A step towards closing the food-waste gap in novel protein sources: Post-harvest protein boost of the seaweed crop Ulva by herring production tub water
Sophie Steinhagen, Kristoffer Stedt, João P. Trigo, Ingrid Undeland, Henrik Pavia
Abstract
Sea lettuce (Ulva) species have been identified as a future protein source, and post-harvest techniques, including the sustainable integration of liquid food side streams, have been developed to further increase their protein content and commercial market value. This study explores the post-harvest treatment of commercially produced seaweed biomass from large-scale, sea-based cultivations of U. fenestrata with residual water streams emerging from industrial storage of herring – so called herring production tub water (TUB). Growth rates of U. fenestrata were significantly higher in TUB treated seaweeds compared to controls. Further, the crude protein content was 71.26% higher when cultivated in TUB, compared to controls, reaching a crude protein content of 37.37 ± 1.83 % dry weight. Notably, there were no limiting amino acids, nor fish-related allergenic activity in the seaweed biomass. Our study demonstrates a new nutrient loop turning food waste into protein-rich biomass by applying sustainable seaweed cultivation.