Papaya: A Nutritious Tropical Fruit

By Kasi Sundaresan, Ph. D., Contributing Editor

Papaya is a fruit from the group of yellow and orange fruits gaining immense popularity in the United States. This tropical fruit was reputedly called The Fruit of the Angels" by Christopher Columbus. Originally from southern Mexico, Central America and northern South America, the fruit is now cultivated throughout the tropical world and in the warmest parts of the subtropics. Papaya fruit is commonly consumed fresh, but it is also cooked or used in salads, preserves, sauces, dressings, juices, nectars, smoothies and pies.

Papaya cultivation

Papaya belongs to the family Caricaceae, which includes four genera and about 20 species native to the growing region. The papaya tree is a rapid-growing perennial that looks like a small palm tree, with a single slender, cylindrical trunk with a crown of leaves. The tree attains an average height of 10 to 13 feet. It is propagated from seeds. Because of open pollination, it is difficult to obtain a pure cultivar for papaya. Papaya trees develop to their full size in less than a year and are ready to bear fruit at any time during the year.

Among the numerous varieties of papaya are important commercial varieties such as 'Red Lady', 'Maradol', Waimanalo and different Solo types. Two kinds of papayas are commonly grown; red papaya has sweet, red (or orange) flesh, and yellow papaya has yellow flesh.  The large-fruited, red-fleshed 'Maradol', 'Sunrise', and 'Caribbean Red' papayas often sold in U.S. markets are commonly grown in Mexico and Belize. Weather conditions, such as cold temperatures, lack of water (drought), high, constant winds, or shade, will reduce papaya growth and production. Papaya plants grow best in areas where temperatures remain warm to hot (70 to 90° F; 21 to 32° C). Papaya trees are not tolerant of freezing temperatures and are damaged or killed below 31° F (-0.6° C). Papaya trees are susceptible to wind damage and will not establish or grow well in continuously windy areas. The fruit is commonly spherical to cylindrical in form. Attached along the walls of the large inner cavity of the fruit are numerous small, round, wrinkled black seeds The juicy flesh is deep yellow, orange, red or salmon, and its flavor profile strongly resembles a muskmelon. Deliciously sweet with musky undertones and a soft, butterlike consistency, it is greatly enjoyed in tropical countries. The soluble-solids level of the mature fruits is typically 11.5% or higher,

Of nutritional note

Puréed papaya is a good source of beta carotene and iron for lactating mothers, according to a study in the Journal of Nutrition (2001; 131:1,497-1,502.). Papaya is an excellent source of ascorbic acid (about 60 mg to 100 mg per 100 grams pulp), a good source of provitamin A, some B complex vitamins and many phytochemicals having antioxidant properties. During the the papayas development, ascorbic acid increases gradually until the fruit reaches maturity. The change in outer color is an indicator of ripeness, and this change is considered mainly due to increase in carotene content and decrease in chlorophyll. Carotenoid contents differ between yellow- and red-fleshed papaya. The red-fleshed papaya has 64 % of the total carotenoids as lycopene.

Papaya has many applications in processed-food products and is available in a variety of forms, including purée, concentrate, powder, and dried or canned slices or chunks. Papaya purée is the major semiprocessed product that finds use in juices, nectars, fruit cocktails, jams and jellies. A number of low-moisture products, such as fruit leather, toffees, chunks, rolls and slices, have also been prepared from papaya purée. Besides its well-known use in food applications, the papaya has many traditional medicinal uses. Shamans in the Amazon used the seeds to cure parasites, which commonly affect native people.

Most villages plant papaya in their medicinal gardens to make use of this treatment. It also is used in medicines to treat arthritis and asthma. An extract from the fruit was also used to treat ulcers and reduce swelling after surgery. Papain is also applied topically (in countries where it grows) for the treatment of cuts, rashes, stings and burns. Women in some Asian 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.

Due to its unique flavor, papaya is a popular ingredient in fruit juices, nectars and squashes in various parts of the world. Papaya pairs well with fruits like mango and guava in fruit-juice formulations.

Enzymatic magic

The latex of the papaya plant and its green fruits contain two proteolytic enzymes, papain and chymopapain. Chymopapain is more abundant in the fruit, but papain is twice as potent in usage. Papain, a cysteine proteinase, also has a vast number of commercial uses. Papain is extracted and purifies to make digestive-enzyme dietary supplements, and is also used as an ingredient in some chewing gums.

One of the best-known uses of papain is as a meat tenderizer, especially for home or foodservice use. The enzyme can be applied to the surface, but is best as part of a marinade. The result depends on the time and temperature of the application. Papain-treated meat should never be cooked rare," but should be cooked sufficiently to inactivate the enzyme, requiring a temperature as high as 170 to185°F to completely inactivate it.

Papain has many other practical applications. It is used to clarify beer, treat wool and silk before dyeing, to de-hair hides before tanning, and also serves as an adjunct in rubber manufacturing. It is used in making toothpaste, and cosmetic products.

Papaya is a delicious and nutritious fruit, and is of considerable economic importance in many tropical countries and export markets in temperate countries.

Kasi Sundaresan, Ph. D, is manager of research, development and quality for iTi Tropicals. For more information visit ititropicals.com.