Protein hydrolysate waste of whitemouth croaker (Micropogonias furnieri) as a way of adding value to fish and reducing the environmental liabilities of the fishing industry

Abstract

As an alternative use of natural marine resources, processing waste from whitemouth croaker was used as raw material for the production of fish protein hydrolysate (FPH). The biometric characterization of the raw material was determined, and the optimal conditions of the protease established using DH (degree of hydrolysis) as the criterion. Bromatological analyses were performed according to AOAC methods. The DH were determined by the TCA (trichloroacetic acid) method and expressed as a percentage of solubilized protein after hydrolysis compared to the total protein in raw material. The average yields of viscera, heads and carcasses were 7.4, 36.3 and 56.3%, respectively. The optimal conditions for enzyme action on the viscera were: 55°C, hydrolysis time of 90 min, and enzyme concentration of 0.4 mg mL -1 . For the muscle, the conditions established were: 45°C, 90 min, and 0.8 mg mL -1 . The dry matter of hydrolysate from viscera yielded 73.5% supernatant (soluble fraction) and 27.5% precipitate (insoluble fraction), while that from muscle yielded 45.7% and 54.3%, respectively. The hydrolysate from viscera presented 86.0% proteins, 0.4% lipids and 4.4% ashes in the soluble fraction, and 51.0% proteins, 25.8% lipids and 5.1% ashes in the insoluble fraction. The hydrolysate from muscle presented 86.0% proteins, 0.4% lipids and 9.0% ashes in the soluble fraction, and 87.0% proteins, 4.4% lipids and 2.4% ashes in the insoluble fraction. A lower degree of hydrolysis of hydrolysate from muscle than that produced from viscera was observed, demonstrating the different interactions between the enzyme and the residues studied.