Proteolytic processing of herring (Clupea harengus): biochemical and nutritional characterisation of hydrolysates

Food research on fish has demonstrated that they constitute excellent nutritional components. The aim of the present work, was to process herring ( Clupea harengus ) using Protamex^® and evaluate the distribution of nutrients in various fractions obtained following membrane filtration. The fish starting material was composed of approximately 88% water and the dry matter contained 59% crude proteins, 33% lipids and 5% minerals. The recovery of fish dry matter in the liquid hydrolysate was 67.8%. Most protein enriched fractions demonstrate a well-balanced amino acid composition, notably the most essential amino acids. These protein fractions are characterised by biomolecules having a relatively low molecular weight (45 kDa and less) range. Even though the process could be optimised, the biochemical and nutritional analyses indicate that the herring may serve as high-value products for future applications in the health and food sectors.