Composition, Functional Properties, Antioxidant Activity and Efficiency as Bacterial Growth Medium of Minced Tilapia (Oreochromis niloticus) Wash-Water

The mechanical deboning of fish carcasses generates large volumes of water with proteins and other nutrients that are directly discarded. This study aimed to demonstrate the industrial value of minced tilapia wash-water (MTW-W) by determining its proximate composition and amino acid content, functional properties (solubility, foaming and emulsifying properties), antioxidant activity and potential as microbial growth medium. MTW-W showed a high crude protein content and a high content in essential amino acids for human and animal nutrition. A high protein diversity was detected in MTW-W by SDS-PAGE, including low-molecular-weight proteins that could serve as nitrogen source in bioprocesses. MTW-W demonstrated a high solubility in water and remarkable foaming properties over a wide pH range, but a limited emulsifying activity. A high antioxidant activity in terms of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging was also detected, probably due to the high content in hydrophobic amino acids and those containing sulphur. Moreover, MTW-W showed a high efficiency for the growth of Escherichia coli , Listeria monocytogenes and Staphylococcus aureus . Therefore, the present study demonstrated the potential of MTW-W as functional additive with antioxidant activity and nitrogen source in bioprocesses, which would increase the sustainability of the tilapia processing and reduce the environmental impact. Graphic Abstract