This is just my second thought.
In japan, we have a recipe called 'shibazuke'.
i just can't dare giving up the idea of this when i had re-read your
thread.
It's a sort of pickles (again a pickles!!!) of cucumbers (not a
eggplant!!!) using some salt, sweet vinegar, extracted juice from red
japanese basil (i think this is the central item for this sort of
pickles that make pickles purple.) and red ginger etc..
You claimed that they were raw cucumbers, but we have another type of
pickles that were made overnight. In such cases, they taste almost the
same with the raw materials, very crunchy.
i 'm not sure about my guess though.
-Ono