Frozen food and technology

Freezing has been successfully implemented worldwide for longterm preservation of an endless variety of food products. The low temperatures achieved in freezing processes change the physical state of water and, consequently, water becomes unavailable to support deteriorative processes. Freezing, when conveniently applied, may preserve some of the original attributes of a food, but overall quality is inevitably affected. Ice crystallization that occurs during freezing processes, and along frozen storage, may cause important physic and/or chemical changes in food products. So, it is important that products have high quality raw characteristics before the freezing stage. Freezing may reduce microbial loads and microbial activity, yet it cannot assure the safety of post-thawed products. To inactivate undesirable microorganisms and enzymes responsible for quality decay, adequate treatments are often applied before the freezing processes of foods. The success of the freezing operation depends mainly on the composition, physical properties and shape of product to be frozen, the freezing method and conditions applied, the type of equipment used and packaging materials selected. This chapter provides an overview of treatments pre-applied in freezing processes of meat, fish, fruits and vegetables products, freezing methods and equipment industrially used, and innovations in freezing processes. Main impacts of frozen technology on food properties are also highlighted.