Citrus sinensis (L.) Osbeck (= Citrus aurantium L. var. Sinensis, Citrus sinensis (L.) Pers., Citrus aurantium ssp. Sinensis Engl.). Commonly known as orange tree. It is a tree belonging to the Rutaceae family, of medium size (7-8 m high), perennial, compact and conical top that becomes spherical thanks to pruning. Its trunk is smooth and brown. The branches have some thorns. The leaves are coriaceous, of an intense and bright green, with an oval or elliptical-lanceolate shape. These leaves have a narrow and inconspicuous petiole.
The flowers, called orange blossom, appear solitary or in small clusters during the spring. They are hermaphroditic in nature. They measure about 5 cm in diameter. The calyx is formed by 4 or 5 sepals. They have 4-5 white petals, fleshy and with glands that give them an intense perfume. The androecium possesses 20-25 stamens. The ovary is superior and pluricarpellar. C.sinensis produces a fleshy fruit of the hesperidium type known as orange. It is globular and 6-9 cm in diameter. Morphologically, we can differentiate three parts: the exocarp or epicarp, the mesocarp and the endocarp. In the exocarp there are cells that contain carotenes, which are the ones that give the characteristic orange colour to the fruit.
The exocarp is glossy and full of depressed oil glands that give the fruit its characteristic smell. Immediately after the exocarp, there is the mesocarp, which is white, thick and corky textured , formed by long parenchymatous cells rich in pectins and hemicellulose. The combination of exocarp and mesocarp is called pericarp, more commonly known as skin or skin. The innermost portion is the endocarp. This portion is composed by many segments; Each segment is filled with vesicles that contain a sweet juice. The seeds are oblong-ovate, white and are found in the endocarp.
C.sinensis is native to eastern and southern Asia. Orange trees require very permeable clay soils to develop. They are present in temperate climates, especially in the Mediterranean area, since the orange trees grow optimally in places that have climates with little variation. Its components (vitamin C, citric acid and flavonoids) have antioxidant and energising properties.
