Rice: which variety is the easiest to digest?
You're asking several questions at once, it seems to me so I'm not quite sure if these are the answers you're really looking for, while I'm no nutritionist, I would imagine that liquidy or soupy preparations like risotto and congee would make the most starch available the fastest, since you purposely cook the starch out of the kernels into the surrounding liquid. How much of a difference it makes when you compare methods with the same rice type, though, I have no idea.
If you're looking for fastest absorption of starch, you're probably best off looking at the glycemic indices of the different rice varieties. White jasmine rice has the highest GI of the more common rices; basmati, the lowest. But I don't know which has more total starch by weight. (There are lots of websites with GI info, it's not something I pay too much attention to myself.)
I don't think the method of preparation much matters as far as the starch is concerned, though germinated rice contains amino acids and vitamins not present in raw rice. (Google "rice" and "GABA".) If you're looking for maximum starch absorption, though, you probably want to avoid boiling rice in water (then draining and finishing in the oven.) I don't think it's any more or less digestible cooked that way, but you will lose a fair amount of starch in the cooking water.
I have no hard evidence or good data, but when my digestive disease is acting up, I just about live on congee made with plain white rice. It would seem that that's about as broken-down as a starch can get. As I start feeling better, I can add in some broth, a few drops of sesame oil, then maybe some other flavorings. Endlessly versatile and extremely comforting. Good luck!
There are two main differences in rice:
- how much bran is left on. Brown has it all. On white it's been removed, leaving the starch. Brown takes longer to cook, and I suspect, longer to digest.
- long v short grain. Not only is there a difference in shape, but also in starch content.
Long grain is higher in amylose. Shorter grain rice is higher in amylopectin, with glutinous, or sticky, rice being the highest. High amylose rice is touted as being better for diabetics, with a lower GI, because it is the harder of the two to digest. So I suppose that means, short sticky rice is the rice for you.
Short grain rice is generally preferred for congee, and rice pudding (though some cultures do use long grain for pudding).