My golden Delicious is in its third year of bearing fruit. When I saw the immature red apples the first year, I thought I had mislabeled the tree. As they ripened, they lost their red blush and turned the familiar golden color.
I still get a smile out of that transition. Here they are today.
Apple color is affected by direct sun exposure. In Japan where perfect fruit commands a high premium tree foliage is pruned at the end of the season, reflectors are place in the ground to bounce sunlight from that direction, and apples are turned by hand to even the coloration.
Heck the super premium apples use a triple bag system, where a layer of the bags are removed at predetermined times. When they come out of the light proof bags they look ghostly, at which point the techniques described above are applied to impart them the perfect coloration and flavor.
This color change happens in a dwarf crabapple I’ve been evaluating. The fruit starts green, then begins turning red as it nears maturation. After turning partially red the red dissipates leaving the fruit a rich golden yellow when ripe.
It reminds me of how yellow food coloring actually looks red in the bottle, but once thinned out is clearly yellow. I wonder if what we’re seeing as red pigment in apples which ripen yellow is actually just a concentration of yellow pigment which later mellows as it disburses throughout the skin.