We all know that if you put a bottle of water into a freezer the ice EXPANDS, breaking the bottle.  On a cellular level, when fish freezes the ice crystals break through the membrane of the cell, and later when the fish is thawed there’s an accompanying pool of water, and a “spongy” texture to the thawed fish.

Maximum ice expansion occurs at -5°C, but CONTRACTS at lower temperatures.  Superfrozen technology takes advantage of this property, wherein  fish “flash frozen” at -60-70°C (superfrozen) temperatures, pass through the -5°C phase so quickly that ice DOESN’T HAVE TIME TO EXPAND THEN CONTRACT, thus never lysing the cell membrane.  The result is firm, springy texture to the meat, with minimal loss of freshness and nutrients.

The most dramatic example of this technology is that after being stored at superfrozen temperature for 2 YEARS some pieces of tuna in fact can “curl up” into rigor upon thaw--as they didn’t have time to go into rigor at time of capture or harvest !