Food drying

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Flattened fish drying in the sun in Madagascar. Fish are preserved through such traditional methods as drying, smoking and salting. Fish drying in the sun poisson seche Madagascar.jpg
Flattened fish drying in the sun in Madagascar. Fish are preserved through such traditional methods as drying, smoking and salting.
A whole potato, sliced pieces (right), and dried sliced pieces (left), 1943 Potato - dehydrated and sliced.jpg
A whole potato, sliced pieces (right), and dried sliced pieces (left), 1943

Food drying is a method of food preservation in which food is dried (dehydrated or desiccated). Drying inhibits the growth of bacteria, yeasts, and mold through the removal of water. 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. [2] Water is traditionally removed through evaporation by using methods such as air drying, sun drying, smoking or wind drying, although today electric food dehydrators or freeze-drying can be used to speed the drying process and ensure more consistent results. [3]

Contents

1890 newspaper advertisement showing tin of dried coconut 1890 newspaper advertisement showing tin of desiccated cocoanut.jpg
1890 newspaper advertisement showing tin of dried coconut

Food types

A collection of dried mushrooms Dried mushrooms.jpg
A collection of dried mushrooms
Sun-drying octopus Octopus drying under the sun in Greece.jpg
Sun-drying octopus

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—known as salt cod, bacalhau (with salt), or stockfish (without). It formed the main protein source for the slaves on the West Indian plantations, and was a major economic force within the triangular trade. Dried fish most commonly cod or haddock, known as Harðfiskur, is a delicacy in Iceland, while dried reindeer meat is a traditional Sámi food. Dried meats include prosciutto (Parma ham), bresaola, biltong and beef jerky.

Dried fruits have been consumed historically due to their high sugar content and sweet taste, and a longer shelf-life from drying. [4] Fruits may be used and named differently when dried. The plum becomes a prune, the grape a raisin. 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 and onion 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. [5] Preservatives such as potassium metabisulfite, 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. 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. [6]

Hurdle technology 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.[ citation needed ]

Other methods

This electric food dehydrator, shown drying mango and papaya slices, has a hot air blower that blows air through food-laden trays. Food dehydrator.jpg
This electric food dehydrator, shown drying mango and papaya slices, has a hot air blower that blows air through food-laden trays.

There are many different methods for drying, [7] each with its own advantages for particular applications. These include:

See also

Related Research Articles

<span class="mw-page-title-main">Food preservation</span> Inhibition of microbial growth in food

Food preservation includes processes that make food more resistant to microorganism growth and slow the oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut during food preparation. By preserving food, food waste can be reduced, which is an important way to decrease production costs and increase the efficiency of food systems, improve food security and nutrition and contribute towards environmental sustainability. For instance, it can reduce the environmental impact of food production.

A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product. Physical preservation entails processes such as refrigeration or drying. Preservative food additives reduce the risk of foodborne infections, decrease microbial spoilage, and preserve fresh attributes and nutritional quality. Some physical techniques for food preservation include dehydration, UV-C radiation, freeze-drying, and refrigeration. Chemical preservation and physical preservation techniques are sometimes combined.

<span class="mw-page-title-main">Spray drying</span> Method of converting liquid or slurry to powder

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 require extremely consistent, fine particle size. Air is most commonly used as the heated drying medium; however, nitrogen may be used if the liquid is flammable or if the product is oxygen-sensitive.

<span class="mw-page-title-main">Jerky</span> Lean meat dried to prevent spoilage

Jerky is lean trimmed meat cut into strips and dehydrated to prevent spoilage. Normally, this drying includes the addition of salt to prevent bacteria growth. The word "jerky" derives from the Quechua word ch'arki which means "dried, salted meat".

