Abstract: Changes in physical and chemical properties such as sensory quality, water-loss rate, stiffness period, hardness degree, total volatitle base-nitrogen (TVB-N) value and water activity during the storage of tilapia fillets subjected to both partial freezing and vacuum packaging at －4 ℃ or －7 ℃ were analyzed to evaluate the fresh-keeping effect of vacuum package and partial freezing storage. Results indicated that tilapia lived in 3 ℃ water for 30 min would die. Its stiffness period was extended to 100 min compared with that of the normally dead tilapia. Initial vacuuming treatment followed by partial freezing treatment could reduce water loss rate by 2.6%, when compared with partial freezing first and then vacuum packaging. After 15 days of storage at －4 ℃ or －7 ℃, (TVB-N) values of tilapia fillets were less than 15 mg/100 g, and the values after the storage period at －7 ℃ were approximately 25% lower than those at －4 ℃.

Key words: tilapia fillet, partial freezing, vacuum packaging, freshness