The Biuret test for proteins may also be extended to quantitatively measure the concentration of total protein using spectrometric methods. Requirements: Biuret reagent i.
It is believed that the color is due to the formation of a copper co-ordinated complex or chelate complex. Shake well and allow the mixtures to stand for 5 minutes.
Repeat steps 1 and 2 with de-ionized water to prepare a negative control and with albumin egg white to prepare a positive control. The quantity of food crushed and water used depends on the number of tests to be conducted. For each of the procedures, a liquid sample must be prepared from solid foods as follows.
What is the procedure for the Biuret Test for proteins using Biuret Reagent? Histidine is the only amino acid that gives Biuret test positive.
Principle: When biuret is treated with dilute copper sulfate in alkaline medium, a purple colored compound is formed. Biuret test is a general test for compounds proteins and peptides having two or more peptide CO-NH bonds.
This liquid should be used for the food test. Colour changes are best visualized against a white background such as a white tile or a sheet of paper.
Add ml of the test solution, egg albumin and deionized water in the respective test tubes.