Freezing and thawing are important food processing operations.
Freezing is one of the key unit operations for preservation of foods.
With notable exceptions such as ice cream, frozen foods must be
thawed before further use or consumption. In a number of food
processing operations, it is a common practice to begin with frozen
foods as raw material. For example, in manufacturing sausages,
frozen meat is used as the raw material. Similarly, large blocks of
frozen fish are processed into fillets for further processing. Different thawing and tempering methods are used for preparing frozen
foods for further processing, and each method has its own advantages and disadvantages (e.g., thawing in air or in water, use of
impingement systems, microwave thawing). The main goal of a
thawing process is to keep thawing time to a minimum so that
the least damage is caused to quality. However, a number of quality attributes might be adversely affected during thawing by moisture (drip) loss, change in the structure of proteins, microbial
growth and textural changes. Thawing of large-size frozen foods