Abstract:

The objective of this study was to use grass carp fillets (stored in ice for 0, 1, 3 or 7 days) to investigate the
changes in freshness indicators including pH, total volatile base nitrogen (TVB-N), soluble sarcoplasmic proteins (SSP),
soluble myofibrillar proteins (SMP) and color (L*, a*, b*) as well as in cooking loss, area shrinkage and color of fish fillets
following pasteurization treatment (80 or 90 ℃ for 10 min). The results showed that TVB-N value continuously increased
from 11.8 to 16.87 mg/100 g over the storage period, slightly lower than the maximum limit of 20 mg/100 g for freshwater
fish, while pH of fish fillets decreased from 6.72 to 6.52 during the first 3 days, and then slowly increased to 6.56. While SSP
value did not changed obviously, SMP value increased in the first 3 days and then slightly decreased. The color difference
value (ΔE) of fish fillets gradually increased with storage time. The above observations implicated a decrease of freshness
during 7 days of ice storage. During thermal processing, the fish fillets gradually turned white. The cooking loss, area
shrinkage and ΔE value slowly decreased with the extension of storage time.

Key words: grass carp, ice storage, freshness, thermal processing, cooking loss rate