What is the Biuret test? How do I interpret the results?

The Biuret test is a test for protein, which detects for the presence of protein bonds. In the test, Biuret reagent (sodium hydroxide, hydrated copper (II) suphate and sodium tartrate) is added to the liquid you are testing. The solution will turn violet if protein is present. Other chemical tests include Benedict's test for reducing and non-reducing sugars, iodine test for starch and the emulsion test for lipids.