Coloring pigments called carotenoids color a pumpkin orange. With more than 70 carotenoids already identified, these pigments are responsible for many beautiful colors in the produce aisle – reds, yellows, and oranges. In pumpkins, the carotenoids are dispersed throughout the skin and flesh. This is different from a red apple which has color localized in the skin, or a mango with brightly colored flesh. Pumpkins start out green due to the chlorophyll levels in the plant. The chlorophylls reduce because of oxidation, an enzyme called chlorophyllases, and a decrease in pH. As pumpkins mature, chlorophylls are replaced with carotenoids, and that signature orange color develops, indicating ripeness.
In fruits with yellow/orange flesh, β-carotene and α-carotene are the dominant carotenoids. And, β-carotene can undergo a conversion to vitamin A (retinol). The benefits of vitamin A have been linked to improved vision and healthy immune function. (I’ll take any excuse to enjoy a lovely pumpkin treat.)
A Food Science tid-bite: Carotenoids aren’t the only thing making food colorful. Anthocyanins are water-soluble pigments that turn produce shades of (deeper) red, blue, and purple. Carotenoids, anthocyanins, and chlorophylls, are of course, all natural. For packaged food, there are MANY natural coloring agents out there, and with artificial options available as well, we’re able to enjoy food with a truly diverse color palate.