It prepared for Undergraduate students teaching purpose.

1. Unit 7B: Analysis of Oil
and Fat
• 7.1 UNSATURATION-IODINE VALUE
• 7.2 SAPONIFICATION - FREE FATTY ACID, SAP. VALUE
• 7.3 MELTING BEHAVIOUR – SOLID FAT CONTENT LOW
TEMPERATUREPROPERTIES
• 7.4 OXIDATION – PEROXIDE VALUE, ANISIDINE VALUE, STABILITY,
SHELF LIFE, STABILITY TRIALS, TASTE PANELS
• 7.5 GAS CHROMATOGRAPHY
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
MICET
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2. Stability
• Stability of oil and fat is generally accepted as the storage life or shelf
life of the product until rancidity becomes apparent. Oxidative
rancidity is usually the principal concern, although other types of
deterioration can occur simultaneously and make the problem more
complex.
• The method for measuring the fats and oils stability combine the
measurement techniques for initial evaluation for long term effects
of temperature, light, moisture, oxygen, and other factors.
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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3. • A number of methods have been developed for evaluating the long-
range stability of fat and oil products. The majority of which are
based on subjecting the sample to conditions that accelerate the
normal oxidation process.
The following methods are frequently used in the industry:
• Active oxygen method stability (AOM)
• Accelerated AOM stability
• Oxygen bomb method
• Oil stability index
• Schaal oven test
• Pastry flavour test
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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4. Active oxygen method of stability
• AOM employs heat and aeration to accelerate deterioration of the fat and oil sample and shorten the time required to reach the end
point.
• AOCS Methods Cd 12-57: Place a 20 milliliter sample in a special aeration tube and then heating it in an oil bath or a heat block
heating it in an oil bath or a heat block controlled at 97.8±0.2 °C with an air flow adjusted to 2.33 milliliter per tube per sec.
• The sample is exposed to the elevated temperature and aeration until a predetermined peroxide value is attained (20 PV for meat fats
and 70 or 100 PV for vegetable oil products).
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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5. Disadvantage of AOM stability
• The procedure involve is highly empirical, requires closer attention to detail if reproducible
results are expected.
• The maximum expected variation in results between laboratories is ±25% for 100-hour AOM
sample.
• The AOM evaluation is faster than normal aging methods.
• A 100-hour AOM sample will still require 4.2 days to reach the expected end point.
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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6. Oil stability index
• Conductimetric method involving Rancimat and oxidative stability instrument to investigate the oil stability, it is an
alternative to AOM stability test. It became official method in 1996.
• AOCS method Cd 12b-92 (Oil Stability Index or OSI): it is based on the measurement of increase in conductivity
of the deionized water resulting from trapped volatile oxidation products produced when the oil product is
heated under a steam of air.
• The increase in conductivity is related to the oxidative stability of the oil products.
• The OSI value is always expressed with time and temperature e.g. OSI 11.7 hour at 110 °C.
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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7. Procedure of OSI
• Place 2 gm of the oil sample in the sample tube that has been preheated to 120 °C (248 ° F) connected to one
side to the air source and the other side to a 50 mL cell of de-ionized water.
• The conductance of the water is measured automatically over time with a strip chart recorder or data acquisition
software.
• The oxidation curve indicates the induction period followed by a rapid rising response as the oxidation rate is
accelerated.
• The end point of this conductivity procedure is the time required for a sudden increase in formic acid production
to occur at the end of the induction period.
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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8. OSI instruments
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9. Advantages of OSI
• OSI can replace traditionally used AOM stability.
• OSI method automatically delivers rapid oxidation stability data that require less technician time
and attention.
• OSI provides more precise and reproducible results.
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10. Disadvantages of OSI
• OSI not solve the unreliability problem for evaluating natural antioxidants.
• High temperature oxidative stability tests, are unreliable due to the rapid oxidative mechanism at
elevated temperature.
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11. Sensory panel evaluation of oil and fat
• Taste assessment is the ultimate method of grading finished oil quality.
• To determine oil flavor , 5 to 10 mL of oil is taken into the mouth, thoroughly swished throughout the mouth with
air drawn over the top and expectorated into a waste cup.
• A panel of experienced tasters rates the flavour of the oil according to an established intensity scale.
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12. • A 10-point scoring system is usually used, the panel members assign numbers representative of the flavour
intensity. Mean of the panellist score is determined.
• The flavour intensity scores of a trained flavour panel should be agree within ± 1 unit.
