Blood orange
The blood orange is a variety of orange with crimson, near blood-colored flesh. It is one of the sweet orange varieties. It is also known as the raspberry orange.
The dark flesh color is due to the presence of anthocyanins, a family of polyphenol pigments common to many flowers and fruit, but uncommon in citrus fruits. Chrysanthemin is the main compound found in red oranges. The flesh develops its characteristic red color when the fruit develops with low temperatures during the night. Sometimes, dark coloring is seen on the exterior of the rind as well. This depends on the variety of blood orange. The skin can be tougher and harder to peel than that of other oranges. Blood oranges have a unique flavor compared to other oranges, being distinctly raspberry-like in addition to the usual citrus notes. The anthocyanin pigments of blood oranges begin accumulating in the vesicles at the edges of the segments, and at the blossom end of the fruit, and continue accumulating in cold storage after harvest.
The blood orange is a natural mutation of the orange, which is itself a hybrid, probably between the pomelo and the tangerine. Within Europe, the arancia rossa di Sicilia has protected geographical status. In the Valencian Community, it was introduced in the second half of the 19th century.
Cultivars
The three most common types of blood oranges are the Tarocco, the Sanguinello, and the very dark Moro, the newest variety of the three.Other less-common types include Maltaise demi sanguine, Washington Sanguine, Ruby, Doblafina, Delfino, Burris Valencia, Vaccaro, Grosse Ronde, Entrefina, and Sanguinello a Pignu.
While also pigmented, Cara Cara navels and Vainiglia sanguignos have pigmentation based on lycopene, not anthocyanins as blood oranges do.
Moro
The Moro is the most colorful of the blood oranges, with a deep red flesh and a rind with a bright red blush. The flavor is stronger and the aroma is more intense than a normal orange. This fruit has a distinct, sweet flavor with a hint of raspberry. This orange possesses a more bitter taste than the 'Tarocco' or the 'Sanguinello'. The 'Moro' variety is believed to have originated at the beginning of the 19th century in the citrus-growing area around Lentini as a bud mutation of the "Sanguinello Moscato". The 'Moro' is a "deep blood orange", meaning that the flesh ranges from orange-veined with ruby coloration, to vermilion, to vivid crimson, to nearly black.Tarocco
The name Tarocco is thought to be derived from an exclamation of wonder expressed by the farmer who was shown this fruit by its discoverer. It is a medium-sized fruit and is perhaps the sweetest and most flavorful of the three types. The most popular table orange in Italy, it is thought to have derived from a mutation of the 'Sanguinello'. It is referred to as "half-blood", because the flesh is not accentuated in red pigmentation as much as with the 'Moro' and 'Sanguinello' varieties. It has thin orange skin, slightly blushed in red tones. The Tarocco is one of the world's most popular oranges because of its sweetness and juiciness. It has the highest vitamin C content of any orange variety grown in the world, mainly on account of the fertile soil surrounding Mount Etna, and it is easy to peel. The 'Tarocco' orange is seedless.The University of California, Riverside Citrus Variety Collection has delineated three subcultivars of 'Tarocco'. The 'Bream Tarocco', which was originally donated by Robert Bream of Lindsay, California, is of medium to large fruit with few to no seeds. 'Tarocco #7', or 'CRC 3596 Tarocco', is known for its flavor, but has a rind with little to no coloration. The 'Thermal Tarocco' was donated by A. Newcomb of Thermal Plaza Nursery in Thermal, California.