# Confusing Jello Directions... **URL:** \ **Category:** Factual Questions\ **Created:** [December 23, 2002, 9:44pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603 "2002-12-23T21:44:09Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Surreal](https://avatars.discourse-cdn.com/v4/letter/s/eada6e/32.png) [@Surreal](https://boards.straightdope.com/u/Surreal)\ **Post date:** [December 23, 2002, 9:44pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/1 "2002-12-23T21:44:09Z")
I’m puzzled by something I read in the directions on a box of Jello. It reads- “DO NOT add fresh or frozen pineapple, kiwi, gingerroot, papaya, figs or guava. Gelatin will not set” What is it that’s in these fruits that prevents the Jello from setting? I was thinking it was something to do with the PH, but other low-PH citrus fruits are not prohibited. What do all of these fruits have in common? Thanks. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [December 23, 2002, 9:46pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/2 "2002-12-23T21:46:05Z")
Enzymes. These fruits (or several of them, that I know for certain) contain enzymes that will break down the gel-forming bonds between the protein molecules. ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [December 23, 2002, 9:56pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/3 "2002-12-23T21:56:58Z")
😕 Fruit salad contains pineapple and yet Jell-O which contains fruit salad _will_ set. Something doesn’t add up. Maybe it’s the amount of pineapple? Or does not setting not apply to pineapple from a can? ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [December 23, 2002, 10:01pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/4 "2002-12-23T22:01:38Z")
Notice the Fresh pineapple. Canned pineapple (and probably the other fruits) will work since something in the canning process kills the enzymes or renders them inactive. ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [December 23, 2002, 10:01pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/5 "2002-12-23T22:01:59Z")
They specify _fresh or frozen_ pineapple. I have not studied canned pineapple, nor fruit cocktail, but I suspect that the canning process (which involves a lot of heat) breaks down the enzymes. ---
**Author:** ![chukhung](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@chukhung](https://boards.straightdope.com/u/chukhung)\ **Post date:** [December 23, 2002, 10:09pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/6 "2002-12-23T22:09:42Z")
> [@](#): > > \*Originally posted by Jeff Olsen \* > \*\*Or does not setting not apply to pineapple from a can? \*\* From the bottom of this page, [http://koning.ecsu.ctstateu.edu/Plant\_Physiology/ch2.html](http://koning.ecsu.ctstateu.edu/Plant_Physiology/ch2.html) > [@](#): > > the gelled Jello containing real pineapple was made with canned pineapple. The natural protease (enzyme) in the real pineapple was irreversibly denatured by the heat treatment involved in the canning process. Thus while there is much Jello with canned pineapple around, you have never had Jello with fresh pineapple in it. Cecil discusses the topic here: [Why you can’t put pineapple in Jell-O](http://www.straightdope.com/classics/a1_344b.html) ---
**Author:** ![ForumBot](https://avatars.discourse-cdn.com/v4/letter/f/ee59a6/32.png) [@ForumBot](https://boards.straightdope.com/u/ForumBot)\ **Post date:** [December 23, 2002, 10:12pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/7 "2002-12-23T22:12:11Z")
So how do those ladies at the caffeteria get the pinapples ine the Jell-O in the first place? ---
**Author:** ![UncleBill](https://avatars.discourse-cdn.com/v4/letter/u/d26b3c/32.png) [@UncleBill](https://boards.straightdope.com/u/UncleBill)\ **Post date:** [December 23, 2002, 10:25pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/8 "2002-12-23T22:25:19Z")
**ForumBot** , please scroll up to answer that question. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [December 23, 2002, 10:26pm UTC](https://boards.straightdope.com/t/confusing-jello-directions/144603/9 "2002-12-23T22:26:24Z")
The proteases from pineapple and papaya, bromelain and papain respectively, are inactivated by boiling water (212 °F). Most canning procedures get _at least_ that hot.