I used red cabbage in my noodles this afternoon. Presto change-o! Blue noodles happened.
It wasn’t necessarily a bad thing, other than that my synesthetic tongue keeps insisting that that is NOT blue! The noodles ARE blue! I saw it with my own eyes.
It also seems to me that, to make the noodles soft, something salty has to be put in, in addition to letting them repose for a bit in the dehydrator. I do recall putting black olives in that one batch that turned out exactly the way I wanted it. I’m trying that again.
PRETTY SMART RAW FOOD IDEAS 
I really want to see a photo of the blue noodles! How fun.