Thanks for your suggestions, Abysmal, but I'm not concerned here with the actual cooking method. i've been doing it for years, and I find that 120C/250F for half an hour to an hour in oil (no water) produces excellent results. I've got a thermometer just for it, just like this one:
The reason for boiling it in water with butter/oil for so long is that water boils at 100C/212F, which is lower than the official decarboxylation temperature of 105C/221F - but boiling for a long time will decarboxylate it eventually. If you want to know why, ask a chemist.
I'm looking more at the process by which cannabinoids are absorbed in the digestive system. I'm guessing that digestive acids and stuff would destroy a fair amount of the cannabinoids, so maybe there is a way to reduce this effect. I'm thinking something alkaline might help, but as I've said, I'm just guessing - I'm no expert on this subject. But maybe someone here
is, or at least knows a fair bit more than me.