Structural properties of gelatin extracted from croaker fish (Johnius sp) skin waste

• Published in: International journal of food properties Vol. 20; no. sup3; pp. S2612 - S2625
• Main Authors: Kumar, D Pavan, Chandra, M V., Elavarasan, K., Shamasundar, B. A.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 10-01-2018; Taylor & Francis Ltd
• Subjects: Alanine; Amino acid composition; bloom strength; Collagen; Croaker fish skin gelatin; Fourier transforms; Gelatin; gelling and melting point; Glycine; Johnius; Molecular weight; Proline; Random coil; Scanning electron microscopy; Skin; texture profile analysis
• ISSN: 1094-2912; 1532-2386
• DOI: 10.1080/10942912.2017.1381702

In the present study, the gelatin from fresh croaker fish (Johnius sp) skin was obtained by rapid extraction and its properties were assessed. The gelling and melting temperature of croaker skin gelatin was 17.4 and 23.8°C as revealed by dynamic visco-elastic analysis using Controlled Stress Rheometer. Croaker skin gelatin (CSG) had the bloom value of 193.4 g. Scanning electron microscopic analysis of freeze dried gelatin showed the presence of voids surrounded by a loose network imitating a sponge or coral like structure. Texture profile parameters such as hardness, springiness, cohesiveness, gumminess, and chewiness of croaker fish skin gelatin gel were relatively lower than the porcine gelatin gel. The amino acid composition of gelatin revealed a higher proportion of glycine, alanine, and hydroxyl proline (30.25, 23.4, and 11.82 g/100 g protein, respectively) content. The electrophoretic analysis showed the presence of two peptide chains with the approximate molecular weight of 200 and 116 kDa corresponds to β and α peptide chain of collagen. The Fourier Transform Infrared (FT-IR) spectra of gelatin showed peaks correspond to the structures like α helix, β sheet, and random coil in the gelatin preparations.