Tag: Negative result

The color change in a Biuret test is a key indicator for the presence of protein. A light blue color indicates a negative test for protein, confirming that the sample lacks a significant concentration of peptide bonds. This simple colorimetric test is a cornerstone of basic biochemistry labs for detecting proteins.

According to scientific principles, iodine reacts with starch to produce a distinctive blue-black color. Therefore, to know if starch is not present in a sample, you must conduct the iodine test and observe for a negative result, where the yellow-brown color of the iodine solution remains unchanged.