LAB 4 - LIPID ANALYSIS
INTRODUCTION
Lipids are classified as organic compound that are soluble in organic solvents ( ether,
hexane or chloroform ), but they are not soluble in water. There are several classes of lipids,
including fatty acids, waxes, pgospholipids, steroids and triacyglycerols. Fatty acids are
components of triacyglycerol, waxes and phospholipids. Fatty acids are known to be
generally long, straight chains of carbon atoms attached to hydrogen atoms. The 18 carbon
fatty acids are the most abundant in our food supply. Lipids are one of the major constituents
of food that are important in our diet. Lipids are a major source of energy and provide
essential nutrients. But, over consumption of lipid can be detrimental to our health ( cholestrol
and saturated fat ). In this lab, we are going to extract lipid from various sample of foods. The
aim of all extraction procedures is to separate cellular or fluid lipids from the other
constituents, proteins, polysaccharide and other small molecules. It is also to preserve the
lipids for further analyses
OBJECTIVE
To extract and detect the lipid presence in various sample of foods
To determine the % of lipid extraction by using calculation
METHODOLOGY
1. Firstly, the empty beaker with glass rod are weighed and recorded in the table.
2. The food samples ( chocolate chips, potato chips, sunflower seeds, cookies and
soybeans ) were crushed and grinded. After that, we placed it into the beaker.
3. The weight of the beaker contained crushed food also recorded in the table.
4. Then, 10 mL of petroleum ether were added to the beaker contained the crushed food.
5. Then, we swirled the beaker for about 10 minutes to get the lipids dissolve in the
petroleum ether.
6. After 10 minutes, we decant the clear liquid from the beaker into a new beaker. The
beaker contained the liquid portion is weight.
7. Then, we placed the beaker ( both the liquid and solid portion of the food ), on a hot
plate to evaporate all the petroleum ether.
8. After the beaker has cooled down, we weight it again and recorded in the table.
9. Tha last step is we calculate the mass of lipid extract from the food sample ( both
liquid and solid portion of the food ) and determined the % of lipid in the food.
RESULT
Food Weight of Weight of beaker Weight of liquid Weight of liquid Weight of solid
empty beaker with food sample (before heat) (after heat) (after heat)
Cookies 66.366 68.321 48.846 45.696 46.644
Potato chips 66.826 68.828 60.819 57.984 47.245
Sunflower seeds 68.019 70.088 49.263 46.214 48.166
Chocolate chips 72.927 74.904 50.088 48.186 53.496
soybeans 73.101 75.120 32.819 28.903 53.477
CALCULATION ( PART A )
Biscuits 48.846 45.696
100 % = 6.45 %
48.846
60.819 57.434
Potato Chips 100 % = 5.57 %
60.819
Sunflower Seeds 49.263 46.214
100 % = 6.19 %
49.263
Chocolate Chips 50.088 48.186
100% = 3.80 %
50.088
Soybeans
32.819 28.903
100 % = 11.93 %
32.819
CALCULATION ( PART B )
Biscuits 68.321 46.644
100 % = 31.7 %
68.321
Potato Chips 68.828 47.245
100 % = 31.4 %
68.828
Sunflower Seeds 70.088 48.166
100 % = 31.3 %
70.088
Chocolate Chips 74.904 53.496
100 % = 28.6 %
74.904
Soybeans 75.120 53.477
100 % = 28.8 %
75.120
DISCUSSION
From the food samples provided which is biscuits, potato chips, sunflower seeds,
chocolate chip and soybeans, we had to extract the lipids it contained. The purpose for the
extraction process is to determine the lipid percentage present in the food samples. Weighing
process is very crucial in this experiment and had to carried out meticulously. All the weight
beaker were recorded as W1, W2, W3, W4 and W5 and will be used for calculation of lipid
percentage. Thus, we can make a comparison in which type of food contain the highest lipid
percentage. The percentage of lipid from both petroleum ether and solid portion can be known
based on the formula :
weight of liquid,W3 weight of liquid after evaporate,W4
a) From P.E : 100 %
weight of liquid,W3
weight of lipid extracted
b) From solid portion : 100 %
weight of food sample
From the calculation for petroleum ether, we get to know that soybeans contain the
highest percentage of lipid which is 11.93 % and chocolate chips has the lowest lipid
percentage which is 3.80 %. Meanwhile for solid portion, it it show that biscuits has the
highest percentage of lipid which is 31.7 % and the lowest is also chocolate chips which is
28.6 %. This experiment should be extend for further analysis as it give us good information
about the content of lipid in foods. As over-consuming of lipid can be detrimental to our
health, the intake of food in our diet must consider for the lipid contents.
CONCLUSION
As a conclusion, we can conclude that soybean and biscuits has the highest lipid
percentage compared to the other 3 samples. While, the chocolate cereals contain the lowest
lipid percentage. So, we can say that chocolate cereals has the least amount of lipid and
should be consumed more . This chocolate cereals is good to be consumed as our breakfast as
it provides us energy in our daily life.
REFERENCES
1. http://people.umass.edu/~mcclemen/581Lipids.html
2. www.ift.org/~/.../Experiments/TeacherGuideLIPIDS.pdf
3. http://studyres.com/doc/20546594/lab-report-lipids-experiment-purpose
PICTURE
Image 1 : liquid portion of food samples
Image 2 : solid portion of food samples
