Effect of temperature fluctuation on the freshness, water migration and quality of cold-storage Penaeus vannamei

This study aimed to simulate cold chain sales temperatures to predict the effects of temperature fluctuations on the physicochemical properties, moisture distribution, and flavor of vacuum-packed Penaeus vannamei. The results showed that the increase in freeze-thaw cycles, the pH, total volatile base nitrogen (TVB-N) and total plate count (TPC) of shrimp increased significantly. Meanwhile, sensory evaluation scores, hardness, elasticity and chewiness decreased. Low-frequency nuclear magnetic resonance (LF-NMR) analysis showed that the water content of shrimp continued to decline during storage as the immobilized water balance fell and the free water ratio increased in the F-T groups. In addition, W1S, W1W, W2S, and W6S in the electronic nose, which were characteristic sensors of whole shrimp odor, could distinguish samples with different sensory freshness, TPC, and TVB-N contents and rapidly detect the occurrence of shrimp quality deterioration. This study provided an experimental basis for the quality control of Penaeus vannamei during storage, transportation, and sales. It can further provide a reference for studying the cold chain preservation of aquatic products.