The commercial mayo maybe white, no doubt. But the real, homemade mayo isn’t quite white, but still rather pale, way lighter in color than the yolk. So why is that?
Well, in the process of making mayo, i.e. heavily whipping egg yolks with olive oil, lot’s of air bubbles are being incorporated & trapped inside the sauce.
Addition of air bubbles to egg yolks & olive oil increases their total volume, therefore, diluting the initial color.
And, when the light touches the surface of the sauce, the air bubbles trapped inside scatter this light in different directions, making the mayo look more white.
Et voila, now you know why every time you’re whipping or heavily mixing something in cooking, the end product turns out much lighter in color.