1. In a small saucepan sprinkle gelatin over 1 cup water. Let stand 5 minutes to soften gelatin. Add 1/3 cup sugar and Sweet'N Low.
2. Cook over low heat, stirring until gelatin and sugar dissolve completely. Pour into large bowl and add remaining water and lemon juice. Chill until syrupy, about 2 1/2 hours.
3. Beat egg whites with remaining tablespoon sugar until stiff but not dry. Fold into syrup mixture with lemon peel. Pour into aluminum loaf pan or rectangular baking pan. Cover with foil and freeze 2 hours or until frozen 1 inch around edges.
4. Spoon into large bowl and beat until smooth. Return to aluminum pan, cover and freeze 3 hours. Transfer to bowl and beat again.
5. Return to pan, cover and freeze until firm, several hours or overnight.
To serve, let sorbet stand at room temperature about 15 minutes for easier scooping.