PROTEIN IDENTIFICATION

INTRODUCTION:
Biuret's test is a chemical test udes for detecting the presence of peptide bonds. Polypeptides as proteins, are chains of amino acids link together by peptides bonds.
A peptide bond can be broken by hydrolysis. In organisms, protein molecules called enzymes facilitate the process.

OBJECTIVES:
1.Identify peptide bonds.
2.Compare protein concentration in different foods.

MATERIALS:
-7x250mL beaker
-5 test tubes
-Test tube rack
-6x10mL pipet
-Mortar
-Glass marking pen
-Gloves
-Goggles
-Milk
-Rice Milk
-Egg
-Potato
-Distilled water
-NaOH 20%
-10 drops of CuSO

PROCEDURE:
We are going to determine protein concentration in some foods: milk, rice milk, potato and eggss.
1.Add 100mL of distilled water to each 250mL beaker.
2.Label them with M (milk), RM (rice milk), EW (egg white), EY (yolk) and P (potato).
3.Separate the egg white and the yolk in another beaker.
4.Smach the potato in a mother and add some amount of the smashed potato to the P beaker.
5.Add 10mL of a dispersion of each food to the indicate beaker. Calculate the final concentration. All the groups will use the same dispersion from the beakers.
6.Prepare 6 test tubes and label the name.
7.Add 2 mL of the every food dilution of each beaker.
8.Add 2mL of 20%NaOH dissolution.
9.Shake gently and add 5 drops of CuCO in each tube. Allow the mixture to stand for 5 minutes.
 
CuCo                      NaOH
10.Note any colour change. Remember that proteins will turn solution pink or purple.
11.Compare the test tube.

RESULTS:
Potato: negative
Yolk: positive
Egg White: positibe
Rice milk: negative
Milk: positive

	Egg white	Yolk
PROTEINS	11	17,5
LIPIDS	0,2	32,5