Drying Model and Quality of Litopenaeus vannamei under Vacuum Freeze Drying

Object:The drying characteristics of vacuum freeze drying of Litopernaeu svannamei were investigated and mathematical model of vacuum freeze drying(VFD)of shrimp was developed. Methods:Based on the moisture content and drying rate,the effect of drying temperature and mass load on drying characteristics were investigated. And the effect of vacuum freeze drying and hot air drying on the quality of prawn were analyzed according to the quality indexes,including shrinkage,rehydration,texture,color difference and sensory evaluation. Results:The results demonstrated that the drying temperature and mass load were the key factors for drying rate. Along with the increase of drying temperature and decrease of mass load,drying time decreased. Meanwhile,with the decrease of moisture content during VFD,the drying rate reduced significantly. After optimization of drying model,Page’s model for VFD shrimp was the most close in accordance with the drying characteristic of shrimp. In addition,in comparison with hot-air drying,VFD shrimp products presented lower shrinkage and higher rehydration(30.11%±0.04% and 74.98%±0.01%,respectively),lower hardness,viscosity and chewiness,and better color and sense qualities. Conclusion:VFD technique could produce dried prawn products with higher quality.