Recovery of protein-rich biomass from surimi rinsing wastewater by using a sustainable cold plasma treatment.

Surimi rinsing wastewater is typically discarded, causing waste of protein resources and environmental pollution. This study investigated the technology of a cold atmospheric plasma jet (CAPJ) for the recovery of protein-rich biomass (PRB), including myofibrillar proteins (MPs) and sarcoplasmic proteins (SPs), from surimi rinsing wastewater. The protein recovery yield was up to 59.84 %. CAPJ induced an increase in carbonyl and decreased sulfhydryl in protein content. Furthermore, the secondary structure of the protein was unfolded, particularly the transition from α-helix to β-sheet. The formation of disulfide bonds and increased hydrophobic interactions promoted protein aggregation (the particle size from 185.76 nm to 1869.07 nm,  < 0.05) and reduced solubility. The proteomic results indicated that CAPJ increased the expression level of antioxidant enzymes. Overall, the CAPJ technology could recover proteins from surimi rinsing wastewater for industrial application, which will promote the sustainable development of the surimi industry.