From the ACS Press Room
Technique Fishes Valuable Nutrients Out of Shrimp Processing Water “Flocculation and Flotation to Recover Pro- branes, but the equipment is expensive and tein-Enriched Biomasses from Shrimp Boil- can clog. A more sustainable option is to ing and Peeling Process Waters: A Case switch to food-grade flocculants in combinaStudy” tion with DAF. Although a few other studies ACS Sustainable Chemistry & Engineering have shown that such a combination could The seafood industry requires large amounts work, these were small-scale experiments. of water for food processing. Before used wa- Ingrid Undeland and Bita Forghani of ter is discharged, some organic matter, in- Chalmers University of Technology and colcluding protein, is typically removed. This leagues wanted to scale up the combined food sludge is usually landfilled or converted into -grade flocculation-DAF process and assess biogas, which results in the valuable nutrients the nutrient composition of the recovered bioit contains being lost from the food chain. mass. Now researchers report in ACS Sustainable At a processing plant, the team treated shrimp Chemistry & Engineering a method to recovprocessing water with alginate or carrageeer these nutrients from shrimp processing wanan, edible flocculants derived ter so they can be incorpofrom seaweed. The resulting parrated in food or feed. ticles were then collected via DAF and dried. The combination At present, food processing technique captured up to 98% of factories remove organic matthe protein present in the water, ter from water by first clumpconsiderably more than flotation ing it together with chemical alone could collect. The recovtreatments (coagulation) and ered shrimp biomass contained up to 61% then raising those clumps to the surface with proteins and 23% total lipids. The researchers a technique such as “dissolved air flotaconcluded the process could be used for retion” (DAF). Coagulation is traditionally carcovering nutrients from shrimp processing ried out with iron or other non-food-grade water for later use in food or feed. flocculants that clean the water efficiently, but render the removed sludge unsuitable for The authors acknowledge funding food or feed purposes. One alternative is to from Nordic Innovation. filter the nutrients from the water using memSeptember 2020
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