Oxidative stability in Atlantic salmon by-products: The role of reactive organs, processing methods, and antioxidants

Abstract

The effect of the presence of reactive organs, antioxidants (rosemary extract), and processing methods (grinding and tumbling) on lipid oxidation in Atlantic salmon (Salmo salar) by-products was investigated. This study is the first to investigate the impact of individually separating all reactive organs from Atlantic salmon by-products and to assess their influence on lipid stability. Whole salmon heads, frames, and viscera were subjected to either tumbling or grinding to compare the effect of a high and low tissue disruption on their storage stability at 10 °C for 7 days. Additionally, salmon heads and viscera were stored either whole or after sorting highly pro-oxidant organs (reactive organs) to assess their role in lipid oxidation. During seven-day storage, peroxide and p-anisidine values and free fatty acid content were analyzed. Grinding reduced the oxidative stability of by-products, while sorting reactive organs increased the oxidative stability of heads and viscera lipids. Viscera lipids were the most susceptible to deterioration. Moreover, lipid oxidation during 90-day storage at −18 °C was evaluated, revealing that by-products without reactive organs remained stable irrespective of antioxidants addition or processing methods. Fatty acid analysis using gas chromatography-mass spectrometry (GC-MS) identified five primary polyunsaturated fatty acids, linoleic, alpha-linolenic, docosahexaenoic, eicosapentaenoic, and docosapentaenoic acids, which remained stable during storage. These findings highlight the importance of eliminating or inhibiting specific pro-oxidants and selecting appropriate processing methods to prevent lipid oxidation in Atlantic salmon by-products.