<span class="mw-page-title-main">Food storage</span> Type of storage that allows food to be eaten after time

Food storage is a way of decreasing the variability of the food supply in the face of natural, inevitable variability. It allows food to be eaten for some time after harvest rather than solely immediately. It is both a traditional domestic skill and, in the form of food logistics, an important industrial and commercial activity. Food preservation, storage, and transport, including timely delivery to consumers, are important to food security, especially for the majority of people throughout the world who rely on others to produce their food.

<span class="mw-page-title-main">Dried fruit</span> Fruit from which the majority of the original water content has been removed

Dried fruit is fruit from which the majority of the original water content has been removed either naturally, through sun drying, or through the use of specialized dryers or dehydrators. Dried fruit has a long tradition of use dating back to the fourth millennium BC in Mesopotamia, and is prized because of its sweet taste, nutritive value, and long shelf life.

<span class="mw-page-title-main">Freeze drying</span> Low temperature dehydration process

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 most conventional methods that evaporate water using heat.

<span class="mw-page-title-main">Modified atmosphere</span>

Modified atmosphere packaging (MAP) is the practice of modifying the composition of the internal atmosphere of a package in order to improve the shelf life. The need for this technology for food arises from the short shelf life of food products such as meat, fish, poultry, and dairy in the presence of oxygen. In food, oxygen is readily available for lipid oxidation reactions. Oxygen also helps maintain high respiration rates of fresh produce, which contribute to shortened shelf life. From a microbiological aspect, oxygen encourages the growth of aerobic spoilage microorganisms. Therefore, the reduction of oxygen and its replacement with other gases can reduce or delay oxidation reactions and microbiological spoilage. Oxygen scavengers may also be used to reduce browning due to lipid oxidation by halting the auto-oxidative chemical process. Besides, MAP changes the gaseous atmosphere by incorporating different compositions of gases.

<span class="mw-page-title-main">Instant mashed potatoes</span> Dehydrated mashed potatoes reconstituted by adding water or milk

Instant mashed potatoes are potatoes that have been through an industrial process of cooking, mashing and dehydrating to yield a packaged convenience food that can be reconstituted by adding hot water and/or milk, producing an approximation of mashed potatoes. They are available in many different flavors.

<span class="mw-page-title-main">Drying</span> Removal of water or another solvent by evaporation from a solid, semi-solid or liquid

Drying is a mass transfer process consisting of the removal of water or another solvent by evaporation from a solid, semi-solid or liquid. This process is often used as a final production step before selling or packaging products. To be considered "dried", the final product must be solid, in the form of a continuous sheet, long pieces, particles or powder. A source of heat and an agent to remove the vapor produced by the process are often involved. In bioproducts like food, grains, and pharmaceuticals like vaccines, the solvent to be removed is almost invariably water. Desiccation may be synonymous with drying or considered an extreme form of drying.

<span class="mw-page-title-main">Outline of food preparation</span> Art form and applied science to make food ingredients palatable and fit to eat

The following outline is provided as an overview of and topical guide to the preparation of food:

<span class="mw-page-title-main">Instant soup</span>

Instant soup is a type of soup designed for fast and simple preparation. Some are homemade, and some are mass-produced on an industrial scale and treated in various ways to preserve them. A wide variety of types, styles and flavors of instant soups exist. Commercial instant soups are usually dried or dehydrated, canned, or treated by freezing.

<span class="mw-page-title-main">Cured fish</span> Fish subjected to fermentation, pickling or smoking

Cured fish is fish which has been cured by subjecting it to fermentation, pickling, smoking, or some combination of these before it is eaten. These food preservation processes can include adding salt, nitrates, nitrite or sugar, can involve smoking and flavoring the fish, and may include cooking it. The earliest form of curing fish was dehydration. Other methods, such as smoking fish or salt-curing also go back for thousands of years. The term "cure" is derived from the Latin curare, meaning to take care of. It was first recorded in reference to fish in 1743.

<span class="mw-page-title-main">Food dehydrator</span> Home food preservation

A food dehydrator is a device that removes moisture from food to aid in its preservation. Food drying is a method of preserving fruit, vegetables and meats that has been practiced since antiquity.

