Fast Food Chemistry Lab

 

   McMush

Introduction:
Carbohydrates, proteins, fats, vitamins, and other nutrients  provide your body with energy  necessary to carry on life activities. These compounds are present in the plants and animals you use as food. In this lab, you will test for specific compounds and then determine if those compounds are present in ordinary foods.

Objective:
To determine the compounds present in food.

Materials:

McDonald’s Happy Meal (fries + drink included) (no toy!), beaker, graduated cylinder, test tubes, test tube clamp,  hot plate, Benedict’s solution, Biuret solution,  Indophenol (DPIP) solution, Lugol’s iodine solution,  1% silver nitrate solution, blender

Procedure:
Part I – Testing of Known Substances

Protein test: 

  1. Place 5 ml of the gelatin solution into your test tube.
  2. Add ten drops of Biuret solution.
  3. Observe any color change 

Glucose test:

  1. Place 5 ml of the glucose solution into your test tube.
  2. Add 3 ml of Benedict’s solution.
  3. Place the tube in a beaker of boiling water and boil for five minutes
  4. Use test tube clamps to hold hot test tubes.
  5. Observe any color change 

Starch test:

  1. Place 5 ml of the starch solution into your test tube.
  2. Add 5 drops of Lugol’s iodine solution.
  3. Observe any color change  

 

Vitamin C test:

  1. Place 5 ml of the vitamin C solution into your test tube.
  2. Add 5 drops of indophenol solution.
  3. Observe any color change

Chloride test:

  1. Place 5 ml of the salt solution into your test tube.
  2. Add 5 drops of silver nitrate solution.
  3. Observe any color change.

 

Record your results in a data table: 

 

Food Substance    Reagent test           Results
Gelatin                  Biuret solution  
Glucose  Benedict’s solution  
Starch Lugol’s iodine solution  
Vitamin C             indophenol solution  
Sodium chloride   silver nitrate solution  

 

Procedure:
Part II –
Testing McMush

  1. Place the Happy in a blender. Add enough water to cover and blend until you get an emulsion.
  2. Filter the mush in to a beaker.
  3. Predict the substances you will find in the McMush solution. Record your predictions in the data table using   a “ +” or “-“.
  4. Repeat the reagent tests above using 5 ml of the McMush solution.
  5. Describe and record your results.

    

Food Substance    Prediction Reagent test           Results
Protein Biuret Solution  
Sugar  Benedict’s Solution  
Starch Lugol’s solution  
Vitamin C Indophenol Solution  
Sodium Chloride Silver Nitrate Solution

 

Procedure:
PART III: McMush – Demonstration of Fat Content

Materials:
McMush, hot plate, 1-500ml beaker,1-200ml graduated cylinder, 100 ml of water, 2 oven mitts, 1 wooden spoon, 1 refrigerator to cool McMush mixture

Overview: 

The complete meal will be blended to make the McMush. A large sample from the blended Happy Meal will then be heated. From the heated sample, 100 ml will be taken and cooled. This cooled sample will represent the complete meal.

Steps:

  1. Preheat the hot plate
  2. Break up meal into small pieces and blend.
  3. Pour part of the blended McMush into a 500 ml beaker.
  4. Add 100 ml of water to the McMush and stir well.
  5. Boil McMush mixture gently for 15 minutes.
  6. Use oven mitts to protect your hands and pour the hot McMush  mixture into a graduated cylinder. Then cool in the refrigerator for 5 minutes.
  7. Remove McMush from the refrigerator and measure the amount of accumulated fat at the top of the graduated cylinder.
  8. Record results.
  9. Clean glassware with warm soapy water.

Expected Outcome: 

  The fat will form a layer at the top and solidify as it cools. You may calculate the percent of fat in the McMush meal by dividing the ml of fat by the total ml of your sample.  For example, you might find 40 ml of fat out of a total of 100 ml of sample. This would indicate that the total meal contained 40% fat.

Adapted from a lab by C. Sheldon