LAB 5: LIPID ANALYSIS


1.0         INTRODUCTION

            Lipids are classified as organic compounds that are soluble (dissolvable) in organic            solvents, but only sparingly soluble in water. Lipids are biologically important for making barriers (membranes of animal cells), which control the flow of water and other materials into a cell. There are several classes of lipids, including fatty acids, waxes, triacyglycerols (fats and oils), phospholipids and steroids. The fatty acids are usually not free in nature, but are components of triacyglycerols, waxes, and phospholipids Lipids are major components of cell membranes, and are responsible for most of the permeability filter functions of membranes. Membranes act as barriers to separate compartments within eukaryotic cells, and to separate all cells   from their surroundings.


1.1             OBJECTIVE
  1. To determine the percentage of lipid extraction of the food samples.
  2. To extract lipids from food samples. 
1.2       MATERIALS

      1.         Food samples (potato chips etc)
      2.         Petroleum ether
      3.         Ethanol
      4.         Deionised water
      5.        Test tubes (small and large) and stand
      6.         Pipette
      7.         Measuring cylinder 
      8.         Dropper and spatula
      9.         Erlenmeyer flask.
    10.       Beaker
    11.       Weighing scale
    12.       Hot plate


1.3       METHODOLOGY

Extraction of lipids from foods.
1.      About 2 grams of food samples (potato chips etc) were weighed.
2.      The food sample were crushed into small pieces using mortar and pestle.

3.      An empty beaker are weighed with a glass rod inside. The weight are recorded in Table 2.
4.      The crushed food were placed in the above beaker.
5.      The beaker (with a glass rod) containing the crushed food were weighed. The weight were recorded in Table 2.
6.      10 ml of petroleum ether were added to the flask containing crushed food and stirred 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 were placed on a hot plate to evaporate all of the petroleum ether (in a well ventilated area).

9.      Check to see that there is no longer a strong smell characteristics of the petroleum ether, and  the beaker was allowed to cooled
10.  After the beaker has cooled to room temperature, the beaker and remaining food were weighed again (with the glass rod). The weight was recorded in Table 2.



1.4         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)


 Bun
49.09g
51.09g
51.09 – 49.09
= 2.00g
50.59g
51.09 – 50.59
= 0.5g
0.5/2.00 X 100
= 25 %
Cracker
47.20g
49.20g
49.20 – 47.20 = 2.00 g
48.69 g
49.20 – 48.69
= 0.51g
0.51/2.00 X
100
= 25.5 %
Potato
45.50
47.50
47.50 - 45.50  =2.00
46.93
47.5 - 46.93 =
0.57
0.57/2.00 X 100
 = 28.5 %
chips






Rempeyet
51.21g
53.21g
53.21 - 51.21
= 2.00g
52.68g
53.21 - 52.68
= 0.53g
0.53/2.00 X 100
= 26.5 %
Sunflower seeds
53.17g
55.17g
55.17–53.17
= 2.00g
54.59g
55.17 – 54.59
 = 0.58g
0.58/2.00  X 100
= 29 %
(% lipid extraction = weight of lipid extracted/weight of crushed food sample x 100%


1.5 DICSUSSION

Based from the result that we obtain from this lipid analysis experiment, we can see clearly which sample has higher lipid content. In this experiment, we choose 5 different samples. To get the reading of the lipid content, we compare the weight of the beaker with raw before and after heating the raw food with petroleum ether. After decant all the petroleum ether, we dried the food to evaporate the petroleum ether. Then we weighed the beaker containing raw food. We found that that the mass of the raw food decreases and this means that the food contain lipid.
     The function of the petroleum ether was actually to extract all the lipid contains in the raw food, leaving non lipid behind.
     To compare, sunflower seeds has the higher percent of lipid content, compare to the other 4 samples, which is 29%.  The samples that has less lipid content is bun, which is only 25%.


1.6 CONCLUSION
To conclude, lipid can be identified and extracted from various of food and different food contain a different percent of lipid.
  

1.7       REFERENCES

  1. Lab report 4 lipid. (n.d.). Retrieved from https://www.scribd.com/document/367097238/lab-report-4-lipid



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