH
CH
2
OH
OH
OH
+
C R
O
OH
C R
O
OH
C R
O
OH
CH
2
CH
CH
2
O
O
O
C
C
C
R
R
R
O
O
O
+
3H
2
O
GLYCEROL
CARBOXYLIC ACID
A TRIGLYCERIDE

6. Fats And Oils
oEster: The chemical linkage that holds an alcoholgroup
(OH) and an acid group (such as COOH) together. An
ester bond is the connection between a fatty acid and
glycerol in glycerides.
oGlycerol: A three carbon chain, with each carbon
containing an alcohol group. One, two or three fatty
acids , may be attached to glycerol to give a mono, di or
triglyceride.
oTriglyceride: Three fatty acids attached to a glycerol
molecule. If the three fatty acids are the same, it is a
simple triglyceride, if they are different from each
other, it is a mixed triglyceride.

7. Fats And Oils
oWhen three OH groups of glycerol are esterified with the same
acid, the triester is known as simple glyceride, where as if two or
more different acids called as mixed glyceride.CH
2
CH
CH
2
O
O
O
C
C
C
(CH2)14 CH3
(CH
2
)
14
CH
3
(CH
2
)
14
CH
3
O
O
O
GLYCERYL TRIPALMITATE
(a smiple glyceride)
CH
2
CH
CH
2
O
O
O
C
C
C
(CH2)14 CH3
(CH
2
)
16
CH
3
(CH
2
)
7
CH=CH=CH(CH
2
)
7
CH
3
O
O
O
GLYCERYL PALMITOSTEAROOLEATE
(a mixed glyceride)

8. Differences
Fats Oils
1. Remains solid at room
temperature. (due to large %
of saturated fatty acid)
2.Relatively more saturated
3. High melting point.(above
20
0
C)
4. More stable.
5. Source: Mainly animals.
6. No double bonds.
7. Vander waal’s forces
between molecules are
stronger.
1. Remains liquid at room
temperature. (due to large %
of unsaturated fatty acid)
2.Relatively more unsaturated
3. Low melting point. (below
20
0
C)
4. Less stable.
5. Source: Mainly Plants.
6. Have double bonds.
7. Vander waal’s forces
between molecules are
weaker.

9. Occurrence and extraction
Plants : Plants are store large quantities of fats in their seeds,
roots and fruits. Castor beans, peanuts, coconuts and olives
have a high fat content.
In animals: in animals, the fat deposits are to be found
mostly under the skin and around the intestineand
kidneys.
Extraction:
1. Rendering: The animal tissues containing the fat are
chopped off and heated dry or with wateruntil the fat
melts and can be removed.
2. Pressing: oil are obtained from seeds by crushing
between steel rollersand then pressed in a hydraulic
press.
3. Solvent extraction: It is applied to the residue after
pressing and renderingfor complete removal of oil or fat.
Solvents used are petroleum ether and benzene.

10. Physical and Chemical properties
Fats and oils are solid or liquidhaving a greasy feel, but
when pure it is colorless, odorless and tasteless.
They are insoluble in water but soluble in organic solvents
like ether, chloroform, benzene, etc.
They have a lower specific gravity than water and
consequently float on surfacewhen mixed with each other.
They form emulsion when agitated with water in presence
of soap or gelatin.

11. Physical and Chemical properties
Fat and oils are triesters of glycerol with saturated
and unsaturated fatty acids. Their reactions are those
of ester group in triplicate and carbon-carbon double
bonds.
1.Hydrolysis
2.Hydrogenation.
3.Hydrogenolysis
4.Rancidification
5.Drying

12. Physical and Chemical properties
1.Hydrolysis: They are hydrolysed by heating with
acids or alkalies or superheated steam.
When boiled with sodium or potassium
hydroxide solution,the products are sodium or
potassium salts. They latter are called as soap and
alkaline hydrolysis are called as saponification.CH
2
CH
CH
2
O
O
O
C
C
C
R
R'
R''
O
O
O
+
3NaOH
A TRIGLYCERIDE
CH
2
CH
CH
2
OH
OH
OH
+
C R
O
Na+-O
C R
O
Na
+
O
-
C R
O
Na
+
O
-
GLYCEROL
Soap

13. Physical and Chemical properties
2. Hydrogenation: Vegetable oils are triglyceridesof
unsaturated fatty acids such as oleic acid and linolec
acid. On catalytic hydrogenation at low pressure,
hydrogen adds across the carbon-carbon double bond
of the acid components of the triglycerides, which results
in formation of saturated triglycerides. This process is
called asHardening GLYCERYL TRIOLEATE
OH
2
C C(CH
2
)
7
CH=CH(CH
2
)CH
3
O
CH C(CH
2
)
7
CH=CH(CH
2
)CH
3
O
CH
2
OC(CH
2
)
7
CH=CH(CH
2
)CH
3
O
+3H
2
Heat
OH
2
C C(CH2)16CH
3
O
CH C(CH2)16CH
3
O
CH
2
OC(CH2)16CH
3
O
Glyceryl triestearate (solid fat)
M.P
-
17
0
LIQUID FAT
M.P.- 55
0
c

14. Physical and Chemical properties
3. Hydrogenolysis: Vlike a ester, the ester group of
triglycerides (fats and oils) can be reduced with hydrogen
in the presence of copper chromite catalyst, CuCr2O4, at
high temperature. This reaction called
hydrogenolysis(hydrogenation involving cleavage) gives
in addition glycerol and long chain primary alcohol.GLYCERYL TRIOLAURATE
CH
3
CH
3
CH
3
(CH
2
)
10 C
O
O CH
2
(CH
2
)
10C
O
O CH
(CH
2
)
10
C
O
O CH
2
+6H
2
Heat
3CH
3
(CH
2
)
10
CH
2
OH
CuCr
2
O
4
+
CH
2
CH
CH
2
OH
OH
OH
LARURYL ALCOHOL
GLYCEROL

15. Physical and Chemical properties
4.Rancidification: When fats and oils are left exposed to
moist air, they develop foul smell and sour taste. They are
said to have become rancid. Rancidification is caused by
two types of reactions:
A. Oxidation: it occurs due to the oxidation of carbon-
carbon double bonds in fats and oils to produce volatile
carboxylic acids.
B. Hydrolysis:it involves the hydrolysis of one or more
ester linkage in fats and oils to produce the original
acid.
Bacteria from the air furnish enzymes to promote such
reactions. So antioxidantsare added to many edible oil
to prevent rancidification.

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

17. Saponification Value
Saponification value is also called as saponification
number.
It determines the approximate molecular weight of a fat
or oil.
Def: Saponification number is defined as the number of
miligrams of KOH required to saponify one gram of fat or
oil.
In saponification one mole of fat or oil react with three
moles of KOH since the former has ester groups.
If M be the molecular weight of fat, M grams of it require
3*56=168 grams or 168,000 miligrams of KOH for
saponification.
Saponification number of fat= 168000/M

18. Saponification Value
As per expression the saponification value of a fat is
inversely proportional to the molecular weight.
A lower value of sap, therefore shows the preponderance
of high molecular weight fatty acid residues.
On other hand high value of sap indicates preponderance
of low molecular weight of fatty acids.