Production of high-quality fish oil from herring byproducts

In this work, the feasibility of producing high-quality fish oil from herring byproducts was evaluated in various ways. With this, a contribution has been made to a more efficient usage of natural resources while yielding a high-quality product. Crude oil extracted from herring byproducts is relatively rich in essentialw-3 PUFAs such as EPA and DHA, and is relatively stable during storage. The main conclusions of this study were: herring byproducts from the entire year are an adequate raw material for fish oil production; good quality fish oil can be produced from salted herring byproducts, and byproducts from different herring processing generate oils with different qualities. It is also shown that sorting of the byproducts does not result in oils of strongly different qualities, showing that this step is not required. However, it is concluded that from stored byproducts oil with higher levels of PUFAs content could be obtained. The best quality oil was achieved while processing at the highest throughput of the pump and at intermediate decanter speed. It has been observed that the best temperature to keep the oil is 0°C. The extracted crude herring oil presented relatively low levels of contaminants, PCBs and dioxins. Finally, the crude herring oil was refined and compared with commercially available menhaden oil. Similar properties such as oxidative stability and off-taste development were found. The currently obtained knowledge of fish oil extracted from herring byproducts is the first essential step towards the valorization of byproducts from different fatty fish species into production of fish oil, thereby contributing to a better utilization of the marine resources that are available.