Frozen Orange Juice Concentrate a gel?

[mark126]

Hello. I was interested to see what everyone thought on this subject:

Is frozen orange juice concentrate (Old South etc) considered a "gel"?

My chemistry teacher suggested this, and I'm interested to see what other people on physics forums thought.

Thanks.

 

[Gokul43201]

And I thought this had something to do with the weather in So Cal. Do frozen oranges make frozen orange juice concentrate?

 

[Moonbear]

Well, what does "slush" count as? That's what "frozen" orange juice concentrate is like...not quite a solid, not quite a liquid. Is that the definition of a gel? It's cheap, buy yourself a can of the stuff and you'll see for yourself what the texture is.

 

[mark126]

I've dealt with orange juice concentrate before, but I'm looking for a definition that would put it into either a "gel" or "not gel" category.

 

[Astronuc]

One has to determine if OJ is a colloidal suspension, which fits the definition of gel - Colloidal suspension of a solid dispersed in a liquid; a semirigid solid - or is it an emulsion.

http://pubs.acs.org/cgi-bin/abstract.cgi/iechad/1934/26/i08/f-pdf/f_ie50296a015.pdf?sessid=6006l3 refers to 'emulsion', but the context is somewhat ambiguous, although they may be referring to orange juice.

OJ is likely considered an emulsion. Presumably one's textbook contains some definition or explanation of 'gel' and 'emulsion'.

Colloid is used in conjuction with both terms.

I am somewhat reluctant to do this but -

http://en.wikipedia.org/wiki/Emulsion -> "An emulsion is a mixture of two immiscible (unblendable) substances. One substance (the dispersed phase) is dispersed in the other (the continuous phase)," which seems a reasonable characterization of pulp (discontinous phase) dispersed in serum (juice, liquid).

http://en.wikipedia.org/wiki/Gel

But please verify with other reliable sources.

 

[JasonRox]

I buy Old South Orange Juice, and if I had to pick whether or not it is gel, I would say it isn't.

It's unlike other frozen juices though. You might think of it like "slush" like Moonbear said, but it really isn't like that. When Old South is frozen, it is frozen. When you thaw it, parts go to liquid, the other parts remain frozen solid. It is a pain in the arse to mix in water compared to other frozen juices. I normally rinse it under hot water for a bit in the beginning, otherwise you'll have a not so fun time trying to get it out of the can. After that, you submerge it in water, and let it completely thaw in the water. Come back later, and stir it up.

Other juices, you can just take out the can from the freezer and mix it up. But with Old South, that's like impossible.