In February, the first WaSeaBi scientific paper was published in Food Control, which describes a new cost-effective strategi to prevent lipid oxidation (rancidity) in side-streams from herring (Clupea harengus) filleting by dipping the side-streams in a solution with antioxidants.

There are many incentives to use our landed fisheries resources in a more complete manner to food production, instead of just taking out the fillet, and sending the rest to low value uses as feed production. Side-streams from fish filleting, such as heads and backbones often contain a lot of prime quality muscle, which is rich in proteins and valuable omega-3 fatty acids.

Today there are techniques available for upgrading these materials to food ingredients such as minces, protein isolates, hydrolysates and oils, even if their structure is complex, with a lot of bones and skin. However, a challenge when producing food ingredients from side-streams is that their unsaturated lipids are very sensitive to oxidative degradation, which prevents storage between their generation, and their subsequent upgrading into food ingredients. This is since they are rich in blood, which in turn contains the protein haemoglobin, a molecule that can accelerate the reaction between oxygen and the unsaturated fish lipids, resulting in rancidity and lowered nutritional value. Rancid taste and odour reduce the sensory impression of both the raw material and final products.

In this study, Chalmers University of Technology investigated a new dipping technology for herring (Clupea harengus) filleting side-streams which is built on a solution containing Duralox MANC 213- a mixture of rosemary extract, ascorbic acid, tocopherols and citric acid. If dipping the herring filleting side-streams in the Duralox-solution prior to their storage at 0 °C or 20 °C, the time until rancidity developed was extended from <0.5 to >3.5 d at 20 °C, and from <1 d to >11 d at 0 °C. To make the technology cost-effective, the possibilities to re-use the antioxidant solution was also investigated, and revealed that even after re-use of the solution up to 10 times, rancidity was completely inhibited at 0 °C. From more detailed studies, it was found that Duralox MANC kept the fish haemoglobin in a more stable form that is less reactive with the lipids, thereby preventing oxidation.

The new technology gives a valuable window of time for herring producers to store or transport the side-streams prior to further value adding to food ingredients. Also, since the dipping covers the side-stream surface with a thin layer of antioxidants, these are carried over to the next process step, providing more high quality mince, protein- or oil-ingredients.

Figure 1. Flowchart of the main steps involved in the procedure of dipping and storage of herring co-products.

Read the publication here:

Controlling hemoglobin-mediated lipid oxidation in herring (Clupea harengus) co-products via incubation or dipping in a recyclable antioxidant solution

Wu H., Sajib M. & Undeland I.; doi.org/10.1016/j.foodcont.2021.107963; Food Control 2021