Freshness preservation of raw fish using contact dehydration sheet - (Freshness-preserving effects of contact dehydration sheet on pacific mackerel and Japanese sardine) [Japanese]

摘要

In this study, we aim to verify the freshness-preserving effects of contact dehydration sheets (CDS) on pacific mackerel and Japanese sardine using K value, total volatile base nitrogen (T-VBN), and viable cell count as freshness indicators. The amounts of drip and moisture contents of two fish, one wrapped with CDS and the other with poly (vinylidene chloride) film (control), were also measured to compare the freshness-preserving effects of CDS. After two days of storage, K values for pacific mackerel wrapped with poly (vinylidene chloride) film reached 30%, indicating that they are unsuitable for raw consumption, while K values for pacific mackerel wrapped with CDS were less than 20%, indicating that they are suitable for raw consumption. Similar differences in T-VBN were also observed after two days of storage. The treatment effects were more pronounced for pacific mackerel than for Japanese sardine. No significant differences in viable cell count between the two treatments throughout the storage period for either fish were observed. Judging from the results of drip loss and moisture content, CDS appears capable of absorbing the majority of the excess moisture. The differences in moisture content between the two treatments were 10% for pacific mackerel and 4% for Japanese sardine after one day of storage. The distinct freshness-preserving effects of CDS on the K value and T-VBN seem to be due to a decline in the catalytic reaction speed of enzymes, which is a result of reduced drip.