<span class="mw-page-title-main">Fish preservation</span> Techniques for preserving fish

Fish preservation is the method of increasing the shelf life of fish and other fish products by applying the principles of different branches of science in order to keep the fish, after it has landed, in a condition wholesome and fit for human consumption. Ancient methods of preserving fish included drying, salting, pickling and smoking. All of these techniques are still used today but the more modern techniques of freezing and canning have taken on a large importance.

<span class="mw-page-title-main">Home canning</span> Process for preserving foods for storage

Home canning or bottling, also known colloquially as putting up or processing, is the process of preserving foods, in particular, fruits, vegetables, and meats, by packing them into glass jars and then heating the jars to create a vacuum seal and kill the organisms that would create spoilage.

<span class="mw-page-title-main">Food spoilage</span> Often due to bacteria and fungi

Food spoilage is the process where a food product becomes unsuitable to ingest by the consumer. The cause of such a process is due to many outside factors as a side-effect of the type of product it is, as well as how the product is packaged and stored. Due to food spoilage, one-third of the world's food produced for the consumption of humans is lost every year. Bacteria and various fungi are the cause of spoilage and can create serious consequences for the consumers, but there are preventive measures that can be taken.

Vacuum drying is the mass transfer operation in which the moisture present in a substance, usually a wet solid, is removed by means of creating a vacuum.

<span class="mw-page-title-main">Intermediate moisture food</span> Shelf-stable food products with moisture contents of 15-40%

Intermediate moisture foods (IMF) are shelf-stable products that have water activities of 0.6-0.85, with a moisture content ranging from 15% - 40% and are edible without rehydration. These food products are below the minimum water activity for most bacteria (0.90), but are susceptible to yeast and mold growth. Historically, ancient civilizations would produce IMF using methods such as sun drying, roasting over fire and adding salt to preserve food for winter months or when preparing for travel. Currently, this form of processing is achieved by using one of four methods: partial drying, osmotic drying using a humectant, dry infusion and by formulation. A variety of products are classified as IMF, such as dried fruits, sugar added commodities, marshmallows, and pie fillings.

References

  1. Grandidier (1899), p. 521
  2. "Historical Origins of Food Preservation". Accessed June 2011.
  3. Rahman, M. Shafiur, ed. (2007). Handbook of Food Preservation (2nd ed.). Boca Raton: CRC Press. ISBN   9781420017373.
  4. Trager, James (1997). The Food Chronology: A Food Lover's Compendium of Events and Anecdotes from Prehistory to the Present. Henry Holt. ISBN   978-0805052473.
  5. "Food Dehydrator reviews". www.dehydratorjudge.com. Retrieved 19 April 2016.
  6. Onwude, Daniel I.; Hashim, Norhashila; Janius, Rimfiel B.; Nawi, Nazmi Mat; Abdan, Khalina (2016-02-04). "Modeling the thin-layer drying of fruits and vegetables: A review" (PDF). Comprehensive Reviews in Food Science and Food Safety. 15 (3): 599–618. doi: 10.1111/1541-4337.12196 . PMID   33401820.
  7. 1 2 3 Si X, Chen Q, Bi J, Wu X, Yi J, Zhou L, Li Z (2016). "Comparison of different drying methods on the physical properties, bioactive compounds and antioxidant activity of raspberry powders". J Sci Food Agric. 96 (6): 2055–62. Bibcode:2016JSFA...96.2055S. doi:10.1002/jsfa.7317. PMID   26108354.
  8. Onwude, Daniel I.; Hashim, Norhashila; Chen, Guangnan (2016-10-30). "Recent advances of novel thermal combined hot air drying of agricultural crops". Trends in Food Science & Technology. 57 (A): 132–145. doi:10.1016/j.tifs.2016.09.012 . Retrieved 2017-03-25.