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Chameleon Eggs Cooking Chemistry Project

Edible Color Change Project

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Orbitz Soda contains edible gelatin beads that float suspended in the soda.

Orbitz Soda contains edible gelatin beads that float suspended in the soda because they are the same density as the liquid.

Goleh, public domain
Have you seen those drinks with the floating edible eggs or beads in them? One interesting brand was Orbitz Soda, which contained colored beads that were suspended in the carbonated soda. You can apply chemistry to make edible eggs or beads. In fact, you can even make them change color. In this project, I'll show you how to make gel eggs that change color in an acidic drink, such as soda or lemonade.

Ingredients

  • 1 tablespoon sodium alginate
  • 1 tablespoon sugar
  • 1-2 teaspoons baking soda
  • 1 can frozen concentrated grape juice
  • 1 teaspoon calcium chloride
  • 3 antacid tablets (magnesium hydroxide) -- doesn't matter whether or not they contain calcium
If you don't see it in your grocery store, you can find sodium alginate in a health food store or online. You want concentrated, deeply-colored grape juice, which is why the frozen concentrate is listed. You can substitute bottled concentrate if that's what you have. Use regular concord grape juice, if that's all you can find.

Materials

  • large glass
  • spoon
  • pipette or dropper
  • jar with lid
  • strainer or slotted spoon

Make the Eggs

  1. Mix together the sodium alginate and sugar.

  2. In a separate container, add baking soda to the grape juice, a pinch at a time. Stir and wait until no more bubbles form before adding a pinch more baking soda. Continue this until very few bubbles form. What you have done is used the alkaline baking soda to neutralize the acidic grape juice. You want to neutralize the grape juice because you need a higher pH in order to dissolve the sodium alginate.

  3. Pour the sodium alginate and sugar mixture into the jar. Stir in the neutralized grape juice.

  4. Tighten the lid on the jar and shake it to thoroughly mix the contents. Allow the jar to sit for an hour (minumum) or overnight (better) so that the sodium alginate will have time to become fully hydrated.

  5. Crush the antacid tablets and mix them together with the calcium chloride.

  6. Stir the calcium chloride and antacid into a large (12-16 oz) glass of water.

  7. Now comes the part where you make the gel beads! Use the dropper or pipette to suck up some of the grape juice solution. While stirring, slowly drip the juice solution into the glass of water, calcium chloride and antacid. Drip the grape juice solution into the glass from above -- if the dropper comes into contact with the antacid solution then the grape juice solution will solidify in your tube.

  8. Leave the eggs or beads in this solution until they turn blue.

Color Change Gel Eggs

Use a slotted spoon or strainer to remove a spoonful of the gel eggs. Add them to an acidic drink, like lemonade or lemon-lime soda or white wine and watch the acidity of the drink change the color of the eggs from blue to red! A carbonated beverage is extra fun because the gel eggs will float up and down with the bubbles. You could use other common edible pH indicators if you want to get other colors, but the grape juice is nice because it adds a pleasant flavor to the "eggs". Although it wouldn't taste fruity, you could use red cabbage juice instead of grape juice if you want the eggs to display a full rainbow of colors.

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