Definitions

fruit

fruit

[froot]
fruit, matured ovary of the pistil of a flower, containing the seed. After the egg nucleus, or ovum, has been fertilized (see fertilization) and the embryo plantlet begins to form, the surrounding ovule (see pistil) develops into a seed and the ovary wall (pericarp) around the ovule becomes the fruit. The pericarp consists of three layers of tissue: the thin outer exocarp, which becomes the "skin"; the thicker mesocarp; and the inner endocarp, immediately surrounding the ovule. A flower may have one or more simple pistils or a compound pistil made up of two or more fused simple pistils (each called a carpel); different arrangements give rise to different types of fruit. A new variety of fruit is obtained as a hybrid in plant breeding or may develop spontaneously by mutation.

Types of Fruits

Fruits are classified according to the arrangement from which they derive. There are four types—simple, aggregate, multiple, and accessory fruits. Simple fruits develop from a single ovary of a single flower and may be fleshy or dry. Principal fleshy fruit types are the berry, in which the entire pericarp is soft and pulpy (e.g., the grape, tomato, banana, pepo, hesperidium, and blueberry) and the drupe, in which the outer layers may be pulpy, fibrous, or leathery and the endocarp hardens into a pit or stone enclosing one or more seeds (e.g., the peach, cherry, olive, coconut, and walnut). The name fruit is often applied loosely to all edible plant products and specifically to the fleshy fruits, some of which (e.g., eggplant, tomatoes, and squash) are commonly called vegetables. Dry fruits are divided into those whose hard or papery shells split open to release the mature seed (dehiscent fruits) and those that do not split (indehiscent fruits). Among the dehiscent fruits are the legume (e.g., the pod of the pea and bean), which splits at both edges, and the follicle, which splits on only one side (e.g., milkweed and larkspur); others include the dry fruits of the poppy, snapdragon, lily, and mustard. Indehiscent fruits include the single-seeded achene of the buttercup and the composite flowers; the caryopsis (grain); the nut (e.g., acorn and hazelnut); and the fruits of the carrot and parsnip (not to be confused with their edible fleshy roots).

An aggregate fruit (e.g., blackberry and raspberry) consists of a mass of small drupes (drupelets), each of which developed from a separate ovary of a single flower. A multiple fruit (e.g., pineapple and mulberry) develops from the ovaries of many flowers growing in a cluster. Accessory fruits contain tissue derived from plant parts other than the ovary; the strawberry is actually a number of tiny achenes (miscalled seeds) outside a central pulpy pith that is the enlarged receptacle or base of the flower. The core of the pineapple is also receptacle (stem) tissue. The best-known accessory fruit is the pome (e.g., apple and pear), in which the fleshy edible portion is swollen stem tissue and the true fruit is the central core. The skin of the banana is also stem tissue, as is the rind of the pepo (berrylike fruit) of the squash, cucumber, and melon.

The Role of Fruits in Seed Dispersal

The structure of a fruit often facilitates the dispersal of its seeds. The "wings" of the maple, elm, and ailanthus fruits and the "parachutes" of the dandelion and the thistle are blown by the wind; burdock, cocklebur, and carrot fruits have barbs or hooks that cling to fur and clothing; and the buoyant coconut may float thousands of miles from its parent tree. Some fruits (e.g., witch hazel and violet) explode at maturity, scattering their seeds. A common method of dispersion is through the feces of animals that eat fleshy fruits containing seeds covered by indigestible coats.

Fruit in which the outer layer is a thin skin, the middle layer is thick and usually fleshy (though sometimes tough, as in the almond, or fibrous, as in the coconut), and the inner layer (the pit) is hard and stony. Within the pit is usually one seed. In aggregate fruits such as the raspberry and blackberry (which are not true berries), many small drupes are clumped together. Other representative drupes are the cherry, peach, mango, olive, and walnut.

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Edible fruit of the vine Actinidia chinensis (family Actinidiaceae), native to mainland China and the island of Taiwan and grown commercially in New Zealand and California. It became popular in the nouvelle cuisine of the 1970s. It has a slightly acid taste and is high in vitamin C. Kiwi can be eaten raw or cooked, and the juice is sometimes used as a meat tenderizer.

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or levulose or fruit sugar

Organic compound, one of the simple sugars (monosaccharides), chemical formula C6H12O6. It occurs in fruits, honey, syrups (especially corn syrup), and certain vegetables, usually along with its isomer glucose. Fructose and glucose are the components of the disaccharide sucrose (table sugar); hydrolysis of sucrose yields invert sugar, a 50:50 mixture of fructose and glucose. The sweetest of the common sugars, fructose is used in foods and medicines.

