A few months ago there was a discussion about the usefulness of
bromelain in pineapples and presumably other bromeliad fruits. People
wondered why a plant would put a feeding deterrent like that in a fruit
when it presumably "wants" the fruit to be eaten so that the seeds will
be distributed. The best hypothesis was that the "desired" consumer was
not affected by the bromelain.

Well, yesterday I had the opportunity to eat a really ripe, some might
say overripe, pineapple, and I'm here to tell you that this extremely
sweet and juicy fruit had no apparent proteolytic effect on the mucous
membranes of my mouth. So I hypothesize that like many other fruits,
the feeding deterrent is no longer present at the time the seeds are
ready for dispersal, and the "purpose" of bromelain is to keep animals
from eating the fruit before maturity.

I hope I don't sound like A.Plutonium....