| Trachinotus blochii is one of the most important economic fishes in the South China Sea,which is rich in protein,vitamins,unsaturated fatty acids,etc.Because of the complex physiological and biochemical reaction and the growth of microorganisms,trachinotus blochii is easy to become spoilage during the refrigerator storage.Therefore,it is necessary to develop the preservation technology of trachinotus blochii.In this study,trachinotus blochii was used as material,to research the effect of Modified Atmosphere Packaging(MAP)combined with F-PL on the quality of trachinotus blochii and dynamic changes of microorganism during the refrigerator storage.The results were summarized as follow:(1)This study aimed to reveal the different effects between vacuum packaging and MAP(80%CO2+10%N2+10%O2)on the preservation of trachinotus blochii during the refrigerator storage.The results showed that:e-PL combined with the anaerobic environment of vacuum packaging can delay the lipid oxidation of trachinotus blochii,the TBARs(thiobarbituric acid reactive substance values)was only 0.22 mg/100g after 9 days of storage;MAP can prolong the growth lag of microorganisms,limit the rise of TVB-N(total volatile basic nitrogen)and pH,keep the quality of trachinotus blochii.After 9 days of storage,the total viable count of trachinotus blochii of MAP was 5.34 lg(CFU/g),TVB-N and TBARs values were 12.42 mg/100g and 0.42 mg/100g,the freshness of trachinotus blochii still belonged to the first grade,the fresh-keeping effect of MAP was better than that of vacuum packaging.(2)Compare the effects of C02(20%CO2+70%N2+10%O2,50%CO2+40%N2+10%O2,80%CO2+10%N2+10%O2)of MAP combined with e-PL on the quality of trachinotus blochii during storage,it was found that:with the increase of CO2 concentrations,the inhibitory effect on microorganisms became obvious.Trachinotus blochii with 80%CO2 packaging showed the lower counts of Enterobacleriaceae,Psychrophilic bacterias and Pseudomonas than that of the groups with 20%CO2 and 50%CO2 packaging,which increased to 4.46 lg(CFU/g),6.20 lg(CFU/g)and 7.10 lg(CFU/g)after 12 days of refrigerator storage.It was indicated that 80%C02 MAP had stronger inhibition on gram-negative bacterias,which has weak tolerance to CO2.In addition,80%CO2 can also delay the rise of TVB-N,TBARs,pH and K value of trachinotus blochii and extend its shelf life to 12 d.(3)High-throughput sequencing technology was applied to analyze the diversity and the structure of bacterial flora of trachinotus blochii during the storage,which were packed with 80%CO2+10%N2+10%O2.The dominant bacteria in fresh trachinotus blochii were Acinetobacter(56.80%),Myroides(15.90%),Unclassified-Enterobacteriaceae(22.70%);After 2 days of refrigeration,the number of Shewanella increased rapidly from 1.50%to 26.40%,and then decreased gradually.The dominant spoilage bacteria were Lactococcus,Weissella and Photobacterium during 4-6 days of refrigeration,their abundance increased to 11.00%,11.70%and 38.30%at the 6th day of storage.As the extension of storage time,Providencia,Serratia and Vagococcus became the dominant spoilage bacteria of trachinotus blochii,their abundance were 21.80%,28.90%and 15.40%after 12 days of storage. |
