frozen food citeureup

Food stored at temperatures below the freezing point of h2o, for extending its shelf life

A frozen processed foods alley at a supermarket in Canada

Freezing nutrient preserves it from the time information technology is prepared to the time it is eaten. Since early times, farmers, fishermen, and trappers have preserved grains and produce in unheated buildings during the wintertime season.^[one] Freezing nutrient slows decomposition by turning residue moisture into ice, inhibiting the growth of near bacterial species. In the food commodity industry, in that location are 2 processes: mechanical and cryogenic (or flash freezing). The freezing kinetics is important to preserve the food quality and texture. Quicker freezing generates smaller ice crystals and maintains cellular structure. Cryogenic freezing is the quickest freezing engineering science available due to the ultra low liquid nitrogen temperature −196 °C (−320 °F).^[2]

Preserving food in domestic kitchens during mod times is accomplished using household freezers. Accepted advice to householders was to freeze food on the day of buy. An initiative by a supermarket group in 2012 (backed past the UK'south Waste & Resources Action Plan) promotes the freezing of food "as soon as possible up to the product'due south 'use by' appointment". The Food Standards Agency was reported as supporting the alter, provided the food had been stored correctly upwardly to that fourth dimension.^[3]

Preservatives [edit]

Frozen products do non require any added preservatives because microorganisms practice not grow when the temperature of the food is below −9.5 °C (15 °F), which is sufficient on its own in preventing food spoilage. Long-term preservation of food may telephone call for food storage at even lower temperatures. Carboxymethylcellulose (CMC), a tasteless and odorless stabilizer, is typically added to frozen food because it does not adulterate the quality of the product.^[4]

History [edit]

Natural nutrient freezing (using winter frosts) had been in utilise by people in cold climates for centuries.

In 1861 Thomas Sutcliffe Mort established at Darling Harbour in Sydney, Australia, the globe'southward first freezing works, which later became the New South Wales Fresh Nutrient and Water ice Company. Mort financed experiments by Eugene Dominic Nicolle, a French born engineer who had arrived in Sydney in 1853 and registered his first water ice-making patent in 1861. The first trial shipment of frozen meat to London was in 1868. Although their mechanism was never used in the frozen meat merchandise, Mort and Nicolle developed commercially viable systems for domestic trade. The financial render on that investment was minimal for Mort.

By 1885 a minor number of chickens and geese were being shipped from Russia to London in insulated cases using this technique. By March 1899, the "British Refrigeration and Centrolineal Interests" reported that a food importing business organization, "Baerselman Bros", was shipping some 200,000 frozen geese and chickens per week from three Russian depots to New Star Wharf, Lower Shadwell, London over 3 or four winter months. This trade in frozen food was enabled past the introduction of Linde cold air freezing plants in three Russian depots and the London warehouse. The Shadwell warehouse stored the frozen goods until they were shipped to markets in London, Birmingham, Liverpool and Manchester. The techniques were later on expanded to the meat packing industry.

From 1929, Clarence Birdseye introduced "flash freezing" to the American public. Birdseye first became interested in food freezing during fur-trapping expeditions to Labrador in 1912 and 1916, where he saw the natives utilize natural freezing to preserve foods.^[5] The Icelandic Fisheries Commission was created in 1934 to initiate innovation in the industry, and encouraged fishermen to starting time quick-freezing their catch. Íshúsfélag Ísfirðinga, one of the showtime frozen fish companies, was formed in Ísafjörður, Iceland, past a merger in 1937.^{[half dozen]} More than advanced attempts include nutrient frozen for Eleanor Roosevelt on her trip to Russia. Other experiments involving orange juice, ice cream and vegetables were conducted by the military well-nigh the end of World War II.

Engineering [edit]

The freezing technique itself, just like the frozen food market, is developing to become faster, more efficient and more price-effective. As demonstrated by Birdeye's work, faster freezing means smaller ice crystals and a ameliorate-preserved production.^[7]

Birdeye's original cryogenic freezing approach using immersion in liquid nitrogen is even so used.^[viii] Due to its cost, however, apply is limited to fish fillets, seafood, fruits, and berries. Information technology is as well possible to freeze food by immersion in the warmer (at −70 °C (−94 °F)), but cheaper, liquid carbon dioxide, which tin can be produced by mechanical freezing (see below).^[seven]

Most frozen nutrient is instead frozen using a mechanical process using the vapor-pinch refrigeration technology similar to ordinary freezers. Such a process is cheaper at scale, but is usually slower. (There is also more upfront investment in the form of construction.) However, a broad variety of processes have been devised to accomplish faster oestrus transfer from the nutrient to the refrigerant:^[7]

