Effects of gas ratio on shelf-life of tilapia fillets with modified atmosphere packaging

Tilapia fillets packaged in controlled atmosphere with 100%CO2（Ⅰ）, 70%CO2/30%N2（Ⅱ）, 50%CO2/50%N2（Ⅲ）and 30%CO2/70%N2（Ⅳ）were stored respectively at －0.70.3℃. The shelf-life of tilapia fillets was evaluated by the sensory evaluation as well as key indexes such as drip loss and chromatic aberration, microbial changes, and TVB-N. The results showed that the shelf-life evaluated by sensory evaluation parameter was 19, 22, 17 and 13 d respectively, and the difference was significant（P0.05）；the shelf-life evaluated by microbial parameterwas 26, 25, 20 and 15 d respectively. There was no significant difference between Ⅰand Ⅱ（P0.05）, but compared with Ⅲ and Ⅳ the difference was significant（P0.05）; the shelf-life evaluated by TVB-N parameterwas 25, 23, 18 and 13 d respectively, and the difference was significant（P0.05）. However, the drip loss of tilapia fillets was positively related to CO2 concentration. In conclusion, the modified atmosphere at the level of 70%CO2/30%N2 wasmost suitable, which could extend the shelf-life of tilapia fillets effectively as well as keep their good appearance.