Water Migration and Quality Changes of Takifugu bimaculatus during Cold Storage

In order to study the correlation between moisture changes and quality deterioration of Fugu bimaculatus during cold storage, this experiment took fresh Fugu bimaculatusas as the research object and stored them at 4 and 0 ℃ for 11 d. Physics (shear force, chewiness, color difference value, water holding capacity, low-field nuclear magnetic T₂ relaxation time), chemistry (pH, volatile base nitrogen value, K value), and microbiological indicators are measured every other day, then the shelf life was evaluated by low field nuclear magnetic resonance (LF-NMR) combined with principal component analysis. The measurement results showed that the contents of shear force, chewability, L^* value, water holding capacity, T₂₁ and T₂₃ of fish meat in 4 and 0 ℃ groups decreased with the extension of refrigeration time. The values of pH, TVC, TVB-N and K increased continuously. It was obvious that T₂₁ and T₂₃ were significantly positively correlated with water holding capacity, chewiness and shear force during storage at 4 and 0℃ (P<0.01), which were extremely significantly correlated with pH, TVC, TVB-N and K values negative correlation (P<0.01). T₂₂ was significantly correlated with TVC and k value (P<0.05). The principal components analysis (PCA) analysis results showed that the puffer fish was at 0 and 4 ℃ respectively. Corruption began to occur on the 5 and 7 d, which was consistent with the analysis results of physical and chemical indicators. Therefore, LF-NMR combined with PCA analysis could more intuitively analyze the relationship between water distribution and quality of Fugu bimaculatus during cold storage, and could better distinguish the changes in moisture and quality of Fugu bimaculatus during different storage periods. Therefore, consider using LF-NMR combined with PCA analysis technology to quickly detect changes in quality and freshness of Fugu bimaculatus during cold storage.