1. Oils and Fats Major Component (%95-99) Minor Components (%1-5)
Triglycerides
Minor Components (%1-5)
Triglyceride Derivatives
Glycerol
Free Fatty Acids
Mono- and Diglycerides
Non-Triglyceride Derivatives
Phospholipids
Sterols
Pigments
Vitamins
Antioxidants
Oxidation Products
Trace Metals
Hydrocarbons

2. Triglyceride StructureO C
- R1
triacylglycerol =
- R2
- R3 HC
H2C OH
glycerol HC
H2C
HO - C O
- R1
3 fatty acids +
- R3
- R2
+3H20 O R
One chiral carbon with 1-3 acyl groups
simpler stereochemistry than sugars - C
more possible substituents
acyl

3. Triglycerides differ from each other in regard to
Number of Carbon Atoms in fatty acid chains
Number of double bonds
Isomerization
Distribution of FA on glycerol backbone

4. Analytical Methods Saponification Value Iodine Value
Gas Chromatographic Analysis for Fatty Acids
Liquid Chromatography

5. Saponification Value
Saponification - hydrolysis of ester under alkaline condition.
The saponification value of an oil or fat is defined as the number of mg of potassium hydroxide (KOH) required to neutralize the fatty acids resulting from the complete hydrolysis of 1 g of the sample.

6. Saponification Value Determination
Saponification # --mgs of KOH required to saponify 1 g of fat.
1. 5 g in 250 ml Erlenmeyer.
2. 50 ml KOH (0.5 N) in Erlenmeyer.
3. Boil for saponification.
4. Titrate with HCl (0.5 N) using phenolphthalein.
Conduct blank determination.
B - ml of HCl required by Blank.
S - ml of HCl required by Sample.
N- Factor of 0.5 N HCL.

7. Saponification Value 3 + 3 K+OH - O - R C H2C H2C OH O HC + HC KO -
triacylglycerol HC
H2C OH
glycerol HC
H2C C O
- R
KO -
+ 3 K+OH - 3 +
Potassium salt
Similarly;
RCOOH KOH RCOO-K Glycerol
MG KOH RCOOK Glycerol
DG KOH 2RCOOK Glycerol

8. Saponification Value 1 mol TG 3 mol KOH required
1 g TG X mol KOH required
MWKOH: 56 g = mg
1 g TG : 1 g / MWTG (g/mol) mol
1 mol TG 3x mg KOH required
1 g TG / MWTG X mg KOH required

9. Saponification Value What is the MWTG ? O O O - R1 - R1 C - R C H2C C

10. Saponification Value Which one’s MW should be taken? O O O - R1 - R1 CHC
H2C O C
- R1
- R2 HC
H2C O C
- R HC
H2C

11. Saponification Value The Answer is the Weighted Average MW O O O - R1HC
H2C O C
- R1
- R2 HC
H2C O C
- R HC
H2C

12. Saponification Value Calculation of AMWTG
Oil consists of only type Simple Triglyceride O C
- R HC
H2C

13. Average Moleculer Weight of FAs in Oil (AMWFA)
Saponification Value
Calculation of AMWTG
Oil consists of Simple and Mixed type Triglyceride with two fatty acids R1 (%90 w/w) and R2 (%10 w/w) O C
- R1 HC
H2C O C
- R1
- R2 HC
H2C O C
- R2 HC
H2C O C
- R1
- R2 HC
H2C
Average Moleculer Weight of FAs in Oil (AMWFA)

14. Saponification Value Generalized Calculation of AMWTG
Oil consists of Simple and Mixed type Triglyceride with N fatty acids
FA xi
R1 x1
R2 x2
. .
RN xN

15. Saponification Value Milk Fat 210-233 Coconut Oil 250-264
Cotton Seed Oil
Soybean Oil
Fat SV
Lard

16. GC Analysis for Fatty Acids
1. Extract fat.
2. Saponify (hydrolysis under basic condition).
3. Prepare methyl ester (CH3ONa).
4. Chromatography methyl ester.
5. Determine peak areas of fatty acids.
Fatty acids are identified by retention time.
6. Compare with response curve of standard.

17. Fatty Acids Methyl Esters:
GC condition: 10% DEGS Column (from supelco)
Column temperature 200C.

18. TRIGLYCERIDE ANALYSIS BY LIQUID CHROMATOGRAPHY
Soybean Oil
Solvent CH3CN/HF
Column ODS- Octadesilsilan (C:18)

19. Iodine Number
The iodine value of an oil or fat is defined as the mass of iodine absorbed by 100 g of the sample.
The unsaturated fatty acid residues of the glycerides react with iodine, and thus the iodine value indicates the degree of unsaturation of the fatty acid residues of the glycerides.
It is constant for a particular oil or fat, but depends on the method used. Animal fats (butter, dripping, lard) Iodine Value
Non-drying oils (olive, almond) Iodine Value
Semi-drying oils (cottonseed, sesame, soya) Iodine Value
Drying oils (linseed, sunflower) Iodine Value
The iodine value is often most useful in identifying the source of an oil. Generally, the higher iodine values indicate oils and the lower values fats. Iodine values are normally determined using Wigs or Hanus methods.

20. Determination of Iodine Number
Iodine Value = (ml of Na2S2O3 volume for blank - ml of Na2S2O3 volume for sample)  N of Na2S2O3  0.127g/meq  100
Weight of Sample (g)
Excess unreacted ICl

21. Theoretical Iodine Value
Monoene + I2 Saturated
Diene + 2*I Saturated
Triene +3* I2 Saturated
Sample: 100 g basis
Assumption: Oil =TG
FA xi
C16:0 5
C18:0 15
C18:1 15
C18:2 40
C18:3 1
C20:0 3

22. Theoretical Iodine Value
1 mol C18:1 1 mol I2 (254 g)
15 g C18:1 X (g) I2
1 mol C18:2 2 mol I2 (2x254 g)
40 g C18:2 X (g) I2
Assumption: Oil =TG
FA xi
C16:0 5
C18:0 15
C18:1 15
C18:2 40
C18:3 1
C20:0 3

23. Theoretical Iodine Value
1 mol C18:3 3 mol I2 (3x254 g)
1 g C18:3 X (g) I2
Theoritical IV= IV C18:1 + IV C18:2+ IV C18:2
Real IV= 0.95xTheoricital Value