• Off-flavours are described with descriptive names such as, green, grassy, weedy, fruity, beany, watermelon,
nutty, raw, painty, musty, metallic, oxidized, buttery, reverted, fishy, rancid, tallowy, and so n.
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13. Gas chromatography (GC)
• GC has been an indispensable analytical technique even since the first exciting
steps in the application of fatty acid determination in oil and fat.
• Contemporary GC methods with high-quality capillary columns allow sensitive
and reproducible fatty acid analysis.
• With the development of flame ionization detector (FID) for GC the fatty acid
analysis became more reliable.
• The open tubular (capillary) column helps in analysis of minor fatty acid
isomers.
• The new sampling methods such as cold on-column injection and programmed
temperature vaporization techniques resulted in considerable improvements in
the reproducibility of GC results.
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14. Sample preparation for GC
• Lipid extraction and fractionation: Solvent extraction method used to
extract fatty acids from food product to study GC analysis. Triacylglycerols
and triglycerol (TAG & TG) can extracted by non-polar solvents such as
hexane or petroleum ether.
• Derivatization of fatty acids: FAME (fatty acid methyl ester) is used in the
GC analysis. Fatty oil saponification followed by acidification and
derivetization by diazomethane in ether, or a more rapid esterification using
sodium methoxide (NaOMe) as a catalysts.
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15. Sampling techniques in GC
• GC sample injection can be done by conventional sampling into a hot injector by means of a
programmed temperature vaporizer (PTV) injector operating at different splitting modes, or by
direct cold on-column injection.
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16. • Optimum qualitative and quantitative information can be obtained from the GC analysis of
complex mixture. The following can be make sure by the GC chromatogram:
• Good resolution, as shown by sharp and symmetric peaks.
• High repeatability and reproducibility of retention times.
• High precision and accuracy in quantitation (measured through peak area).
• Minimum thermal and catalytic decomposition of sensitive sample components.
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17. Interpretation of
GC results
• The interpretation of GC
chromatogram is base on the
peak comparison with the
standard.
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18. Example of flaxseed oil GC results
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Reference of fatty acids peaks Chromatogram of Flaxseed oil

19. Tables of GC data
Table 2: Supelco 37 Component FAME Mix
Elution Analytes Short Name Group
1 C4:0 - Butyric Acid C4:0 Saturated Fatty Acids (SAFA)
2 C6:0 - Caproic Acid C6:0 Saturated Fatty Acids (SAFA)
3 C8:0 - Caprylic Acid C8:0 Saturated Fatty Acids (SAFA)
4 C10:0 - Capric Acid C10:0 Saturated Fatty Acids (SAFA)
5 C11:0 - Undecanoic Acid C11:0 Saturated Fatty Acids (SAFA)
6 C12:0 - Lauric Acid C12:0 Saturated Fatty Acids (SAFA)
7 C13:0 - Triundecanoic Acid C13:0 Saturated Fatty Acids (SAFA)
8 C14:0 - Myristic Acid C14:0 Saturated Fatty Acids (SAFA)
9 C14:1 - Myristoleic Acid C14:1 Mono-Unsaturated Fatty Acids (MUFA)
10 C15:0 - Pentadecanoic Acid C15:0 Saturated Fatty Acids (SAFA)
11 C15:1 - cis-10-Pentadecenoic Acid C15:1 Mono-Unsaturated Fatty Acids (MUFA)
12 C16:0 - Palmitic Acid C16:0 Saturated Fatty Acids (SAFA)
