ABSTRACT
Low-temperature preservation, which implies shelf-life extension through lowering of temperature, generally encompasses two distinct techniques for the storage of foods: refrigerated storage and frozen storage, the first one generally offering a shortterm solution, whereas the latter results in a relatively longer storage life. The foods subjected to refrigerated storage are fresher, because they are mostly subjected to minimal processing. The product is marketed and consumed before significant loss in the quality and, hence, these foods are generally perceived to be the next best alternative to fresh foods. However, although most chemical/biological, biochemical/physiological activities continue, albeit at a lower rate, their shelf life is severely limited. The refrigerated storage generally encompasses a temperature range of –2 to about 15°C, whereas frozen storage operates at temperatures of –10°C or less. Refrigerated storage does not induce significant structural changes in the stored commodities, whereas in frozen storage, the moisture in the food undergoes a phase transformation resulting in tissue breakdown and softening. Refrigerated storage does not stop the activity of microorganisms, whereas frozen storage suppresses their activity. The principal differences between the two are summarized in Table 4.1.
