Pour the orange juice into a medium bowl. Peel and core the apples, then grate them into the orange juice using the large-hole side of the grater. Add the pineapple, sugar, and coconut. Mix well, adding more orange juice if the mixture is not juicy enough. The apples will continue to absorb juice, and orange juice can be added as needed to keep it as juicy as you like. Store in the refrigerator until ready to serve.