Fruit

Inbotany, afruitis theseed-bearing structure inflowering plants(angiosperms) that is formed from theovaryafterflowering(seeFruit anatomy).
Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propagated using the movements of humans and other animals in asymbiotic relationshipthat is the means forseed dispersalfor the one group andnutritionfor the other; humans, and many other animals, have become dependent on fruits as a source of food.Consequently, fruits account for a substantial fraction of the world'sagriculturaloutput, and some (such as theappleand thepomegranate) have acquired extensive cultural and symbolic meanings.
In common language and culinary usage,fruitnormally means the seed-associated fleshy structures (or produce) of plants that typically are sweet (or sour) and edible in the raw state, such as apples, bananas, grapes, lemons, oranges, and strawberries. In botanical usage, the termfruitalso includes many structures that are not commonly called as such in everyday language, such as nuts, bean pods, corn kernels, tomatoes, and wheat grains.
Many common language terms used for fruit and seeds differ from botanical classifications. For example, in botany, afruitis a ripenedovaryorcarpelthat contains seeds, e.g., an orange, pomegranate, tomato or a pumpkin. Anutis a type of fruit (and not a seed), and aseedis a ripenedovule.
In culinary language, afruitis the sweet- or not sweet- (even sour-) tasting produce of a specific plant (e.g., a peach, pear or lemon);nutsare hard, oily, non-sweet plant produce in shells (hazelnut,acorn).Vegetables, so-called, typically aresavoryor non-sweet produce (zucchini, lettuce, broccoli, and tomato). but some may be sweet-tasting (sweet potato).
Examples of botanically classified fruit that are typically called vegetables includecucumber,pumpkin, andsquash(all arecucurbits);beans,peanuts, andpeas(alllegumes); andcorn,eggplant,bell pepper(or sweet pepper), and tomato. Many spices are fruits, botanically speaking, includingblack pepper,chili pepper,cuminandallspice.In contrast,rhubarbis often called a fruit when used in makingpies, but the edible produce of rhubarb is actually the leaf stalk orpetioleof the plant.Ediblegymnospermseeds are often given fruit names, e.g.,ginkgonuts andpine nuts.
Botanically, acerealgrain, such ascorn,rice, orwheatis a kind of fruit (termed acaryopsis). However, the fruit wall is thin and fused to the seed coat, so almost all the edible grain-fruit is actually a seed.
The outer layer, often edible, of most fruits is called thepericarp. Typically formed from the ovary, it surrounds the seeds; in some species, however, other structural tissues contribute to or form the edible portion. The pericarp may be described in three layers from outer to inner, i.e., theepicarp,mesocarpandendocarp.
Fruit that bears a prominent pointed terminal projection is said to bebeaked.
A fruit results from the fertilizing and maturing of one or more flowers. Thegynoecium, which contains thestigma-style-ovarysystem, is centered in the flower-head, and it forms all or part of the fruit.Inside theovary(ies)are one or moreovules. Here begins a complex sequence calleddouble fertilization: a femalegametophyteproduces an egg cell for the purpose of fertilization.(A female gametophyte is called amegagametophyte, and also called theembryo sac.) After double fertilization, the ovules will become seeds.
Ovules are fertilized in a process that starts withpollination, which is the movement of pollen from the stamens to the stigma-style-ovary system within the flower-head. After pollination, apollen tubegrows from the (deposited) pollen through the stigma down the style into the ovary to the ovule. Two sperm are transferred from the pollen to a megagametophyte. Within the megagametophyte, one sperm unites with the egg, forming azygote, while the second sperm enters the central cell forming the endosperm mother cell, which completes the double fertilization process.Later, the zygote will give rise to the embryo of the seed, and the endosperm mother cell will give rise toendosperm, a nutritive tissue used by the embryo.
