Characteristics of the fish protein isolate recovered from Sardine by-products using the Isoelectric Solubilization- Precipitation method

The purpose of this study is to restore and characterize fish-protein-isolates (FPI) from the by-products of the sardine canning industry through the application of the isoelectric method of precipitation-solubilization (pH shift) method. The study was conducted in the laboratory of the Department of Fisheries Microbiology at Airlangga University with two treatments of solubilization (pH 2.5 and 11.5). Fish protein isolates were then characterized by yield, water holding capacity, oil binding capacity, TVBN and microbiological analysis (total bacterial count, coliform detection, Salmonella and Vibrio). This study found that FPI which was processed by alkali had better results (39.50 ± 11.75 b / b) compared to acid-processed samples (36.00 ± 8.97 b / b). Water retention capacity from FPI produced by alkali treatment reached 0.96 ± 0.18 mg / L while FPI produced by acid treatment reached 0.52 ± 0.19 mg / L. The binding capacity of oil from FPI in processing alkali was also more high compared to acid treatment. However, the quality of microbiological acid is better, but both treatments do not meet microbiological standards. The research suggestion that is isoelectric precipitation- solubilization method can be applied to produce new values on the by-products of the fishing industry but by adding antibacterial substances as needed.