Are you just looking for color or taste also. Red Raspberries Or ripe Stanley Plumbs will give a great read blush to your pineapple. I would not recommend this to others but I have used beet juice from fresh beets boiled down. Just because I wanted a red color in a wine and did not want to use artificial coloring. It was a small batch and I could not distinguish the flavor of beets. Again I would caution against this unless you want to do a small amount for an experiment.