Quality changes of bighead carp (Aristichthys nobilis) during chilled and partial freezing storage

We investigated the effect of storage temperature (－3 ℃ and 4 ℃) on quality changes of bighead carp (Aristichthys nobilis) by observing total volatile basic nitrogen (TVB-N), 2-thiobarbituric acid (TBA), K value, pH, drip loss, cooking loss and organoleptic properties. Results show thatA.nobilislost sensory and edible quality when stored at 4 ℃ at 10th day and at-3 ℃ at 30th day. However, the K value exceeded the critical limit at 4 ℃ at 6th day and at －3 ℃ at 20th day. The TVB-N at 4 ℃ was significantly higher than that at －3 ℃. The TBA did not exceed the limit of 2.00 mgkg-1 at both －3 ℃ and 4 ℃ throughout the storage, indicating that TBA is not a good indicator for assessing the quality changes ofA.nobiliswhen used alone. The pH reached the minimum of 6.81 at 4 ℃ at 4th day and of 6.76 at -3 ℃ at 10th day. The drip loss and cooking loss at －3 ℃ were higher than those at 4 ℃, which may due to the reformation of ice crystals and decline of water-retaining capability. It is concluded that the shelf life ofA.nobilisis 6 d at 4 ℃ and 20 d at －3 ℃. Besides, partial freezing at -3 ℃ can extend the shelf life significantly.