Effects Of Ozone Treatment On Quality Of Crisped Grass Carp Fillets During Controlled Freezing-Point Storage

The crisped grass carp is a characteristic product for freshwater fish, whose meat quality is crispy and shredded meat is not easy to split, but maidly saled with fresh way. At present, fresh recuperation aquatic product has been taken serious as a new sale mode. However, it needs kinds of preservation measure for the freshness dropped quickly after the freshwater fish was killed. In order to solve the problem, such as the shelf life is short, the influence on the quality induced by the preservation technical. This assay take the crisped grass carp as the object, the ozone water, ozone ice and ozone gas-filled package were applied in crisped grass carp fillet preservation, the effects of bacteria number reducing treatments, storage methods and the package ways on the quality of crisped grass carp fillets were studied. Results were summarized as follows:(1) The effects of bacteria number reducing treatments and storage conditions on the quality of crisped grass carp fillets were studied. The ozone water or the chlorine dioxide concentration had extremely significant effects on sensory quality of crisped grass carp fillets, but not the higher the better. The optimal treatment condition with ozone water was leaching the fillets with 2 mg/L ozone water at 150 mL/min for 10 min, and the aerobic bacterial counts reduced by 91.5% after the treatment. Under their optimal treatment conditions, ozone water leaching was superior to chlorine dioxide leaching considering the fillets residual bacteria rate, total volatility basis nitrogen, rigidity, chewiness and sensory quality as indexes. The shelf life of crisped grass carp fillets treated by ozone water during controlled freezing-point storage (CFS) was 14 days,9 more days than blank group. Under their optimal treatment conditions, the shelf life of 100%CO2 package was 21 days during controlled freezing-point storage.(2) The effects of ozone gas-filled package on the quality of crisped grass carp fillets were studied.100%CO2 package and ozone gas-filled package could control microbial growth and quality change during controlled freezing-point storage, the effect of ozone is stronger. The fillets residual bacteria rate, total volatility basis nitrogen, drop loss rate and sensory quality of the fillets was better using ozone gas-filled package than vacuum package and 100%CO2 package, while accelerated the fat oxidation. The shelf life of vacuum package,100%CO2 package and ozone gas-filled package were 13 d,16 d and 19 d respectively. (3) The quality of crisped grass carp fillet stored with ozone ice is better than ordinary ice obviously. Replacing the ordinary ice with the ozone ice could effectively control microbial growth, delay the TVB-N value rise and extend shelf life of crisped grass carp fillets. The open air temperature had significant effects on the quality of crisped grass carp fillet stored with ozone ice. The aerobic bacterial counts and the TVB-N value of crisped grass carp fillet were firstly decreased and then increased during storage. When the outside temperature is 5℃, the center temperature of fish maintains at 0℃for long time, quality change for fillet is the slowest. Under the outside temperature of 25℃,15℃and 5℃, the shelf life of crisped grass carp fillets stored with ozone ice were 3 days,7 days and 13 days respectively.