Quantification of biomolecules in herring (Clupea harengus) industry processing waters and their recovery using electroflocculation and ultrafiltration

Journal article, 2015

Abstract Four types of herring industry processing waters; refrigerated sea water (RSW), storage water (SW), processing water from cutting (PW) and pre-salting brines (SB) were subjected to chemical characterization and biomolecule recovery using electroflocculation (EF) and ultrafiltration (UF). The highest protein and fatty acid content were found in SB´s, up to 12.7±0.3 and 2.5±0.1 g L-1, respectively. Long chain n-3 polyunsaturated fatty acids represented up to 44.5% of total fatty acids. In all samples, leucine and glutamic acid/glutamine were the dominating amino acids whilst calcium and magnesium were the dominating trace elements. EF plus UF in series recovered up to 80% proteins and fatty acids from SB´s and reduced chemical oxygen demand by 70%. Foaming and emulsifying properties of biomolecules were improved or unaffected by EF/UF treatment. To conclude, large amounts of biomass are currently lost per tonne of processed herring, e.g. ~9.2 kg pure proteins and ~4.1 kg fatty acids; EF/UF represents a promising way of turning such losses to a potential income.