RED ORANGE or Sanguine is a variety of orange with dark red flesh , like raspberry juice . The degree of this coloration depends mainly on strong changes in temperature between day and night, as well as variety.
The taste is significantly more acidic than the common orange. Depending on the variety , is slightly smaller , while its shell is somewhat harder and harder to peel, but often the same texture and color, can occasionally be somewhat smoother and partly reddish. The distinctive dark red color of the meat is due to the presence of anthocyanins , a family of pigments with antioxidant properties common in many flowers and fruit, but uncommon in citrus.