There are many bioactive components present in citrus fruits, including vitamins, ascorbic acid (vitamin C), and folic acid; phytochemicals, flavonoids and limonoids; citric acid and dietary fiber.
The antioxidant capacity of citrus is attributed to vitamin C and flavonoids.
Fresh orange juice (248 mL) is a concentrated source of vitamin C, containing 50% more than a single orange.
Similarly, the antioxidant capacity of fresh orange juice is higher than that of a single orange.
Orange juice processing (pasteurization and storage), however reduces its vitamin C content (frozen reconstituted juice > chilled juice in plastic jugs > chilled juice in cartons), as well as its antioxidant capacity.
This is an important consideration because chilled juices account for a majority of the orange juice purchased by Americans.
In fact the popularity of chilled orange juice caused a marked shift in the industry in the early 1990s causing a decrease in the number of factories producing frozen concentrates and an increase in the number producing chilled orange juices.
