IQF generally relates to "Individual Quick Freezing" of solid foods/pieces/grains like green peas, cut beans, cauliflower pieces, shrimps, meat chunks, fish (whole or cut), poultry portions; etc.
In IQF foods, there is no clumping together of pieces or grains. They remain individual separate pieces. Hence the term 'IQF".
'Quick-freezing' is, at present, the only process whereby, virtually all the properties of most of the parent foodstuffs can be preserved. A great reduction in the temperature of a product halts the activities of the micro-organisms that cause foodstuffs to deteriorate and generate toxic substances; in addition, the enzymatic and biochemical reactions of the digestive enzymes which are found in all living tissues and whose activities continue even after death, are also greatly slowed down.
The main advantages of "Individual Quick Freezing" are :
- The ice crystals formed are much smaller, which therefore, cause much less damage to the cell structure or texture of the food
- The freezing period being much shorter, less time is allowed for the diffusion of salts and the separation of water in the form of ice.
- The product is quickly cooled below the temperature, at which bacterial, mould, and yeast growth occur, thus preventing decomposition of foods during freezing.
- The fourth and very practical reason in favor of IQF over 'slow-freezing', is the inherent speed and greater output and hence, higher capacity for commercial freezing plants with the resultant cost reduction.
Glazing is an effective and economic means of protecting frozen fish and shellfish during storage and transport. Glazing forms a protective film or coating over the frozen product, which retards moisture loss and prevents oxidative rancidity. Glazing is done by spraying cold water over the product or sometimes by dipping in water, which freezes almost instantly, with slight increase in temperature of the product. The product lakes up water to the extent of 5-10% of its weight, providing a coating of ice of 0.5-2 mm thick.