Temperature intervals are very important in cooking because choosing the temperature affects how the foods behave, and what effect with regards to taste, texture, and consistency is achieved. This is especially true for proteins, which behave very differently at different temperatures. As the temperature increases, the amino acid molecules that make up the proteins and are curled into a ball-like shape, start to uncoil. Because of this the structure and texture of the protein change.
Thus starts the process of coagulation or denaturation in proteins. It is important to note that other factors, such as the duration of heat exposure, contact with other foods such as those containing acids, etc. Some recipes call for the eggs to be cooked at this temperature range to produce the semi-liquid texture for the yolk and the slightly more liquefied texture for the white.
The latter is a Japanese breakfast dish, served with the traditional breakfast meal, and often accompanied by rice, miso soup, grilled fish, and pickled vegetables. Proteins contained in the egg whites require a higher temperature to set and as a result, the egg whites set at higher temperatures than the yolks. Chemical reactions in the proteins in the meat make it change color and become tender, as the temperature rises. In this case, the internal core temperature is measured, because it may not be as high as the temperature of the outer parts.
The color changes from red to brown are due to a change in the oxidation of iron contained in muscle tissue proteins. Meat also releases juice at this stage and changes its texture. This process takes a long time, however, so if the cuts of meat are tough because they came from older animals or from muscle areas that were frequently used by the animal, it is better to cook them for a longer time. Pressure cooking, described above, helps reduce the cooking times.
Cutting the meat into smaller pieces also helps with making it tender, because it physically decreases the volume of the piece and makes it possible to heat it more quickly. This speeds up the process of breaking down the collagen molecules and converting collagen to gelatin. Proteins are high in amino acids, allowing for this reaction to occur. Maillard reaction also occurs in other products, such as bread, coffee beans, maple syrup, etc.
During this process the sugars brown, and cause the meat to brown as well. Caramelization happens in any foods that have sugars in them. Food is thermally processed to enhance the taste, but high temperatures also kill bacteria and other microorganisms. Thus, most foods that can host these microorganisms are heated or sometimes cooled before consumption. Simply using eggs with clean shells will not address the potential danger of Salmonella because it can be present inside of even the cleanest eggs.
Eggs need to be cooked to kill the bacteria. Salmonella and E. Often they disappear after a week without additional treatment, but sometimes the infection can be severe enough to cause hospitalization and even death.
Therefore it is better to cook foods at temperatures high enough to kill these microorganisms, especially when preparing food for the more vulnerable people: children and infants, the elderly, and people with low immunity. There are numerous cooking methods so one should be able to find a way to make these foods delicious even for picky eaters.
Pasteurization also prevents E. During this process, milk and other products such as juices are heated to a certain temperature for a given duration of time. Pasteurization denatures the enzymes in the bacteria and makes the water inside the bacterial cells expand and break the bacterial cell wall. Bacteria have proteins in their structure, and high temperatures change the structure of these proteins and weaken the structural elements of the bacteria, such as the envelope that surrounds their cell.
This process does not kill all the bacteria, but it reduces their numbers enough to prevent infection. Thanks to pasteurization, milk is now one of the safest foods, when pasteurized and properly handled.
This article was written by Kateryna Yuri. Specific energy, Heat of Combustion per Volume Converter. Coefficient of Thermal Expansion Converter. The kelvin and thus Celsius is defined based on the Boltzmann constant, k, which equals 1. Celsius as a unit and a scale was not widely used until this original definition was inverted.
In , the unit, "degree Celsius," as well as the Celsius scale were again re-defined to instead be based on absolute zero This is the definition that was used up until , when the kelvin was redefined based on the definitions of the second, meter, and kilogram.
Current use: The Celsius scale replaced the Fahrenheit scale in most countries in the mid to late 20 th century. As one degree Celsius is equal to one Kelvin, boiling point of water is equal to The Fahrenheit temperature range is based on setting the freezing point of water at 32 degrees, and boiling to degrees.
This means that boiling and freezing point are degrees apart. Absolute zero is defined as Because both Celsius and Fahrenheit scales are offset— ie neither are defined as starting at zero.
On top of that, for every additional unit of heat energy the Celsius and Fahrenheit scales add a different additional value.
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