Hey Joe, here are scientist/cook Shirley Corriher's notes on keeping red cabbage red:

[marilynfl]

Basically, her advice is to add a little acid to bring back the red that has changed when cooking. A teaspoon of lemon juice or vinegar should do it. She also suggests actually cooking the cabbage with something acidic, like an apple. So...it's red when it's acidic, but starts to turn blue/purple as it goes toward alkaline.

Multi-syllabic words thrown about are anthocyanins, betalains, and carotenoids. Red cabbage falls mostly into the first category and is water-soluble. That's why it will change color as it is processed..

 

[richard-in-cincy]

That's the beauty of the southern German/Austrian Red Cabbage

it is cooked with vinegar, diced apples, red current jelly, red wine, etc. It stays nice and red after an hour simmering on the stove.