Oh, I didn't notice you were using a whole egg. Blender mayonnaise usually uses whole eggs; I don't know why. But if you whisk it, you don't need the whites. They may even make it thinner, but I'm really not sure what their effect is. I don't use them because I don't like egg whites, especially raw.

Happy whisking! I've gotten big strong arms from making mayonnaise several times a week.