Study On New Technology Of Frozen Oyster Storage

In order to determine the freezing parameters and guarantee the qualities of frozen Crassostrea plicatula, the cold sterilization system with ozone generator and Modified Atmosphere Package technology was employed. The technological parameters, the qualities and color change kinetics of Crassostrea plicatula were explored during frozen storage .The all results were showed as follows:(1)The weight ratio 1: 6 of oyster and Ozone water solution in the bacteria-killing experiment was proved to be the optimal. The sterilization influences of dissolved ozone concentration (p<0.01) and treating time (0.050.05) was not significant, 5°C water with 9mg/L dissolved ozone concentration for 10 min was appropriate for oyster sterilization and pre-cooling. This method killed bacteria more effectively, kept lower TVBN value but hardly affected on fat oxidation (p>0.05) in oyster comparing with the control.(2) The higher oxygen percentage of MAP produced the higher a value and b value and the lower L value, and accelerated the oyster surface color turning into tawny and lessened the surface brightness, furthermore , the degree of fat oxidation was closed relative to storage temperature (X₃) , oxygen component (X₂) and salt water concentration(X₁) through the quadratic regression of orthogonal and rotational combination design. The effects of all of the above factors on TBA value which usually was used to evaluate the degree of fat oxidation were drawn as following equation: Ytba=0.37822+0.00267X₁+0.05557X₂-0.09314X₃+0.02181X₁²+0.02234X₂²-0.00559X₃² +0.01312X₁X₂ -0.00862X₁X₃.Storage temperature (p<0.01) had the most significant effect on fat oxidation, followed by oxygen content (p<0.01) and salt water concentration (0.012 or N₂ alone) or coating, and then -20℃ storage could not only effectively inhibit the loss of Ca²⁺-ATP-ase activities, the degeneration of EPN, the raise of TVBN and TBA value, the reduction of L value, the raise of a and b value, and the change of total color difference (ΔE) value in oyster, but also delayed the arrival of minimum pH value, and inhibit the FAAN raise at late storage.