Guar Gum (Or, Your Tax Dollars at Work).
11th May 2006
Have you ever wondered whether you would swim faster in syrup or water? I hadn’t, either, until I found out someone had actually brought a swimming pool up to to Mrs. Butterworth’s-level viscosity and had people swim in it. Then I became intensely curious.
Proell admits he was slightly taken aback when he first heard Cussler’s proposal to dump 700 pounds of guar gum, a thickening agent, into one of the University’s pools. Fortunately, though, he recognized the proposal’s educational merits.
“Cussler is persuasive, but we didn’t need much persuading. We all agreed that we had an opportunity here to be part of the University’s educational mission. [The experiment] involved movement through water. [I]n aquatics, that’s our business. It intrigued us.”
It turns out, the enhanced resistance from the goo and the swimmer’s enhanced ability to push against the goo cancel out, and you swim the same speed in goo. This was the work of Ed Cussler, University of Minnesota ChemE professor, who must be proud as a parent. Click here for the full article. Click here for more information and a picture of guar gum. (I’m catching up on literature tonight, no time to draw it out, sorry!)
What makes guar gum so special? Polysaccharides (polymers of sugars) can have some unique properties. They are long enough that they can influence the rheological (response to deformation) properties of fluids, and their polarity affords them substantial interactions with water. If you’ve ever used cornstarch, taro, or roux (to name a few examples) to thicken, say, a sauce, gravy, or lemon curd, you’ve been taking advantage of the unique rheological properties of solutions of polysaccharides.
Sugars are incredibly useful things like this. Their affinity for water largely determines their behaviour. Back in the day, guar gum was an ingredient in oral diet products. The idea was that its appetite for water would cause it to swell, and this would distend your stomach, making you feel full. This works fine, but it also can happen in your esophagus. Ever had a pill stuck in your throat? Imagine a pill that gets stuck in your throat and grows.
You can find out more uses for guar gum from Whole Foods.
Night!