LAB 5 : LIPID ANALYSIS
LAB
5
LIPID
ANALYSIS
INTRODUCTION
Lipid are another word for fat.A lipid is chemically defined as a substance that is insoluble in
water and soluble in alcohol, ether, and chloroform.
Lipids are an important component
of living cells. Together with carbohydrates and proteins, lipids are the main
constituents of plant and animal cells.
Cholesterol and triglycerides are lipids. Lipids are easily stored in the
body. They serve as a source of fuel and are an important constituent of the
structure of cells.
Lipids include fatty acids,
neutral fats, waxes and steroids (like cortisone). Compound lipids (lipids
complexed with another type of chemical compound) comprise the lipoproteins,
glycolipids and phospholipids. Lipids include fats, oils, waxes, cholesterol,
other sterols, and most steroids. In the body, fat serves as a source of
energy, a thermal insulator and cushion around Lipids are biologically
important for making barriers (membranes of animal cells), which control the
flow of water and other materials into a cell.
OBJECTIVES
To determine the presence of
lipids in solid and liquid food samples.
MATERIALS
Food samples (potato chips etc)
Petroleum ether
Ethanol
Deionised water
Test tubes (small and large) and stand
Pipette
Measuring
cylinder
Dropper and spatula
Erlenmeyer flask.
Beaker
Weighing scale
Hot plate
METHODOLOGY
Extraction of lipids from foods.
1. About 2 grams of food
samples were weight. (potato chips etc).
2. The food sample were crushed into
small pieces using mortar and pestle.
3. An empty beaker was weight with a
glass rod inside. The weight were recorded in Table 2.
4. The crushed food was placed in
the above beaker.
5. The beaker (with a glass rod)
containing the crushed food were weight.The
weight were recorded in Table 2.
6. Add
10 ml of petroleum ether to the flask containing your crushed food. Stir
with the glass rod for 10 minutes to get the lipids to dissolve in the
petroleum ether (in a well ventilated area or use a hood).
7. Carefully decant the petroleum
ether from the beaker (pour only the clear liquid, not the solid portion of the
food).
8. The beaker containing the
remaining solid food was placed on a hot plate to evaporate all of the
petroleum ether (in a well ventilated area).
9. When it has all evaporated, checked
to see that there is no longer a strong smell characteristics of the petroleum
ether, and allow the beaker to cool.
10. After the beaker has cooled to
room temperature, the beaker and remaining food were weight again (with the
glass rod). The weight were recorded in Table 2.
11. Table 2 was used to guide and to
calculate the mass of lipid extracted from the food sample The weight percent
of fat in that food were determined.
RESULT
Table
2. Extraction of lipid.
Foods
|
Weight of
|
Weight of
|
Weight of
|
Weight of
|
Weight lost
|
% Lipid
|
empty
|
beaker with
|
crushed
|
beaker
|
from food
|
extraction
|
|
beaker (with
|
crushed raw
|
raw food
|
with dried
|
(weight of lipid
|
||
glass rod)
|
food (with
|
food (with
|
extracted)
|
|||
glass rod)
|
glass rod)
|
|||||
Potato
|
52.01
|
54.07
|
2.06
|
52.71
|
1.36
|
66%
|
chips
|
||||||
Biscuit
|
55.01
|
60.49
|
3.73
|
58.74
|
1.75
|
47%
|
Oat
|
63.58
|
65.60
|
2.02
|
65.22
|
0.38
|
19%
|
Cookies chips
|
38.95
|
40.61
|
1.66
|
40.12
|
0.49
|
30%
|
Peanut
|
45.53
|
50.95
|
5.42
|
49.97
|
0.98
|
18%
|
(% lipid extraction = weight of lipid extracted/weight
of crushed food sample x 100%)
Potato chips : 1.36/2.06 x
100 % = 66%
Biscuits : 1.75/3.73 x 100 % = 47%
Biscuits : 1.75/3.73 x 100 % = 47%
Oat : 0.38/2.02 x 100 % = 19%
Cookies chips : 0.49/1.66 x 100 % = 30%
Peanut : 0.98/5.42 x 100 % = 18%
DISCUSSION
In this experiment, we did
extraction process to know the percentage of lipid from the five types of food
which are potato chips, biscuit, oat,cookies chips, and peanut.
Thus comparison can be made from which type of foods
have the highest content of lipids. Weighing process was carried out
after several steps based on the procedure and all the weights was recorded.
The separation of liquid and
solid portion of food was made after the addition of petroleum ether and the
stirring process for about 20minutes was carried out. From that separation, we
could extract the lipid of solid portion after the separation process. The
percentage of lipid from solid portion of food can be known based on the
formula
(%
lipid extraction = weight of lipid extracted/weight of crushed food sample x
100%)
From this calculation, the potato
chips showed the highest percentage rank of lipid which is 66 % followed by
biscuits, 47 %, cookies chips, 30 % , oat, 19 % and peanut which was 18%. It
was clearly stated that the extraction of lipid after the separation with
petroleum ether, showed that potato chips has highest lipid content compared
to biscuit, oat, cookies chips, and peanut. This experiment actually give us
info about the content of lipid of food and give us awareness for which
food among this five types of food should we take with the consideration of
lipid content. The intake of food should be consider for its lipid content as
it will affect our health. Peanut, which have the lowest percentage of
lipid good to be consumed for us and we should avoid junk food like potato
chips ,or be taken in minimum rate.
CONCLUSION
The extraction from lipids and
alcohol will show an emulsion when added to water.. Potato chips have the most
percentage of lipid extracted, followed by biscuits,cookies chips, oat, and peanut.
The lipid extracted from oat and peanut may contained saturated fatty acids.
Whereas the lipid extracted from potato chips may contain unsaturated fat.
In conclusion, lipids are an essential
component of human physiology at the molecular level. Finding the proper balance
between the intake of saturated and unsaturated fats are necessary to avoid
cardio vascular diseases and reducing obesity and weight gain.
Despite that, we also should
recognise that sugar and fat mus be included as part of a healthy diet. These elements
are the precursors of energy production of cellular tissues.
REFERENCES
Lab Report 4 Lipid, (2017), Scribd.com.(online)
retrieved from
lab
report lipid, (2009), Slideshare, (online) retrieved from
Food
Science Lab Report : Lipid Analysis, (2016), Blogger.com (online) retrieved
from
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