Qualitative Analysis of Oils and Fats.pdf

BIOCHEMISTRY QUALITATIVE ANALYSIS OF FATS AND OILS

1. QUALITATIVE ANALYSIS
OF OILS AND FATS
ROSECHELLE S. ELARCO, RN, MAN

2. SOLUBILITY TEST:
•Lipid or Fat is an organic compound found in living organisms.
•Fats/Lipids are soluble in organic solvents ( nonpolar solvent) like chloroform, alcohol,
•It is insoluble in water. So, if the given sample forms an oily layer above the surface of
the water then fat is present. Partially soluble in alcohol and fully soluble in chloroform
than the presence of fat is confirmed.
•Immiscible liquids: Liquids that don't mix or are not soluble in each other ( insoluble)
•Miscible liquids: Liquids which mix with each other ( soluble)
•Note: If the sample is miscible with chloroform and immiscible with water then, the fat
presence is confirmed.
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3. SOLUBILITY TEST
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1. Take three test tubes which contains 5ml of given
sample solution to be tested.
2. Add 5ml of water to the first test tube and observe the
solution to the second test tube, add 5ml of alcohol.
to the third test tube add 5ml of chloroform.
3Observe the change in solubility of the given sample.
❑If it is soluble in water then fat is absent
❑Ifit is sparingly soluble in ethanol then fat is present
and same for chloroform.

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6. TRANSLUCENT SPOT TEST:
•Fats and oils have higher boiling points so at room temperature they
cannot absorb enough heat to evaporate. When fat or oil is place on a
sheet of paper, it diffracts light. The diffracted light can pass from one
side of the paper to another side and produces a translucent spot.
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7. TRANSLUCENT SPOT TEST:
1. Take the sample to be tested,
press a little in the folds of the
filter paper.
2. On folding, if there is the
appearance of greasy spot
indicates the presence of oils or
fats.
3. The spot grows larger on
heating and drying the filter
paper.
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Note: If there is a presence of translucent spot then
the presence of fats is confirmed.

8. ACROLEIN TEST
•Fats and oils when heated with some crystals of potassium bisulfite KHSO4 in a test
tube. A pungent irritating odor or smell of acrolein confirms the presence of fat or oil.
•Principle: Formation of acrolein or acrylic aldehyde that has characteristic pungent
odor is the key principle. In general lipids upon heating with potassium bisulphate
produce ACROLEIN.
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9. ACROLEIN TEST
•Take the sample to be tested in a
test tube.
•Add few crystals of potassium
bisulfate to it.
•Heat the mixture and observe the
change in odor.
•If there is pungent irritating odor
then the presence of fat or oil is
confirmed.
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10. BAUDOUIN TEST
•This test is used to detect the presence of seasameoil.
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11. BAUDOUIN TEST
•Take 5ml of melted ghee in a
test tube.
•Add 5ml of concentrated
hydrochloric acid and 2-3% of
furfural solution in alcohol to it.
•Keep it aside for 5 to 10
minutes.
•If there is the appearance of
rose-red color then sesame oil
is present or other oil.
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12. HUBLES TEST
•This test is used to detect the degree of unsaturation in oil or fat. Huble'sreagent
reacts with alcoholic solution of iodine that contains some mercuric chloride.
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13. HUBLES TEST
•Take two test tubes and add 3ml of chloroform in
each.
•Add cottonseed oil in one and linseed oil in the
second test tube.
•Shake the mixture well and add 3 drops of Huble’s
reagent in each test tube.(Huble'sreagent –Mix
equal volumes of 7% mercury chloride in alcohol
with 5% solution of iodine in 96% of alcohol.)
•The violet color of iodine fades away in linseed oil
test tube while the colourdoes not fade away in
cottonseed oil.
•This shows that linseed oil is more unsaturated
than cotton seed oil.
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14. THANK YOU