Preheat the oven to 350 degrees . In a large bowl, combine the pineapple juice and soy sauce. Add the wings and let marinate for 15 minutes. On a foil-lined rimmed baking sheet, arrange the wings in a single layer. Pour 1/2 cup of the marinade over the wings, then sprinkle with half of the gelatin; bake for 30 minutes. Flip and sprinkle with the remaining gelatin and the poppy seeds, then bake until browned, about 30 minutes.