How does butter react to yeast extract?

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Neil S. Briscoe

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How does butter react to yeast extract?
« on: 23/02/2010 13:30:02 »
Neil S. Briscoe  asked the Naked Scientists:
I've just had a slice of buttered toast and added yeast extract to it.  When you spread the latter you find that the butter sort of emulsifies.  I know butter is a grease, but what in the yeast extract is reacting with the butter to make it act the way it does?


Neil Briscoe
Bristol, UK

p.s. I use Vegemite as it is less gloopy than Marmite

What do you think?
« Last Edit: 23/02/2010 13:30:02 by _system »


Offline NothaShrubry

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How does butter react to yeast extract?
« Reply #1 on: 23/02/2010 17:26:49 »
I can't answer fully because I have no idea what's in yeast extract really. However, I'm dubious as to whether it's a chemical reaction. If it emulsifies it's probably a liquid dynamic problem - i.e. a physical reaction, due to the repulsive electrostatics and van de Waals' attractions between the particles in the two different media.

This is similar to the observed reaction when oil is added to water or vice versa. They separate out - the hydrocarbon that is oil (or grease) and the polar molecule which is water. If you add lots of oil to water and shake it up you will observe tiny oil globules in the water, and these will eventually settle into two separate layers due to the repulsive forces dominating after agitation ceases.

Poorly explained, but you get what I mean.