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The present study sought to evaluate the effect of basic amino acid (L-arginine (Arg), L-lysine (Lys), and L-histidine (His)) pretreatment on the quality of canned Antarctic krill. Additionally, the changes in krill meat at different pretreatment conditions and processing stages were measured. The Lys-pretreated krill meat exhibited 39.9% lower hardness, 19.8% lower chewiness, and 47.2% lower thiobarbituric acid reaction substances (TBARS) compared to the control group. The low-field nuclear magnetic resonance (LF-NMR) and the magnetic resonance imaging (MRI) analyses revealed that the Lys-pretreated krill meat showed a larger peak area of immobile water and a higher pseudo-color image brightness. The scanning electron microscopy (SEM) results showed that the microstructure of krill meat in the control group was broken and disordered, while the microstructural network of Lys-pretreated krill meat was more complete. This result indicated that Lys effectively improved the texture, water-holding capacity, and color of krill meat, protecting the microstructure and reducing the degree of oxidation. The sensory evaluation results showed that the Lys-treated canned Antarctic krill had a better flavor and texture than other canned products. Overall, Lys could be a potential regulatory strategy for effectively enhancing the quality of canned Antarctic krill. [ABSTRACT FROM AUTHOR]

Antarctic krill (Euphausia superba) is an important source of biomass and high-quality protein. However, heat treatment negatively impacts the quality of Antarctic krill and compromises its utilization in the food industry. This study aimed to investigate the mechanisms underlying changes in Antarctic krill meat characteristics and physicochemical properties treated at different temperatures and holding times. Our findings indicated that hardness and cooking loss of Antarctic krill meat increased dramatically at higher temperatures and holding times. The low-field nuclear magnetic resonance (LF-NMR) analysis revealed that the loss of immobilized water increased, whereas the SDS-PAGE analysis showed that the content of myosin heavy chain decreased significantly and that protein degradation occurred. Fourier transform infrared spectroscopy (FT-IR) and intrinsic fluorescence spectra suggested that α-helix motifs were transformed into β-sheets and that more hydrophobic groups were exposed. The scanning electron microscopy (SEM) results showed that Antarctic krill meat formed corrugated folded regions after heat treatment without forming a three-dimensional water-entrapped structure, which led to significant water loss, resulting in rapid deterioration of Antarctic krill meat. These results provide the basis for a deeper understanding of the processing characteristics of Antarctic krill meat. [ABSTRACT FROM AUTHOR]

BACKGROUND: The quality deterioration of Antarctic krill (Euphausia superba) after thermal processing limits its industrial application. This study sought to improve the texture characteristics of Antarctic krill after heat treatment through pre‐soaking using l‐lysine (Lys) solution and sodium tripolyphosphate (STPP). Moreover, the effects of Lys on heat‐treated Antarctic krill were explored. RESULTS: Lys significantly reduced the cooking loss and improved the texture characteristics of Antarctic krill during heat treatment. The low‐field nuclear magnetic resonance results showed that Lys reduced the water loss of Antarctic krill during heat treatment. Additionally, the surface hydrophobicity, Fourier transform infrared spectroscopy, and endogenous fluorescence spectroscopy results showed that Lys could inhibit the structural damage of Antarctic krill protein under the thermal denaturation condition and enhance the thermal stability of the protein. The scanning electron microscopy results showed that Lys could protect the structural integrity of Antarctic krill muscle fibers during heat treatment. CONCLUSION: The cooking loss in the Lys added groups was better than the sodium tripolyphosphate added group, and 2.0% Lys solution could minimize the cooking loss of Antarctic krill. The secondary and tertiary structures of the Antarctic krill protein were actively protected by Lys during heat treatment. Overall, the study will provide insights into the application of Lys in the food industry as a natural additive and an alternative to phosphate. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]