Ultrastructural Changes and Structure and Mobility of Myowater in Frozen-Stored Hake (Merluccius merlucciusL.) Muscle: Relationship with Functionality and Texture

The ultrastructural changes and the main Raman spectral features of water (3100−3500 and 50−600 cm-1 ranges) in frozen-stored hake were studied with the aim of connecting these changes with loss of some functional properties such as water holding capacity, and with modifications of muscle texture. The following results were obtained: (a) The changes in the spaces between myofibrils can be related to modifications of shear resistance. (b) The behavior of the strong 160 cm-1 band can be related to conformational transitions of muscle proteins, to changes in the structure of muscle water, and/or to alterations in protein−water interactions. (c) There were intensity changes in the νs(OH) band that may be attributable to transfer of water to larger spatial domains during frozen storage. Keywords: Fish muscle water; Raman spectroscopy; ultrastructure; WHC; texture