Science Buddies: "Ask an Expert"

Hi! My project that I did was testing how well different sugar substitutes fermented with yeast compared to sugar. Below are the results of my experiment.
Sugar: 100+ (mL)
Splenda/Sucralose: 37 (mL)
Equal/Aspartame: 20 (mL)
Truvia/Erythritol: 2 (mL)
Sweet'N Low/Saccharin: 50 (mL)
No Addition: 2 (mL)

I then researched the molecular buildups of each of the elements. I then concluded that the more rich something is in hydrogen, oxygen, and carbon, the better it will ferment. I'm not sure if that is true, since I don't really know much about chemistry. I would like it if someone who understands these kinds of things can tell me if my conclusion is correct. If not, then I would like to know what am I doing wrong. Thank you!

Hi Sadia22551,

I'm assuming that you're working on the project described here:

https://www.sciencebuddies.org/science- ... es#summary

The carbon dioxide volumes that you posted seem reasonable. And I think your conclusion is on the right track. If you don't add a source of oxygen/carbon there's nothing to feed the yeast and very little carbon dioxide is produced. That explains the low carbon dioxide for your “no addition” test.

Carbon dioxide differences between sugar and the substitutes might be due to the ability of the yeast to metabolize the various sweeteners. That is, the yeast may metabolize sugar better than any of the substitute sweeteners. And the yeast may metabolize each of the substitute sweeteners differently.

You might want to try a little more background research to see if this might be a reasonable conclusion from your results. There are some questions at the end of the project background section that may be useful.

I hope this helps. Please ask again if you have more questions.

A. Norman