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Fruit fly (Trypetidae)

Any dipteran species of two families: large fruit flies (Trypetidae) and small fruit flies, or vinegar flies (family Drosophilidae; see drosophila). The larvae feed on fruit or other vegetation. The adults' wings are banded or spotted with brown. Many species attack cultivated fruits, sometimes causing enough damage to create significant economic loss. Some species are leaf miners; others burrow in plant stems. Well-known fruit-fly pests include the Mediterranean fruit fly and the apple maggot of the U.S., the Mexican and Oriental fruit flies, and the olive fruit fly of the Mediterranean region.

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Any of numerous tropical Old World bats in the family Pteropodidae as well as several species of herbivorous New World bats. Old World fruit bats are widely distributed from Africa to South Asia and Australasia. Most species rely on vision rather than on echolocation to avoid obstacles. Some species are solitary, some gregarious; most roost in the open in trees, though some inhabit caves, rocks, or buildings. Some are red or yellow, and some are striped or spotted. They eat fruit or flowers (including pollen and nectar). The smallest species in the family, the long-tongued fruit bats, reach a head and body length of about 2.5 in. (6–7 cm) and a wingspan of about 10 in. (25 cm). The same family contains the largest of all bats, the flying foxes, which attain lengths up to 16 in. (40 cm) and a wingspan of 5 ft (1.5 m). New World fruit bats are generally smaller and make use of echolocation. They are found in the tropics, with many species belonging to the genera Artibeus and Sturnira.

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In its strict botanical sense, the fleshy or dry ripened ovary (enlarged portion of the pistil) of a flowering plant, enclosing the seed or seeds. Apricots, bananas, and grapes, as well as bean pods, corn grains, tomatoes, cucumbers, and (in their shells) acorns and almonds, are all technically fruits. Popularly, the term is restricted to the ripened ovaries that are sweet and either succulent or pulpy. The principal botanical purpose of the fruit is to protect and spread the seed. There are two broad categories of fruit: fleshy and dry. Fleshy fruits include berries, such as tomatoes, oranges, and cherries, which consist entirely of succulent tissue; aggregate fruits, including blackberries and strawberries, which form from a single flower with many pistils, each of which develops into fruitlets; and multiple fruits, such as pineapples and mulberries, which develop from the mature ovaries of an entire inflorescence. Dry fruits include the legumes, cereal grains, capsules, and nuts. Fruits are important sources of dietary fiber and vitamins (especially vitamin C). They can be eaten fresh; processed into juices, jams, and jellies; or preserved by dehydration, canning, fermentation, and pickling.

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or Med fly

Fruit fly (Ceratitis capitata) proven to be particularly destructive to citrus crops, at great economic cost. The Med fly lays up to 500 eggs in citrus fruits (except lemons and sour limes), and the larvae tunnel into the fruit, making it unfit for human consumption. Because of this pest, quarantine laws regulating fruit importation have been enacted worldwide.

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The term fruit has different meanings dependent on context, and the term is not synonymous in food preparation and biology. In botany, which is the scientific study of plants, fruits are the ripened ovaries of flowering plants. In many plant species, the fruit includes the ripened ovary and surrounding tissues. Fruits are the means by which flowering plants disseminate seeds, and the presence of seeds indicates that a structure is most likely a fruit, though not all seeds come from fruits. No single terminology really fits the enormous variety that is found among plant fruits. The term 'false fruit' (pseudocarp, accessory fruit) is sometimes applied to a fruit like the fig (a multiple-accessory fruit; see below) or to a plant structure that resembles a fruit but is not derived from a flower or flowers. Some gymnosperms, such as yew, have fleshy arils that resemble fruits and some junipers have berry-like, fleshy cones. The term "fruit" has also been inaccurately applied to the seed-containing female cones of many conifers.

Fruit development

A fruit is a ripened ovary. Inside the ovary is one or more ovules (eggs). The ovules are fertilized in a process that starts with pollination, which is the movement of pollen from the stamens to the stigma of flowers. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule and sperm are transferred from the pollen to the ovule, when the sperm enters the nucleus of the ovule and the endosperm mother cell, the fertilization process is completed. As the developing seeds mature, the ovary begins to ripen. The ovules develop into seeds and the ovary wall, the pericarp, may become fleshy (as in berries or drupes), or form a hard outer covering (as in nuts). In some cases, the sepals, petals and/or stamens and style of the flower fall off. Fruit development continues until the seeds have matured. In some multiseeded fruits, the extent to which the flesh develops is proportional to the number of fertilized ovules.

