Prompted by this question I would like to know what the nutritional properties of soy whey are.

By soy whey I mean the nearly clear liquid left behind after soya milk has been coagulated to make tofu.

Dairy milk whey is added to all kinds of supplements and "workout" or "healthy" snacks to boost their protein content, so I'm wondering if soy whey is also high in protein.

My assumption has been that it's basically water, and I usually use it as if it were; typically I'll just cook rice or pasta in it or use it to loosen a sauce etc, not wanting to throw it away!

So, what are the macro- and micro-nutrient contents of soy whey?