1. OIL AND FAT TECHNOLOGY 1st WEEK

2. Food Lipids
Definition:Nonpolar, hydrophobic, poorly water soluble components which are soluble in organic solvents such as alkanes (e.g. hexane)
Includes fats: solid at room temperature
oils: liquid at room temperature
Definition based on physical properties
Triglycerides
Fatty Acids
Phospholipids
Terpenes/Terpenoids
Steroids
Waxes
Primary topics

3. 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

4. Triglyceride Structure
Food fats/oils are primarily triacylglycerols, commonly called triglycerides.
3 fatty acid chains on a glycerol backbone O 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

5. Triglyceride (b - palmityl distearin)
GLYCERIDES
Monoglyceride (a - monostearin) Diglyceride (a, a' - distearin)
Triglyceride (b - palmityl distearin)

6. a - oleodipalmitin
1 - oleodipalmitin
a - Linoleyldiolein
1 - Linoleyldiolein

7. Fatty Acids

8. Fatty Acid Structure
R-groups on fatty acid chains are generally linear hydrocarbons, e.g. O
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH3
H- O - C
CH2
CH2
CH2
CH2
CH2
CH2
CH2
which may be more simply represented as O
H- O - C

9. Fatty Acid Chain Representation
The symbol  followed by the carbon number is used to indicate the position of the double bond
E.g. 18:19
consists of 18 carbons with 1 double bond located between the 9th and 10th carbon. O 2 4 6 11 8 13 15 17
- O - C 1 3 5 7 9 10 12 14 16 18

10. Saturated Fatty Acids
Octanoic Acid

11. Unsaturated Fatty Acids
3 - Octenoic Acid
3, 6 - Octadienoic Acid
Short hand: 8:1 (D3)
8:2 (D3,6)

12. Important Food Fatty Acid Constituents

13. Chain Lenght – Molecular Weight
Fatty Acids
Common Name
General Formula
Formula
Mol
Weight (g)
C 12:0
Lauric
CnH2nO2
C12H24O2
200
C 14:0
Myristic
C14H28O2
228
C 16:0
Palmitic
C16H32O2
256
C 18:0
Stearic
C18H36O2
284
C 18:1
Oleic
CnH2n-2O2
C18H34O2
282
C 18:2
Linoleic
CnH2n-4O2
C18H32O2
280
C 18:3
Linolenic
CnH2n-6O2
C18H30O2
278

14. Melting Points and Solubility in Water of Fatty Acids
mg/100 ml Soluble in H2O
Fatty Acids
M.P.(0C) C4
- 8  - C6
- 4
970 C8 16 75
C10 31 6
C12 44
0.55
C14 54
0.18
C16 63
0.08
C18 70
0.04

15. Effects of Double Bonds on the Melting Points
16:0 60
16:1 1
18:0 63
18:1 16
18:2 -5
18:3
-11
20:0 75
F. A.
M. P. (0C)
20:4
-50

16. 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

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

18. 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.

19. 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

20. 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

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

22. 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

23. 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

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

25. 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)

26. 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

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

28. 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.

29. 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

30. 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

31. 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

32. 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