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Freezing is a common method of food preservation that slows both food decay and the growth of micro-organisms. Besides the effect of lower temperatures on reaction rates, freezing makes water less available for bacteria growth. Freezing is a widely used method of food preservation. Freezing generally preserves flavours, smell and nutritional ...
To produce larger crystals, the product should be frozen slowly or can be cycled up and down in temperature in a process called annealing. The freezing phase is the most critical in the whole freeze-drying process, as the freezing method can impact the speed of reconstitution, duration of freeze-drying cycle, product stability, and appropriate ...
In physics and chemistry, flash freezing is the process whereby objects are rapidly frozen. [1] This is done by subjecting them to cryogenic temperatures , or it can be done through direct contact with liquid nitrogen at −196 °C (−320.8 °F).
Fractional freezing is a process used in process engineering and chemistry to separate substances with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, as in freeze distillation, also called normal freezing or progressive freezing.
The freezing of small water droplets to ice is an important process, particularly in the formation and dynamics of clouds. [1] Water (at atmospheric pressure) does not freeze at 0 °C, but rather at temperatures that tend to decrease as the volume of the water decreases and as the concentration of dissolved chemicals in the water increases. [1]
In laboratories, a slurry of dry ice in an organic solvent is a useful freezing mixture for cold chemical reactions and for condensing solvents in rotary evaporators. [38] Dry ice and acetone forms a cold bath of −78 °C (−108 °F; 195 K), which can be used for instance to prevent thermal runaway in a Swern oxidation .
Sleet and freezing rain occur by a similar process, but are different forms of precipitation. Both are most common in the winter. Sleet occurs when snowflakes melt into a raindrop in a wedge of ...
Tunnel freezing is a variant of air-blast freezing where food is put onto trolley racks and sent into a tunnel where cold air is continuously circulated. Fluidized bed freezing is a variant of air-blast freezing where pelletized food is blown by fast-moving cold air from below, forming a fluidized bed. The small size of the food combined with ...