title: Estimation of freezing storage time and quality changes in hake (Merluccius merluccius, L.) by low field NMR.
abstract: The potential of low field NMR (LF NMR) as a fast monitoring technique to estimate the quality of hake (Merluccius merluccius) frozen stored at -10°C for up to 6months was evaluated. LF NMR clearly detected three populations of water: water strongly bound to macromolecules (T(2b)), trapped water (T(21)) and free water (T(22)). As storage time increased, and concomitant with an increase in the T(22) and a decrease in the T(21) water populations, the water holding capacity (WHC) and apparent viscosity values decreased and the shear strength increased, reflecting the characteristic loss of juiciness and tougher texture developed by hake during frozen storage. Two mathematical models were constructed: a simple regression using the biexponential analysis of the relaxation times (T(21), T(22)) and amplitudes (A(21), A(22)) and a partial least square regression (PLS) of CONTIN analysis. Both models seemed suitable to estimate the quality of the product.
authors.affiliation: Instituto de la Estructura de la Materia (IEM-CSIC), C/Serrano n-121, E-28006 Madrid, Spain. isabel.sanchez@iem.cfmac.csic.es
authors.forename: Isabel
authors.initials: I
authors.lastname: Sánchez-Alonso
authors.forename: Iciar
authors.initials: I
authors.lastname: Martinez
authors.forename: Javier
authors.initials: J
authors.lastname: Sánchez-Valencia
authors.forename: Mercedes
authors.initials: M
authors.lastname: Careche
mesh_terms: D000818:Animals; D003080:Cold Temperature; D005519:Food Preservation; D048388:Gadiformes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008460:Meat / Q000032:analysis* / Q000592:standards; D011786:Quality Control; D017747:Seafood / Q000032:analysis* / Q000592:standards; D013997:Time Factors; D014867:Water / Q000032:analysis
chemical_list: D014867:Water