Marshmallow Chemistry

Physical Science Class Considers Organic Compounds

Take powdered gelatin, sugar, and egg whites, apply chemistry skills, and VOILA! Marshmallows. A little salt and vanilla help with flavor.

Basic organic compounds:
  • Marshmallows are mostly sugar, sucrose, C12H22O11
  • Egg whites are mostly albumen, a protein consisting of 584 amino acids.
  • Gelatin is basically made of collagen, giving us the molecular formula of collagen, C2H5NOC5H9NOC5H10NO2
Egg whites, beaten to a stiff peak.

 Chemistry Science Skills

I've been working on a master list of science skills that must be developed to provide competency in chemistry (to be posted at a later date). Each lesson Science skills practiced in this activity are all skills related to comparing and measuring: using simple measurement tools to provide consistency in an investigation; sensory observations; quantity; quality; and capacity/volume.


 Gelatin

Here is how one food scientist describes gelatin: Gelatin is a mixture of polypeptides. Its amphiphilic nature gives it foam-stabilizing properties. A typical gelatin polypeptide contains the amino acids alanine, glycine, proline, arginine, glutamic acid, and hydroxyproline. It is prepared from collagen, which is isolated from animal bones and fish skins with a dilute acid.  Now doesn't that sound just yummy?


Beating cooked sugars and gelatin.
How Marshmallows Are Made

 Our recipe came from the Smitten Kitchen. In essence, 1) gelatin was dissolved in cold water; 2) sugars were boiled to the soft ball stage; 3) syrup was beaten into the gelatin until tripled in size; 4) beaten egg whites and vanilla were added to the mix; and 5) the creme was spread into prepared pans to set.
What's in the chemistry?  Gelatin is "dissolved" in cold water, loosening and spreading out its long protein fibers. The heat of the sugar dissolves gelatins original bonds, and air is beaten in. The protein bonds will reform as the gelatin mixture cools, combining them with the other ingredients (remember, egg whites are also proteins), and creating the classic, bouncy, marshmallow texture.

Pans of marshmallow, awaiting cutting.


Marshmallows cut into squares using pizza cutter.



Tomorrow we will make sterno and roast our marshmallows.

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Barbie Chiu said...
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