Dynamic Water Mobility in Sea Cucumber (Stichopus japonicas) During Drying Process Assessed by LF-NMR and MRI in situ

The purpose of this study is to elucidate the water dynamics in sea cucumber (Stichopus japonicas) during drying process in situ by the fast and non-destructive low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) methods. T-2 relaxation spectra in three-dimensional (3D) color map surface image from LF-NMR showed three main peaks assigned to bound water with relaxation time less than 2 ms, immobilized water in the range of 15-150 ms and extra-collagen fibrillar bulk water or free water adhered onto the sea cucumber with the longest relaxation time 200-1600 ms. The water dynamics in sea cucumber during drying process was clearly observed from the 3D color map surface image. Significant correlations between the LF-NMR T-2 parameters (A(Total), A(23) and T-23) and TPA parameters were observed, demonstrating that LF-NMR might be a complementary technique in monitoring the textural properties of sea cucumber during drying process.