Optimising drying parameters to maximise omega-3 essential fatty acid yields in striped weakfish (Cynoscion striatus) industry waste

Fish processing produces high amounts of wastes with low commercial value. Nevertheless, this material could be valorised through the extraction of its polyunsaturated fatty acids. Therefore, the purpose of this study was to evaluate the drying process of striped weakfish (Cynoscion striatus) waste in an air-circulating oven, aiming to preserve the omega-3 content. The microbiological and chemical characteristics of the dried product were evaluated. In addition, the lipid quality of the Soxhlet-extracted oil from the dried material was analysed. The drying condition of 70 °C and 10 h was the most suitable, because it preserved 98.7% of the original content of omega-3. The dry material presented 14.7% of lipids and 58% of protein, and it was microbiologically safe. The Soxhlet extraction, in spite of using high temperature, did not promote the oxidation of polyunsaturated acids. The applied drying process, followed by Soxhlet extraction, yielded 7.6 g of omega-3 fatty acids per kg of fresh sample. These results indicate that this residue presents large potential for oil extraction.