Internal migration of sodium chloride, sorbitol and moisture in fish meat during soaking and cold preservation

Migration of NaCl, sorbitol or moisture inside fish meat strips was investigated. Meat strips were soaked in 1.5 M NaCl or 2.0 M sorbitol solution at 4 deg C and were then cold preserved at 4 deg C. The contents of NaCl or sorbitol in the internal deep parts of the soaked meat strips were considerably lower than in the superficial parts. During the subsequent cold preservation of the soaked meat strips, migration of both compounds from the outside to the inside was promoted. The migration rate of sorbitol during the cold preservation was markedly lower than that of NaCl. The moisture content in the superficial parts of the NaCl-soaked meat strips was higher than that in the internal deep parts, while the trend in the distribution of moisture was quite the opposite in the sorbitol-soaked meat strips. Moisture migrated from the inside to the outside in the sorbitol-soaked meat strips during the cold preservation. However, the migration of moisture in the NaCl-soaked meat strips hardly proceeded. These results suggested that the moisture migration was affected by the moisture imbalance as well as by the increase in water-holding capacity of myofibrillar proteins by raising the NaCl concentration in the meat strips.