The lemon (Citrus × limon) is a small evergreen tree native to Asia, and the tree’s ellipsoidal yellow fruit. The fruit is used for culinary and non-culinary purposes throughout the world, primarily for its juice, though the pulp and rind (zest) are also used in cooking and baking. The juice of the lemon is about 5% to 6% citric acid, which gives lemons a sour taste. The distinctive sour taste of lemon juice makes it a key ingredient in drinks and foods such as lemonade.

Nutrition

Nutritional value and phytochemicals

emon contains a wide range of health benefits and other nutritional values. As they are rich source of vitamin C, providing 64% of the Daily Value in a 100 g serving (table). Other essential nutrients, however, have insignificant content (table).

Lemons contain numerous phytochemicals, including polyphenols, terpenes, and tannins. Lemon juice contains slightly more citric acid than lime juice (about 47 g/l), nearly twice the citric acid of grapefruit juice, and about five times the amount of citric acid found in orange juice.

Production

In 2016, world production of lemons (combined with limes for reporting) was 17.3 million tonnes. The top producers were India, Mexico, China, Argentina and Brazil, collectively accounting for 62% of total production (table).

Lemon (and lime) production, 2016
(in millions of tonnes)

Food Idea (Culinary uses)

Lemon juice, rind, and peel are used in a wide variety of foods and drinks. The whole lemon is used to make marmalade, lemon curdand lemon liqueur. Lemon slices and lemon rind are used as a garnish for food and drinks. Lemon zest, the grated outer rind of the fruit, is used to add flavor to baked goods, puddings, rice, and other dishes.

Juice

Lemon juice is used to make lemonade, soft drinks, and cocktails. It is used in marinades for fish, where its acid neutralizes amines in fish by converting them into nonvolatile ammonium salts. In meat, the acid partially hydrolyzes tough collagen fibers, tenderizing the meat, but the low pH denatures the proteins, causing them to dry out when cooked. In the United Kingdom, lemon juice is frequently added to pancakes, especially on Shrove Tuesday.
Lemon juice is also used as a short-term preservative on certain foods that tend to oxidize and turn brown after being sliced (enzymatic browning), such as apples, bananas, and avocados, where its acid denatures the enzymes.

Peel

In Morocco, lemons are preserved in jars or barrels of salt. The salt penetrates the peel and rind, softening them, and curing them so that they last almost indefinitely. The preserved lemon is used in a wide variety of dishes. Preserved lemons can also be found in Sicilian, Italian, Greek, and French dishes.
A major industry use of the peel is the manufacturing of pectin – a polysaccharide used as a gelling agent, thickening agent, and stabilizer in food and other products.

Oil

Lemon oil is extracted from oil-containing cells in the skin. A machine breaks up the cells and uses a water spray to flush off the oil. The oil/water mixture is then filtered and separated by centrifugation.

Leaves

The leaves of the lemon tree are used to make a tea and for preparing cooked meats and seafoods.