Effect of edible coating on the whole large yellow croaker (Pseudosciaena crocea) after a 3-day storage at −18 °C: With emphasis on the correlation between water status and classical quality indices

Abstract

In order to find a suitable alternative for water glazing of frozen fish, the effect of coating (sodium alginate or chitosan) on the whole large yellow croaker (Pseudosciaena crocea) after a 3-day storage at −18 °C was compared. Besides the classical quality indices, such as color, texture properties and water-holding capacity, the change of water status and distribution of the sample were also examined by low field NMR (LF-NMR) and magnetic resonance imaging (MRI), and the correlation between water status and classical quality indices was investigated. The coating of sodium alginate (SA) presented lower cooking and drip loss, better texture and muscle color acceptability. The LF-NMR result also revealed that higher proportion of immobilized water trapped within the myofibrillar protein network was obtained after SA coating. This was also confirmed by the MRI result of more evenly distributed proton in the sample. Meanwhile, good correlations between LF-NMR results and drip loss, cooking loss, texture properties, as well as L* value were obtained. In conclusion, the coating of SA provided a promising approach to minimize the undesirable changes of frozen whole large yellow croaker. LF-NMR is a potential approach to rapidly assess the quality of frozen fish.