Effect Of Partial Freezing With Different Conditions On Quality Of Rainbow Trout During Storage

Rainbow trout is a high quality fish with high nutritional value and economic value.Its muscle protein content is high and its amino acids are complete.It is loved by consumers,but it tends to decay during processing and storage.Partial freezing can maintain the freshness of aquatic products in the shortest storage period,adding different treatment methods on the basis of partial freezing,and can improve the quality of rainbow trout under the condition of partial freezing storage.In this paper,to analysis the influence of rainbow trout quality during different storage processing methods,the rainbow trouts has been frozen at-3?for 30 days,meanwhile,determined the physical-chemical properties?Volatile salt based nitrogen,thiobarbituric acid reactant,K value,pH value,electrical conductivity,thawing juice loss rate?,texture?hardness,elasticity,chewiness?,enzyme content?AG enzyme and NAG enzyme?,the total number of colonies,microstructure,explore the modes of death?death,death,frozen ice on death?and salt solution rinse?0.3%NaCl,0.5%NaHCO3,0.5%sodium citrate?,preservative?0.5 g/kg lactic acid nisin,2.5 g/kg,3g/kg sea shrimp Compal freshwater fish and shrimp shellfish common preservative?.Finally,we could screened out the best way of death methods and the best way of salt solution and the preservation.Specific results are as follows:?1?By measuring the freezing curve of rainbow trout,it was determined that the freezing point was-1.4?,and the storage condition of the partial freezing was-3?.?2?With the micro freezing,the TVB-N values of three different ways of death?beating death,freezing death and ice water killing?,the decay stage when they are stored for thirtieth days.The K value of the knocking death group entered the period of corruption for twentieth days,and the total number of the three groups had not exceeded the standard.During the storage period,the microstructure of rainbow trouts,which was killed by ice water,had a compact structure and less fiber breakage.The physical and chemical indexes?TBARS value,electrical conductivity,defrosting juice loss rate,K value,pH value?were lower than that of two groups of fatality death and freezing death.The TVB-N value was lower than the other two groups of experimental groups after 15 days of storage.Its texture characteristics?hardness,elasticity,chewiness?were higher than those of the other two groups.The enzyme content?AG and NAG enzyme?was significantly lower than that of the other two groups.During the storage,the microorganism index?total number of colony?of the rainbow trout with knocking death was significantly lower than the other two groups.?3?During the storage of frozen rainbow trout,the TVB-N value of distilled water group exceeded 20mg/100g at thirtieth days,and K value exceeded 60%at twenty-third days.The total colony count of all experimental groups did not reach the upper limit.The experimental group used 0.5%sodium citrate solution rinse,the microstructure of fiber structure compared to the other two groups are more compact and the physicochemical index?TBARS value,TVB-N value,conductivity,K value,pH value?than the other 3groups,the texture?hardness,elasticity,chewiness?was higher than 0.3%,NaCl 0.5%NaHCO₃ and control group.The contents of enzyme?AG enzyme and NAG enzyme?were lower than that of other groups.The defrosting juice loss rate of the 0.5%NaHCO₃ experimental group was lower than that of the other 3groups.The total number of colonies using 0.3%NaCl was lower than that of the other 3 groups.?4?During partial freezing storage of rainbow trout,the total number of colonies of all experimental group did not reach the upper limited?7 log?CFU/g??,the use of 3 g/kg experimental group Sea freshwater fish and shrimp shellfish general antistaling agent,the microstructure compared to several other experimental groups,the integrity was good,the structure was compact,the index properties?TBARS value,TVB-N value,conductivity,K value,thawing loss rate?were lower than the other 3 groups,the texture?hardness,elasticity,chewiness?was higher than the rest of the experimental group,enzyme contents?AG and NAG enzyme?were lower than the other 3 groups.The pH value of the 0.5 g/kg nisin group was at relative lower level after 10 days of storage,and the total number of colonies was always lower than that in the rest of the experimental groups.