1. Heat the fruit juice and sugar gently in a small saucepan over low heat until the sugar has dissolved.
2. Stir in the glucose and gelatine until the gelatine has dissolved.
3. Dampen a 6 inch (15 cm) square tin, pour in the mixture and leave to set.
4. Dip the tin in hot water for a few seconds, then turn out the jelly onto a flat surface.
5. Cut into small squares and roll in caster sugar.