ABSTRACT
The aim of the study was to utilize the waste generated from Bullseye (Priacanthus hamrur) fish processing to recuperate proteins. Considering the cost-effectiveness, versatility, and color improvement after the pH shift method, proteins from this waste were extracted by the pH shift method using hydrochloric acid and sodium hydroxide. The properties of extracted proteins were studied in detail. During the protein solubility measurement, maximum solubilization was found at pH 3.0 (13.10 mg/mL) on the acidic side and pH 11.0 (14.25 mg/mL) on the alkaline side with a total yield of 51.62 ± 0.23 and 45.42 ± 0.29 (%), respectively. The process variables tested in this study showed a significant effect on protein solubility (p < 0.05). The protein content of the isolates extracted from the waste was 23.80 ± 0.49 and 22.48 ± 0.39% for acid and alkali processed isolates, which was significantly higher than the mince (19.46 ± 0.67%). pH shift processing of Bullseye proteins caused a significant reduction in its pigments, lipids, and myoglobin content (p < 0.05). Proteins extracted using alkali had significantly higher values for foaming stability, water holding capacity, and emulsion capacity than proteins extracted using acid. An overall assessment indicated that protein isolates obtained using alkali extraction were better in terms of textural attributes, gelling ability, and amino acid profile than protein isolates extracted using the acid process.
