Sciencemadness Discussion Board

Food storage

tom haggen - 4-12-2004 at 02:18

Just kind of had an off the wall question. I know that the little packets in shoes contain silica to remove moisture, but I noticed that the little packets in my beef jerky claim to remove oxygen. What type of chemical is used for this type of reactions in food grade material?

Esplosivo - 4-12-2004 at 07:27

Most probably pyrogallic acid or one of its salts. I don't know how the reaction proceeds but it is used in biochem experiments to deprive growing media from oxygen. I have no idea for its synthesis. It is also called pyrogallol. Pyrogallic acid turns greyish on exposure to light and oxygen, therefore you can check out if this is what is in the packets (assuming that there is no bulking agent for the mixture which would most probably 'hide' the colour). Hope this helps.

Edit found the following on this site.

Quote:

PYROGALLOL, or PYROGALLIC ACID, a trioxybenzene, C6HI(OH)3 (1: 2: 3), prepared by Scheele in 1786 by heating gallic acid, C6H2(OH)3COIH. It is also obtained by heating para-chiorphenoldisuiphonic acid with potassium hydroxide.
It forms white plates, melting at 132, readily soluble in water, and subliming without decomposition. It is an energetic reducing agent, a propert3s utilized in its application in gas analysis to absorb oxygen, and in photography (q.v.) as a developer. The aqueous solution is turned bluish black by ferrous sulphate containing a ferric salt. It does not combine with hydroxylamine, as does the isomeric phlorogiucin which yields a trioxime(see POLYMETnYLENES). Pyrogallol dimethyl ether is found in beechwood tar. Pyrogallol has antiseptic properties and is employed medicinally in the treatment of psoriasis. Eugallol, or monacetyl pyrogallol and lenigallet~ or triacetyl pyrogallol, are also used.


[Edited on 4-12-2004 by Esplosivo]

Saerynide - 4-12-2004 at 10:05

The packets in beef jerky are powdered iron, charcoal, salt, and some other crap that looks like sand (but 9 dont think its sand). A minute or two after you open a beef jerky pack, feel the little packet. If its warm, its the iron kinda I'm talking about. Test if theyre magnetic :D

cyclonite4 - 8-12-2004 at 05:22

i was just thinking.... when storing food... you would want to keep moisture to a minimum, right?

Then maybe Calcium Chloride would be used in some of the moisture removal packets... probably with silica as well (some1 told me they used silica). A pack of lebanese bread i got from the store just says "Moisture absorber sachet - DO NOT EAT".

One question is, would calcium chloride be used in those sachets, or is it inappropriate/unsafe.

tom haggen - 8-12-2004 at 12:09

They use silica in those packets that remove moisture. But I specifically said, that the packets in question apparently remove oxygen. That is why I was so damm curious.

EDIT: I imagine that CaCl2 would be anymore dangerous than silica. The both would dehydrate your internal organs.:D

[Edited on 8-12-2004 by tom haggen]

neutrino - 8-12-2004 at 14:14

Silica might do damage to your digestive system, but calcium chloride is a simple salt. I doubt that they use it though, as it turns into a liquid after absorbing a good deal of water.

cyclonite4 - 9-12-2004 at 03:59

Quote:
Originally posted by tom haggen
EDIT: I imagine that CaCl2 would be anymore dangerous than silica. They both would dehydrate your internal organs.:D
[Edited on 8-12-2004 by tom haggen]


@tom haggen: Yes, dangerous if you choose to eat it. But as written on the packet, you are not supposed to eat the sachet or its contents. :P

CaCl2 is whats used in desicators, right?

@neutrino: good point, you wouldnt want a CaCl2 solution all over your food, so they probably wouldnt use it, unless of course they knew that only a limited amount of moisture inside the sealed packet, and it wouldnt be enough to dissolve the CaCl2.

neutrino - 9-12-2004 at 14:37

Calcium chloride is sometimes used in desiccators, depending on budget constraints and what’s being dried. It’s also used as a room dehumidifier in some cases.

As far as bread goes, it probably has a good deal of moisture in it. Why would they add a desiccant, anyway?

cyclonite4 - 11-12-2004 at 23:29

Quote:
Originally posted by neutrino
It’s also used as a room dehumidifier in some cases.


Yeah, thats how i get mine. It's a moisture prevention agent used to prevent mildew from forming in the bathroom. It costs me about $5/kg and it's called "Dampsorb Refill", I don't know how pure it would be, but it's probably pure enough for what i use it for, which is dessication.

unionised - 12-12-2004 at 06:35

I seem to remember reading about using glucose + glucose oxidase as an oxygen scrubber. I can't find the ref, and Google isn't helping a lt.

cyclonite4 - 13-12-2004 at 04:53

Even though you probably find dessicant in food i though i'd mention this anyway. I found a dessicant sachet in an old shoebox.

It says its contains silica.... by silica.... does it mean silicon dioxide? What gives silica it's dessicating properties?

axehandle - 13-12-2004 at 11:14

No, it contains <b>silica gel</b>. Here's a small article about this substance: http://en.wikipedia.org/wiki/Silica_gel

And here's an entire homepage devoted to silica gel: http://users.adelphia.net/~jthm/


[Edited on 2004-12-13 by axehandle]

cyclonite4 - 14-12-2004 at 05:38

Actually, I was just browsing through the oxford dictionary of chemistry this morning (the things boredom does to you :D )

I think i remember correctly that it said, sodium silicate is dissolved in water i think, then boiled down to leave a rigid gel.

Thanks, for those references axehandle, i'll take a look now :)