It might be of interest to put together a list of foods that create patina more than others. If you will tell me what foods have what degree of reactivity in developing patina, I will compile a list and update it as data is provided.
Perhaps a scale of zero (none) to five (most) would help express the degree to which various foods develop patina. For instance:
FOOD DEGREE comments
blood 5 blue patina
mustard 4 brown patina
citrus fruit 4 brown patina
collard greens 0
If there is interest in this, please provide your input.