Festive Fat Extraction: A Chocolaty Christmas Chemistry Caper for all the Family

🗂 Workshop overview: The detectives provide a free workshop on fat extraction for a local charity. DIY experiments for determining fat content are provided for people of all ages. Ready for some festive fun for all the family? Then read on.

After the drama of their last case solving the mystery of the zombie of Foghaven , the detectives are in need of some respite. Thankfully, Shallot Holmes has a plan to get the team in a festive mood while putting their food knowledge to the test.

 

“Good morning, detectives; I have a challenge for you. We have been asked to provide a workshop at this year's Christmas fair,” says Holmes. “I love the Christmas fair; what do you propose?” asks Nancy Beef. Shallot Holmes says he’d like them to think of a way to give the local population an insight into the work of the food detectives. “You never know, the next generation of food detectives may well be at the fair, and our mission is to instil a love of chemistry to foster their love of science,” declares Holmes. “Chocolate,” shouts Cornlumbo. “Is that a suggestion, or has your belly taken hold of your mind again?” asks Miss Mapple. “It’s a suggestion; I mean, everyone loves chocolate, right, no matter your age,” says Cornlumbo. “This is true; I have never met someone who doesn’t like chocolate in some form or another,” says Eggcule Poirot.

 

What makes chocolate so delicious?

Shallot Holmes likes the suggestion but wants to know how to use chocolate to educate the people at the fair. Cornlumbo says that the fat content of chocolate is what makes it so delicious, as it is a crucial carrier of flavor compounds. “The cocoa butter helps release the flavor compounds when it melts at body temperature; it’s this melting characteristic that creates the smooth, delicious mouthfeel, and a higher fat content typically leads to a creamier, luxurious texture that enhances the indulgent sensory experience that makes chocolate so yummy, and...” Miss Mapple must interject as she knows that once Cornlumbo gets started talking about chocolate there is no stopping him. She also feels that she needs to remind Cornlumbo that although the high-fat content of chocolate does indeed factor into the yumminess, as with any food, moderation is key! Something Cornlumbo has always had trouble grasping! “I still haven’t forgotten about the excessive amount of food you ate last Christmas, Cornlumbo,” says Miss Mapple.

 

Shallot has an idea. “How about we educate the people at the fair all about fat content so they know how to make yummy chocolate treats while being aware that a treat is just that – something that should be enjoyed in moderation!” says Holmes before giving each of the detectives a task for the fair. Holmes’ plan is this: Cornlumbo must teach the younger children about how to determine fat content, Nancy Drew can teach young teens, Eggcule Poirot can educate the older teens and adults, and Miss Mapple can provide a recipe and explain the importance of nutrition to everyone to ensure they don’t end up gluttons like Cornlumbo.

 

“Let’s educate the people at the fair about fat content so they know how to make yummy chocolate treats while being aware that a treat is just that – something that should be enjoyed in moderation!”

 

It is the day of the fair, and locals of all ages gather at the marketplace. Cornlumbo has taken the stage and explains an experiment that all the children can perform at home to determine fat content.

 

How can children perform DIY fat extraction?

“Okay, children, here is what you’ll need to work out which chocolate is the yummiest… um, I mean, which has the highest fat content,” says Cornlumbo.

 

Materials Required

  • Brown Paper Bags (uncoated simple brown paper bags or parchment paper).
  • Food Samples (a selection of chocolates or other foods, such as nuts, crisps, cheese, etc.)
  • A Pen or Marker (to label the paper)
  • A Ruler (to measure the oil stains)

 

Steps

Preparation: Cut the brown paper bags into equal-sized squares. Label each square with the name of a different food you are testing.

Apply Food Samples: Place a small piece of each food item on its respective square. You can gently rub it on the paper to transfer some of its fat. Make sure you are using the same amount of each sample to compare.

Observation Time: Let the paper sit for about 30 minutes. This allows time for any fat in the food to be absorbed by the paper, creating an oil stain.

Analysis: After 30 minutes, observe the size and intensity of the oil stains on the paper. More fat in the food will result in a larger, more transparent oil stain.

Comparing Results: Use the ruler to measure the diameter of each oil stain. Record these measurements and compare which foods left the biggest stains, indicating higher fat content.

Discussion: Discuss with the child why some foods left bigger stains and what this means about fat content—a great opportunity to talk about healthy eating and the role of fats in our diet.

 

Safety Tips

  • Ensure the child is supervised, especially when cutting the paper bags or handling food items that might be hard or require cutting.
  • Remind the child not to eat the food samples after they have been used in the experiment.

 

How can young teens perform DIY fat extraction?

