Macromolecules Test Results
Lugol’s Solution (KI)—starch test.
Add Iodine-KI reagent to a solution or directly on a potato or other materials
such as bread, crackers, or flour. A blue-black color results if starch is
present. If starch amylose is not present, then the color will stay orange or
yellow.
Biuret’s Solution-- proteins (gelatin)
Biuret reagent is a blue solution that, when it reacts with protein, will change
color to pink-purple. This colour change is dependent on the number of
peptide bonds in the solution, so the more protein, the more intense the
change. When the peptides are very short, the solution turns a pink colour,
rather than violet.
Benedict's solution – glucose test.
Used to test for simple sugars, such as glucose. It is a clear blue solution
of sodium and copper salts. In the presence of simple sugars, the blue
solution changes color to green, yellow, and brick-red, depending on the
amount of sugar.
Sudan IV—lipid (fats/oil) test.
It’s used to identify the presence of lipids in liquids. The Sudan IV test will
test positive for lipids. The test procedure involves adding a few drops of
Sudan IV to the test solution. Sudan IV is a dye that will stain lipids. If no
lipids are present then the dye will sink to the bottom of the test tube.
Macromolecules Test Results
Lugol’s Solution (KI)—starch test.
Add Iodine-KI reagent to a solution or directly on a potato or other materials
such as bread, crackers, or flour. A blue-black color results if starch is
present. If starch amylose is not present, then the color will stay orange or
yellow.
Biuret’s Solution-- proteins (gelatin)
Biuret reagent is a blue solution that, when it reacts with protein, will change
color to pink-purple. This colour change is dependent on the number of
peptide bonds in the solution, so the more protein, the more intense the
change. When the peptides are very short, the solution turns a pink colour,
rather than violet.
Benedict's solution – glucose test.
Used to test for simple sugars, such as glucose.
It is a clear blue solution of sodium and copper salts. In the presence of
simple sugars, the blue solution changes color to green, yellow, and brickred, depending on the amount of sugar.
Sudan IV—Lipid (fats/oil) test.
It’s used to identify the presence of lipids in liquids. The Sudan IV test will
test positive for lipids. The test procedure involves adding a few drops of
Sudan IV to the test solution. Sudan IV is a dye that will stain lipids. If no
lipids are present then the dye will sink to the bottom of the test tube.