RESUMEN
As dark meat has a faster deterioration rate and its unintentional mixing occurs during processing, it is crucial to know the status and freshness indicators of dark meat to ensure fishery product quality. In this method, fluorescence fingerprints (FFs) was applied as a rapid and noninvasive quality authentication method to determine differences between white and dark meat in the evaluation of freshness indicators at frozen state. Spotted mackerel (Scomber australasicus) fish chunks with different postmortem conditions (0-40 h ice stored) were obtained and frozen. A new generation of fluorescence spectrophotometer (F-7100) was used to acquire FFs of the frozen fish chunks (containing white and dark meat). Adenosine triphosphate metabolites and pH were determined in both white and dark meat using their relevant biochemical methods. Higher K-values in dark meat might be attributed to a higher accumulation rate of inosine (HxR) in dark meat than in white meat. The pH decrease rate in white meat was higher than that in dark meat during postmortem ice storage periods of fish. Principal component analysis of FFs spectra demonstrated clear discrimination (PC1 + PC2 = 91.7%) between white and dark meat of frozen fish due to the influence of freshness parameters based on the fluorescence features of fish meat. Furthermore, partial least squares regression validation models revealed that freshness indicators of white meat could be predicted more accurately at the frozen state than those of dark meat. This method could be applied during the processing of fishery products, thereby facilitating quality control activities and making it a promising authentication tool for the fisheries industries.
Asunto(s)
Hielo , Perciformes , Animales , Carne/análisis , Peces , CongelaciónRESUMEN
Selenoneine is a selenium-containing imidazole compound in the blood and tissues of tuna and other marine fish that has strong free-radical scavenging activity. This compound may have antioxidant functions, i.e., preventing metmyoglobin formation in fish muscle, which affects meat quality. This study examined the relationship between meat color and total selenium concentration in the muscle of two Scomber species, spotted mackerel (Scomber australasicus) and Pacific mackerel (S. japonicus), to assess the role of selenium as an antioxidant preventing meat discoloration. The color of chilled and frozen-thawed muscle was compared between spotted mackerel and Pacific mackerel. The a* values, indicating the red-green component of color, of the white and red muscle of spotted mackerel were higher than those of Pacific mackerel (p < 0.05). We also analyzed the blood selenium concentration of Pacific mackerel according to the L* value and protein concentration in the blood during spawning migration in June. The blood selenium concentration was negatively correlated with the L* value (r = - 0.46) and blood protein concentration (r = - 0.56). The blood selenium concentration in summer was related to the brightness of the muscle surface and blood protein concentration, suggesting that it is responsible for deterioration of meat quality.These findings suggest that antioxidant properties of selenium prevent the mackerel muscle discoloration that can occur during chilled and frozen storage.