Abstract:
Research Objective: To investigate the specific impact of sous vide technology on the quality of salmon, and to explore the feasibility and potential of sous vide salmon as a series of pre-cooked food products. Methodology: This study measured key quality indicators of salmon, including sensory evaluation, juice loss rate, major nutrient content, fatty acid composition, lipid oxidation, protein degradation, and microstructural analysis. Experiments were conducted under various cooking temperatures (38, 46, 54, 62℃), durations (10, 25, 40, 55 minutes), and vacuum levels (0.1Mpa、0.05Mpa、0.025Mpa) and atmospheric pressure. By utilizing lipidomics technology, this study further explored the impact of temperature on the changes in key lipid molecules, providing deeper insights into lipid molecular oxidation. Results: As the cooking temperature increases, the brightness, juice loss rate, hardness, total protein content, POV (peroxide value) and TBARS (thiobarbituric acid reactive substances) value of salmon all increase, while the sensory score (with odor indicators first improving and then declining as temperature rises), total fat content, and degradation of myosin and actin also intensify. Extending the cooking duration leads to an increase in brightness, yellowness value, juice loss rate, elasticity, and hardness, along with a decrease in sensory score (due to decreased color, tenderness, texture, and resilience). The content of saturated fatty acids first increases and then decreases, while the content of polyunsaturated fatty acids decreases, accompanied by degradation of myosin heavy chains. The results of HE staining and electron microscopy showed that the muscle fibers were tightly packed with the increase of cooking temperature, and the muscle fibers would be destroyed when the temperature was too high. Under high vacuum conditions, the total fat content rises, while the impact on sensory quality, fat oxidation, and actin degradation is relatively minor, resulting in the lowest POV and TBARS values obtained. Lipidomics analysis indicates that higher temperatures lead to more significant changes in lipid molecules in salmon samples, showing an upward trend with amplified differences. The total content of oxidized phospholipids gradually accumulates as the temperature rises. Vacuum cooking at lower temperatures can reduce the formation of oxidized phospholipids, demonstrating the outstanding effectiveness of vacuum low-temperature slow cooking in maintaining the high quality of salmon. Conclusion: The comprehensive analysis has yielded results indicating that steaming temperature has the most significant impact on the quality of salmon, followed closely by steaming duration and vacuum level. The sous vide technique, by leveraging the combined effects of low temperature and vacuum, effectively minimizes the formation of oxidized phospholipids and lipid oxidation in salmon. This technique not only mitigates the adverse effects of processing on key quality indicators of salmon but also preserves its superior quality and sensory attributes. The optimal parameters for this sous vide process have been established: steaming salmon at a temperature of 46℃ for 25 minutes under high vacuum conditions of 0.1MPa, resulting in relatively good quality and sensory experience. The findings of this study not only provide comprehensive data support and a robust theoretical foundation for optimizing the sous vide technology for salmon but also establish a solid groundwork for advancing the high-quality industrial production of salmon products. This, in turn, will facilitate the maximization of their market value, ultimately contributing to the sustainable growth and development of the salmon industry.