I supplement protein, filtered for vegan because my body doesn't like whey, and Pea protein is pretty solid. It's a "complete" protein and doesn't require any complicated processing steps, just drying, pulverizing, and a centrifuge step to spin out the fiber.
Yep, here's an article [1] describing the process. Here's some youtube video I found showing the various steps [2].
They don't have to use any chemical solutions more exotic than water and air. I bungled the explanation with "centrifuge", it's more complicated than that, but the fiber content is removed in that step.
Hence the "spinning out the fiber" bit. Likewise, whey protein is a byproduct of cheesemaking where fat gets separated from milk, otherwise it'd be a very high-fat powder.
