In broad terms, a fruit is a structure of a plant that contains its seeds. The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state, such as apples, oranges, grapes, strawberries, juniper berries and bananas. Seed-associated structures that do not fit these informal criteria are usually called by other names, such as vegetables, pods, nut, ears and cones.
In biology (botany), a "fruit" is a part of a flowering plant that derives from specific tissues of the flower, mainly one or more ovaries. Taken strictly, this definition excludes many structures that are "fruits" in the common sense of the term, such as those produced by non-flowering plants (like juniper berries, which are the seed-containing female cones of conifers), and fleshy fruit-like growths that develop from other plant tissues close to the fruit (accessory fruit, or more rarely false fruit or pseudocarp), such as cashew fruits. Often the botanical fruit is only part of the common fruit, or is merely adjacent to it. On the other hand, the botanical sense includes many structures that are not commonly called "fruits", such as bean pods, corn kernels, wheat grains, tomatoes, the section of a fungus that produces spores, and many more. However, there are several variants of the biological definition of fruit that emphasize different aspects of the enormous variety that is found among plant fruits.
Fruits (in either sense of the word) are the means by which many plants disseminate seeds. Most plants bearing edible fruits, in particular, coevolved with animals in a symbiotic relationship as a means for seed dispersal and nutrition, respectively; in fact, many animals (including humans to some extent) have become dependent on fruits as a source of food. Fruits account for a substantial fraction of world's agricultural output, and some (such as the apple and the pomegranate) have acquired extensive cultural and symbolic meanings.
Many fruits that, in a botanical sense, are true fruits are actually treated as vegetables in cooking and food preparation, because they are not particularly sweet. These culinary vegetables include cucurbits (e.g., squash, pumpkin, and cucumber), tomatoes, peas, beans, corn, eggplant, and sweet pepper. In addition, some spices, such as allspice and chilies, are fruits, botanically speaking. In contrast, occasionally a culinary "fruit" is not a true fruit in the botanical sense. For example, rhubarb is often referred to as a fruit, because it is used to make sweet desserts such as pies, though only the petiole of the rhubarb plant is edible. In the culinary sense of these words, a fruit is usually any sweet-tasting plant product, especially those associated with seed(s), a vegetable is any savoury or less sweet plant product, and a nut is any hard, oily, and shelled plant product.
Technically, a cereal grain is also a kind of fruit, a kind which is termed a caryopsis. However, the fruit wall is very thin, and is fused to the seed coat, so almost all of the edible grain is actually a seed. Therefore, cereal grains, such as corn, wheat and rice are better considered as edible seeds, although some references do list them as fruits. Edible gymnosperm seeds are often misleadingly given fruit names, e.g., pine nuts, ginkgo nuts, and juniper berries.
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 general modes of fruit development:
- Apocarpous fruits develop from a single flower having one or more separate carpels, and they are the simplest fruits.
- Syncarpous fruits develop from a single gynoecium having two or more carpels fused together.
- Multiple fruits form from many different flowers.
Plant scientists have grouped fruits into three main groups, simple fruits, aggregate fruits, and composite or multiple fruits. The groupings are not evolutionarily relevant, since many diverse plant taxa may be in the same group, but reflect how the flower organs are arranged and how the fruits develop.
Fruits are generally high in fiber, water, vitamin C and sugars, although this latter varies widely from traces as in lime, to 61% of the fresh weight of the date. 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 (especially coronary heart disease), stroke, Alzheimer disease, cataracts, and some of the functional declines associated with aging.
Diets that include a sufficient amount of potassium from fruits and vegetables also help reduce the chance of developing kidney stones and may help reduce the effects of bone-loss. Fruits are also low in calories which would help lower one's calorie intake as part of a weight-loss diet.
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 opium which contains the drugs morphine and codeine, as well as the biologically inactive chemical theabaine from which the drug oxycodone is synthysized. 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.
For food safety, the CDC recommends proper fruit handling and preparation to reduce the risk of food contamination and foodborne illness. Fresh fruits and vegetables should carefully be selected. At the store, they should not be damaged or bruised and pre-cut 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 utensils that have come in contact with raw foods. Fruits and vegetables, if they 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.