EXPERIMENT 1 – CHICKEN LIVER

INTRODUCTION

Molisch Test
Our sample was a piece of a chicken liver that was run through a centrifuge until its
contents were separated. The supernate (liquid) and the sediment (solid) part. We then put the
solid part (about 1mL) into a vial and 1mL a supernate in another vial. The leftover sediment
was put to the centrifuge again and we separated it again and put it to vial. Same process was
performed with the 3rd vial of sediments and 3rd vial for supernate. Together, there would be 6
vials proximately 3 for sediments and 3 for supernate. The vials are then labeled according to
the first cycle up to the last followed by adding drops of Molisch reagent to each vial. The
Molisch test is a test used to see the presence of carbohydrates in a substance.

Sudan Test
Sudan test is used to identify the presence of lipids in liquids. In this experiment, the
presence of a chicken liver and the Sudan reagent is required. The blended chicken liver after
being run by the centrifuge, would serve as the source for testing the amount of fats or the
lipids. Combined with the Sudan reagent, changes in color and texture must be observed,
particularly a stain of red would appear. But for its accuracy of resuts, 5 drops of Sudan’s
reagent would account.

Xanthoproteic Test
The Xanthoproteic Test is conducted to detect amino acids containing an aromatic
nucleus (tysosine, tryptophan, and phonylalanine) in a protein solution which gives yellow color
when poured with concentrated HNO3 (Nitric acid).

In our experiment, we prepared 1mL of the chicken liver sediments in three test tubes
and also 1mL of the supernate in three other test tubes. Next, we added 1mL of concentrated
HNO3 (Nitric acid). Then, we observed as the color changed indicating the presence of proteins.
Finally, we tested the acidity of the solutions by adding a piece of litmus paper to each of test
tube.

Biuret Test
To be able to determine the total protein in a sample, the commonly used method is
Biuret Test. Biuret reagent, made of sodium hydroxide and copper (II) sulfate, is used for
determining the presence of protein in a sample. The test relies on the reaction between
copper ions and peptide bonds in an alkaline solution. For the indication of the presence of
proteins, a violet color will be observed.

In our experiment, we mixed 1.0mL of the specimen (minced) and 10 drops of 6M NaOH
into 6 separated test tubes, 3 samples for the supernate (liquid) and 3 samples for the sediment
(solid). Each test tubes are added 0.5% of CuSO4 solution

RESULTS & DISCUSSIONS

Molisch Test
SEDIMENTS COLOR SHOWN SUPERNATES COLOR SHOWN
I Light violet ring I Light vibrant violet ring
II Violet ring II Very dark violet ring
III Dark violet ring III Violet ring

As observed, the sediment II has the darkest violet ring. The reason for this is that it was
the last sample left and so it has a more solid part which is due to extraction. For the supernate
samples, all of the three are positive for the presence of carbohydrates with supernate II having
a slightly darker color and maybe because we had more solid particles in our test tube 2 within
the supernate.
Sudan Test
SEDIMENTS PRESENCE OF LIPIDS (RED SUPERNATES PRESENCE OF LIPIDS (RED
STAIN) STAIN)
I Positive I Negative
II Negative II Negative
III Negative III Negative

The results have come up with a conclusion that the presence of the lipids (with color
red stain) is only evident within the sediment test tube #1. However, the other test tubes have
no other color but is close to transparency. This is because the chicken liver we obtained
doesn’t have much fat on it. As the division of the chicken occurs, the fats would dissolve and
would lessen in each process that is performed through centrifuge.

Xanthoproteic Test
SEDIMENTS COLOR SHOWN SUPERNATES COLOR SHOWN
I Light yellow I Yellow
II Light yellow II Faded yellow
III Bright yellow III Faded yellow

.According to the results, the samples that showed a bright color was sediment III, and a
yellow color in supernate I. With this, the results would be claimed as positive because of the
high presence of protein in them. It is for the reason that these samples had great amounts of
the chicken liver left. On the other hand, sediments I and II and supernates II and III were also
positive for proteins. Nevertheless, the color was different from the other samples because
they had less amounts of chicken liver.
Biuret Test
SEDIMENTS PRESENCE OF PROTEINS SUPERNATES PRESENCE OF PROTEINS
(VIOLET STAIN) (VIOLET STAIN))
I Positive I Negative
II Positive II Negative
III Positive III Negative

Based on our experiment, the given results were all positive, the colors were changed
into violet in which this color indicates high presence of proteins. On the other hand, all of the
supernate samples have negative results since the solid particles of the specimen was already
dissolved.

CONCLUSION

Molisch Test
We therefore conclude that the results of our molisch test by the use of a chicken liver is
indeed a positive result for having the presence of carbohydrates. By following all the indicators
of this positive result and of having a violet ring, it is therefore a successful process of a molisch
test.

Sudan Test
Consequently, the expected positive results of the presence of lipids is the observation
of its colors that would come up with having a red stain in the test tube. The darker the color,
the more lipids are present within the sample.

Xanthoproteic Test
On the whole, all of the samples resulted as positive for proteins because the chicken
liver is good source of protein. It has all the essential amino acids in which are body cannot
produce.
Biuret Test
In conclusion, our group were able to perform correctly and followed the procedures
accordingly. Knowingly, the indicator for the presence of proteins was a dark violet color is achieved as a
result f the experiment.