Next up is Nancy Beef, who provides an experiment for the younger teens to perform.

 

The Solvent Extraction Method

“This method is more chemically involved and requires handling solvents. Therefore, it may not be suitable for very young children but is a good project for older kids under adult supervision,” explains Nancy Beef to the audience.

 

Materials Required

  • Food Blender or Grinder
  • Solvent (like isopropanol or ethanol, available at pharmacies or chemical supply stores)
  • Coffee Filter or Cheesecloth
  • Glass Jar
  • Kitchen Scales

 

Steps

Blending: Blend or grind the food sample into a paste or powder.

Mixing: Weigh a glass jar before use. Place the food into it and add a measured amount of sample – enough to fully immerse the sample.

Shaking and Settling: Place the lid on the jar, shake the mixture well, and let it settle. Fat will be dissolved in the solvent.

Filtering: Pour the mixture through a coffee filter or cheesecloth to separate the liquid (which contains the fat) from the solid residue.

Evaporating: Let the solvent evaporate naturally from the liquid in a well-ventilated area – leaving behind the fat.

Weighing: Weigh the glass jar containing the remaining fat to estimate the fat content.

 

Safety and Tips

  • These methods, especially the solvent extraction, should be performed with adult supervision.
  • Ensure good ventilation when working with solvents.

 

How can older teens and adults perform DIY fat extraction?

To round off the day’s experiments, Eggcule Poirot takes the stage and explains an even more advanced method of fat analysis that can be performed by adults.

 

Acid Hydrolysis Followed by Solvent Extraction

This method uses an acid to break down the food matrix to release any fats encased within. Eggcule explains that the prior methods of analysis only determined the crude fat content, whereas this method gives an estimate of the total fat content.

 

Materials Required

  • Strong Acid (diluted hydrochloric )
  • Solvent (such as petroleum ether or hexane)
  • Heat Source (a hot plate or stove)
  • Glassware (beakers, flasks)
  • Strainer or Cheesecloth
  • Evaporation Dish

 

Steps

  • Acid Treatment: Mix the blended food sample with a diluted strong acid in a beaker and heat the mixture to hydrolyze it.
  • Extraction: Add a solvent to the sample and mix well.
  • Separation: Allow the mixture to settle into two layers.
  • Recovery: Collect the top layer, which contains the solvent and fat.
  • Evaporation: Evaporate the solvent to obtain the fat.
  • Weighing: Weigh the fat to estimate the sample’s fat content.

 

Safety and Tips

  • Safety is paramount. Use gloves and goggles, and work in a well-ventilated area.
  • Be cautious with acids and solvents and familiarise yourself with how to handle spills or exposure.
  • Dispose of chemicals responsibly according to regulations.

 

Once Eggcule finished his talk, Miss Mapple took to the stage and offered a recipe for a delicious and indulgent chocolate cake after explaining the importance of nutrition and enjoying treats in moderation.

 

The detective’s workshop was rounded off by Shallot Holmes, who pointed out that all the experiments offered a great introduction to laboratory processes. He also provided the attendees with information about prior cases the detectives have solved that involved the most meticulous fat extraction methods made possible by dedicated laboratory equipment.

 

Miss Mapple’s Indulgent Chocolate Cake

 

Ingredients

  • 240g unsalted butter
  • 265g dark chocolate (52% cocoa)
  • 95g dark chocolate (70% cocoa)
  • 290g light muscovado sugar
  • 4 tbsp water
  • 5 large free-range eggs (separated)
  • A pinch of salt.
  • Some raspberries

 

Method

  • Preheat oven to 170˚C.
  • Grease a 20 cm cake tin and line it with baking paper.
  • Add butter & chocolate to a large bowl.
  • Put the sugar and water in a saucepan, stir to mix, and bring to a boil over medium heat.
  • Pour the boiling mixture over the butter and chocolate and stir until melted.
  • Stir in the egg yolks, one at a time.
  • Let the mixture come to room temperature.
  • Put the egg whites and salt in a large bowl and whisk to a firm but not too dry meringue.
  • Fold the meringue into the cooled chocolate mixture with a rubber spatula, a third at a time.
  • Pour about a third of the final mixture into the prepared cake tin and level gently.
  • Bake for about 40 minutes until an inserted skewer comes out almost clean.
  • Remove from oven and let it cool completely.
  • Flatten the top of the cake with a palette knife.
  • Pour the rest of the mixture on top and gently level the surface again.
  • Return to the oven and bake for 20-25 minutes.
  • Leave to cool completely before removing from the tin.
  • Dust with cocoa powder, cover the top with raspberries and serve.


Enjoy! And Merry Xmas from the Food Detectives!