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I need to make a model of the digestive system. It would be really nice to actually show it in action, such as by breaking down bread into glucose or something similar. Is this feasible with a small budget and non-dangerous chemicals? If so, how? This should be as similar too the real digestive system as possible.

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Isn't this an exact duplicate of the question you asked a couple days ago?… – mikemanne May 29 '12 at 11:02
@mikemanne: I'm asking about how to break down starch into glucose. Before, I was asking about how to do something with the glucose obtained from this. The answer to one is apparently Amylase, while the answer to the other is some kind of combustion or something like that – Glycan May 29 '12 at 14:26
up vote 4 down vote accepted

Amylase would be worth a try. The enzyme breaks down bread (starch), and you can buy it relatively cheaply online or probably at a chemist. Amylase is secreted in your saliva and in your stomach, so it would be most realistic if it was added in your model at those two points.

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Would have thought you'd need some mechanical action to break down the bread too – Rory M May 28 '12 at 9:21
If you just keep some bread crust in your mouth without chewing, it does become sweet at some point. You will just be waiting for quite some time... I spent a whole school day with bread crust in my mouth XD Adding the mechanical action might be hard in a model. – Armatus May 28 '12 at 9:30
@Armatus: Great. About how much time would it take, and what could I do with an glucose solution? – Glycan May 28 '12 at 13:36
That depends on the concentration you use. I would aim for a ridiculously high concentration to try and get it done quickly. As for the resulting glucose-containing solution... I don't know, you could pump it out of the model stomach around the rest of the model? – Armatus May 28 '12 at 15:57
I think the easier strategy would be to use saliva and coca-cola. It's a very visible process. – bobthejoe May 28 '12 at 21:56

Generally speaking and as suggested by Rory, mechanical force probably plays a role in most instances (crustless bread may be different):

I was hoping to post more about this but the websites of one of the institutes involved in developing the model gut doesn't provide much accessible information on first read.

Maybe this still gives you something of a starting point:

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