• Air-smash freezing is the oldest and cheapest arroyo. Food is placed into freezing rooms where the air is cold. Air is either forced ("blasted") onto the food or left static. This setup allows large chunks of food (ordinarily meat or fish) to be easily processed compared to other methods, but is quite deadening.
  • Belt freezers simply put a conveyor belt within a common cold room.
  • Tunnel freezing is a variant of air-blast freezing where nutrient is put onto trolley racks and sent into a tunnel where common cold air is continuously circulated.
  • Fluidized bed freezing is a variant of air-boom freezing where pelletized food is blown past fast-moving cold air from below, forming a fluidized bed. The small size of the food combined with the fast-flowing air provides good heat transfer and therefore quick freezing.
• Contact freezing uses concrete contact other than air to transfer the estrus. Direct contact freezing puts the product directly in contact with the refrigerant, while indirect contact freezing uses a plate in between.
  • Plate freezing is the well-nigh common form of contact freezing. Food is put betwixt cold metal plates and then lightly pressed to maintain contact.
  • Contact chugalug freezing combines a conveyor belt with plate freezing. It is usually used for fruit pulps, egg yolk, sauces and soups.
  • Immersion freezing dips the product into a common cold refrigerant liquid to freeze information technology, usually on a conveyor belt. The production may be in direct contact with the liquid, or be separated by a membrane. It tin can be used for freezing the outer shell of large particles to reduce h2o loss.

Individual Quick Freezing is a descriptive term that includes all forms of freezing that is "individual" (not in a whole cake) and "quick" (taking a maximum of several minutes). It may correspond to cryogenic freezing, fluidized bed freezing, or whatsoever other technique that meets the definition.

Packaging [edit]

Frozen food packaging must maintain its integrity throughout filling, sealing, freezing, storage, transportation, thawing, and often cooking.^[9] As many frozen foods are cooked in a microwave oven, manufacturers have developed packaging that can go straight from freezer to the microwave.

In 1974, the beginning differential heating container (DHC) was sold to the public. A DHC is a sleeve of metal designed to allow frozen foods to receive the correct amount of oestrus. Various sized apertures were positioned around the sleeve. The consumer would put the frozen dinner into the sleeve according to what needed the most heat. This ensured proper cooking.^[x]

Today there are multiple options for packaging frozen foods. Boxes, cartons, bags, pouches, Boil-in-Numberless, lidded trays and pans, crystallized PET trays, and composite and plastic cans.^[11]

Scientists go on to enquiry new aspects of frozen food packaging. Active packaging offers many new technologies that tin actively sense and so neutralize the presence of bacteria or other harmful species. Active packaging can extend shelf-life, maintain product safety, and help preserve the food over a longer menstruum of fourth dimension. Several functions of active packaging are being researched:

• Oxygen scavengers
• Time Temperature Indicators and digital temperature data loggers
• Antimicrobials
• Carbon Dioxide controllers
• Microwave susceptors
• Moisture control: H2o activity, Moisture vapor transmission rate, etc.
• Flavor enhancers
• Odour generators
• Oxygen-permeable films
• Oxygen generators^[12]

Furnishings on nutrients [edit]

The process of wink freezing itself generally effectively retain the food content of foodstuff with minor losses of vitamin, making them a cost-constructive and nutritious substitute for fresh equivalents. Still, pre-seasoned frozen nutrient, such as packaged meals, may have a meaning amounts of salt and fats added. It is therefore recommended to read the nutrition label.^[13]

Vitamin content of frozen fruits and vegetables [edit]

• Vitamin C: Usually lost in a higher concentration than whatever other vitamin.^[14] A report was performed on peas to determine the cause of vitamin C loss. A vitamin loss of x% occurred during the blanching phase with the residuum of the loss occurring during the cooling and washing stages.^[15] The vitamin loss was not actually accredited to the freezing procedure. Another experiment was performed involving peas and lima beans. Frozen and canned vegetables were both used in the experiment. The frozen vegetables were stored at −23 °C (−10 °F) and the canned vegetables were stored at room temperature 24 °C (75 °F). After 0, 3, half-dozen, and 12 months of storage, the vegetables were analyzed with and without cooking. O'Hara, the scientist performing the experiment said, "From the view bespeak of the vitamin content of the 2 vegetables when they were ready for the plate of the consumer, there did not appear to be any marked advantages attributable to method of preservation, frozen storage, processed in a can, or processed in glass."^[16]
• Vitamin B₁ (Thiamin): A vitamin loss of 25% is normal. Thiamin is hands soluble in water and is destroyed by rut.^[17]
• Vitamin B_two (Riboflavin): Not much inquiry has been done to determine how freezing affects Riboflavin levels. Studies that have been performed are inconclusive. I report institute an xviii% vitamin loss in greenish vegetables, while another found a 4% loss.^[xviii] It is ordinarily accustomed that the loss of Riboflavin has to do with the preparation for freezing rather than the freezing procedure itself.
• Vitamin A (Carotene): There is little loss of carotene during preparation for freezing and freezing of most vegetables. Much of the vitamin loss is incurred during the extended storage period.^[19]

