Fish drying in the sun poisson seche Madagascar

Food drying is a method of food preservation in which food is dried (dehydrated or desiccated). Drying inhibits the growth of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constit ...

s, and

mold A mold () or mould () is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not ...

through the removal of

water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...

. Dehydration has been used widely for this purpose since ancient times; the earliest known practice is 12,000 B.C. by inhabitants of the modern Middle East and Asia regions."Historical Origins of Food Preservation".
Accessed June 2011. Water is traditionally removed through evaporation by using methods such as air drying, sun drying, smoking or wind drying, although today electric

food dehydrator Tomato slices ready to be dried in a convection-type food dehydrator. In this model, multiple trays can be stacked on top of each other and warm air flows around the food. A food dehydrator is a device that removes moisture from food to aid in its ...

s or freeze-drying can be used to speed the drying process and ensure more consistent results. 1890 newspaper advertisement showing tin of desiccated cocoanut

1890 newspaper advertisement showing tin of desiccated cocoanut

Food types

Many different foods can be prepared by dehydration. Meat has held a historically significant role. For centuries, much of the European diet depended on dried

cod Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not call ...

—known as salt cod,

bacalhau () is the Portuguese word for cod and—in a culinary context—dried and salted cod. Fresh (unsalted) cod is referred to as (fresh cod). Portuguese and other cuisines dishes are common in Portugal, and also in former Portuguese colonies ...

(with salt), or stockfish (without). It formed the main protein source for the slaves on the

West Indian A West Indian is a native or inhabitant of the West Indies (the Antilles and the Lucayan Archipelago). For more than 100 years the words ''West Indian'' specifically described natives of the West Indies, but by 1661 Europeans had begun to use it ...

plantations, and was a major economic force within the

triangular trade Triangular trade or triangle trade is trade between three ports or regions. Triangular trade usually evolves when a region has export commodities that are not required in the region from which its major imports come. It has been used to offset ...

Dried fish Fresh fish rapidly deteriorates unless some way can be found to preserve it. Drying is a method of food preservation that works by removing water from the food, which inhibits the growth of microorganisms. Open air drying using sun and wind has b ...

most commonly cod or haddock, known as

Harðfiskur Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks (which are called "hjell" in Norway) on the foreshore. The drying of food is the world's oldest known preservation method, and dried fish has a storage li ...

, is a delicacy in

Iceland Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...

, while dried

reindeer Reindeer (in North American English, known as caribou if wild and ''reindeer'' if domesticated) are deer in the genus ''Rangifer''. For the last few decades, reindeer were assigned to one species, ''Rangifer tarandus'', with about 10 sub ...

meat is a traditional

Sami Acronyms * SAMI, ''Synchronized Accessible Media Interchange'', a closed-captioning format developed by Microsoft * Saudi Arabian Military Industries, a government-owned defence company * South African Malaria Initiative, a virtual expertise ...

food. Dried meats include

prosciutto ''Prosciutto crudo'', in English often shortened to prosciutto ( , ), is Italian uncooked, unsmoked, and dry-cured ham. ''Prosciutto crudo'' is usually served thinly sliced. Several regions in Italy have their own variations of ''prosciutto crud ...

(

Parma ham ''Prosciutto crudo'', in English often shortened to prosciutto ( , ), is Italian uncooked, unsmoked, and dry-cured ham. ''Prosciutto crudo'' is usually served thinly sliced. Several regions in Italy have their own variations of ''prosciutto crudo ...

bresaola Bresaola ( , , , ) is air-dried, salted beef (but it can also be made of horse, venison and pork) that has been aged two or three months until it becomes hard and turns a dark red, almost purple color. It is made from top (inside) round, and ...

biltong Biltong is a form of dried, cured meat that originated in Southern African countries (South Africa, Zimbabwe, Malawi, Namibia, Botswana, and Zambia). Various types of meat are used to produce it, ranging from beef to game meats such as ...

and

beef jerky Jerky is lean trimmed meat cut into strips and dried (dehydrated) to prevent spoilage. Normally, this drying includes the addition of salt to prevent bacteria growth before the meat has finished the dehydrating process. The word "jerky" derive ...

. Dried fruits have been consumed historically due to their high sugar content and sweet taste, and a longer

shelf-life Shelf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. In other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use), or no longer on a ...

from drying.

Fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

s may be used differently when dried. The plum becomes a

prune A prune is a dried plum, most commonly from the European plum (''Prunus domestica''). Not all plum species or varieties can be dried into prunes. A prune is the firm-fleshed fruit (plum) of '' Prunus domestica'' varieties that have a high so ...

, the grape a

raisin A raisin is a dried grape. Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking, and brewing. In the United Kingdom, Ireland, New Zealand, and Australia, the word ''raisin'' is reserved for the ...

. Figs and

date Date or dates may refer to: *Date (fruit), the fruit of the date palm (''Phoenix dactylifera'') Social activity *Dating, a form of courtship involving social activity, with the aim of assessing a potential partner ** Group dating *Play date, a ...

s may be transformed into different products that can either be eaten as they are, used in recipes, or rehydrated. Freeze-dried vegetables are often found in food for backpackers, hunters, and the military. Garlic and

onion An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the onio ...

are often dried. Edible mushrooms, as well as other

fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...

, are also sometimes dried for preservation purposes or to be used as seasonings.

Preparation

Home drying of vegetables, fruit and meat can be carried out with electrical dehydrators (household appliance) or by sun-drying or by wind. Preservatives such as

potassium metabisulfite Potassium metabisulfite, K2S2O5, also known as potassium pyrosulfite, is a white crystalline powder with a pungent odour. It is mainly used as an antioxidant or chemical sterilant. As a disulfite, it is chemically very similar to sodium metabi ...

, BHA, or BHT may be used, but are not required. However, dried products without these preservatives may require refrigeration or freezing to ensure safe storage for a long time. Industrial food dehydration is often accomplished by freeze-drying. In this case food is flash frozen and put into a reduced-pressure system which causes the water to sublimate directly from the solid to the gaseous phase. Although freeze-drying is more expensive than traditional dehydration techniques, it also mitigates the change in flavor, texture, and

nutritional value Nutritional value or nutritive value as part of food quality is the measure of a well-balanced ratio of the essential nutrients carbohydrates, fat, protein, minerals, and vitamins in items of food or diet concerning the nutrient requirements of t ...

. In addition, another widely used industrial method of drying of food is convective hot air drying. Industrial hot air dryers are simple and easy to design, construct and maintain. More so, it is very affordable and has been reported to retain most of the nutritional properties of food if dried using appropriate drying conditions. Another form of food dehydration is

irradiation Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve ...

. Irradiation uses

x-rays An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nbs ...

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

, and ionizing radiations to penetrate food to the point of sterilization. Astronauts and people who are highly at risk for microbial infections benefit from this method of food drying.

Hurdle technology Hurdle technology is a method of ensuring that pathogens in food products can be eliminated or controlled. This means the food products will be safe for consumption, and their shelf life will be extended. Hurdle technology usually works by combining ...

is the combination of multiple food preservation methods. Hurdle technology uses low doses of multiple food preservation techniques in order to ensure food is not only safe but is desirable visually and texturally.

Packaging

Packaging ensures effective food preservation. Some methods of packaging that are beneficial to dehydrated food are vacuum sealed, inert gases, or gases that help regulate respiration, biological organisms, and growth of microorganisms.

Other methods

There are many different methods for drying, each with their own advantages for particular applications. These include: * Convection drying * Bed dryers *

Drum drying Drum drying is a method used for drying out liquids from raw materials with a drying drum. In the drum-drying process, pureed raw ingredients are dried at relatively low temperatures over rotating, high-capacity drums that produce sheets of drum-dr ...

Freeze Drying Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product and lowering pressure, removing the ice by sublimation. This is in contrast to dehydration by most conve ...

* Microwave-vacuum drying * Shelf dryers *

Spray drying Spray drying is a method of changing a dry powder from a liquid or slurry by rapidly drying with a hot gas. This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals, or materials which may requ ...

* Infrared radiation drying *

Combined thermal hybrid drying Combined may refer to: * Alpine combined (skiing), the combination of slalom and downhill skiing as a single event ** Super combined (skiing) * Nordic combined (skiing), the combination of cross country skiing and ski jumping as a single event * T ...

* Sunlight * Commercial

s * Household oven

References

External links