Sustainable development of fishery resources: Precipitation of protein from surimi rinsing wastewater by low-temperature plasma

This study aimed to determine the impact of low-temperature plasma (LTP) on the protein stability and composition in surimi rinsing wastewater (SRW). When SRW (300 mL) was treated with LTP at a power of 420 W and a flow rate of 1.1 L/min for 106 s, the protein precipitation was 76.04 %, the pH was close to the estimated value of the isoelectric point (pI). In comparison with the pI precipitation treatment, non-precipitated proteins in the SRW after LTP precipitation treatment showed significant changes in amino acids susceptible to oxidation but had minor changes in the hydrophobic amino acid content. LTP showed a markedly differentiated response to the different protein types in the SRW, increasing the relative amounts of several enzyme proteins in the non-precipitated protein. The combined effect of the active ingredients provided by LTP on protein conformation and hydrophobic interactions may be responsible for this 'screening' phenomenon.