To prepare a tropical pineapple banana bread recipe, first preheat the oven to 350 degrees F (180 degrees C). Grease and flour two 9-inch loaf pans and set aside. Sift the flour, baking powder, sugar, cinnamon and salt into the bowl of an electric mixer fitted with the paddle attachment. Add the wet ingredients to the dry ingredients and beat until the mixture is light and fluffy, about 5 minutes. Scrape down the sides of the mixing bowl with your fingers to make sure all the ingredients are evenly distributed. Pour in the pineapple juice and vanilla extract and mix until combined. Spread the batter evenly on the prepared pan and bake for 35 to 40 minutes, or until toothpick inserted in center comes out clean. Allow to cool before removing from the pan.