Prick the aubergines all over with a fork. Place them in a large bowl of salted water and leave to soak overnight.
Rinse the aubergines in plenty of running water, then drop into boiling water and cook for 10 minutes. Drain and set aside.
Put the sugar into a large saucepan with the water and allow to dissolve slowly. Pour in the lemon juice, then add the spices, gum arabic and the drained aubergines. Once the aubergines have absorbed the sugar, turn off the heat and drain.