Influence of Freezing–Thawing Cycle on Water Dynamics of Turbot Flesh Assessed by Low-Field Nuclear Magnetic Resonance and Magnetic Resonance Imaging

Abstract

Abstract Turbot is a valuable commercial species due to its high nutrient content. Moisture is an important indicator of meat spoilage. This study elucidated distinctive water dynamics in turbot flesh in the freezing–thawing process by nondestructive low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) techniques. T 2 relaxation spectra were utilized to describe the mobility and content of different types of water. Principal component analysis (PCA) revealed a clear discrimination of various freezing–thawing cycles. T 1- and T 2-weighted MRI provided further visualization of internal information for turbot flesh. Microscopic examination clearly identified protein denaturation and structural shrinkage. Furthermore, NMR parameters and conventional physicochemical parameters of color, shear force and thiobarbituric acid-reactive substances showed good correlations. To sum up, the study revealed that LF-NMR and MRI are promising techniques to portray the relationship between the water dynamics and changes of turbot quality properties during the freezing–thawing process.