Effectiveness [edit]

Freezing is an constructive form of food preservation because the pathogens that crusade food spoilage are killed or do non grow very rapidly at reduced temperatures. The process is less effective in food preservation than are thermal techniques, such as boiling, because pathogens are more likely to be able to survive cold temperatures rather than hot temperatures.^[20] One of the problems surrounding the use of freezing as a method of food preservation is the danger that pathogens deactivated (but not killed) by the process will in one case again become agile when the frozen nutrient thaws.

Foods may exist preserved for several months past freezing. Long-term frozen storage requires a abiding temperature of −eighteen °C (0 °F) or less.^[21]

Defrosting [edit]

To exist used, many cooked foods that have been previously frozen require defrosting prior to consumption. Preferably, some frozen meats should be defrosted prior to cooking to achieve the best outcome: cooked through evenly and of proficient texture.

The defrost system in freezers helps the equipment to perform properly, without thick layers of water ice developing, thus preventing the evaporator curlicue from absorbing heat and cooling the cabinet.

Ideally, nearly frozen foods should be defrosted in a refrigerator to avert meaning growth of pathogens. Nonetheless, this tin can crave considerable time.

Food is oft defrosted in one of several means:

• at room temperature; this is dangerous since the exterior may exist defrosted while the inside remains frozen^[22]
• in a refrigerator^[22]
• in a microwave oven^[22]
• wrapped in plastic and placed in cold h2o^[22] or under cold running water

People sometimes defrost frozen foods at room temperature because of time constraints or ignorance. Such foods should be promptly consumed afterward cooking or discarded and never be refrozen or refrigerated since pathogens are not killed past the refreezing process.^{[ commendation needed ]}

Quality [edit]

The speed of freezing has a directly bear on on the size and the number of ice crystals formed within a food product'southward cells and extracellular space. Slow freezing leads to fewer but larger ice crystals while fast freezing leads to smaller but more than numerous ice crystals. This difference in ice crystal size can affect the caste of rest enzymatic activity during frozen storage via the process of freeze concentration, which occurs when enzymes and solutes present in a fluid medium are concentrated between ice crystal formations.^[23] Increased levels of freeze concentration, mediated by the formation of large ice crystals, can promote enzymatic browning.^[24] Large ice crystals tin also puncture the walls of the cells of the food production which will cause a degradation of the texture of the product likewise as the loss of its natural juices during thawing.^[25] That is why there will exist a qualitative difference observed between food products frozen past ventilated mechanical freezing, not-ventilated mechanical freezing or cryogenic freezing with liquid nitrogen.^[26]

Reaction [edit]

According to a study, an American consumes frozen food on average 71 times a year, virtually of which are pre-cooked frozen meals.^[27]

See also [edit]

• List of frozen food brands
  • List of frozen dessert brands
  • List of ice cream brands
• Refrigerator
• Boil-in-bag
• Cold chain

Notes [edit]

