Lemon (or yellow lemon) is a citrus, fruit of the lemon tree (Citrus limon), which exists in two forms: the sweet lemon, decorative fruit of cultivars with little or no acid juice nevertheless classified Citrus limon (L.) Burm. f. (Tanaka classification) and acid lemon, the most common nowadays whose juice has a pH of about 2.5.
This ripe fruit has a bark that goes from tender green to bright yellow under the action of the cold. Maturity is in late fall and early winter in the northern hemisphere. Its flesh is juicy, the acid lemon is rich in vitamin C, which is worth - with its easy conservation - to have been diffused on all the planet by the navigators who use it to prevent scurvy. From the bark an essential oil is extracted which contains, among other substances, limonene and citral.
Description of the fruit
At the level of the external morphology, the lemon is a particular fleshy fruit, a type of berry called hesperide, resulting from the development of a multicarpellated ovary. Oval in shape, it is endowed in many varieties, with a mucron or a nipple surrounded by an areola, circular depression more or less deep and wide at the stylar end. The growth of the peduncle during fruiting gives rise to the columella, a more or less fibrous central axis of the fruit which comprises as many libero-woody bundles as there are carpels to which they lead. The persistent calyx at the level of the peduncle region, has 5 green sepals, welded in the shape of a cup.
At the anatomical level, the pericarp of this citrus fruit, also called bark, is composed of two superimposed layers: the outer layer, also called "flavedo" (rich in flavonoids, yellow pigments, from Latin flaveo, "yellow"), is formed of the epicarp and external mesocarp, and corresponds to the zest; the white and spongy inner layer, also called "albedo" (from the Latin albedo, "whiteness"), is the inner mesocarp which is the most important source of pectins and carbohydrates. Depending on the maturity of the lemon, the color of the flavedo varies from green to bright yellow. It contains many essential oil glands with a very distinctive aroma. These glands, rich in terpenes, constitute a real chemical barrier against insects and microorganisms and help protect the fruit from external attacks. The bark consists of the epicarp and the mesocarp.
The thin endocarp limits the fleshy pulp. It emits inside bags or juice vesicles (these bags are endocarpal hairs, spindle cells made up of a large vacuole where water, carbohydrates and citric acid accumulate) contained in 8 to 12 quarters (or segments) well differentiated separated by a septum, a thin membrane formed from the inner epidermis of the carpels (this carpal wall containing cellulose, hemicellulose and pectins delimits the segments corresponding to the carpal lodges). Seeds of the seed type are formed in the carpal lodges from two rows of ova placed on the sides of the angle formed by the septa at their confluence with the columella.
Use
It has multiple uses in cooking:
- Fresh juice is used in seasonings on fish;
- It replaces vinegar in salads;
- It is often used in candied form in Moroccan tagines;
- Adding water and sugar, it makes lemonade, a refreshing drink;
- It is also an essential ingredient in lemonade, limoncello and the cherbet drink very popular in Algeria;
- It is used in baking, especially in the recipe for lemon pie;
- Marmalade can be made with lemons.
- At room temperature, it keeps for ten days, so it must be consumed quickly.
Lemon can be used to prevent oxidation of certain fruits and vegetables that turn black on contact with air. You can rub the flesh of the fruit (apple, pear, avocado) with half a lemon or sprinkle grated raw vegetables like celeriac with lemon juice.
The addition of a few drops of lemon or vinegar makes the shortcrust pastry more tender and less elastic, because the acid breaks up gluten (protein from flour).
Alcohol can be produced from lemon, such as lemon liqueur.