Cut the pineapple and persimmon into small pieces and bring to the boil in a large saucepan with the apple juice (make up to 1 kg total) and the preserving sugar. Add lemon as desired (use all the lemon juice for a nicely sour note).
If you don`t like pieces in the jam, you should puree the mixture before boiling. After 3 minutes of cooking, carry out the gelling test and pour the jam into clean glasses.