The amylopectin details may be right, but the rest is wrong. Conbini's sell brown rice onigiri (look for 玄米), it's just usually a very limited selection. They don't fall apart, and you eat them the same as normal onigiri.
After posting this comment I then decided to look into it (in my usual way) and just looking for homemade brown rice onigiri what I found was that at least the couple of recipes I looked at used short grain brown rice (which I did not even realize existed) and/or recommended using more water than usual.
Whole Foods carries a store brand short grain brown rice at a reasonable price that I really like. It’s one of my go-to rices and essentially the only thing I go to Whole Foods for, as I haven’t found a comparable product or price point elsewhere. I think it’s about $2.50/lb these days.
I just finished some tonight, and I’m certain it’s sticky enough to hold its shape.
Yup, if you want to do it at home, make it a little bit mushier. I don't like it, but it is very doable. Commercially they may use a binder, I don't know, I just wanted to make sure people knew they're available!
I did it tonight and when i picked up the rice i used wet fingers to give it just a touch more binding ability. Worked well. Kids loved it. Am excited to eat the brown rice onigiri tomorrow.
