Wife's pineapple jell-o experiment didn't work

[Frylock]

Hi,

Two days ago, my wife made jello-o in little cups, and put a chunk of pineapple in each. Depending on how the chunk had been treated beforehand (boiled, canned, immersed in cold water, etc) the jello sometimes set, sometimes did not. That is as expected.

This morning she did it again, using pineapple chunks from the very same set as yesterday, and it didn't work. They all set.

(She's a science teacher, in case you're wondering what this is for.)

The only differences I can think of are

--The fact that the pineapple chunks are a day older
--The fact that the pineapple chunks are now refrigerated.
--She used the "quick set" jello making method this time.

Should any of these have made a difference?

She is hoping that the "quick set" is causing the problem and that over time the enzymes from the pineapple will work their way into the jello and break it up. Is this likely?

[samclem]

While this one would be fine in General Questions, it's probably better suited to Cafe Society. Moved.

samclem, Moderator

[Qadgop the Mercotan]

For those who want some background on this issue, we have this from the Master: why you can't put pineapple in jello (http://www.straightdope.com/columns/read/308/why-you-cant-put-pineapple-in-jell-o).

[Frylock]

While this one would be fine in General Questions, it's probably better suited to Cafe Society. Moved.

samclem, Moderator

Sorry! (Where did I put it? I thought I did put it in GQ.)

[silenus]

You did. sam just thought it more food-related and kicked it here.

[Swords to Plowshares]

You can't put fresh pineapple in jello (or chicken salad or mixed with any meat) because the enzymes break everything down to mush. Canned pineapple works fine, though.

[Hello Again]

The only differences I can think of are

--The fact that the pineapple chunks are a day older


My WAG is this one. I imagine oxidation has to have some sort of effect on enzymes. Were the chunks beginning to brown? This would be proof that oxidation occured.

[jasg]

You can't put fresh pineapple in jello (or chicken salad or mixed with any meat) because the enzymes break everything down to mush. Canned pineapple works fine, though.Sometimes this is good. For years I have used chunks of fresh pineapple to stuff my Thanksgiving turkey... Moist, tender meat and the drippings make great gravy!

[Anaglyph]

Papain and related proteases as the ones found in pineapple have a cystein residue in their active site and can therefore be inactivated by oxydation