Fruit formation is associated withmeiosis, a central aspect ofsexualreproduction in flowering plants. During meiosishomologous chromosomesreplicate,recombineand randomly segregate, and then undergo segregation ofsister chromatidsto producehaploidcells.Union of haploid nuclei frompollenandovule(fertilisation), occurring either byself- or cross-pollination, leads to the formation of a diploidzygotethat can then develop into anembryowithin the emerging seed. Repeated fertilisations within theovaryare accompanied by maturation of the ovary to form the fruit.
As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, thepericarp, may become fleshy (as in berries ordrupes), or it may form a hard outer covering (as in nuts). In some multi-seeded fruits, the extent to which a fleshy structure develops is proportional to the number of fertilized ovules.The pericarp typically is differentiated into two or three distinct layers; these are called theexocarp(outer layer, also called epicarp),mesocarp(middle layer), andendocarp(inner layer).
In some fruits, thesepals,petals,stamensorthe styleof the flower fall away as the fleshy fruit ripens. However, for simple fruits derived from aninferior ovary– i.e., one that liesbelowthe attachment of other floral parts – there are parts (including petals, sepals, and stamens) that fuse with the ovary and ripen with it. For such a case, when floral parts other than the ovary form a significant part of the fruit that develops, it is called anaccessory fruit. Examples of accessory fruits include apple, rose hip, strawberry, and pineapple.
Because several parts of the flower besides the ovary may contribute to the structure of a fruit, it is important to understand how a particular fruit forms.There are three general modes of fruit development:
Consistent with the three modes of fruit development, plant scientists have classified fruits into three main groups: simple fruits, aggregate fruits, and multiple (or composite) fruits.The groupings reflect how the ovary and other flower organs are arranged and how the fruits develop, but they are not evolutionarily relevant as diverse planttaxamay be in the same group.
While the section of afungusthat producessporesis called afruitingbody,fungi are members of thefungi kingdomand not of theplant kingdom.
Simple fruits are the result of the ripening-to-fruit of a simple or compound ovary in asingle flowerwith asinglepistil. In contrast, a single flower with numerous pistils typically produces anaggregate fruit; and the merging of several flowers, or a 'multiple' of flowers, results in a 'multiple' fruit.A simple fruit is further classified as either dry or fleshy.
To distribute their seeds, dry fruits may split open and discharge their seeds to the winds, which is calleddehiscence.Or the distribution process may rely upon the decay and degradation of the fruit to expose the seeds; or it may rely upon the eating of fruit and excreting of seeds byfrugivores– both are calledindehiscence. Fleshy fruits do not split open, but they also are indehiscent and they may also rely on frugivores for distribution of their seeds. Typically, the entire outer layer of the ovary wall ripens into a potentially ediblepericarp.
Types of dry simple fruits, (with examples) include:
Fruits in which part or all of thepericarp(fruit wall)is fleshy at maturity are termedfleshy simple fruits.
Types of fleshy simple fruits, (with examples) include:
Berries are a type of simple fleshy fruit that issue from a single ovary.(The ovary itself may be compound, with several carpels.) The botanical termtrue berryincludes grapes, currants, cucumbers, eggplants (aubergines), tomatoes, chili peppers, and bananas, but excludes certain fruits that are called "-berry" by culinary custom or by common usage of the term – such as strawberries and raspberries. Berries may be formed from one or more carpels (i.e., from the simple or compound ovary) from the same, single flower. Seeds typically are embedded in the fleshy interior of the ovary.
Examples include:
The strawberry, regardless of its appearance, is classified as a dry, not a fleshy fruit. Botanically, it is not aberry; it is anaggregate-accessoryfruit, the latter term meaning the fleshy part is derived not from the plant's ovaries but from thereceptaclethat holds theovaries.Numerous dryachenesare attached to the outside of the fruit-flesh; they appear to be seeds but each is actually an ovary of a flower, with a seed inside.
Schizocarpsare dry fruits, though some appear to be fleshy. They originate from syncarpous ovaries but do not actuallydehisce; rather, they split into segments with one or more seeds. They include a number of different forms from a wide range of families, includingcarrot,parsnip,parsley,cumin.
