- Area & Production
- Cultivation
- Varieties
- Training & Pruning
Table of Contents
Suggested Readings
Introduction to Papaya
Papaya(Carica papaya), a tropical fruit crop, holds immense commercial significance due to its exceptional nutritional value and medicinal properties. It ranks as the third most cultivated tropical crop globally, with Brazil and India being the largest producers, while Mexico takes the lead as the primary exporter. Among common fruits, papaya stands out as the richest source of numerous essential vitamins, minerals, and dietary fiber.
Nomenclature and Description
- Papaya is also known as “pawpaw” in certain regions, particularly Australia and the West Indies, although this name is better reserved for the distinct wild species Asimina triloba Dunal, belonging to the Annonaceae family.
- The name “papaya” has been corrupted into various forms, such as kapaya, kepaya, lapaya, or tapaya, in Southern Asia and the East Indies.
- In French, it is referred to as “papaye” (the fruit) and “papayer” (the plant), or sometimes “figuier des Iles.”
- Spanish-speaking countries use names like “melón zapote,” “lechosa,” “payaya” (fruit), “papayo” or “papayero” (plant), “frutabomba,” “mamón,” or “mamona,” depending on the region.
- In Brazil, the common name is “mamao.”
- Initially encountered by Europeans, it was aptly nicknamed “tree melon.”
Composition and Nutritional Value
- Papaya fruit is an excellent source of vitamin A, although the yellow pigment in the fruit is not carotene but caricaxanthin.
- In red-fleshed cultivars, lycopene is the major pigment, accounting for 61% in Solo, 56% in Formosa, and 66% in Tailandia (Huerta-Ocampo et al., 2012).
- Ripe fruits are rich in vitamins A, B, B1, B12, C, and D, as well as various biologically active and tonic substances.
- Papaya fruit and leaves contain several enzymes, including invertase , UDP-glucose phenol-B-D-glucosyl transferase , proteinases , pectinesterase, and cysteine endopeptidase from C. candamarcensis fruits .
- Air-dried papaya seeds were found to contain moisture (4%), oil (25.6%), ash (17.8%), and protein (26.6%) (Raie et al., 1992).
- Papaya seed oil is similar in composition to olive oil, with a high content of fatty acids and triacylglycerols.
Botanical Description
- Papaya is a large herbaceous plant, often mistakenly referred to as a tree, growing rapidly to a height of 6 to 10 feet (1.8-3 m) in the first year and reaching up to 20 or even 30 feet (6-9 m) in height.
- It has a hollow green or deep-purple stem that can become up to 12 to 16 inches (30-40 cm) or more thick at the base, with a rough texture due to leaf scars.
- The leaves emerge directly from the upper part of the stem in a spiral pattern, supported by nearly horizontal petioles that are 1 to 3.5 feet (30-105 cm) long, hollow, succulent, and either green or dark purple in color.
- The leaf blade is deeply divided into 5 to 9 main segments, each irregularly subdivided, varying in width from 1 to 2 feet (30-60 cm), with prominent yellowish ribs and veins.
- Both the stem and leaves contain copious white, milky latex.
Origin and Distribution
- Papaya is native to tropical America and was introduced to India in the 16th century.
- The cultivated papaya might have originated as a cross between two species of the genus Carica native to Mexico.
- Papaya is now grown in all tropical and subtropical countries, including Australia, Hawaii, Taiwan, Peru, Florida (USA), South Africa, Pakistan, Bangladesh, and India.
- Within India, the major papaya-growing states are Tamil Nadu, Karnataka, Kerala, Odisha, Assam, West Bengal, and Bihar.
- Historical accounts suggest that papaya seeds were taken from Mexico to Panama, then to the Dominican Republic before 1525, and cultivation spread to warm elevations throughout South and Central America, southern Mexico, the West Indies, Bahamas, and Bermuda in 1616.
- Spaniards carried seeds to the Philippines around 1550, and from there, the papaya traveled to Malacca and India.
- Seeds were sent from India to Naples in 1626, and the papaya became familiar in nearly all tropical regions of the Old World, the Pacific Islands, and naturalized in many areas.
- Seeds were likely brought to Florida from the Bahamas, and until around 1959, papaya was commonly grown in southern and central Florida in home gardens and on a small commercial scale before natural enemies severely reduced the plantings.
- A similar decline in the papaya industry occurred in Puerto Rico about 10 years prior to the setback in Florida.
- Successful commercial production today is primarily in Hawaii, tropical Africa, the Philippines, India, Sri Lanka, Malaysia, Australia, South Africa, and Latin America.
Uses and Applications
Food Uses
- Ripe papayas are commonly eaten fresh, peeled, seeded, cut into wedges, and served with a squeeze of lime or lemon.
- The flesh can be cubed or shaped into balls for use in fruit salads, fruit cups, sauces for shortcakes or ice cream sundaes, pies, pickles, marmalades, or jams.
- Papaya and pineapple cubes can be covered in sugar syrup and quick-frozen for later use as a dessert.
- Half-ripe fruits can be sliced and crystallized as a sweetmeat.
- Papaya juice and nectar are prepared from peeled or unpeeled fruits and sold fresh or canned.
- In Hawaii, papayas are reduced to puree with added sucrose and frozen for later use in juice blending or jam making.
- Unripe papaya is typically not eaten raw due to its latex content but can be peeled, seeded, boiled until tender, and then chilled for use in salads or cooked as a vegetable in soups or mixed vegetable dishes.
- Green papaya is commonly canned in sugar syrup in Puerto Rico for local consumption and export.
