The main building blocks to create a protein are amino acids. There are 20 amino acids with a different structure. Together they form large protein molecules.
For testing sugar, it is expedient to use Benedict's test, where there is a change in the color of the solution on brick-red. For testing fat, it is possible to use brown paper test (if the paper is translucent there was fat). Starch can be identified using iodine, where there is a change in color. For testing protein, biuret test can be applied. The reaction results in the changing the color of the solution to the violet