Comparative Research On The Dark Fish And White Fish During Chilled Storage Of Modified Atmosphere Packaging

The storage conditions may exist the distinction between white fish and dark fish due to the difference of physical properties.So far a variety of fish have been storaged together by circulation sales?such as supermarkets?,rather than do a classification of storage according to the distinction of physical properties.Modified Atmosphere Packaging?MAP?is a kind of preservation methods using the gases,which can prolong the shelf life of food well.So it is of great significance to do a comparative research of quality changes between white fish and dark fish as well as establish the mathematical model between multiple factors during MAP storage which is from the angle of mainly influencing factors?such as temperature,light,gas proportion,packaging films and so on?.Grass carp fillets and salmon fillets are regarded as the research objects in this paper,first of all,systematically comparative research were conducted between the white fish and dark fish during MAP storage,then,comprehensive evaluation model was established based on the principle component analysis according to the physical properties of fish meat,at last mathematical models among the physical properties of fish meat,gas content and films were established as well.The details are as follows:1.Grass carp fillets?without dark meat?and salmon fillets were stored at 4,10?without illumination?,10?5000 LX?and 25?,the significant differences?P<0.05?were observed in pH?TBA and color difference value during storage between grass carp and salmon fillets.Meanwhile,illumination?5000 LX?could enhance the pH value in both of grass carp fillets?without dark meat?and salmon fillets,and elevate the increasing rate of TBA value induced by photooxidation as well.Also,the storage temperatures exhibited the significant effect on fish quality during storage?P<0.05?.2.During the MAP storage at 4?,salmon fillets consumed more O₂ and generated more CO₂ than grass carp fillets,the significant differences?P<0.05?were observed in pH?TBA and color difference value during storage between grass carp and salmon fillets.Comparing with the control group,there existed a good preservation effect on the grass carp and salmon fillets of different CO₂,O₂ groups.Among the CO₂ groups,there was a better preservation effect in 10%O₂/60%CO₂/3 0%N₂ group and 10%O₂/80%CO₂/10%N₂ group than in 10%O₂/40%CO₂/5 0%N₂ group,while there was no obvious difference between 10%O₂/60%CO₂/30%N₂ group and 10%O₂/80%CO₂/10%N₂ group.However,among the groups of different O₂,no significant differences?P>0.05?were observed in TVC,TVB-N,K value and pH value,TBA value and AE value would elevate with the increasing of O₂ content,the main substance which restrained the microorganism was 60%CO₂.3?Different kinds of packaging films worked as a positive role in preservation between grass carp and salmon fillets during MAP storage,what was more,packaging films?PP/Tie/Nylon6/EVOH/Nylon6/Tie/LLDPE?which had a lower oxygen permeability could maintain the quality of grass carp and salmon fillets?including TVC?TVB-N?K?TBA?pH?AE?best,NY15/PE35 was better,and BOPP/PES was worst.4?There was a good correlation among TVC?TVB-N?K and TBA,the composite scores among 40%CO₂/10%02/50%N₂,60%CO₂/10%O₂/30%N₂,80%CO₂/10%O₂/10%N₂,60%CO₂/20%O₂/20%N₂,60%CO₂/30%O₂/10%N₂ groups in grass carp fillets were 26.490,24.840,24.892,24.992,25.111,separately,the best group was 60%CO₂/10%O₂/30%N₂ group.Meanwhile,the composite scores of salmon fillets were 60%CO₂/20%O₂/20%N₂ group.The best group of packaging films between grass carp and salmon fillets were both the PP/Tie/Nylon6/EVOH/Nylon6/Tie/LLDPE group.5?The mathematical model between the reaction rate constant of the total number of colonies in grass carp and salmon fillets and the content of O₂ and CO₂ were k₁= 0.05022 +0.000972x + 0.0003779y + 0.00003987x2-0.00004719xy?R² = 0.9888?,k₂ = 0.08036 +0.0005594x-0.0009204y-0.00001204xy + 0.000008071y2?R² = 0.9875?,separately,moreover,the relationship between the reaction rate constant of the TVB-N value and the content of O₂ and CO₂ was according with the binary polynomial as well,x?y were standing for O₂ and CO₂ content.The mathematical model between the reaction rate constant of the total number of colonies in grass carp and salmon fillets and the oxygen permeability of packaging films were y₁ = 0.0496x^0.02769,y₂ = 0.04703x^0.03834.What was more,the relationship between the reaction rate constant of the TVB-N value and the oxygen permeability of packaging films was according with the model of power function relationship.