Jumbo squid (Dosidicus gigas) mantle collagen: Extraction, characterization, and potential application in the preparation of chitosan–collagen biofilms

Collagen-based biomaterials have been widely used due to its binding capabilities. However the properties and potential use of new collagen sources are still under investigation. Fish by-products are an excellent source of collagen. Thus, acid-soluble collagen (ASC) was extracted, and biochemical and physicochemically characterized from one under-utilized specie, jumbo squid (Dosidicus gigas). In addition, commercial chitosan (95–50%)-ASC (5–50%) blend films were successfully prepared by casting, and characterized by infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The molecular masses of the ASC subunits were about 190 kDa, 110 kDa, and 97 kDa, the content of proline and hydroxyproline was 10.9% and 2.8%, respectively. The FT-IR and nuclear magnetic resonance spectra (1H NMR) confirmed collagen peptidic crosslinks, and one endothermic peak was found at 119 °C. The FT-IR spectrum showed that chitosan and ASC remain linked into the films mainly due to hydrogen bonding. The 85:15 (chitosan:ASC) ratio was selected for its thermal and mechanical analyses. The thermograms of this film indicated the presence of two peaks, one at 87–98 °C and the other at 142–182 °C. The chitosan:ASC blend produced a transparent and brittle film, with high percentage of elongation at break, and low tensile strength in comparison to chitosan films. D. gigas mantle might be useful as a new source of plasticizer agent in the preparation of biofilms in composites with chitosan.