Influence of freezing before or after hot-smoking on the quality and sensory attributes of canned deep-skinned Atlantic mackerel

• Listeria was efficiently removed by freezing and hot-smoking; smoking was crucial. • Processing order of freezing and smoking did not affect the proximate composition. • Lipid oxidation and hydrolysis were limited, regardless of the processing order. • Freezing before smoking and canning led to firmer, not mushy texture and appearance. • Freezing before smoking leads to better quality in canned products, concluded study. Growing fish consumption worldwide has driven fish processors to introduce innovative seafood products with extended shelf-life and desirable organoleptic properties. Atlantic mackerel ( Scomber scombrus ) enters the Icelandic catching waters during a well-fed and fatty stage during summer, providing several challenges for its processing and utilization for human consumption. This study investigates the impact of freezing this well-fed and fatty deep-skinned Atlantic mackerel fillets before and after smoking, prior to canning to assess its suitability for processing of smoked and canned products for human consumption. Physicochemical and organoleptic properties of canned fillets were evaluated after 1 and 12 months of storage at room temperature. The formation of primary oxidation products (peroxide value, PV) was similar in both cases, while the secondary oxidation products (thiobarbituric acid reactive substances, TBARS) were notably lower when the fillets were smoked before freezing. Additionally, PV and TBARS levels were significantly reduced in all canned mackerel samples after prolonged storage compared to those stored for a shorter period. However, lipid oxidation and hydrolysis were minimal after both treatments, indicating that these factors do not pose a significant issue for these products. Instrumental texture analysis and product evaluation of canned mackerel revealed more favourable characteristics (firmer fillets, nor mushy) when fillets were frozen first and then hot-smoked (FSC). In contrast, fillets that were smoked first and then frozen (SFC), irrespective of the canning storage time, exhibited a mushy texture and appearance, which could negatively impact consumer acceptance. Therefore, freezing prior to hot-smoking may represent a better option if the fillets are intended for canning.