Chapter 1. Physical –Chemical Principles in Freezing.

NOEMI ZARITZKY

Handbook of Frozen Food Processing and Packaging

CRC Taylor and Francis

Lugar: Boca Raton, London, New York; Año: 2006; p. 3 - 31

Water is the most abundant substance in the Earth, it is the major component of most foods and biological specimens and it is essential to life. In almost all living cells water is the most abundant molecule accounting for 60% to 90% of the mass of the cell. Water is also a very important component in foods affecting quality attributes and shelf life stability .Freezing is regarded as one of the best methods for long term food preservation. During freezing water is converted to ice, thus chemical reactions and microbial growth are reduced at low temperatures; besides the formation of ice removes water from food systems lowering the water activity. In this Chapter water and ice structures, ice formation (nucleation and crystal growth), state diagrams, vitrification, freezing mechanisms in plant and animal tissues, and the physical and chemical effects of freezing will be discussed.