Sprinkle gelatin over lemon juice in small bowl; set aside. In small heavy saucepan, whisk together egg yolks, granulated sugar and orange juice. Cook and stir over medium heat until thickened. Remove from heat, stir in softened gelatin until dissolved. Stir in lemon rind.
Pour into bowl and place in a pan of ice water to cool and thicken slightly, 5 to 10 minutes. Stir in sour cream.
Beat egg whites until stiff peaks form; fold in citrus mixture. In parfait glasses or dessert dishes, layer fruit and mousse mixture. Refrigerate at least 2 hours.
Per serving: 4 g protein, 3 g fat (2 g saturated fat), 14 g carbohydrates, 68 mg cholesterol, 4 g fibre.