1. Chapter IX (the last chapter)

2. OILS Mineral oils Organic oils ( lipids) Compound lipids HETEROLIPIDS
Simple lipid
HOMOLIPIDS
Derived lipids
Steroids
Phospholipids
Testosterone, estrogen,
Cholesterol
vitamins
Triglicerides
Waxes
Esential oils

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

4. Fats and oils
Edible Non edible
Analysis

5. Chemical analysis of oils quantitative and qualitative

6. Analytical Methods Saponification Value
(Polanski value or the Reichert-Meissl-Wollny value)
Iodine Value
Acid Value
Thiocyanogen value or thiocyanogen number
Active Oxygen Method (AOM)
Peroxide value
Ultraviolet Spectroscopy
FT-IR spectroscopic method

7. saponification Show the reaction of saponification of the next esters:
Trimyristin (Myristic acid C14:0)
Triolein (Oleic acid 18:1cis-9)

8. 1. 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

9. 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.

10. 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

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

12. Saponification Value Determination
Saponification # --mgs of KOH required to saponify 1 g of fat.
1. 5 g of fat 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.

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

14. iodination
Linoleic acid 18:2 cis,cis-9,12

15. 2. Iodine Number Halogenation (iodination)
  unsaturated
fatty acids

16. Determination of Iodine Number
Excess unreacted ICl
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)

17. 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 freshneess oils.

18. Theoretical Iodine Value
Monoene + I2 Saturated
Diene + 2*I Saturated
Triene +3* I2 Saturated

19. Theoretical Iodine Value
1 mol C18:3 3 mol I2 (3x254 g)
1 g C18:3 X (g) I2

20. 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

21. Write the structural formula and give the name of this fatty acid:
C18:3, Omega-3
Explain where belongs to the MUFA or PUFA class of fatty acids.

22. 3. Acid Value Number of mgs of KOH required
to neutralize the Free Fatty Acids
in 1 g of fat.

23. 4.Thiocyanogen value or thiocyanogen number
a measure of unsaturation (as of an oil or fat) expressed usually as the number of grams or percentage of iodine equivalent to the thiocyanogen absorbed by 100 grams of the substance.
Serving as a supplement to the iodine number because thiocyanogen adds to double bonds to a different extent from the usual reagents for determining iodine number … is thus different from the ordinary value in that it differentiates between oleic C18:1cis-9, linoleic C18:2 cis,cis-9,12., and linolenic groups C18:3 cis-6,9,12
Thiocyanogen, (SCN)2, is a pseudohalogen derived from the pseudohalidethiocyanate, [SCN]−. This hexatomic compound exhibits C2 point group symmetry and has the connectivity NCS-SCN.
 The oxidation ability is greater than bromine. 

24. Lipid Oxidation

25. Measurement of lipid oxidation
Active Oxygen Method (AOM)
Iodine value or Peroxide Value is measured over time as Oxygen is bubbled through an oil sample
This method is also used to evaluate antioxidants

26. 5. CHOLESTEROL DETERMINATION
total cholesterol levels should be:
5mmol/L or less for healthy adults
4mmol/L or less for those at high risk
Enzymatic Determination: Cholesterol Oxidase
In enzymatic analysis (which is widely used in medical laboratories) the color reaction is preceded by a reaction catalyzed by an enzyme.

27. Cholesterol by GLC
1. Prepare cholesterol butyrate.
2. Analyze by GLC.
time in GC - 15 min.
sensitivity g.

28. 7. Peroxide Value Hydrolytic Rancidity Definition
7. Peroxide Value
Definition
The peroxide value (PV) is a figure used for determining the peroxide oxygen (especially hydroperoxides). It is expressed in milliequivalents of active oxygen per 1 kg of fat.
The peroxide value is used for identifying the onset of oxidative change in fats and oils, during which the oxygen (O2) molecule penetrates the fat molecule in the form of a peroxide group (H2O2).
The peroxide value is a quality criterion for explain the freshness of edible oils. The lower the figure, the fresher the oil.
Crude pressed oils have a PV of 5-20, refined oils 0-1.

29. The peroxide value is defined as the amount of peroxide oxygen
per 1 kilogram of fat or oil.

30. 8. Analyzing Olive Oil Purity with Ultraviolet Spectroscopy using the UV-1800 Spectrophotometer from Shimadzu

31. Methyl bromide Methyl Iodide
Chromophore
Example
Excitation
λmax, nm ε
Solvent
C=C
Ethene
π  __>   π*
171
15,000
hexane
C≡C
1-Hexyne
180
10,000
C=O
Ethanal
n  __>  π* π  __>  π*
15 10,000
hexane hexane
N=O
Nitromethane
17 5,000
ethanol ethanol
C-X   X=Br       X=I
Methyl bromide Methyl Iodide
n  __>  σ* n  __>  σ*
Measured K Values
Olive Oil Sample Type
K232
K264
K268
K272 ΔK
Extra Virgin Sample 1
2.379
0.179
0.173
0.165
0.001
Extra Virgin Sample 2
1.911
0.207
0.214
0.209
0.006
Extra Virgin Sample 3
2.085
0.130
0.135
0.134
0.003
Olive Oil Sample 4
2.373
0.686
0.759
0.663
0.085
Olive Oil Sample 5
2.180
0.701
0.772
0.675
0.084
Criteria K Values
Extra Virgin Olive Oil
≤ 2.50
≤ 0.22
≤ 0.01
Olive Oil -
≤ 0.90
≤ 0.15

32. 9. Analysis of Degraded Machine Oil by FTIR