Drain the peaches, cut them into pieces and puree them. Mix peach puree, lemon juice, rum and sugar well. Add Prosecco. Beat egg whites until stiff and fold in.
Freeze the sorbet mixture in a metal bowl for about 5 hours. Stir vigorously with a whisk every 20 minutes. Divide the sorbet between 4 glasses. Serve garnished with carambola, kiwano and mint