Place the chicken broth in a medium saucepan over high heat and bring to a boil. Stir in the rice, cover the pan, lower the heat, and simmer for 20-25 minutes, until all the water is absorbed.
Transfer the rice to a large bowl and stir in the Parmesan cheese, parsley, garlic powder, and pepper. Allow the rice to cool slightly and then stir in the egg yolks.
In a separate shallow bowl, beat the egg whites until frothy. Place the breadcrumbs in a third bowl.
Take 1 tablespoon of the rice mixture in the palm of your hand, place a cube of cheese in the middle, and form a ball around the cheese. Continue until all the rice balls are made, occasionally rinsing your hands to keep the rice from sticking to your hands. Roll the rice balls in the egg whites and then in the bread crumbs, placing them on a platter as you bread them.
In a large saucepan, heat 3 inches of vegetable oil until a deep-fat thermometer reads 360 degrees. Carefully lower 6-8 rice balls at a time into the hot oil and cook until dark golden brown, 1-2 minutes. Remove with tongs or a slotted spoon and drain on paper towels. The rice balls can be kept warm in a low oven until ready to serve.