I'm pretty sure that he used illusions in that case. In his fight with Laxus, he uses illusions to make it appear as if the building dissapear, Laxus is caught and the heaven was opened in half to release a giant monster (chapter 120 pages 3-6). Althought Laxus realised it's an illusion, it's probably mostly because it was too absurd to be true.
But a fellow man, famous for being mysterous, to eat apples through his scarf might not be something as easily taken as an illusion than, say the armageddon of mankind.
So I'd say without actually watched the anime, Mystogun was hungry, physically removed the scarf, but created an illusion of still wearing his scarf meanwhile, thus being able to cover his face and enjoy delicious apples.