GotGarlic
Chef Extraordinaire
As I understand it, it is the protein in the Maillard method that makes them brown, the same way that meat does. You're making me stretch my brain, GG!
I'm stretching my own brain trying to understand the difference between caramelization and the Maillard reaction - and there *is* a difference. If I'm getting this right, caramelization involves sugars and the Maillard reaction involves sugars and proteins. So you're right about the onions.
http://modernistcuisine.com/2013/03/the-maillard-reaction/