Improving the Stability of Red Blood Cells in Rainbow Trout (Oncorhynchus mykiss) and Herring (Clupea harengus): Potential Solutions for Post-mortem Fish Handling to Minimize Lipid Oxidation

S Ghirmai,M Axelsson,H Wu,L Eriksson,I Undeland

doi:10.1007/s11947-020-02472-3

S Ghirmai, M Axelsson + Show 3 more

Open Access

https://doi.org/10.1007/s11947-020-02472-3

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Abstract

This study aimed at limiting hemolysis of fish red blood cells (RBCs) as a strategy to limit hemoglobin (Hb)-induced lipid oxidation during post-mortem handling and processing. Effects of varying temperature, salinity, and mechanical impact were studied using washed resuspended RBCs (wr-RBCs) and whole blood (WB) from rainbow trout (Oncorhynchus mykiss) and herring (Clupea harengus). The wr-RBCs were most stable avoiding mechanical stress, keeping isotonic conditions (0.9–1.3% NaCl) and low temperature 0–6 °C, with predicted minimum at 2.5 °C. When compared at the same salinity, it was found that hemolysis was more pronounced in herring than trout wr-RBCs. Furthermore, WB was more stable than wr-RBCs, showing protecting the effects of blood plasma. Studying individual plasma components, stabilizing effects were found from glucose, proteins, and ascorbic acid. This study indicates that small adjustments in the early handling and processing of fish such as changing salinity of storage and rinsing solutions could minimize Hb contamination of the fish muscle and thereby improve quality.

Highlights

Post-mortem, fish muscle is highly susceptible to lipid oxidation due to its abundance of polyunsaturated fatty acids (PUFAs) and, in some cases, blood, the latter containing the strong pro-oxidant hemoglobin (Hb) (Larsson et al 2007; Li et al 2005; Richards and Hultin 2002; Undeland and Lingnert 1999)
The wrRBCs or whole blood (WB) in 3% (513 mM) NaCl gave the second-fastest hemolysis, with 50% hemolysis (T50) after around 3 and 6 days, for wr-red blood cells (RBCs) and WB respectively. Both washed resuspended RBCs (wr-RBCs) and WB incubated in physiological salt concentration, 0.9% (154 mM)
Results with 0.9% NaCl were significantly different (p < 0.001) from those obtained in wr-RBCs with 3% NaCl at 4 and 7 days and from WB in 3% NaCl during the whole time span

Summary

Introduction

Post-mortem, fish muscle is highly susceptible to lipid oxidation due to its abundance of polyunsaturated fatty acids (PUFAs) and, in some cases, blood, the latter containing the strong pro-oxidant hemoglobin (Hb) (Larsson et al 2007; Li et al 2005; Richards and Hultin 2002; Undeland and Lingnert 1999). By-products from the filleting industry are highly susceptible to lipid oxidation due to richness in both blood and PUFAs (Wu et al 2020) This renders food production from by-products difficult, despite their large amounts of high-quality muscle. The practice of bleeding is not applicable or economically feasible in commercial vessels targeting small pelagic fish species, as such fish is captured in large hauls, and bleeding has to be performed within minutes to ensure efficient removal of the blood (Olsen et al 2014)

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