Pineapple, ananas (Ananas comosus)

BROMELIACEAE, Pineapple Family

The pineapple (Ananas comosus) is one of the world's most popular and bizarre dessert fruits. Pineapples were eaten by Amerinds before Columbus arrived in the New World, and the natives called it ananas, which is its name in some languages (e.g., French). Others prefer to use the common name that notes the similarity to a pine cone. In early times in the American colonies, pineapple from the tropics was considered very special, and there was an interest, unsuccessful, to cultivate this crop in Virginia. Upon returning home from a long voyage, a tradition began whereby the American ship captain would place a pineapple or top of a pineapple outside his home, to announce his arrival home. The pineapple motif, often stylized, was thence adopted on American furniture, bannisters, glassware, and elsewhere as a symbol of hospitality, and can be seen in early American "pineapple quilts."

Pineapple originated in South America, and the Guarani Indians of northern Paraguay were the first to domesticate this crop. During the 16th century, this plant was transported around the world by traders. Pineapples grow well in dry, well-drained tropical habitats, e.g., tropical America, Southeast Asia, and South and West Africa, but about one-third of the world's supply comes from the Hawaiian Islands, where the crop was successfully developed in 1896.

A pineapple plant is a rosette with radiating, dagger-like leaves (it is a monocotyledon), and the plant is cultivated as a biennial. The first year the plant produces the leaves and the second year a flowering stalk arises from the center. On this stalk are produced up to 200 flowers, an inflorescence, and each flower has an inferior ovary. The ovary of each becomes a berry that normally lacks seeds because the flowers are not cross-pollinated; therefore, each of the polygonal units of the pineapple is a ripened ovary, and the berries coalesce into a solid structure, called a multiple fruit or a sorosis. The rind of a pineapple retains the persistent bracts. A cluster of leaves is produced at the top of the inflorescence; this entire top or some plantlets produced in the leafy top ("slips") can be used for propagation. Normally, pineapple is propagated by suckers found at the base of the plant. Wild pineapples in South America have seeds.

Typically, cultivated pineapple yields two crops. The first "ratoon" is a terminal large fruit. When this is carefully removed, several new pineapples develop on the stalk of the inflorescence, so several smaller, sweeter fruits can be harvested later. After the second ratoon, the plants commonly are thrown away, and new plantings started.

The Hawaiian Islands, which produces more than one million tons per year of this multiple fruit, have ideal growing conditions on the volcanic soils. Warm days and cool nights are best for carbon dioxide uptake in a process called Crassulacean acid metabolism, wherein stomates are open at night and closed during the day, as in a cactus plant or sisal (Agave) and unlike a typical plant that opens stomates during the daylight and closes them at night. Pineapple plants need at least 1 to 1.5 meters of rainfall per year. Plants flower first in December (early winter), when air temperatures is below 25 degrees C and typically stimulated by applying a spray of ethylene gas. No pollinator is desired to produce the parthenocarpic fruit, and by law therefore hummingbirds are prohibited in the islands. A majority of Hawaiian pineapple is cv. Smooth Cayenne. Ripe fruits, harvested from mid-June through August, must be eaten within five days, but half-ripe fruits kept at 7-10 degrees C can last for 6-12 days, long enough to ship to mainland markets.

Most pineapples are canned, juiced, or eaten raw. During canning, the shell is first removed, then the central cylinder is cut to remove the tough stalk of the inflorescence. The remaining slices may be cut into chunks or diced, and hot syrup from juices and sugar are added. Sugar-syrup from the excess pineapple juices may be used to produced alcohol or pineapple wine via fermentation or to extract citric acid. On interesting by-product is bromelin, a protein-digesting enzyme similar to papain (papaya, Carica papaya) that occurs in the juice, and this enzyme stops gelatin from solidifying, which is why you cannot use raw pineapple for those recipes. Leaves of bromeliad relatives of pineapple can be used as hard fiber for commercial uses.

[Return to Economic Botany Menu]