Waldorf Chicken Wraps

Ingredients

• 1 cup nonfat plain yogurt or 3/4 cups nonfat Greek-style yogurt
• 2 tablespoons mayonnaise
• 1 tablespoon lemon juice
• 2 teaspoons Dijon Mustard
• 1/4 teaspoon salt
• 1 teaspoon minced thyme
• 1 pound cooked, skinless chicken breast cut into 1/2-inch cubes
• 1/2 cup seedless grapes, sliced in 1/2
• 1/4 cup toasted, coarsely chopped walnuts
• 1 medium apple, cored and diced (about 3/4 cup)
• Freshly ground black pepper
• 5 large leaves Romaine lettuce, rinsed and patted dry
• 5 whole-wheat wraps, about 8 inches in diameter