FOS 3042 Lecture 9: Module 9 FOS3024
16 Feb 2017
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Document Summary
Food processing: refrigeration and freezing: cold preservation. Not as common in less developed countries: refrigeration. Retards water loss and wilting compared with no refrigeration. Need to start refrigeration soon after harvest or slaughter. A key factor in food quality and extension of shelf life. Packaging materials play a key role (map: refrigeration. Must be super cooled to below 0. Temp rises to 0 as ice forms. Last portion of water is very hard to freeze. As long as unfrozen water is present in a foods the temperature will remain near 0 due to the latent heat of crystallization. Less concentration effect smaller ice crystals smaller ice crystals. Get larger ice crystals as water re frozen. Fat and air have low thermal conductivity. Use refrigerant with greater heat capacity: freezing methods. Cold air blown up through light weight products. Very quick, good for iqf of small pieces. Solid food (puree) may freeze faster than pieces.
