I was able to turn mine Regal Purple. I fed my Chocobo 17x O'Ghomoro Berry, 15x Xelphatol Apple and 18x Valfruit all at the same time, which turned it Blood Red after 6 hours in the stables. After I fed it 3x Valfruit and 1x O'Ghomoro Berry waited 6 hours and Regal Purple was achieved.

You can see the video of it here: http://youtu.be/UI8YBoeLe3I

~ Mithrie