Utilizing bull's eye fish processing frame waste to produce edible proteins and quality assessment of the recovered proteins

Abstract With an aim to utilize the waste generated from Bull's eye (Priacanthus hamrur) fish processing, proteins were extracted from this waste using the pH shift method. The properties of extracted proteins were studied in detail. During the protein solubility measurement, maximum solubilisation 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 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%). Processing of Bull’s eye proteins caused a significant reduction in its pigments, lipids and myoglobin content (p < 0.05). Proteins processed 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 extracted using the acid process.