SCIENTIFIC NAME: Carica papaya
FAMILY: Caricaceae

Papaya is a native of tropical America where it has been cultivated for a very long time. It is known as 'papaw' in some countries. The Spanish explorers discovered it in Panama and North Western South America around the sixteenth century, and its cultivation began in the Far East by the end of the eighteenth century. Today, it is grown widely throughout the tropics and cultivation has also been carried out in some of the subtropical regions. Besides, it is one of the most common fruit trees planted on small farms and backyards in Singapore and Malaysia.

It is a sappy, softwood evergreen plant with latex vessels spread throughout. The trunk is straight, normally unbranched and may grow to a height of 2-10 metres. It has a smooth surface but clearly bears the scars where old leaves have fallen off. A tuft of hand-shaped leaves spiral round the top of the trunk.

The leaves are large, palmate and deeply-lobed, growing on long petioles that are attached to the trunk. They are smooth and bluish-green on the upper surface but pale green and much ridged by the veins underneath.

Papaya plants are usually dioecious, with either male or female flowers. These are then referred to as male or female plants respectively. However, hermaphrodite or bisexual trees that produce complete flowers also occur.

Inflorescences arise in the axils of the leaves. The male flowers grow on long hanging panicles while female and complete flowers occur singly or ,in cluster close to the stems on female and hermaphrodite trees. The female and complete flowers are larger in size than the male flowers. The flowers are sweet-smelling, with waxy, dull, creamy yellow petals. The sex of the plant is determined only when it starts to flower.

Photo of hermaphrodite flowersPhoto of female flowers
Complete flowers (hermaphrodite tree)Female flowers

The fruits are large berries which vary greatly in size, shape and flavour. The weight of each fruit may range from 0.5 kg to 9 kg, depending on varieties. Fruits produced from hermaphrodite flowers are either cylindrical or pear-shaped, whereas female flowers give rise to elliptical or more round fruits. The skin is smooth and thin. It is green at first, then changes to a yellow or orange colour as the fruit ripens. The flesh of the fruit also varies in colour from creamy yellow to orangey-red, the latter of which is in greater demand in our local market. The central cavity is hollow, with numerous tiny, dark grey seeds attached to its wall. However, seedless fruits occur too.

Papaya is a short-lived tree which grows at a fast rate in fertile, well-drained soil. Propagation is by seeds which take about 2 weeks to germinate, and from then on two leaves emerge each week. Under optimum conditions, the plant will fruit in the first year of planting. The fruits take four to six months to mature depending on climate and variety.

The tree fruits continuously all year round and remains in prime condition for two to three years. Its economic life comes to an end after the third year, as the yield declines and the fruits diminish in size.

A fruit is considered ready for harvest when the latex of the fruit becomes watery. For local consumption, it is best to pick the fruit when the green colour is halfway changed into yellow. But for distant transport, it is advisable to pick sooner, after the blossom end has turned colour. Fruits are stored to soften up fully at room temperature before table consumption. There are several varieties available locally. Among the better known ones, the yellow-fleshed type includes Hawaii Solo and Honey Dew, while the red-fleshed type includes a local dwarf variety and the Pacific Strain from Guam.

Photo of fruits of a hermaphrodite treePhoto of fruits of a female tree
Fruits (hermaphrodite tree)Fruits (female tree)

The fleshy part of the fruit contains carbohydrate, protein, calcium and abundant vitamins A and C. Papaya fruit is considered a mild laxative by many locals. Ripe fruits are mainly eaten as fresh fruit or blended with milk to make a refreshing drink. The immature fruits may be pickled in sugar or vinegar, or cooked and used as a vegetable.

The flavour of the fruit is usually very delicate, but there are also tasteless ones. Some of the fruits may even have an unpleasant smell.

Papaya has other commercial importance apart from its value as a fruit. The milky latex from the plant contains the enzymes which have protein-digesting and milk-clotting properties. It is obtained from the sap which oozes from a cut made in the bark, and from immature fruits. After drying, it forms a powder commercially known as papain. Papain is used medicinally in cases of weak digestion and also as a meat tenderiser. Besides this, the latex is also used in the manufacture of chewing-gum and in leather-tanning, as well as in the textile industry where it helps to prevent shrinkage of wool and silk.

Mrs Yong-Ho Siew Yee
Extract from Primary Production Bulletin Singapore December, 1989

DATE: March 1991

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