The wall of the fruit, developed from the ovary wall of the flower, is called the pericarp. The pericarp is often differentiated into two or three distinct layers called the exocarp (outer layer - also called epicarp), mesocarp (middle layer), and endocarp (inner layer). In some fruits, especially simple fruits derived from an inferior ovary, other parts of the flower (such as the floral tube, including the petals, sepals, and stamens), fuse with the ovary and ripen with it. The plant hormone ethylene causes ripening. When such other floral parts are a significant part of the fruit, it is called an accessory fruit. Since other parts of the flower may contribute to the structure of the fruit, it is important to study flower structure to understand how a particular fruit forms.

Fruits are so diverse that it is difficult to devise a classification scheme that includes all known fruits. Many common terms for seeds and fruit are incorrectly applied, a fact that complicates understanding of the terminology. Seeds are ripened ovules; fruits are the ripened ovaries or carpels that contain the seeds. To these two basic definitions can be added the clarification that in botanical terminology, a nut is not a type of fruit and not another term for seed, on the contrary to common terminology.

There are three basic types of fruits:

  1. Simple fruit
  2. Aggregate fruit
  3. Multiple fruit

Simple fruit

Simple fruits can be either dry or fleshy, and result from the ripening of a simple or compound ovary with only one pistil. Dry fruits may be either dehiscent (opening to discharge seeds), or indehiscent (not opening to discharge seeds). Types of dry, simple fruits, with examples of each, are:

Fruits in which part or all of the pericarp (fruit wall) is fleshy at maturity are simple fleshy fruits. Types of fleshy, simple fruits (with examples) are:

Aggregate fruit

An aggregate fruit, or etaerio, develops from a flower with numerous simple pistils. An example is the raspberry, whose simple fruits are termed drupelets because each is like a small drupe attached to the receptacle. In some bramble fruits (such as blackberry) the receptacle is elongated and part of the ripe fruit, making the blackberry an aggregate-accessory fruit. The strawberry is also an aggregate-accessory fruit, only one in which the seeds are contained in achenes. In all these examples, the fruit develops from a single flower with numerous pistils.

Some kinds of aggregate fruits are called berries, yet in the botanical sense they are not.

Multiple fruit

A multiple fruit is one formed from a cluster of flowers (called an inflorescence). Each flower produces a fruit, but these mature into a single mass. Examples are the pineapple, edible fig, mulberry, osage-orange, and breadfruit.

In the photograph on the right, stages of flowering and fruit development in the noni or Indian mulberry (Morinda citrifolia) can be observed on a single branch. First an inflorescence of white flowers called a head is produced. After fertilization, each flower develops into a drupe, and as the drupes expand, they become connate (merge) into a multiple fleshy fruit called a syncarpet.

There are also many dry multiple fruits, e.g.

Fruit chart

To summarize common types of fruit (examples follow in the table below):

  • Berry -- simple fruit and seeds created from a single ovary
  • False berries -- Epigynous fruit made from a part of the plant other than a single ovary
  • Compound fruit, which includes:
    • Aggregate fruit -- multiple fruits with seeds from different ovaries of a single flower
    • Multiple fruit -- fruits of separate flowers, packed closely together
  • Other accessory fruit -- where the edible part is not generated by the ovary

Types of fruit
True berry Pepo Hesperidium False berry (Epigynous) Aggregate fruit Multiple fruit Other accessory fruit
Blackcurrant, Redcurrant, Gooseberry, Tomato, Eggplant, Guava, Lucuma, Chili pepper, Pomegranate, Avocado, Kiwifruit, Grape, Pumpkin, Gourd, Cucumber, Melon Orange, Lemon, Lime, Grapefruit Banana, Cranberry, Blueberry Blackberry, Raspberry, Boysenberry, Hedge apple Pineapple, Fig, Mulberry Apple, Apricot, Peach, Cherry, Green bean, Sunflower seed, Strawberry

Seedless fruits

Seedlessness is an important feature of some fruits of commerce. Commercial cultivars of bananas and pineapples are examples of seedless fruits. Some cultivars of citrus fruits (especially navel oranges and mandarin oranges), table grapes, grapefruit, and watermelons are valued for their seedlessness. In some species, seedlessness is the result of parthenocarpy, where fruits set without fertilization. Parthenocarpic fruit set may or may not require pollination. Most seedless citrus fruits require a pollination stimulus; bananas and pineapples do not. Seedlessness in table grapes results from the abortion of the embryonic plant that is produced by fertilization, a phenomenon known as stenospermocarpy which requires normal pollination and fertilization.

Seed dissemination

Variations in fruit structures largely depend on the mode of dispersal of the seeds they contain. This dispersal can be achieved by animals, wind, water, or explosive dehiscence.

Some fruits have coats covered with spikes or hooked burrs, either to prevent themselves from being eaten by animals or to stick to the hairs, feathers or legs of animals, using them as dispersal agents. Examples include cocklebur and unicorn plant.

