冷藏基围虾水分迁移和品质变化的相关性

以基围虾为对象，测定其在4、0 ℃贮藏过程中菌落总数、pH值、总挥发性盐基氮（total volatile basic nitrogen，TVB-N）含量、K值、水分含量等理化指标的变化，利用低场核磁共振技术分析基围虾肌肉中水分迁移规律，进而研究品质变化与水分迁移的相关性。结果表明：在贮藏过程中，菌落总数、TVB-N含量均随贮藏时间的延长而呈增大趋势，pH值先降低后升高，水分含量呈降低趋势；横向弛豫时间T2测定结果表明，随着贮藏时间的延长，结合水（T21）含量无明显变化，不易流动水（T22）含量逐渐降低，自由水（T23）含量逐渐升高；通过分析横向驰豫时间T2与各理化指标之间的相关性表明，T22、T23与多个理化指标具有相关性。因此，运用低场核磁共振技术检测基围虾贮藏期间的品质变化具有可行性。

Correlation between Moisture Migration and Quality Changes of Greasyback Shrimp (Metapenaeus ensis) during Chilled Storage

The changes in the total viable count (TVC) and physicochemical properties such as pH value, total volatile basic nitrogen (TVB-N) content and water content of greasyback shrimp during storage at 4 or 0 ℃ were measured. Low field nuclear magnetic resonance (LF-NMR) was used to analyze the pattern of moisture migration in shrimp muscle and its correlation was investigated with quality changes. The results showed that the TVC and TVB-N content increased during storage, the pH value exhibited an ascending trend after an initial decline, and the water content decreased. The transverse relaxation time (T2) spectrum showed that with the extension of storage time, the content of bound water (T21) did not obviously change, the content of immobile water (T22) gradually decreased, and the content of free water (T23) gradually increased. T22 and T23 had a significant correlation with many physicochemical indices. Therefore, it is feasible to detect the quality changes of shrimp during storage by LF-NMR.