On 2018-08-08 14:48:54
Heat transfer mode of food heat treatment
Three different ways of heat treatment and heat transfer in food industry
Food safety and labeling are becoming more and more important for producers because of the introduction of government regulations and the increase of consumer demand; heat treatment equipment has many kinds and uses, ranging from industrial drying to roasting, baking, reaction and cooling, which enables producers to kill pathogens and inactivating enzymes without affecting food labeling. In some cases, a thermal system may be used to achieve multiple unit operations, such as drying, grinding, reaction, and drying.
There are three different heat transfer modes: conduction, convection and radiation. Conduction is the direct heat transfer through the vessel wall with heat transfer medium; convection is the direct heat transfer with heat transfer medium; radiation is the transfer of heat by using the electromagnetic wave of separated energy.
An example of direct drying of thermosensitive food involves the removal of moisture. To minimize discoloration and preserve flavor, this process uses evaporative cooling to prevent degradation, in which case the heat transfer medium is usually hot air. This ensures that the taste and taste meet the consumer's expectations without adding anything to the end product label.
Indirect heat transfer is often used in dry applications where liquids are not water, such as flammable organic solvents that require an inert environment. Indirect heating greatly reduces the use of expensive inert gases, and indirect heat transfer can also be used to process materials under vacuum or pressure.
Radiation heat transfer can be in the original form of drying, where food is simply exposed to sunlight and allows moisture to evaporate, or it can involve infrared and ultraviolet treatment.