Pineapple is indeed a very acidic fruit, according to About.com. It contains an enzyme called bromelain that helps break down protein structure. Thailand, Costa Rica and Brazil are three of the top pineapple producers in the world.
Pineapple is mostly harvested in season from May to July, but it can be harvested year round thanks to modern farming techniques. A pineapple is not just one fruit but actually many fruits produced from many flowers, all coming from a single spike. Due to pineapple's acidity, it can act as a substitute for tomatoes in salsa. Pineapple contains vitamin C and manganese, and a cup of fresh pineapple contains about 82 calories.