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Author Topic: yeast fermentation  (Read 6587 times)

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jwrn7d

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yeast fermentation
« on: April 30, 2008, 11:10:53 AM »

I recently conducted an experiment using yeast fermentation on glucose, sucralose, aspartame, and saccharin. My initial hypothesis was that of the 3 artificial sweeteners sucralose would produce the closest to glucose in terms of CO2 because of their similar structures. But, sucralose actually came in last with saccharin producing the closest to glucose. I can't seem to figure out why this is!
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Arkcon

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Re: yeast fermentation
« Reply #1 on: April 30, 2008, 11:51:28 AM »

You can start with some quick googling on those compounds and their structure, wikipedia will give you the answer quickest, but you might want to search wider if you have a large report to write.  Can you talk about the actual values, and what they mean?  Hint:  Did you use a control, like plain water?  Did you do one sample of each, or do you have multiple repetitions to cancel out random variability?
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jwrn7d

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Re: yeast fermentation
« Reply #2 on: April 30, 2008, 11:54:32 AM »

Yes I used water as a control and it was of course the lowest and also there were 3 of each sweetener and I used the average CO2 production of the 3.
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Arkcon

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Re: yeast fermentation
« Reply #3 on: April 30, 2008, 12:12:35 PM »

Great.  Let's see 'em.  Is it like, as a guess, 10 for sucrose, and 7, or 5, or 3 for the others?  What are the reps like, if for example, you get a 5, is that a 4, a 5 and a 6, or a 7, a 5, and a 3.  What else do you know about what you used as substrates, from the labels of the packets (or from wikipedia.)
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jwrn7d

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Re: yeast fermentation
« Reply #4 on: April 30, 2008, 12:19:59 PM »

yea I don't have the numbers with me right now but they were all pretty close together. As for the packets...I know that they all contain Dextrose(glucose) and maltodextrin for bulking and to reduce some of the sweetness involved. But I'm guessing also that they all have the same amount of the two b/c it doesn't state it.
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Arkcon

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Re: yeast fermentation
« Reply #5 on: April 30, 2008, 12:47:49 PM »

OK, correlate your values for CO2 production to each sweetener, draw up some new theories, and try to support them with some research into the  biochemistry.  And state the reason your hypothesis was not supported by the results.  Or how your experiment failed to give you a clear answer to disprove your hypothesis, that's an option, as well.

Listen, I hope you're OK working through this with us.  That's how we do it on this board, we give hints, and ask questions, that lead to more questions from you, that lead to the answer.  It's less like cheating, and you end up with a better understanding of the general concepts, which you'll need at exam time. 

Lately, people have forgotten that you're not supposed to dump complete answers on these forums.
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jwrn7d

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Re: yeast fermentation
« Reply #6 on: April 30, 2008, 12:52:30 PM »

Oh no I understand and appreciate your help very much. What I'm thinking is that the number of C = O double bonds have something to do with it b/c glucose and saccharin both have just one while aspartame has 3 and sucralose has zero?
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Arkcon

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Re: yeast fermentation
« Reply #7 on: April 30, 2008, 12:59:30 PM »

Oh no I understand and appreciate your help very much. What I'm thinking is that the number of C = O double bonds have something to do with it b/c glucose and saccharin both have just one while aspartame has 3 and sucralose has zero?

Hmm... OK, the structural chemistry you're displaying here is too specific for this application, if you continue along this way, you'll end up over complicating it to your own detriment.  Nothing in your actual experimental procedure gave you a picture of the structure, so save that for later.

What is the real question this lab asked of you?  What did you observe?  Try and start there.
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jwrn7d

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Re: yeast fermentation
« Reply #8 on: April 30, 2008, 01:22:27 PM »

It was our job to create the experiment so we had nothing to go on. What I observed was that water produced the least amount of CO2 and respectively sucralose, aspartame, saccharin and glucose. The question to answer is why did saccharin produce the closest to glucose and the other sweeteners didn't. Considering they each contain dextrose and maltodextrin, the only thing to go on here is their chemical makeup.
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Arkcon

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Re: yeast fermentation
« Reply #9 on: April 30, 2008, 02:38:54 PM »

Considering they each contain dextrose and maltodextrin, the only thing to go on here is their chemical makeup.

I would review the manufacturer's website to see if there's something along this angle that you can work with.
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jwrn7d

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Re: yeast fermentation
« Reply #10 on: April 30, 2008, 03:31:34 PM »

The websites list ingredients but not the percentages...so I'm just going to go on the assumption that some contain more dextrose than others and therefore produce more CO2 during fermentation...
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Arkcon

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Re: yeast fermentation
« Reply #11 on: May 01, 2008, 01:53:56 AM »

OK, good, now what does your experiment tell you about the samples you've chosen?  What did you want your experiment to tell you, what did it tell you, and why?  That'll make a good lab writeup.
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