Papaya

The papaya (from Carib via Spanish), papaw, or pawpaw is the fruit of the plant Carica papaya, the sole species in the genus Carica of the plant family Caricaceae. It is native to the tropics of the Americas, and was first cultivated in Mexico several centuries before the emergence of the Mesoamerican classic cultures.

The papaya is a large tree-like plant, with a single stem growing from 5 to 10 metres (16 to 33 ft) tall, with spirally arranged leaves confined to the top of the trunk. The lower trunk is conspicuously scarred where leaves and fruit were borne. The leaves are large, 50–70 centimetres (20–28 in) diameter, deeply palmately lobed with 7 lobes. The tree is usually unbranched, unless lopped. The flowers are similar in shape to the flowers of the Plumeria, but are much smaller and wax-like. They appear on the axils of the leaves, maturing into the large 15–45 centimetres (5.9–18 in) long, 10–30 centimetres (3.9–12 in) diameter fruit. The fruit is ripe when it feels soft (like a ripe avocado or a bit softer) and its skin has attained an amber to orange hue.

Common names

Carica papaya plants, and their fruits, are generally known as papayas. However, the papaya is also commonly called pawpaw or papaw, although in North America the term pawpaw usually refers to plants in the unrelated North American genus Asimina, especially A. triloba, which produces large, edible fruits. The papaya is also sometimes called mugua, a name used in traditional Chinese medicine for Chaenomeles speciosa (flowering quince) or Pseudocydonia sinensis (Chinese quince). In the Dominican Republic, the papaya is usually called "lechoza", a name associated with the plant's milky sap.

Cultivation

Originally from southern Mexico (particularly Chiapas and Veracruz), Central America, and northern South America, the papaya is now cultivated in most tropical countries. In cultivation, it grows rapidly, fruiting within 3 years. It is, however, highly frost sensitive, limiting papaya production to tropical lands.

In the 1990s, the papaya ringspot virus threatened to wipe out Hawaii’s papaya industry completely. Cultivars that had been genetically modified to be resistant to the virus (including 'SunUp' and 'Rainbow'), were then introduced there. There is still no conventional or organic method of controlling the ringspot virus. In 2004, it was found that papayas throughout Hawaii had experienced hybridization with the genetically modified varieties and that many seed stocks were contaminated. By 2010, 80% of Hawaiian papaya plants were genetically modified

Cultivars

Two kinds of papayas are commonly grown. One has sweet, red (or orangish) flesh, and the other has yellow flesh; in Australia these are called "red papaya" and "yellow papaw", respectively. Either kind, picked green, is called a "green papaya."

The large-fruited, red-fleshed 'Maradol', 'Sunrise', and 'Caribbean Red' papayas often sold in U.S. markets are commonly grown in Mexico and Belize.

'SunUp' and 'Rainbow', grown in Hawaii, are genetically modified to be resistant to the papaya ringspot virus.

Uses

Papayas can be used as a food, a cooking aid, and in medicine. The stem and bark are also used in rope production.

Gastronomy

The ripe fruit of the papaya is usually eaten raw, without skin or seeds. The unripe green fruit can be eaten cooked, usually in curries, salads, and stews. Green papaya is used in south east Asian cooking, both raw and cooked. Papayas have a relatively high amount of pectin, which can be used to make jellies.

The black seeds of the papaya are edible and have a sharp, spicy taste. They are sometimes ground and used as a substitute for black pepper.

In some parts of Asia, the young leaves of papaya are steamed and eaten like spinach. In some parts of the world, papaya leaves are made into tea as a preventative for malaria, although there is no scientific evidence for the effectiveness of this treatment.

Meat tenderizing

Green papaya fruit and the tree's latex are both rich in an enzyme called papain, a protease which is useful in tenderizing meat and other proteins. Its ability to break down tough meat fibers was used for thousands of years by indigenous Americans. It is now included as a component in powdered meat tenderizers.

Folk medicine

Papaya is marketed in tablet form to remedy digestive problems.

Papain is also applied topically (in countries where it grows) for the treatment of cuts, rashes, stings and burns. Papain ointment is commonly made from fermented papaya flesh, and is applied as a gel-like paste. Harrison Ford was treated for a ruptured disc incurred during filming of Indiana Jones and the Temple of Doom by papain injections.

Women in India, Bangladesh, Pakistan, Sri Lanka, and other countries have long used green papaya as a folk remedy for contraception and abortion. Enslaved women in the West Indies were noted for consuming papaya to prevent pregnancies and thus preventing their children from being born into slavery. Medical research in animals has confirmed the contraceptive and abortifacient capability of papaya, and also found that papaya seeds have contraceptive effects in adult male langur monkeys, and possibly in adult male humans, as well. Unripe papaya is especially effective in large amounts or high doses. Ripe papaya is not teratogenic and will not cause miscarriage in small amounts. Phytochemicals in papaya may suppress the effects of progesterone.

Allergies and side effects

Papaya is frequently used as a hair conditioner, but should be used in small amounts. Papaya releases a latex fluid when not quite ripe, which can cause irritation and provoke allergic reaction in some people. The papaya fruit, seeds, latex, and leaves also contains carpaine, an anthelmintic alkaloid (a drug that removes parasitic worms from the body), which can be dangerous in high doses.

It is speculated that the latex concentration of unripe papayas may cause uterine contractions, which may lead to a miscarriage. Papaya seed extracts in large doses have a contraceptive effect on rats and monkeys, but in small doses have no effect on the unborn animals.

Excessive consumption of papaya can cause carotenemia, the yellowing of soles and palms, which is otherwise harmless. However, a very large dose would need to be consumed; papaya contains about 6% of the level of beta carotene found in carrots (the most common cause of carotenemia)

Medicinal potential

The juice has an in vitro antiproliferative effect on liver cancer cells, probably due to its component of lycopene[18] or immune system stimulation.

Papaya seed could be used as an antibacterial agent for Escherichia coli, Staphylococcus aureus or Salmonella typhi, although further research is needed before advocating large-scale therapy.

Papaya seed extract may be nephroprotective (protect the kidneys) in toxicity-induced kidney failure

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