Why Is the Skin of an Orange Pitted?
The skin (outer covering) of an orange is dotted with oil glands. Thousands of tiny oil bags lie just below the surface of the skin. When you peel an orange, the oil bags burst, spraying mists of fragrant moisture and oil. The function of the oil is not completely understood.
In addition to giving the orange its distinctive odor, the oil may provide protection against insects and plant parasites. Under the orange skin is a layer of white, spongy material. While the orange is growing on the tree, this extra layer helps to protect it from the cold.
In general, the skin in some tough-layered fruits such as pomegranate, passion fruit, mangosteen…etc., is known as the rind, while in citrus fruits such as in oranges, it is better termed as peel (zest).
Besides its outer cover protect underlying edible portion of fruit from harsh environmental factors as well as micro, and macro organisms, it, indeed, holds some of vital health benefiting constituents such as dietary fiber, and phyto-nutrients that help accomplish overall wellness.
Fruit peel characteristics: Fruit peel is either firmly adherent to its underlying flesh as in berries, and apples or rather loosely, as in oranges, banana…etc. Its thickness varies widely, even in the same family fruits, ranging from paper thin to very thick shell-like as in mangosteen.
In some raw fruits, the peel has neutral flavor, as in grapes and apples. It can be bitter and inedible because of high tannin (astringent) content in unripe sapodilla and proteolytic enzymes in papaya. As the fruit ripens, the peel becomes easily separable from the pulp (bananas). In addition, its components turn sweeter and become pleasant-tasting as in sapodilla, guava, kiwifruit, and kumquat.
Fruit ripening is purely an enzymatic process, which brings certain characteristic changes to the fruit color, aroma, taste, maturity (hardening) of seeds…etc.
The peel in some fruits like guava is firmly cohesive to its pulp and, indeed, in some fruits it turns tastier than the flesh as the fruit ripens.
Fruit peel is very rich in essential oils which give a characteristic aroma to the fruit. These oil glands are spread all over the peel but denser near its pits. These oil glands are quite uniquely prominent in citrus fruits like lemons, and oranges.