Giant squid skin gelatin: Chemical composition and biophysical characterization

Gelatin was extracted from the skin of giant squid (Dosidicus gigas) with a yield of 7.5% on a wet weight basis through a novel cold maturation process and it was chemical, physicochemical and structurally characterized. Squid skin gelatin (SSG) had high protein content (89%) with an amino acid profile similar to that of interstitial collagen. Infrared spectroscopy and circular dichroism confirmed the existence of specific bands of collagen and gelatin which are modified during their thermal transition. Amino acids present in SSG were revealed by NMR signals. Fluorescence spectroscopy revealed emission due to pyridinoline cross-links. Differential scanning calorimetry confirmed that SSG is a weak thermo-reversible gel. Scanning electron microscopy showed porous components within the SSG structure which agree with the viscosity and water holding capacity values obtained. These results led to a better understanding on the molecular structure of SSG which accounts for its well known rheological and physicochemical properties.