Utilizing Bullseye fish processing frame waste to produce edible proteins and quality assessment of the recovered proteins.

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.

Utilization of fish protein isolates to supplement oat-based cookies and assessment of end product quality.

Bullseye and Pacu fish processing waste were valorized through its conversion into functional protein isolates, followed by the utilization of recovered proteins to supplement oat-based cookies at different levels (0, 2, 4, 6, 8 and 10 g/100 g) and baking temperatures (100, 150, 170, 180, 190 ˚C). With different replacement ratios and baking temperatures, the best selection was made at (4 and 6%) and baking temperatures (160 and 170 ˚C) for BPI (Bullseye protein isolate) and PPI (Pacu protein isolate) based cookies, respectively based on sensory and textural characteristics. The developed products were analyzed for its nutritional, physical, textural, and sensory quality. No significant differences were found in the moisture and ash contents of the cookies from different lots, while the protein content was highest for cookies with 6% PPI. The spread ratio was lower reported for the control cookies compared to the fish protein isolate-based counterpart (p < 0.05), and it decreased with increasing thickness of cookies. Significantly higher total essential amino acid values were obtained in cookies supplemented with 6% Pacu protein isolates, whereas 4% Bullseye protein isolate-supplemented cookies were higher in total non-essential amino acid content. The total plate count was higher in control cookies (0.35 ± 0.33 cfu/g) compared to fish protein isolate-supplemented cookies. The hardness values were maximum for control group cookies (19.14 ± 0.98 N) compared to protein isolate incorporated cookies (17.22 ± 1.05 N and 16.26 ± 0.9 N). However, the difference among the all-treatment group is not significant (p > 0.05).