An aggregate fruit is also called an aggregation, oretaerio; it develops from a single flower that presents numerous simplepistils.Each pistil contains onecarpel; together, they form a fruitlet. The ultimate (fruiting) development of the aggregation of pistils is called anaggregate fruit,etaerio fruit, or simply anetaerio.
Different types of aggregate fruits can produce different etaerios, such as achenes, drupelets, follicles, and berries.
Some other broadly recognized species and their etaerios (or aggregations) are:
The pistils of theraspberryare calleddrupeletsbecause each pistil is like a smalldrupeattached to the receptacle. In somebramblefruits, such asblackberry, the receptacle, an accessory part, elongates and then develops as part of the fruit, making the blackberry anaggregate-accessoryfruit.The strawberry is also an aggregate-accessory fruit, of which the seeds are contained in theachenes.Notably in all these examples, the fruit develops from a single flower, with numerous pistils.
A multiple fruit is formed from a cluster of flowers, (a 'multiple' of flowers) – also called aninflorescence. Each ('smallish') flower produces a single fruitlet, which, as all develop, all merge into one mass of fruit.Examples includepineapple,fig,mulberry,Osage orange, andbreadfruit. An inflorescence (a cluster) of white flowers, called a head, is produced first. Afterfertilization, each flower in the cluster develops into a drupe; as the drupes expand, they develop as aconnateorgan, merging into a multiple fleshy fruit called asyncarp.
Progressive stages of multiple flowering and fruit development can be observed on a single branch of the Indian mulberry, ornoni. During the sequence of development, a progression of second, third, and more inflorescences are initiated in turn at the head of the branch or stem.
Fruits may incorporate tissues derived from other floral parts besides the ovary, including the receptacle, hypanthium, petals, or sepals. Accessory fruits occur in all three classes of fruit development – simple, aggregate, and multiple. Accessory fruits are frequently designated by the hyphenated term showing both characters. For example, a pineapple is a multiple-accessory fruit, a blackberry is an aggregate-accessory fruit, and an apple is a simple-accessory fruit.
Seedlessness is an important feature of some fruits of commerce. Commercialcultivarsof bananas and pineapples are examples ofseedless fruits. Some cultivars ofcitrusfruits (especiallygrapefruit,mandarin oranges,navel oranges,satsumas),table grapes, and ofwatermelonsare valued for their seedlessness. In some species, seedlessness is the result ofparthenocarpy, where fruits set without fertilization. Parthenocarpic fruit-set may (or may not) require pollination, but most seedless citrus fruits require a stimulus from pollination to produce fruit.Seedless bananas and grapes aretriploids, and seedlessness results from the abortion of theembryonicplant that is produced by fertilization, a phenomenon known asstenospermocarpy, which requires normal pollination and fertilization.
Variations in fruit structures largely depend on themodes of dispersalapplied to their seeds. Dispersal is achieved by wind or water, byexplosive dehiscence, and by interactions with animals.
Some fruits present their outer skins or shells coated with spikes or hooked burrs; these evolved either to deter would-be foragers from feeding on them or to serve to attach themselves to the hair, feathers, legs, or clothing of animals, thereby using them as dispersal agents. These plants are termedzoochorous; common examples includecocklebur,unicorn plant, andbeggarticks (or Spanish needle).
By developments of mutual evolution, the fleshy produce of fruits typically appeals to hungry animals, such that the seeds contained within are taken in, carried away, and later deposited (i.e.,defecated) at a distance from the parent plant. Likewise, the nutritious, oily kernels ofnutstypically motivate birds andsquirrelstohoardthem, burying them in soil to retrieve later during the winter of scarcity; thereby, uneaten seeds are sown effectively under natural conditions togerminateand grow a new plant some distance away from the parent.
