The lemon (Citrus limon) is part of the Rutaceae family. This small, oval fruit is approximately 2 to 3 inches/5 to 71/2 cm in diameter. With its bright yellow, pitted outer peel, like that of other citrus fruits, the inner flesh of the lemon is encased in approximately eight to ten segments. The lemon has a characteristic, sour odor with an acidic, tart, astringent taste that is unexpectedly refreshing.

The fruit juice contains mainly sugars and fruit acids, which are principally citric acid. Lemon peel consists of two layers: the outermost layer (“zest”), which contains essential oils (6 percent) that are composed mostly of limonene (90 percent) and citral (5 percent), plus a small amount of citronellal, alpha-terpineol, linalyl, and geranyl acetate. The inner layer contains no essential oil but instead houses a variety of bitter flavone glycosides and coumarin derivatives.

Despite the misconception that lemons are only sour, there is also a sweet variety. The most notable sweet lemon is the Meyer lemon, which is becoming increasingly popular in markets and restaurants. This lemon is relatively easy to grow (indoors) in the U.K. too. It has a much rounder form and a smooth unpitted skin, and takes on a deep yellow to orange color when mature. Meyer lemons have an amazing tangy aroma and are less acidic.

The two main sour lemons are the Eureka and Lisbon. The Eureka has few seeds and a more textured skin (there is now a seedless variety of Eureka in the U.K.), while the Lisbon is smoother and seedless.

Lemon trees are much less hardy in their tolerance for cold than orange trees, hence they have been difficult to cultivate. However, the lemon tree flowers continuously and has fruit in all stages of development most of the year. A tree may bear as many as 3,000 lemons annually.

History of Lemon

Citrus fruits are native to southern China and Southeast Asia, where they have been cultivated for approximately 4,000 years. In fact, ancient Asian literature includes stories about these fruits. The citron was carried to the Middle East sometime between 400 and 600 B.C.E. Arab traders in Asia carried lemons, citrons, limes, oranges, and shaddocks to eastern Africa and the Middle East between C.E. 100 and 700.

During the Arab occupation of Spain, citrus fruits arrived in southern Europe. From there, they were taken to the New World by Christopher Columbus and Portuguese and Spanish explorers. Lemons became quite well known in Florida and Brazil by the sixteenth century.

Superior varieties from Southeast Asia arrived in Europe with Portuguese traders in the sixteenth century. Mandarin oranges from southern China did not arrive in Europe and the New World until the nineteenth century.

The desire for citrus fruits increased greatly after the 1890’s when physicians found that people suffering from scurvy (a disease of vitamin C deficiency) could be cured by drinking citrus juice. Lemons were in such demand that people were willing to pay up to $1 per lemon, an astronomical price for that time! Later, scientists discovered that the juice is beneficial because it is the most potent and concentrated source of Vitamin C. Lemons also contain vitamins A, B 1, and bio-flavonoids, as well as potassium, magnesium, and folic acid.

The United States (California and Florida lead in U.S. production), Italy, Spain, Greece, Israel, and Turkey are the major producers of lemons.

Nutritional Highlights of Lemon


Lemons are an excellent source of vitamin C. In addition, they are a good source of vitamin B 6, potassium, folic acid, flavonoids, and the important phyto-chemical limonene. A 100 gram serving is about 2 medium lemons and provides 29 calories, 1.1 grams of protein, 0.3 grams of fat, and 9.3 grams of carbohydrate, with 2.8 grams of fiber and 2.5 grams of natural sugars.

Health Benefits

The phyto-chemical limonene, which is extracted from lemons, is currently being used in clinical trials to dissolve gallstones and is showing extremely promising anticancer activities. The highest content of limonene is found in the white spongy inner parts of the lemon.

How to Select and Store Lemon

When choosing a lemon, one should hold the fruit and determine if it is heavy. The heavier the fruit and the thinner the skin, the more juice it has. A ripe lemon should be firm, with a fine-textured peel with a deep yellow color. Acidity varies with the color of the lemon.

A deep yellow lemon is less acidic than a lighter or greenish yellow one. Surface marks usually do not affect the fruit inside, but you should try to avoid buying bruised or dried-out fruit, as well as shriveled or hard-skinned lemons.

Store lemons at room temperature, away from sunlight, and enjoy their cheerful color. They keep without refrigeration for about two weeks. If kept in the refrigerator crisper, it is best to use a plastic bag, where they can remain up to six weeks.

Lemons can also be juiced and stored for later use. First, squeeze the lemons and pour the juice into ice cube trays for freezing. You can then transfer the frozen cubes to a plastic freezer container, where they will keep for up to three months. Lemon zest, which is usually used as a spice, can be dried and stored in a cool place for up to two to three months.

Tips for Preparing Lemon

Lemons in many forms are called for in countless recipes. To produce more lemon juice for a recipe, it is always better for the lemon to be warm (or at least room temperature). If time is a factor, the lemon can be placed in a bowl of warm water or in the microwave for 5 to 10 seconds, or juiced in a juicer or extractor. Rolling the lemon under the palm of your hand on a flat surface will also ensure the extraction of more juice.

It is also important to note that before cutting a lemon, it is a good idea to wash the skin of the lemon so that any dirt or bacteria on the skin is not transferred to the fruit’s interior. Use caution if you have a citrus allergy.

It is always recommended, if you are using the skin or “zest” of any citrus, to purchase organic fruit. Most conventionally harvested fruits have pesticide residue concentrated on their skin. To obtain the zest of a lemon, first wash and dry the lemon, then use a paring knife or vegetable peeler to remove the colored part of the lemon.

The white pith that is under the peel has a very bitter taste and should not be used. The zest can be chopped, diced, candied, or used in whatever fashion called for by the recipe.

Quick Serving Ideas for Lemon

  • Place thinly sliced lemons, peel and all, underneath and around fish before cooking. Baking or grilling will soften the slices so that they can be eaten along with the fish.
  • Combine lemon juice with olive or linseed oil, freshly crushed garlic, and pepper to make a light, refreshing salad dressing.
  • If you are watching your salt intake (and even if you are not), serve lemon wedges with meals, as the tart lemon juice makes a great salt substitute.

Lemon Safety

Some people are allergic to citrus peels. When such an allergy is suspected caution must be employed when eating citrus fruit (see “Tips for Preparing”). But whether you are allergic or not, citrus peels should not be eaten in any significant quantity. Citrus peels contain some beneficial oils, but these oils can interfere with some body functions. For example, citrus peels contain a compound known as citral that antagonizes some of the effects of vitamin A.

Lemons contain low levels of oxalates; lemon peel, however, contains high levels of oxalates. Individuals with a history of calcium oxalate-containing kidney stones should limit their consumption of this food. Since lemons are among the foods on which pesticide residues have been most frequently found, we recommend selecting organically grown lemons.