Vary the fruit juice and fruit puree combinations to develop your own creative desserts according to the seasons. It takes almost two cups of fruit to make one cup of puree. bananas can be mashed with a fork; other fruits do better in a blender or a soften gelatin in cold water for 2-3 minutes. Combine gelatin, lemon juice, fruit puree, grated rind or seasoning, fruit juice concentrate and yogurt and mix thoroughly. Freeze until crystals begin to form around the edges. Beat egg whites until stiff. Break up the yogurt mix with a spoon and beat with an electric mixer until smooth. Fold in beaten egg whites. Freeze until firm. About 30 minutes before serving, remove from freezer to refrigerator to allow dessert to soften. Scoop into stemmed dessert dishes for a festive presentation. Note: if