Other fruits have evolved flattened and elongated wings or helicopter-like blades, e.g.,elm,maple, andtuliptree. This mechanism increases dispersal distance away from the parent via wind. Other wind-dispersed fruit have tiny "parachutes", e.g.,dandelion,milkweed,salsify.
Coconutfruits can float thousands of miles in the ocean, thereby spreading their seeds. Other fruits that can disperse via water arenipa palmandscrew pine.
Some fruits have evolved propulsive mechanisms that fling seeds substantial distances – perhaps up to 100 m (330 ft) in the case of thesandbox tree– via explosive dehiscence or other such mechanisms (seeimpatiensandsquirting cucumber).
A large variety of fruits – fleshy (simple) fruits from apples to berries to watermelon; dry (simple) fruits including beans and rice and coconuts; aggregate fruits including strawberries, raspberries, blackberries, pawpaw; and multiple fruits such as pineapple, fig, mulberries – are commercially valuable as human food. They are eaten both fresh and as jams, marmalade and otherfruit preserves. They are used extensively in manufactured and processed foods (cakes, cookies, baked goods, flavorings, ice cream, yogurt, canned vegetables, frozen vegetables and meals) and beverages such as fruit juices andalcoholic beverages(brandy,fruit beer, wine).Spices like vanilla, black pepper, paprika, andallspiceare derived from berries.Olive fruitis pressed forolive oiland similar processing is applied to other oil-bearing fruits and vegetables.Some fruits are available all year round, while others (such as blackberries and apricots in the UK) are subject toseasonalavailability.
Fruits are also used for socializing and gift-giving in the form offruit basketsandfruit bouquets.
Typically, many botanical fruits – "vegetables" in culinary parlance – (including tomato, green beans, leaf greens, bell pepper, cucumber, eggplant, okra, pumpkin, squash, zucchini) are bought and sold daily in fresh produce markets andgreengroceriesand carried back to kitchens, at home or restaurant, for preparation of meals.
All fruits benefit from proper post-harvest care, and in many fruits, the plant hormoneethylenecausesripening. Therefore, maintaining most fruits in an efficientcold chainis optimal for post-harvest storage, with the aim of extending and ensuring shelf life.
A meta-analysis of 83 studies showed fruit or vegetable consumption is associated with reduced markers of inflammation (reducedtumor necrosis factorandC-reactive protein) and enhanced immune cell profile (increasedgamma delta T cells).
Various culinary fruits provide significant amounts offiberand water, and many are generally high invitamin C.An overview of numerous studies showed that fruits (e.g., whole apples or whole oranges) are satisfying (filling) by simply eating and chewing them.
The dietary fiber consumed in eating fruit promotessatiety, and may help to control body weight and aid reduction of bloodcholesterol, arisk factorforcardiovascular diseases.Fruit consumption is under preliminary research for the potential to improve nutrition and affect chronic diseases.Regular consumption of fruit is generally associated with reduced risks of several diseases and functional declines associated with aging.
Forfood safety, theCDCrecommends proper fruit handling and preparation to reduce the risk offood contaminationandfoodborne illness. Fresh fruits and vegetables should be carefully selected; at the store, they should not be damaged or bruised; and precut pieces should be refrigerated or surrounded by ice.
All fruits and vegetables should be rinsed before eating. This recommendation also applies to produce with rinds or skins that are not eaten. It should be done just before preparing or eating to avoid premature spoilage.
Fruits and vegetables should be kept separate from raw foods like meat, poultry, and seafood, as well as from utensils that have come in contact with raw foods. Fruits and vegetables that are not going to be cooked should be thrown away if they have touched raw meat, poultry, seafood, or eggs.
All cut, peeled, or cooked fruits and vegetables should be refrigerated within two hours. After a certain time, harmful bacteria may grow on them and increase the risk of foodborne illness.
Fruit allergies make up about 10 percent of all food-related allergies.
Because fruits have been such a major part of the human diet, various cultures have developed many different uses for fruits they do not depend on for food. For example: