It's widely accepted that the body can process 60g of glucose per hour into glycogen. Up until a few years ago, it was also accepted that the body could concurrently process 30g of fructose. This is where the advised 2:1 ratio was born.
However, more recently, Wendy J O'Brien and her fellow performance nutrition researchers learned that the body could, in actual fact, process more than this 30g of fructose. Their studies pushed the limit to 48 grams with positive effects on performance.
You can find the study here.