HUMAN NUTRITION

Detailed explanation-1: -A second test that differentiates between cholesterol and lecithin is the acrolein reaction. When lipids containing glycerol are heated in the presence of potassium hydrogen sulfate, the glycerol is dehydrated, forming acrolein, which has an unpleasant odor.

Detailed explanation-2: -The basis for the Sudan III test is that red dye is composed of hydrophobic molecules. It identifies non-polar substances, such as lipids, because non-polar molecules are also hydrophobic and will group together by hydrophobic interactions to get away from surrounding water molecules.

Detailed explanation-3: -There is a special colorimetric test, the Lieberman–Burchard reaction, which uses acetic anhydride and sulfuric acid as reagents, that gives a characteristic green color in the presence of cholesterol. This color is due to the –OH group of cholesterol and the unsaturation found in the adjacent fused ring.