Personally, i would just use maltodextrin for a 90 min ride, and save the combined fuels for 5 hour runs or runs with a lot of hard climbing. its just cheeper that way. The recommendation i have seen on some brands is 90min plus; - but hey that just me.
i have found one paper that suggests fructose digestion of 3 - 6 hours in a normal person, and 2 - 3 hour when exercising. However he know that metabolism increases with intensity.
What i am struggling with it the lead times or “time till the energy is available”. I know it has to be processed again by the liver once it has passed the gut.
This is the paper i am working through at the moment to try and undertand it tall ;