Freezer burn is a condition that occurs when frozen food has been damaged by dehydration and oxidation due to air reaching the food. [1] It is generally caused by food not being securely wrapped in air-tight packaging.
Freezer burn appears as grayish-brown leathery spots on frozen food and occurs when air reaches the food's surface and dries the product. Color changes result from chemical changes in the food's pigment. Freezer burn does not make the food unsafe; it merely causes dry spots in foods. [2] The food remains usable and edible, but removing the freezer burns will improve the flavor.
The dehydration of freezer-burned food is caused by water sublimating from the food into the surrounding atmosphere. The lost water may then be deposited elsewhere in the food and packaging as snow-like crystals. [3] [4] Fluctuation of temperatures in a freezer above 0 degrees Fahrenheit (-17.7 degrees Celcius), can also speed up freezer burn. [5]
The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is called a compression-ignition engine. This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine or a gas engine.
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.
Ice cream is a frozen dessert typically made from milk or cream that has been flavoured with a sweetener, either sugar or an alternative, and a spice, such as cocoa or vanilla, or with fruit, such as strawberries or peaches. Food colouring is sometimes added in addition to stabilizers. The mixture is cooled below the freezing point of water and stirred to incorporate air spaces and prevent detectable ice crystals from forming. It can also be made by whisking a flavoured cream base and liquid nitrogen together. The result is a smooth, semi-solid foam that is solid at very low temperatures. It becomes more malleable as its temperature increases.
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog affects many human activities, such as shipping, travel, and warfare.
Food drying is a method of food preservation in which food is dried. 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. 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.
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.
Freezing food preserves it from the time it 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 winter season. Freezing food slows decomposition by turning residual moisture into ice, inhibiting the growth of most bacterial species. In the food commodity industry, there are two processes: mechanical and cryogenic. 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 technology available due to the ultra low liquid nitrogen temperature −196 °C (−320 °F).
A frozen meal, prepackaged meal, ready-made meal, ready meal (UK), frozen dinner, and microwave meal is ultra-processed food portioned for an individual. A frozen meal in the United States and Canada usually consists of a type of meat, fish, or pasta for the main course, and sometimes vegetables, potatoes, and/or a dessert. Some frozen meals feature Indian, Chinese, Mexican, and other foods of international customs. Another form of convenience food, which is merely a refrigerated ready meal that requires less heating but expires sooner, is popular.
Gelato is the common word in Italian for all kinds of ice cream. In English, it specifically refers to a frozen dessert of Italian origin. Artisanal gelato in Italy generally contains 6–9% butterfat, which is lower than other styles of frozen dessert. Gelato typically contains 35% air and more flavoring than other kinds of frozen desserts, giving it a density and richness that distinguishes it from other ice creams.
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.
A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump that transfers heat from its inside to its external environment so that its inside is cooled to a temperature below the room temperature. Refrigeration is an essential food storage technique around the world. The low temperature lowers the reproduction rate of bacteria, so the refrigerator reduces the rate of spoilage. A refrigerator maintains a temperature a few degrees above the freezing point of water. The optimal temperature range for perishable food storage is 3 to 5 °C. A similar device that maintains a temperature below the freezing point of water is called a freezer. The refrigerator replaced the icebox, which had been a common household appliance for almost a century and a half. The United States Food and Drug Administration recommends that the refrigerator be kept at or below 4 °C (40 °F) and that the freezer be regulated at −18 °C (0 °F).
Clarence Birdseye was an American inventor, entrepreneur, and naturalist, considered the founder of the modern frozen food industry. He founded the frozen food company Birds Eye. Among his inventions during his career was the double belt freezer.
Pancetta is a salt-cured pork belly meat product in a category known as salume. In Italy, it is often used to add depth to soups and pastas.
Auto-defrost, automatic defrost or self-defrosting is a technique which regularly defrosts the evaporator in a refrigerator or freezer. Appliances using this technique are often called frost free, frostless, or no-frost.
Vacuum packing is a method of packaging that removes air from the package prior to sealing. This method involves placing items in a plastic film package, removing air from inside and sealing the package. Shrink film is sometimes used to have a tight fit to the contents. The intent of vacuum packing is usually to remove oxygen from the container to extend the shelf life of foods and, with flexible package forms, to reduce the volume of the contents and package.
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.
Frozen noodles and chilled noodles are types of instantly prepared Asian noodles that are sold frozen or chilled. These products differ from prepackaged dehydrated noodles in a number of ways: in flavor, in texture, and in that they normally come packaged with ingredients besides the noodles, such as vegetables, meat, and soup stock.
Instant noodles, or instant ramen, is a type of food consisting of noodles sold in a precooked and dried block with flavoring powder and/or seasoning oil. The dried noodle block was originally created by flash-frying cooked noodles, and this is still the main method used in Asian countries; air-dried noodle blocks are favored in Western countries. Dried noodle blocks are designed to be cooked or soaked in boiling water before eating. Ramen, a Japanese adaptation of Chinese noodle soup, is sometimes used as a descriptor for instant noodle flavors by some Japanese manufacturers. It has become synonymous in the United States with all instant noodle products.
Individual quick freezing, usually abbreviated IQF, is a descriptive term for freezing methods used in the food processing industry. The food is in individual pieces, and is frozen quickly. Products commonly frozen with IQF technologies are typically smaller pieces of food, and can include berries, fruits and vegetables both diced or sliced, seafood such as shrimp and small fish, meat, poultry, pasta, cheese and grains. Products that have been subjected to IQF are referred to as individually quick frozen.
The mango fruit is commonly dried and eaten as a snack.
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