A novel integrated process for the recovery of protein-enriched biomasses from shrimp boiling water (SBW) and shrimp peeling water (SPW) was investigated by combining flocculation (F) and dissolved air flotation (DAF) into an F-DAF process. Alginate and carrageenan were used as flocculants. It was found that the protein yield from SPW and SBW in the F-DAF process was 68−97% and 26− 45%, respectively. This led to a reduction in protein content of the influent SBW and SPW (12.4 and 1.4 g/L, respectively) by up to 76% and 85%, resulting in outlets with 2.9 and 0.2 g/L protein, respectively. Further, the F-DAF recovery process concentrated the proteins of SBW and SPW up to 7 and 29 times, respectively, thus, generating a protein-enriched biomass. After spray drying, biomass from SBW had up to 61% proteins, and out of the total amino acids, up to 47% were essential ones. Further, the spray dried powder contained up to 23% total lipids, 2.7% long chained n-3 polyunsaturated fatty acids and 49.7 mg/g total astaxanthin. The studied F-DAF recovery system can thus be successfully used for recovering nutrients from process waters generated during the production of peeled shrimps.

Shrimp boiling water (SBW) and shrimp peeling water (SPW), generated during shrimp processing, were characterized in terms of crude composition, volatile compounds, as well as nutritional and potentially toxic elements over a 13 month sampling period. The storage stability of both waters was also evaluated. Results showed that SBW contained on median 14.8 g/L protein and 2.2 g/L total fatty acids with up to 50% comprising eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Astaxanthin esters, which dominated the total astaxanthin, were 2.8 mg/L on median. SPW, on the other hand, contained on median 1.0 g/L of protein, 0.21 g/L of total fatty acids, and 1.2 mg/L astaxanthin esters. For both side-streams, essential amino acids were up to 50% of total amino acids. For SBW and SPW, the most abundant nutritional elements were Na, K, P, Ca, Cu, and Zn. The contents of all potentially toxic elements were below the detection limits, except for As. SBW was more stable at 4 °C compared to SPW as shown, e.g., by thiobarbituric acid reactive substances and relative changes in total volatile basic nitrogen. The extensive compositional mapping of SBW/SPW provides crucial knowledge necessary in the exploitation and value-adding of such side-streams into food or feed products.