|  | Diet Nutrition | Healthy Eating

Science Fair Project: Testing Phenols in Dark Chocolate

Phenols are chemical compounds found in most foods. They are water-soluble and can therefore cross many barriers in the body, such as the placenta, and be readily absorbed into the bloodstream. It is of scientific importance to study phenols to better understand their effects on the body. A science fair project that tests the presence of phenols in dark chocolate will show that this compound occurs in everyday foods.

  1. Background

    • While the goal of your science fair project is to showcase the phenol content of dark chocolate, you also have the opportunity to show that there are many subgroups of phenols. For example, there is a group of non-food phenols that can be harmful if ingested. These phenols are present in foil wrap, sunscreen and pesticides, just to name a few. The naturally-occurring subgroup of phenols that you are testing for in dark chocolate aren't harmful to people when ingested and shouldn't be confused with manufactured, non-food phenol groups. Dark chocolate contains polyphenols that have beneficial antioxidants.

    Preparation

    • You will need to gather a few bars of dark chocolate, the same amount of flasks, a mortar and pestle, eyedroppers, a metric scale, a project display board, any materials necessary to decorate your board and a small amount of ferric chloride, available from your school's science department. For an added element, choose dark chocolate bars with varying levels of cocoa, such as 60 percent, 75 percent and 90 percent cocoa. Gather background information about phenols, as well as a written explanation of what you're doing in the experiment. Preferably, all of the text on your board will be typed and then glued onto the board.

    Construction

    • Grind the chocolate down to a powder with a mortar and pestle, making sure to keep each type separate. Put 15mg of chocolate into each flask. Keep water and the ferric chloride solution on your display table next to the ground chocolate. Arrange your board so that those watching your experiment can clearly read the explanation of what you're doing.

    Presentation

    • Now that your board is prepared and your table is set up, place the flasks with chocolate at the center of your table and mix in 0.5mL of water to each and stir vigorously until well-blended. Add 2 drops of ferric chloride to each flask, pick up the flasks and stir them gently. Your solution will turn a deep purple color -- this shows that there are phenols present in the dark chocolate.

Healthy Eating - Related Articles