Effect of low and ultra-low temperature applications during freezing and frozen storage on quality parameters for fish

• Deterioration in fish tissues is observed between −86.0 °C and −30.0 °C.
• Almost complete inhibition of deterioration is achieved at −86.0 °C.
• The improvement of stability from −45.0 to −86.0 °C is negligible.
• Effective long-term shelf-life for industrial storage is achieved at −35.0 °C.
• Prevention of oxygen penetration into tissues is important for fatty fish.

The article reviews recent investigations in the application of ultra-low temperatures for high-quality long-term storage of fish. Changes in fish quality were discussed with respect to thermal events, which occur at low and ultra-low temperatures. Excellent stability of proteins was found at temperatures below the end of freezing point, when the unfrozen water content is at its minimum. Lipid oxidation was inhibited by preventing oxygen penetration to fish tissues rather than decreasing storage temperature. Thus, a significant part of fish oils remains unfrozen until temperatures of −110.0°C. The recommended storage temperature for high-quality long-term storage of fish is −35.0°C. Further decreasing storage temperature is unnecessary for industrial needs.