The external part of the rind, which consists of several morphologically different tissues, is called the flavedo because of the presence of flavonoid compounds. The flavedo of fruit contains pigments like chlorophyll and carotenoids. Albedo is rich in content of cellulose, hemicellulose, lignin and pectin.
Flavedo also contains oil glands from which essential oils are extracted to use in cosmetics and perfume industry.
The outermost layer of the fruit is the epidermis which is formed by a layer of isodiametric, polygonal cells that cover the entire surface of the fruit.
The outer cell walls of this layer are heavily cutinized and partly covered with a waxy substance. These cutinized walls and the wax prevent excess loss of water from the fruit.
Acid lime fruits are high in acid. Citrus aurantifolia grow throughout tropical and warm subtropical regions of the world and the world's leading producers are Mexico, Florida, the West Indies, and Egypt. The most common acid lime is the small-fruited acid lime or Citrus aurantifolia Swingle.
‘Mexican’ lime (Citrus aurantifolia Swingle) has a smooth, thin skin, is greenish-yellow in color, and has a very small neck, a flat base, and a small nipple at the apex. The highly acidic flesh is juicy with a distinct aroma and flavor.
On the other hand, Persian lime (Citrus latifolia Tanaka) has bigger; oval, obovate, oblong or short-elliptical fruits; with rare or lacking seeds. They present a thin rind, smooth surface; and a pale lemon-yellow color at maturity.
Acid lime can be used as fresh fruit or as juice to increase the flavor of drinks. The acid lime fruit is rich source of vitamin C, which helps in increasing the resistance to diseases. Toothache, dental caries and swollen gums are reduced by using the fruit. Lime improves the digestion and helps in reducing acidity problem, constipation and peptic ulcers. It will also help in curing obesity.
Citrus fruit of lime
