INFLUENCE OF STUNNING METHODS ON THE FRESHNESS OF RAINBOW TROUT MEAT (Oncorhynchus mykiss Walbaum, 1792)

Abstract

The method of fish harvesting, which largely causes stress in fish and a number of other changes in the postmortem phase, reflects on the freshness and quality of the fish meat. The main goal of this research is to determine the impact of stunning methods on the incidence of stress and other postmortem processes that take place on the freshness and quality of fish meat during storage and conservation, since the fish, due to their chemical composition of meat and increased water content, is a perishable food. The research included a number of tasks: determining the chemical composition of fish meat, the implementation of sensory analysis (QIM) of fish meat, monitoring the degree of rigor mortis in fish, color shift tracking of fish meat and fillets, and a number of other non
core analyses and measurement. The trial included working with three different groups of stunned fish: by dull thud (hammer) in the head, stunning in ice/freshwater mixture and in CO2 solution. From the third group (CO2) have been prepared fillets, 10 fresh and 10 vacuum. The pH measurements of fish and the concentration of lactate in the blood, after harvesting and stunning showed no statistically significant difference between the groups, which means that they have almost the same level of stress. The obtained values of rigor mortis during the analysis showed constant decline for both groups, and that there are no statistically significant differences between two fish groups. QIM grades showed no significant differences between groups.