Heat oven to 325 degrees F.
In food processor, crush graham crackers to fine crumbs. Transfer to bowl. Stir in butter, sugar, rind and salt until evenly moistened. Press over bottom and part way up side of 9-inch springform pan. Refrigerate.
In a small glass bowl, microwave jelly on medium-high for 20 seconds, or until smooth. Let cool. In large bowl, beat cream cheeses until smooth. Add sugar-cornstarch mixture, lemon rind and juice; beat until smooth. Add eggs; beat until creamy. Remove 1 cup batter to a small bowl. Beat cooled jelly into 1 cup batter. Tint light purple with red and blue food coloring. Dollop white batter into crust, alternating with purple batter. Swirl to combine.
Bake in 325 degree F oven about 55 to 60 minutes, or until center is set on top but still jiggles slightly when tapped. Transfer to wire rack; run a thin knife between cake and edge of pan. Cool 2 hours, then refrigerate 2 hours or more.
Rinse grapes; pat dry. Place egg whites in a bowl. Place sugar in a second bowl. Working with 4 grapes at a time, coat with egg whites, then with sugar. Place on a sheet of waxed paper to dry. Repeat.
Remove side of pan. Remove cake from bottom using thin spatula. Microwave jelly on high for 15 seconds. Pour onto cheesecake; spread with pastry brush. Top with grapes. Makes 12 servings.
