A short-lived perennial in tropical regions and an annual in temperate climates, the tomato grows on a bush, sometimes creeping plant requiring long periods of sunshine and warm temperatures. It is produced mainly in the United States, Russia, Turkey, Egypt, China, Spain, and Italy. There are over 1,000 different varieties of tomatoes including the cherry tomato and the plum tomato (also known as the Italian tomato); there is also a bioengineered variety that has been genetically altered for longer preservation, while another variety is cultivated in soil less conditions. Tomatoes can be round, globular, or oval. There is every a square variety that was created by American agronomists in 1984 to meet industry requirements for a tomato that is easy to pick and ideal for packing.

The size of the fruit varies according to the species; the small cherry tomato is about 6cm in diameter. The roma tomato, which resembles a small pear, is 5-25cm long and 2½-5cm in diameter; this variety is less juicy and contains fewer seeds than the others. The common round type is 2-5cm in diameter and varies in weight between 85g and more than 1kg. Some varieties stay green even as they ripen, but most tomatoes turn red, pink, orange, or yellow. The flavour of tomatoes depends on a number of factors, including when they were harvested, their degree of acidity, their sugar and water content, as well as the texture of their skin and flesh (which can be relatively starchy). Most tomatoes on the market today are firm and thick-skinned.

History

Native to Mexico and Central America, the tomato was originally a small round fruit resembling what is known today as the cherry tomato. Spanish settlers were introduced to the tomato by the Indians who cultivated it. Long considered poisonous, it was used mainly as an ornamental plant until the 18th century. The belief that tomatoes can make people sick is not so far-fetched, considering that the unripe fruits as well as the leaves and stems of this plant contain a toxic alkaloid. Nevertheless, the tomato found its way into Italian cooking by the 16th century; the Italians named it pomadoro, meaning "golden apple." The word "tomato" is derived from tomalt, the name for this fruit in Nahuatl, the language of the Aztecs.

Nutritional Value

Tomatoes are a good source of vitamin C and potassium; the also supply folic acid and vitamin A. Green tomatoes are veil acidic and contain solanine, a toxic substance that is neutralized during cooking. Tomatoes are said to be diuretic and mineralizing: they also stimulate the appetite, combat scurvy, and cleanse the system of toxins.

Buying

Choose firm, smooth tomatoes with good colour and no wrinkles or cracks. They should be pleasant-smelling and yield to light pressure of the fingers. Avoid soft, mottled or bruised fruits, as they are likely to be water and quite flavourless, and will spoil rapidly, Fresh tomatoes are best bought at the end of summer, when local vine-ripened tomatoes are abundant.

Storage

Tomatoes can be kept for a week at room temperature, as long as they are not exposed to direct sunlight. Overripe tomatoes should be stored in the refrigerator, where they will keep for 2-3 days. For the fullest flavour, take them out about 30 minutes before serving. Tomatoes should be washed just before use.

Green tomatoes can be ripened slowly at room temperature and will keep for several weeks away from direct sunlight. To hasten the ripening process, wrap them individually in paper or cover them with a cloth. Temperatures below 10ºC will halt the ripening process. Tomatoes can be frozen, but they tend to fall apart and lose their juice when thawed and are thus mainly used for cooking, preferably before they have completely thawed. Whole frozen tomatoes can be blanched for 30-60 seconds and rinsed briefly under cold water before being peeled. Tomatoes can also be cooked for 5-6 minutes, or until tender, with a teaspoon of salt and sugar before freezing.

Home preserving of tomatoes is very popular, but the success of this method requires that the appropriate jars be used and that they be properly sterilized. The tomatoes should also be sufficiently acidic to prevent the development of micro-organisms. Since the acid content of tomatoes depends on the variety, climatic conditions, and the time of harvesting (unripe tomatoes are particularly acid), it is best to add a bit of citric acid or bottled lemon juice, which is more concentrated than fresh lemon juice. Use I tablespoon lemon juice or 1/5 teaspoon citric acid for every 500g of tomatoes. A little added salt (less than half a teaspoon) will also ensure better conservation. Incorporate these ingredients once the tomatoes have been poured into the jars.

Preparing

To prepare tomatoes, wash them first, and then, depending on the use, peel, seed and pare them. To peel tomatoes, immerse the tomatoes in boiling water for 15-30 seconds (without cooking or soaking them), and let cool or rinse under cold water before peeling them with a knife. A strainer or metal basket can be used to facilitate this operation. Overripe tomatoes can be peeled directly, by piercing the skin with a knife and grasping it between the thumb and the blade to peel it off.

To seed tomatoes, simply cut the tomato in half and squeeze the halves to extract the seeds and the juice; remove any remaining seeds by hand. To pare tomatoes, cut a circle around the stem end and remove the hard part to which the peduncle was attached.

Cooking

Avoid cooking tomatoes in aluminium pots, as the corrosive effect of their acid makes them take on in unpleasant metal taste that can also be harmful. The acidity of cooked tomatoes can be diminished by-adding a small amount of sugar or honey; the quantity required depends on the variety of tomato. Tomato sauce should be cooked slowly over low beat, as prolonged cooking over high beat can make the sauce difficult to digest.

Using

Tomatoes are eaten raw or cooked and can be prepared in a wide variety of ways. Raw, they may be consumed on their own, with or without dressing, or added to salads, appetizers, and sandwiches. Cherry tomatoes are often used raw as ornamental garnishes. The versatility of cooked tomatoes is endless: they can be stuffed, incorporated into soups, sauces, stews, omelettes, and risottos, or made into jam or mari¬nades. They are also the basic ingredient in gazpacho, ratatouille, pizza, and caponata. They blend deliciously with garlic, shallots, basil, tarragon, thyme, bay leaf, oregano, and cumin and are often combined with olives, peppers, and eggplant.

Tomatoes figure prominently in the cuisine of a number of countries and regions, including Italy, Provence, Greece, Mexico and Spain. Tomato puree and crushed tomatoes are used to flavour or garnish numerous dishes. Tomatoes are perfect as an accompaniment to mullet, sardines, and tuna fish, or to beef, chicken, veal, and eggs in addition to being a classic ingredient in various Italian sauces and dishes.

Green tomatoes can also be eaten when cooked beforehand. They are often sauteed, fried, or used to make marinades. Tomatoes can be processed to make juice, sauce, puree, or concentrate; these preparations are sometimes interchangeable in recipes. Dried tomatoes are wrinkled and reddish brown in appearance and have an exquisite flavour that goes particularly well with antipasto. Store them in a container, preferably covered with olive oil.