Efficiency of fishmeal and fish oil processing of different pelagic fish species: Identification of processing steps for potential optimization toward protein production for human consumption

Abstract

Most fish meal and fish oil production facilities run with outdated processes, producing low‐value products, typically not intended for human consumption. The aim of the study was to perform a detailed analysis of the current fishmeal and oil production processes of capelin (Mallotus villosus), and compare the key locations of both fattier and leaner pelagic raw material to identify which steps need to be improved for the production of higher‐value products. Results indicated inefficient draining and concentration during the production process and ineffective break‐down of the raw material, as lipid separation was ineffective in all studied species. Although the raw material initially differed in lipid content (2%–20%, depending on the species), all fishmeal produced resulted in high‐lipid fishmeal (9%–14%). Chemical composition variations in the solid steams entering the dryers suggested that drying these streams individually could lead to more process and product flexibility, which can result in higher‐value products, such as fish meal and protein powders for human consumption. Practical applications Traditional production lines of fishmeal and fish oil factories have remained the same for decades, resulting in low‐quality products with a low market price. Therefore, optimization and redesign of the production processes are needed to increase the product quality. This study analyzed the lipid quality and water content in all processing steps. The current evaluations will help to shift the traditional fishmeal and fish oil production process from low‐quality to high‐quality products intended for human consumption by presenting a detailed analysis of the production process not available in the literature to date. Our results can act as reference values for other fishmeal and fish oil producers to assess their production quality. That includes identification of bottlenecks affecting the efficiency and effectiveness of their production processes.

Pilot-Scale Ensilaging of Herring Filleting Co-Products and Subsequent Separation of Fish Oil and Protein Hydrolysates

“…For example, in Sweden, around 20,000 tons of herring are processed annually into convenience products (e.g., fillets), generating around 12,000 tons of co-products. These co-products have traditionally been exported for lower value applications like mink feed or fishmeal production, which can be questioned considering, e.g., environmental impacts of transportation and high energy use in fish meal/fish oil and subsequent feed productions (Hilmarsdottir et al, 2020 , 2021 , 2022 ). Here, ensilaging—endogenous protease-mediated autolysis under acidic conditions—could provide a cost-efficient and “green” process option to valorize these co-products into protein hydrolysates (Olsen & Toppe, 2017 ), traditionally known as silage, which is also easily implementable locally at fish processing plants.…”

Changes in Protein and Non-Protein Nitrogen Compounds during Fishmeal Processing—Identification of Unoptimized Processing Steps

“…The BW was refrigerated at 2 ± 2 • C on board for 24 h before being transferred to the fishmeal processing facility, where it was processed in the same way as the MHB as described in the following section. More detailed information about the raw materials and their handling were described by Hilmarsdottir et al [16].…”

“…However, only 26% of the lipid content of the BW raw material was extracted to form the BW fish oil, whereas 86% of the MHB lipid content in the MHB raw material was extracted to form the MHB fish oil. This could partially be dependent on differences in the total lipid content as well as the lipid composition and availability of lipid classes between the species [16]. Improving the lipid separation from the solid streams and directing them toward the liquid streams would therefore not only increase the fishmeal quality but also increase the oil yield.…”

“…Globally, 65-75% of the fishmeal and fish oil is produced from small pelagic fish [3,6,16]. Pelagic fish species constitute a large part of the captured fish in Iceland and made up 51% of the total catch in 2020.…”

“…These production processes are primarily purposed toward water removal. Meanwhile, the protein quality, lipid removal, and separation of unwanted non-protein nitrogen compounds have not been considered in detail [16,25]. Furthermore, the processes are not optimized towards variations in the raw materials or the processing of different species.…”