Combine first 5 ingredients in a small bowl; stir well.
Heat oil in an ovenproof Dutch oven over medium-high heat. Add spice mixture, eggplant, and next 6 ingredients (eggplant through garlic); sauté 3 minutes. Add tomato juice, orange juice, and water; bring to a boil. Reduce heat, and simmer 2 minutes. Remove from heat; stir in couscous. Cover and bake at 350° for 20 minutes.