It's more of a dual action. Mucus and saliva protect you from the enzymes but if the skin or fiber rubs the saliva off your mouth. That part of your mouth is now exposed to the protein dissolving enzymes.
This was a very helpful post. Thank you! I found that the digestive enzyme in figs is actually ficain, but that is in the same family of proteases as bromlase (the family known as the cysteine endopeptidases, according to wikipedia:)
We can avoid the burning sensation by discarding the stem of the figs and the flesh nearest to it and by consuming only fully ripened figs. Yesterday, I got 1.5 lbs into a bowl of figs that I thought were all completely ripened, but I reached a point where my tongue burned so badly all of a sudden, I couldn't eat one more thing. I had no idea figs could do this, so thanks for the discussion, everyone! Now we know.
Cool, I Learned something new today :)
Quote: "Psoralens are "phytoalexins" used by plants as a defense against fungi and insects"
I've found that this only happens to me if they aren't fully ripe. Make sure they are nice and mushy when you pick them. I find that when the skin starts to get some little stretch marks is a good indication of ripeness.
Dr. Doug showed us how to eat them properly. Provided they are indeed ripe, touch the inside flesh to your lips and mouth first and then you can eat them and the skin won't bother you.
make sure the figs (or whatever) are really ripe ... and only eat as much as your body wants to have. listen to your reactions & stop eating as soon as it does not taste heavenly anymore or at the latest when you start to feel any slightest discomfort. some fruit, like figs & pineapple, give very strong signals!