Fish drying in the sun poisson seche Madagascar

Food drying is a method of

food preservation Food preservation includes processes that make food more resistant to microorganism growth and slow the redox, oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that in ...

in which food is dried (dehydrated or

desiccated Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. ...

). Drying inhibits the growth of

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

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

s, and

mold A mold () or mould () is one of the structures that certain fungus, fungi can form. The dust-like, colored appearance of molds is due to the formation of Spore#Fungi, spores containing Secondary metabolite#Fungal secondary metabolites, fungal ...

through the removal of

water Water is an inorganic compound with the chemical formula . It is a transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance. It is the main constituent of Earth's hydrosphere and the fluids of all known liv ...

. 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 Asian and Middle Eastern regions."Historical Origins of Food Preservation".
Accessed June 2011. Water is traditionally removed through

evaporation Evaporation is a type of vaporization that occurs on the Interface (chemistry), surface of a liquid as it changes into the gas phase. A high concentration of the evaporating substance in the surrounding gas significantly slows down evapora ...

by using methods such as air drying, sun drying, smoking or wind drying, although today electric food dehydrators or

freeze-drying Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature Food drying, dehydration process that involves freezing the product and lowering pressure, thereby removing the ice by Sublimation (phase transition), sublimat ...

can be used to speed the drying process and ensure more consistent results. 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 (: cod) is the common name for the demersal fish genus ''Gadus'', belonging to the family (biology), 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 ''Gad ...

—known as

salt cod Dried and salted cod, sometimes referred to as salt cod or saltfish or salt dolly, is cod which has been preserved by drying after salting. Cod which has been dried without the addition of salt is stockfish. Salt cod was long a major export o ...

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 colonie ...

(with salt), or

stockfish 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 ...

(without). It formed the main protein source for the

slaves Slavery is the ownership of a person as property, especially in regards to their labour. Slavery typically involves compulsory work, with the slave's location of work and residence dictated by the party that holds them in bondage. Enslavemen ...

on the

West Indian A West Indian is a native or inhabitant of the West Indies (the Antilles and the Lucayan Archipelago). According to the ''Oxford English Dictionary'' (''OED''), the term ''West Indian'' in 1597 described the indigenous inhabitants of the West In ...

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 (food), 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 ...

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 a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

, while dried

reindeer The reindeer or caribou (''Rangifer tarandus'') is a species of deer with circumpolar distribution, native to Arctic, subarctic, tundra, taiga, boreal, and mountainous regions of Northern Europe, Siberia, and North America. It is the only re ...

meat is a traditional

Sámi 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 Food is any substance consumed by an organism for Nutrient, nutritional support. Food is usually of plant, animal, or Fungus, fungal origin and contains essential nutrients such as carbohydrates, fats, protein (nutrient), proteins, vitamins, ...

. Dried meats include

prosciutto Prosciutto ( ; ), also known as ''prosciutto crudo'', is an uncooked, unsmoked, and dry-cured ham. It is usually served thinly sliced. Several regions in Italy have their own variations of ''prosciutto crudo'', each with degrees of protected ...

(

Parma ham Prosciutto ( ; ), also known as ''prosciutto crudo'', is an uncooked, unsmoked, and dry-cured ham. It is usually served thinly sliced. Several regions in Italy have their own variations of ''prosciutto crudo'', each with degrees of protected ...

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 colour. It is made from top (inside) round, and it is le ...

biltong Biltong is a form of air-dried, cured meat which originated in Southern Africa. Southern African countries include South Africa, Zimbabwe, Namibia, Zambia, Malawi, Botswana, Lesotho and Eswatini. Various types of meat are used to produce ...

and

beef jerky Jerky is lean trimmed meat strips which are dehydrated to prevent spoilage and seasoned to varying degrees. Normally, this drying includes the addition of salt to prevent microbial growth through osmosis. The word "jerky" derives from the ...

. 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 s ...

from drying.

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

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

prune A prune is a dried plum, most commonly from the European plum (''Prunus domestica'') tree. Not all plum species or varieties can be dried into prunes. Use of the term ''prune'' for fresh plums is obsolete except when applied to varieties of ...

, the grape a

raisin A raisin is a Dried fruit, 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, Republic of Ireland, Ireland, New Zealand, Australia and South Afri ...

. Figs and dates 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 Garlic (''Allium sativum'') is a species of bulbous flowering plants in the genus '' Allium''. Its close relatives include the onion, shallot, leek, chives, Welsh onion, and Chinese onion. Garlic is native to central and south Asia, str ...

and

onion An onion (''Allium cepa'' , from Latin ), 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 onion which was classifie ...

are often dried and stored with their stalks braided. Edible mushrooms are sometimes dried for preservation 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

. 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 ...

. 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.

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 combinin ...

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

microorganism A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen ...

Other methods

There are many different methods for drying, each with its 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, thereby removing the ice by sublimation. This is in contrast to dehydration by ...

* Microwave-vacuum drying * Shelf dryers *

Spray drying Spray drying is a method of forming 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 *

Sunlight Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible spectrum, visible light perceptible to the human eye as well as invisible infrare ...

* Commercial food dehydrators * Household

oven upA double oven A ceramic oven An oven is a tool that is used to expose materials to a hot environment. Ovens contain a hollow chamber and provide a means of heating the chamber in a controlled way. In use since antiquity, they have been use ...

References

* Mendonca, Aubrey F., and Norman N. Potter. "Food Preservation." AccessScience, McGraw-Hill Education, 2016.

External links