Effect of Pilot-Scale Decanter Centrifuge Processing Parameters on the Quality of Fish Meal Produced from Smoked Salmon Processing By-Products

Fish waste (FW) serves as an underutilized resource in agriculture, especially among small-scale processors. The trimmings and skins generated during the manufacturing of smoked salmon often end up in landfills due to insufficient quantities and logistical challenges to promote upcycling. An additional consideration is the high fat and mineral content in the smoked Atlantic salmon (Salmo salar) used for this study. We tested the feasibility of technology that small-scale processors can adapt to upcycle smoked salmon by-products into fish meal (FM) and fish oil (FO). A two-phase decanter centrifuge was optimized by manipulating acceleration, differential speed, flow rate, weir disc diameter, sample temperature, and the number of decanter runs. FW, processed through the decanter three times, produced FM with the least fat content compared to other trials. The optimized FM contained 74.09% protein, 8.56% fat, 15.41% ash, and 0.20% salt. FO production involved running a 9:1 water-to-by-product dilution through a three-phase clarifier centrifuge, followed by batch centrifugation and storage. Proximate, amino acid, and fatty acid profiles of the produced FM and FO aligned with industry standards. This study highlights a potentially sustainable solution for small-scale processors to transform FW into high-quality FM and FO, reducing waste and supporting sustainable resource recovery.