Today, most fish by-products are targeted feed production, or are even wasted. Techniques to separate food grade muscle, proteins and oil from complex bony raw materials exist, but applying such techniques to fish by-products is rendered difficult by their high susceptibility to hemoglobin-mediated lipid oxidation.
Based on this, Haizhou Wu and Ingrid Undeland from the WaSeaBi partner organisation halmers University of Technology, have conducted a study with the aim of prolonging the shelf-life of herring by-products by rinsing/dipping them in water or 0.9% salt-solution without or with antioxidants added.
The results from the study showed that:
- Rinsing with 0.9% salt only removed small amounts of Hb and had limited effect on lipid oxidation development during subsequent storage.
- Dipping or rinsing by-products in solutions with added antioxidants however had remarkable effects on lipid oxidation; shelf life went from <1 day to >12 days.
- The dipping solutions could be re-used up to 10 times and could still inhibit lipid oxidation of herring by-products.
- These novel antioxidative strategies could be powerful industry tools to allow upgrading of fish by-products to food ingredients.