- Young papaya leaves can be cooked and eaten like spinach in the East Indies, while mature leaves require boiling with a change of water to remove their bitterness.
- Male flower sprays are sold in Asian and Indonesian markets and in New Guinea for boiling and consuming as a vegetable after removing the bitterness.
- Young stems can be cooked and served in Africa, while older stems are peeled, grated, and the bitter juice is squeezed out before mixing with sugar and salt.
- In India, papaya seeds are sometimes found as an adulterant in whole black pepper.
Industrial and Medicinal Uses
- The milky latex collected from unripe papaya fruits by tapping contains two proteolytic enzymes, papain and chymopapain, which break down proteins, carbohydrates, and fats.
- Papain is used in meat tenderizing, manufacturing chewing gum, cosmetics, degumming natural silk, providing shrink resistance to wool, and in the pharmaceutical, textile, garment cleaning, paper, and adhesive industries, as well as in sewage disposal.
- Carpine, a major alkaloid obtained from papaya, is utilized as a diuretic and heart stimulant.
- Papain has been employed to treat ulcers, dissolve membranes in diphtheria, and reduce swelling, fever, and adhesions after surgery.
- Chemopapain is sometimes injected in cases of slipped spinal discs or pinched nerves.
- Precautions should be taken as some individuals are allergic to papain in any form and even to meat tenderized with papain.
Antibiotic Activity
- Studies at the University of Nigeria have revealed that extracts of ripe and unripe papaya fruits and seeds exhibit antibacterial activity against gram-positive bacteria, with strong doses also effective against gram-negative bacteria.
- The active substance has protein-like properties.
- Fresh crushed papaya seeds yield the aglycone of glucotropaeolin, benzyl isothiocyanate (BITC), which is bacteriostatic, bactericidal, and fungicidal. A single effective dose is 4-5 g of seeds (25-30 mg BITC).
- In a London hospital in 1977, a post-operative infection in a kidney-transplant patient was cured by applying strips of papaya to the wound for 48 hours after all modern medications had faile
Botany and Reproductive Biology
Flowering and Sex Expression
- Papaya is a polygamous plant with various sex forms: pistillate (female), hermaphrodite (perfect), and staminate (male).
- The pistillate form is stable and not affected by environmental factors, while male flowers lack a functional pistil and have ten stamens arranged in two groups of five each, attached to the corolla tube.
- Hermaphrodite flowers can be classified into three groups: intermedia, elongate (normal bisexual flowers with a corolla tube formed by the fusion of petals to two-thirds of their length, ten stamens in two series, and five fused carpels), and penitandria (short corolla tube, five stamens, and a furrowed ovary comprising five to ten carpels).
- Pollens from hermaphrodite flowers are inferior to those from staminate flowers.
Pollination
- Earlier reports suggested that papaya is primarily pollinated by wind and small insects, but this was contradicted by Allan (1963), who proposed that honey bees and butterflies are more effective pollinating agents.
- The time from pollination to the first ovule penetration was observed to be 25 hours at 8°C, with no in vitro pollen germination observed at 5°C and retarded pollen tube growth at 40°C.
Fruit Growth and Development
- The pattern of fruit development in papaya follows a double sigmoid growth curve.
- Depending on the cultivar, the papaya fruit takes 145 to 165 days to attain the edible ripe stage from the date of flowering, with an additional 10 days if allowed to ripen on the plant.
- In general, an increasing pulp-to-peel ratio is observed as the fruit ages.
Agro-climatic Requirements
- As a tropical crop, papaya requires high levels of humidity and temperature but is sensitive to frost and heavy rains and cannot withstand waterlogged conditions.
- Papaya is a thermo-sensitive crop suitable for subtropical areas, with areas near foothills being ideal for its cultivation in India.
- It can be grown at sea level and up to an altitude of 600 meters above sea level, beyond which the fruit quality decreases.
- Although the crop favors high humidity for growth, it requires a warm and dry climate for ripening.
- The shallow root system of papaya plants makes them unable to withstand strong winds.
- Papaya can also be cultivated through greenhouse farming (forced cultivation).
- The optimum temperature range for papaya cultivation is reported to be 21°C to 33°C.
- High temperatures tend to induce more maleness in papaya plants, which produce flowers with varying degrees of maleness and femaleness. Intermittent sprinkling of the canopy might be useful to reduce heat stress through evaporative cooling.
- Low temperatures of -1°C or lower can cause severe damage to plants, and -0.6°C can lead to freezing damage. In northern India, the occurrence of low temperatures and frost restricts papaya cultivation.
- A relative humidity of 60% has been reported as essential for optimum growth
Botanical Classification & Carica Species
Botanical Classification
- Papaya belongs to the Caricaceae family, a small group comprising four genera and 31 species.
- The four genera are Carica (22 species), Jacaratia (6 species), Jarilla (1 species), and Cylicomorpha (2 species).
- The only genus with edible fruits is Carica, with the common papaya (Carica papaya) being the most widely cultivated species.
Carica Species
- Carica chilensis, also known as the mountain papaya, is a tall tree reaching up to 10 meters in height. It produces multi-seeded fruits throughout the year, rich in vitamins A and C.
- Carica erythrocarpa is similar to the common papaya but has thin, red flesh.
- Carica quercifolia grows up to 2 meters tall and bears clusters of small, ellipsoid fruits.
- Carica gracilis is a slender, ornamental species. e. Carica monoica is a monoecious plant susceptible to viruses and is found in the Amazon basin.
