Heat the oil in your deep-fat fryer to 350 degrees F. Whisk the beer, vegetable oil, egg yolk, salt, cayenne pepper and white pepper together in a bowl. Whisk in the flour until a slightly lumpy batter forms. Beat the egg white until stiff peaks form. Fold into the batter. Dip the fillets in the batter coating them evenly. Deep-fry for 4-5 minutes, or until golden brown and cooked through.