The most important components in fruit can be group as follows: water, proteins, carbohydrates, fats, minerals and vitamins.
The primary portions of carbohydrates in citrus fruit are the three simple sugars that present about 80% of the total soluble solids of orange juice: sucrose (49-59%), glucose (20-25%) and fructose (20-25%).
Citrus pulp is used as a source of energy because of its composition. Fat and protein of citrus pulp vary with the seed content, which ranges from 1.0% to 17.7% depending upon the variety of fruit.
The citrus cultivars are recognized as one of the most important sources of ascorbic acid. Ascorbic acid is the only vitamin present in citrus fruit in amounts of major nutritional significance: one orange has 50 mg of vitamin C, which is nearly double of the recommended daily intake.
The mild acid and bitter taste in citrus are good for digestion and blood circulation. Citrus peels are rich in pectin which is valuable in making jellies, marmalades, candies, jams and pharmaceutical preparations.
Citrus fruits are particularly abundant in flavonoids which may account for up to 75% of the total solids.
Major pigments found in citrus fruit include chlorophylls, carotenoids, and anthocyanins. Chlorophylls (a and b) impart green colors and predominate in the peel of citrus fruits during growth and maturation.
It is well known that enormous differences exist in the composition of citrus fruits, as influenced by factors such as those that follow:
*The stage of maturity at which citrus is picked
*The handling, harvesting and time between harvesting and consumption
*Environmental factors affect the composition and quality of citrus fruits
Nutritional composition of citrus fruit
