How can the presence of lipids be tested?

The presence of lipids can be tested using the grease spot test and the Sudan Red test. The grease spot test involves placing a sample on an unglazed brown paper bag and looking for translucent spots that are left behind. The Sudan Red test involves using Sudan Red, a fat-soluble dye, that stains lipids red.

Lipids are molecules that contain mostly hydrocarbons, and they are one of the main building blocks of life. As a result, they can be extracted from both plants and animals. Some examples of lipids include fats, oils, certain vitamins and hormones. Lipids make up a huge component of the non-protein membranes of all cells.