Changes in the Free Amino Acid Content of the Shucked Oyster Crassostrea gigas Stored in Salt Water at 3°C

Shucked oysters were soaked in an equal weight of salt water and stored at 3°C for 7 days. Changes in the free amino acid content of the whole body and in the adductor muscle were evaluated by a practical distribution method. With the exception of aspartic acid and tyrosine, no significant changes in free amino acids or ammonia were observed in whole-body shucked oysters during the storage period. In contrast, the majority of free amino acids in the adductor muscle decreased significantly. Most of these free amino acids were detected in considerable amounts in the surrounding salt water after 7 days of storage. Both the weight of the whole body and the salinity of the surrounding salt water decreased significantly during the storage period. These results suggest that free amino acids were eluted from the cutting surface of the adductor muscle and indicate that the free amino acid content per shucked oyster and in the adductor muscle, decreases during cold storage