1. ^ Tressler, Evers. The Freezing Preservation of Foods pp. 213-217
2. ^ Lord's day, Da-Wen (2001). Advances in food refrigeration. Leatherhead Food Inquiry Association Publishing. p.318. (Cryogenic refrigeration)
3. ^ Smithers, Rebecca (February ten, 2012). "Sainsbury's changes food freezing advice in bid to cut nutrient waste". The Guardian . Retrieved February 10, 2012. Long-standing communication to consumers to freeze food on the solar day of purchase is to be changed past a leading supermarket chain, as part of a national initiative to further reduce nutrient waste matter. [...] instead advise customers to freeze food as shortly as possible up to the product's 'use by' engagement. The initiative is backed past the regime's waste advisory body, the Waste and Resource Action Programme (Wrap) [...] Bob Martin, food safe expert at the Nutrient Standards Agency, said: "Freezing later on the day of buy shouldn't pose a nutrient safe risk as long as nutrient has been stored in accordance with whatever instructions provided. [...]"
4. ^ Arsdel, Michael, Robert. Quality and Stability of Frozen Foods: Time-Temperature Tolerance and its Significance. pp. 67-69
5. ^ "Frozen Foods". Massachusetts Constitute of Technology. Archived from the original on 2003-02-25.
6. ^ Hraðfrystihúsið - Gunnvör hf. (10 Jan 2012), Öld frá stofnun Íshúsfélags Ísfirðinga hf. (in Icelandic), archived from the original on 9 October 2018, retrieved 2017-05-31
7. ^ ^{a b c} "Freezing of fruits and vegetables". world wide web.fao.org . Retrieved 2022-04-06 .
8. ^ p.157-170, Institute for Practical Biology, Springer-Verlag
9. ^ Decareau, Robert. Microwave Foods: New Product Development. pp. 45-48
10. ^ Whelan, Stare. Panic in the Pantry: Facts and Fallacies About the Food You lot Purchase
11. ^ Russell, Gould. Food Preservatves. pp. 314
12. ^ Sun, Da-Wen. Handbook of Frozen Nutrient Processing and Packaging. pp. 786-792
13. ^ "Frozen Foods: Convenient and Nutritious". world wide web.eatright.org.
14. ^ Tressler, Evers. The Freezing Preservation of Foods. pp. 620-624
15. ^ Tressler, Evers. The Freezing Preservation of Foods. pp. 961-964
16. ^ Tressler, Evers. The Freezing Preservation of Foods. p. 627
17. ^ Gould, Grahame. New Methods of Food Preservation. pp. 237-239
18. ^ Tressler, Evers. pp. 973-976
19. ^ Tressler, Evers. The Freezing Preservation of Foods. pp. 976-978
20. ^ Mathlouthi, M. Food Packaging and Preservation. pp. 112-115
21. ^ Tressler, Evers, Evers. Into the Freezer - and Out. pp. 56-82
22. ^ ^{a b c d} "Consumer Resources - NSF International". world wide web.nsf.org.
23. ^ Samsel G, Meghani A. The Furnishings of Commercial Freezing on Vitamin Concentrations in Spinach (Spinacia oleracea). J Undergrad Life Sci. 2021 Jul.23
24. ^ van der Sman, R.G.M. Bear upon of Processing Factors on Quality of Frozen Vegetables and Fruits. Food Eng Rev 12, 399–420 (2022)
25. ^ W.F.Stoecker,Industrial Refrigeration Handbook, 2000, Chapter 17 Refrigeration and freezing of foods, 17.x The freezing procedure
26. ^ Food analysis laboratory manual. Nielsen, South. Suzanne. (2nd ed.). New York: Springer. 2010. ISBN978-1-4419-1463-7. OCLC 663096771. {{cite book}}: CS1 maint: others (link)
27. ^ Harris, J. Michael and Rimma Shipstova, Consumer Demand for Convenience Foods: Demographics and Expenditures (PDF), AgEcon, p. 26, retrieved 16 July 2011

References [edit]

• Arsdel, Wallace, B. Van, Michael, J Copley, and Robert, L. Olson. Quality and Stability of Frozen Foods: Time-Temperature Tolerance and its Significance. New York, NY: John Wiley & Sons,INC, 1968.
• "Clarence Birdseye." Encyclopedia of Globe Biography. Vol. 19. 2nd ed. Detroit: Gale, 2004. 25-27. Gale Virtual Reference Library. Gale. Brigham Young University - Utah. Nov. three 2009. (subscription required)
• Copson, David. Microwave Heating. 2nd ed.. Westport, CT: The AVI Publishing Company, INC., 1975.
• Decareau, Robert. Microwave Foods: New Product Development. Trumbull, CT: Food & Nutrition Press, INC., 1992.
• Gould, Grahame. New Methods of Nutrient Preservation. New York, NY: Chapman & Hall, 2000.
• Mathlouthi, Mohamed. Food Packaging and Preservation. New York, NY: Chapman & Hall, 1994.*^Robinson, Richard. Microbiology of Frozen Foods. New York, NY: Elsevier Engineering Publishers LTD, 1985.
• Russell, Nicholas J., and Grahame Due west. Gould. Food Preservatives. 2nd ed. New York, NY: Kluwer Academic/Plenum Publishers, New York, 2003.
• Sun, Da-Wen. Handbook of Frozen Food Processing and Packaging. Boca Raton, Fl: Taylor & Francis Group, LLC, 2006.
• Tressler, Donald M., Clifford F. Evers, and Barbara, Hutchings Evers. Into the Freezer - and Out. 2nd ed. New York, NY: The AVI Publishing Company, INC., 1953.
• Tressler, Donald Grand., and Clifford F. Evers. The Freezing Preservation of Foods. tertiary ed. 1st book. Westport, CT: The AVI Publishing Visitor, INC., 1957.
• Whelan, Elizabeth M., and Fredrick J. Stare. Panic in the Pantry: Facts and Fallacies About the Nutrient You Purchase. Buffalo, NY: Prometheus Books, 1998.

External links [edit]

• Media related to Frozen food at Wikimedia Eatables
• Food and Agriculture

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