The sweet flesh of many fruits is "deliberately" appealing to animals, so that the seeds held within are eaten and "unwittingly" carried away and deposited at a distance from the parent. Likewise, the nutritious, oily kernels of nuts are appealing to rodents (such as squirrels) who hoard them in the soil in order to avoid starving during the winter, thus giving those seeds that remain uneaten the chance to germinate and grow into a new plant away from their parent.

Other fruits are elongated and flattened out naturally and so become thin, like wings or helicopter blades, e.g. maple, tuliptree and elm. This is an evolutionary mechanism to increase dispersal distance away from the parent via wind. Other wind-dispersed fruit have tiny parachutes, e.g. dandelion and salsify.

Coconut fruits can float thousands of miles in the ocean to spread seeds. Some other fruits that can disperse via water are nipa palm and screw pine.

Some fruits fling seeds substantial distances (up to 100 m in sandbox tree) via explosive dehiscence or other mechanisms, e.g. impatiens and squirting cucumber.

Uses

Many hundreds of fruits, including fleshy fruits like apple, peach, pear, kiwifruit, watermelon and mango are commercially valuable as human food, eaten both fresh and as jams, marmalade and other preserves. Fruits are also in manufactured foods like cookies, muffins, yoghurt, ice cream, cakes, and many more. Many fruits are used to make beverages, such as fruit juices (orange juice, apple juice, grape juice, etc) or alcoholic beverages, such as wine or brandy. Apples are often used to make vinegar.

Many vegetables are botanical fruits, including tomato, bell pepper, eggplant, okra, squash, pumpkin, green bean, cucumber and zucchini. Olive fruit is pressed for olive oil. Spices like vanilla, paprika, allspice and black pepper are derived from berries.

Nutritional value

Fruits are generally high in fiber, water and vitamin C. Fruits also contain various phytochemicals that do not yet have an RDA/RDI listing under most nutritional factsheets, and which research indicates are required for proper long-term cellular health and disease prevention. Regular consumption of fruit is associated with reduced risks of cancer, cardiovascular disease, stroke, Alzheimer disease, cataracts, and some of the functional declines associated with aging.

Nonfood uses

Because fruits have been such a major part of the human diet, different cultures have developed many different uses for various fruits that they do not depend on as being edible. Many dry fruits are used as decorations or in dried flower arrangements, such as unicorn plant, lotus, wheat, annual honesty and milkweed. Ornamental trees and shrubs are often cultivated for their colorful fruits, including holly, pyracantha, viburnum, skimmia, beautyberry and cotoneaster.

Fruits of opium poppy are the source of the drugs opium and morphine. Osage orange fruits are used to repel cockroaches. Bayberry fruits provide a wax often used to make candles. Many fruits provide natural dyes, e.g. walnut, sumac, cherry and mulberry. Dried gourds are used as decorations, water jugs, bird houses, musical instruments, cups and dishes. Pumpkins are carved into Jack-o'-lanterns for Halloween. The spiny fruit of burdock or cocklebur were the inspiration for the invention of Velcro.

Coir is a fibre from the fruit of coconut that is used for doormats, brushes, mattresses, floortiles, sacking, insulation and as a growing medium for container plants. The shell of the coconut fruit is used to make souvenir heads, cups, bowls, musical instruments and bird houses.

Production

India is world leader in fresh fruit production followed by Vietnam and then China.

Top Ten Fresh Fruit Producers – 2005
Country Production (Int $1000) Footnote Production (MT) Footnote
1,052,766 C 6,600,000 F
438,652 C 2,750,000 F
271,167 C 1,790,000 F
255,216 C 1,600,000 F
223,314 C 1,400,000 F
223,314 C 1,400,000 F
183,436 C 1,150,000 F
129,203 C 810,000 F
82,945 C 520,000 F
78,160 C 490,000 F
No symbol = official figure,F = FAO estimate, * = Unofficial figure, C = Calculated figure;
Production in Int $1000 have been calculated based on 1999-2001 international prices
Source: Food and Agricultural Organization of United Nations: Economic and Social Department: The Statistical Division

Philippines is world leader in tropical fresh fruit production followed by Indonesia and then India.

Top Ten Tropical Fresh Fruit Producers – 2005
Country Production (Int $1000) Footnote Production (MT) Footnote
389,164 C 3,400,000 F
377,718 C 3,300,000 F
335,368 C 2,930,000 F
177,413 C 2,164,000 F
131,629 C 1,150,000 F
83,556 C 730,000 F
60,893 C 532,000 F
55,513 C 485,000 F
31,934 C 279,000 F
28,615 C 250,000 F
No symbol = official figure, F = FAO estimate, * = Unofficial figure, C = Calculated figure;
Production in Int $1000 have been calculated based on 1999-2001 international prices
Source: and Agricultural Organization of United Nations: Economic and Social Department: The Statistical Division

References

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