School of Food Science and Technology Polytechnic University, National Engineering Research Center of Seafood, Qinggongyuan1, Ganjingzi District, Dalian 116034, China; Engineering Research Center of Seafood of Ministry of Education of China, Dalian 116034, China; Liaoning Key Laboratory of Seafood Science and Technology, Dalian 116034, China.
School of Food Science and Technology Polytechnic University, National Engineering Research Center of Seafood, Qinggongyuan1, Ganjingzi District, Dalian 116034, China; Engineering Research Center of Seafood of Ministry of Education of China, Dalian 116034, China; Liaoning Key Laboratory of Seafood Science and Technology, Dalian 116034, China.
Food Res Int. 2018 Jul;109:65-71. doi: 10.1016/j.foodres.2018.04.029. Epub 2018 Apr 17.
Instant sea cucumber has become one popular product due to its convenience to eat, favourable taste and minimal loss of nutrients and bioactive components. However, there was rare information about the water dynamic of instant sea cucumber subjected to multiple freeze-thaw cycles. In this study, low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance image (MRI) were employed to investigate the effect of freeze-thaw cycles on water status of instant sea cucumber. Four water populations corresponding to strongly bound water, weakly bound water, immobile water and free water were observed in instant sea cucumber. With the increase of freeze-thaw cycles, the transverse relaxation time of immobile and free water increased, while the peak area of free water decreased significantly. MRI enabled the visualization of water migration of instant sea cucumber during multiple freeze-thaw cycles. Multiple freeze-thaw cycles also led to significant changes of other quality properties including thawing loss, WHC, color parameters, texture and protein content, and enlarge the interspace between fiber network in microstructure. Good correlations between T, A, A and thaw loss, WHC, L*, hardness and collagen content (0.873 ≤ r ≤ 0.958) revealed LF-NMR may be an effective real-time monitoring method of these physicochemical parameters as a non-destructive technique.
即食海参由于食用方便、口感好、营养成分和生物活性成分损失小而成为一种受欢迎的产品。然而，关于多次冻融循环对即食海参水分动态的信息却很少。本研究采用低场核磁共振（LF-NMR）和磁共振成像（MRI）技术研究了冻融循环对即食海参水分状态的影响。在即食海参中观察到与强结合水、弱结合水、不可动水和自由水相对应的四个水分群体。随着冻融循环次数的增加，不可动水和自由水的横向弛豫时间增加，而自由水的峰面积显著降低。MRI 能够可视化多次冻融循环过程中即食海参的水分迁移。多次冻融循环还导致其他质量特性发生显著变化，包括解冻损失、水分保持能力、颜色参数、质地和蛋白质含量，并使微观结构中纤维网络之间的间隔增大。T、A、A 与解冻损失、水分保持能力、L*、硬度和胶原蛋白含量之间存在良好的相关性（0.873≤r≤0.958），表明 LF-NMR 可能是一种有效的实时监测这些物理化学参数的方法，是一种非破坏性技术。
