Study On The Preservation Effect Of Slurry Ice On Quality Loss Of Litopenaeus Vannamei During The Storage

Take fresh Litopenaeus vannamei as material, using slurry ice as medium to study quality and melanism inhibitory effect of slurry ice combined with 4-HR、sodium phytate、stable chlorine dioxide on the basis of slurry ice treatment on the quality of fresh Litopenaeus Vannamei, which is aimed at obtaining the best method of slurry ice combined bacteriostatic agent 、 melanism inhibitory agent and preservation mechanism of Litopenaeus vannamei. The main results of this study were as follows:(1) Compared with traditional flake ice group, the aim was to study changes of physical and chemical properties of shrimp which was treated by slurry ice. The results indicated that the sensory quality of the blank and flake ice-treated samples were seriously degraded compared with the slurry ice-treated samples which were slightly browning, still resilient and elastic, with clear shell, tentacles and fantail. The values of spring and chewiness of the shrimp in slurry ice were 0.73 mm and 8.53 m J respectively, after 12 days storage at-2°C, compared with the blank and the samples chilled in traditional flake ice as 0.53 mm and 6.01 m J, 0.66 mm and 7.46 m J. These results indicated that slurry ice treatment showed significantly effective on the texture properties of the shrimp(P<0.05). In addition, the values of p H, TVB-N and TBA were increased in the three treated-groups after 16 days storage at-2°C, while the quality of the samples treated with slurry ice was significantly higher than the other two treatments(P<0.05). The activity of polyphenol oxidase and the reaction of the oxygen with the shrimp were significantly inhibited by the filled slurry ice particles and its low temperature condition, leading to the decrease of the melanosis in shrimp(P<0.05), compared with the blank and the flake ice-treated samples. The slurry ice treatment was showed a good result on the inhibition of the shrimp spoilage. These above findings confirmed that the slurry ice had shown that it’s a suitable medium for previous storage of the fresh shrimp.(2) At-2℃ storage condition, study the changes of sensory、texture properties 、colour、TVB-N 、PPO activities、TBC on shrimp which controlled by slurry ice combined bacteriostatic agent、melanism inhibitory agent, the results indicated that: After 16 d storage at-2℃, slurry ice combined with 0.030g/L 4-HR、stable chlorine dioxide group was evidently better than other treatment groups at sensory quality、texture properties 、colour、TVB-N, at the same time, inhibitory effect of PPO activity and the total number colonies were the best(U value was 7.76, TBC value was 5.41 lg CFU/g); but PPO activity and the total number colonies of the slurry ice group respectively was 10.83 U and 6.01 lg CFU/g. Therefore, slurry ice combined with high-concentration 4-HR、stable chlorine dioxide can significantly control shrimp melanism.(3) For myofibrillar protein content、Ca2+-ATPase activities, pure slurry ice group、salty ice group、slurry ice combined with 4-HR、stable chlorine dioxide treatment group showed downward trend, but the speed of slurry ice combined with 4-HR、stable chlorine dioxide treatment group was significantly slower than other groups. slurry ice combined with high-concentration 4-HR、stable chlorine dioxide treatment group significantly affected protein of shrimp. According to total protein and muscle microstructure of shrimp, the result showed that: slurry ice combined with 4-HR 、 stable chlorine dioxide treatment group could significantly delay the decomposition of protein of shrimp and protect shrimp muscle from destroying, so the treatment could delay the shrimp sensory quality deterioration.