13 C16:1 - Palmitoleic Acid C16:1 Mono-Unsaturated Fatty Acids (MUFA)
14 C17:0 - Heptadecanoic Acid C17:0 Saturated Fatty Acids (SAFA)
15 C17:1 - cis-Heptadecenoic Acid C17:1 Mono-Unsaturated Fatty Acids (MUFA)
16 C18:0 - Stearic Acid C18:0 Saturated Fatty Acids (SAFA)
17 C18:1 - trans-9-Elaidic Acid C18:1n9t Trans-Fatty Acids (TFA)
18 C18:1(n-9) - Oleic Acid C18:1n9c Mono-Unsaturated Fatty Acids (MUFA)
19 C18:2 - trans-Linolelaidic Acid C18:2n6t Trans-Fatty Acids (TFA)
20 C18:2(n-6) - Linoleic Acid C18:2n6c Poly-Unsaturated Fatty Acids (PUFA)
21 C20:0 - Arachidic Acid C20:0 Saturated Fatty Acids (SAFA)
22 C18:3(n-6) - g-Linolenic Acid C18:3n6 Poly-Unsaturated Fatty Acids (PUFA)
23 C18:3(n-3) - a-Linolenic Acid (ALA) C18:3n3 Poly-Unsaturated Fatty Acids (PUFA)
24 C20:1(n-9) - cis-11-Eicosenic Acid C20:1 Mono-Unsaturated Fatty Acids (MUFA)
25 C21:0 - Heneicosanoic Acid C21:0 Saturated Fatty Acids (SAFA)
26 C20:2 - cis-11,14-Eicosadienoic Acid C20:2 Poly-Unsaturated Fatty Acids (PUFA)
27 C22:0 - Behenic Acid C22:0 Saturated Fatty Acids (SAFA)
28 C22:3n6 - cis-8,11,14-Eicostrienoic Acid C20:3n6 Poly-Unsaturated Fatty Acids (PUFA)
29 C20:3n3 - cis-11,14,17-Eicosatrienoic Acid C20:3n3 Poly-Unsaturated Fatty Acids (PUFA)
30 C22:1(n-9) - Erucic Acid C22:1n9 Mono-Unsaturated Fatty Acids (MUFA)
31 C20:4(n-6) - Arachidonic Acid C20:4n6 Poly-Unsaturated Fatty Acids (PUFA)
32 C23:0 - Tricosanoic Acid C23:0 Saturated Fatty Acids (SAFA)
33 C22:2 - cis-13,16-Docasadienoic Acid C22:2 Poly-Unsaturated Fatty Acids (PUFA)
34 C20:5(n-3) - cis-5,8,11,14,17-Eicosapentaenoic
Acid (EPA)
C20:5n3
Poly-Unsaturated Fatty Acids (PUFA)
35 C24:0 - Lignoceric Acid C24:0 Saturated Fatty Acids (SAFA)
36 C24:1 - Nervonic Acid C24:1 Mono-Unsaturated Fatty Acids (MUFA)
37 C22:6(n-3) - cis-4,7,10,13,16,19-
Docosahexaenoic Acid (DHA)
C22:6n3
Poly-Unsaturated Fatty Acids (PUFA)
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
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SN Fatty Acids Analytes in FLAX SEED OIL Fatty Acid Groups RT
% Fat (of Total
Fat)
1 C14:0 - Myristic Acid SAFA 12.388 0.046
2 C16:0 - Palmitic Acid SAFA 15.457 5.687
3 C16:1 - Palmitoleic Acid MUFA 16.806 0.096
4 C18:0 - Stearic Acid SAFA 19.571 5.578
5 C18:1 - trans-9-Elaidic Acid TFA 20.441 0.086
6 C18:1(n-9) - Oleic Acid MUFA / ω9FA 20.757 20.591
7 C18:2 - trans-Linolelaidic Acid TFA 21.649 0.090
8 C18:2(n-6) - Linoleic Acid PUFA / ω6FA 22.445 15.801
9 C20:0 - Arachidic Acid SAFA 23.412 0.204
10 C18:3(n-6) - g-Linolenic Acid PUFA 23.705 0.234
11 C18:3(n-3) - a-Linolenic Acid (ALA) PUFA / ω3FA 24.370 51.376
12 C22:0 - Behenic Acid SAFA 27.275 0.178
13 C24:0 - Lignoceric Acid SAFA 32.014 0.034
14 Sum of Omega-3 (n-3) ω3FA - 51.376
15 Sum of Omega-6 (n-6) ω6FA - 15.801
16 Sum of Omega-9 (n-9) ω9FA - 20.591
17 Saturated Fats (SAFA) SAFA - 11.727
18 Trans-Fats (TFA) TFA - 0.176
19 Monounsaturated Fats (MUFA) MUFA - 20.687
20 Polyunsaturated Fats (PUFA) PUFA - 67.410
21 Total Unsaturated Fats (TUFA) TUFA - 88.097

20. The slides end here!
THANKS FOR YOUR PATIENCE!
4/30/2020 Dr. Mohammed Danish/ Oil and Fat Technology/UniKL MICET 20

21. Project tiles
1. Margarin products
2. Mayonnaise products
3. Baking shotenings
4. Frying Sortenings
5. Emusifiers
6. Dairy Analog Shortening
7. Biodiesel production from edible oil
8. Lubricants production from oil and fat
9. Soap and Detergents from oil and fat
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Dr. Mohammed Danish/ Oil and Fat Technology/UniKL
MICET
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