To follow that train of thought, ripe bananas have a huge "lectin"load and these lectins are what cause the damage to the gut as they affix themselves to the gut wall and eat holes through it. I would like to suggest that it is the lectin content of ripe bananas that cause mucus for you...which is really an inflammatory sensitivity reaction. I have recently being following the work of Dr. Stephen Gundry who has written a great book on the subject of lectins and how they work. It's called The Plant Paradox.