Healthy Fruit: Papaya

The papaya (from Carib via Spanish), papaw or pawpaw is the fruit of the plant Carica papaya, in the genus Carica. 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.

It 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 if unlopped. 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. It is the first fruit tree to have its genome deciphered.

In North America the term pawpaw may also refer to the fruit of trees in the unrelated North American genus Asimina. However, pawpaw and papaw are common synonyms of papaya both in North America and elsewhere. It is sometimes called mugua and is therefore confused with Chaenomeles speciosa or Pseudocydonia sinensis which are called mugua in Traditional Chinese Medicine.

Originally from southern Mexico, particularly Chiapas and Veracruz, Central America and northern South America, the papaya is now cultivated in most tropical countries, such as Brazil, Bangladesh, Pakistan, India, Indonesia, South Africa, Sri Lanka, Vietnam, Philippines and Jamaica. In cultivation, it grows rapidly, fruiting within 3 years. It is, however, highly frost sensitive. The papaya fruit is susceptible to the Fruit Fly. This wasp-like fly lays its eggs in young fruit.

In the 1990s, the papaya ringspot virus threatened to wipe out Hawaii’s papaya industry completely. Two varieties of papaya, SunUp and Rainbow, that had been genetically modified to be resistant to the virus, were introduced into Hawaii. By 2010 80% of Hawaiian papaya was genetically modified. Today there is still no conventional or organic method of controlling the ringspot virus. In 2004, non-genetically modified and organic papayas throughout Hawaii had experienced hybridization with the genetically modified varieties.

Papaya can be used as a food, a cooking aid, and in medicine. The stem and bark are also used in rope production. The ripe fruit is usually eaten raw, without skin or seeds. The unripe green fruit of papaya can be eaten cooked, usually in curries, salads and stews. It has a relatively high amount of pectin, which can be used to make jellies. Green papaya is used in Thai cuisine, both raw and cooked.

The black seeds are edible and have a sharp, spicy taste. They are sometimes ground up 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 parts of the world papaya leaves are made into tea as a preventative for malaria, though there is no real scientific evidence for the effectiveness of this treatment.

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 included as a component in powdered meat tenderizers.

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 unripe papayas may cause miscarriage due to latex content that 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) per 100g.

The juice has an antiproliferative effect on in vitro liver cancer cells, probably due to its component of lycopene 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.

Papaya, raw : Nutritional value per 100 g (3.5 oz)

Energy 163 kJ (39 kcal) | Carbohydrates 9.81 g

Sugars 5.90 g | Dietary fiber 1.8 g

Fat 0.14 g | Protein 0.61 g

Vitamin A equiv. 55 μg (6%) | - beta-carotene 276 μg (3%)

Thiamine (Vit. B₁) 0.04 mg (3%)

Riboflavin (Vit. B₂) 0.05 mg (3%)

Niacin (Vit. B₃) 0.338 mg (2%)

Vitamin B₆ 0.1 mg (8%) | Vitamin C 61.8 mg (103%)

Calcium 24 mg (2%) | Iron 0.10 mg (1%)

Magnesium 10 mg (3%) | Phosphorus 5 mg (1%)

Potassium 257 mg (5%) | Sodium 3 mg (0%)

Percentages are relative to US recommendations for adults.

Source: USDA Nutrient database

Source, Images: http://en.wikipedia.org/wiki/Carica_papaya