Place all fruit in a bowl and mix in frozen orange juice concentrate. In a blender, combine yogurt, ricotta, ginger, cinnamon and vanilla. Portion the friut into dessert bowls, top each with yogurt-ricotta sauce and garnish with a walnut half. Other fruits may be substituted, such as melon, kiwifruit, strawberries, blueberries, pears, or pineapple. The fruit medley may also be served without topping. Food Exchange per serving: 1 FRUIT EXCHANGE + 1/2 FAT EXCHANGE; CAL: 87; CHO: 2mg; CAR: 17g; PRO: 2g; SOD: 20mg; FAT: 2g;