Comparative study on the gel properties and nanostructures of gelatins from chicken, porcine, and tilapia skin.

To clarify the feasibility of replacing commercial gelatin with chicken skin gelatin, we investigated the gel properties and nanostructures of chicken skin gelatin (CG), commercial porcine skin gelatin (PG), and tilapia skin gelatin (FG). Compared with PG and FG, CG exhibited the better gel strength, hardness, chewiness, melting point, gelling temperature, and thermostability. The different physicochemical properties of CG might be caused by its higher imino acid content (25.43 residues/100 total residues), which make it more liable to form intramolecular H-bonds (lower amplitude of amide A wave number). In addition, atomic force microscopy (AFM) result was shown that CG contained larger spherical aggregates (483 nm) than PG and FG (334 and 224 nm, respectively), and the lack of chain and ring-like structure promoted the formation of a dense rigid gel. These results revealed that the intramolecular H-bond and the aggregation behavior are the fundamental explanations for the different gel properties of gelatins from three sources. PRACTICAL APPLICATION: This research provides guidance for the application of chicken skin gelatin as a replacer for commercial gelatin. And the results provide a theoretical basis for the modification of chicken skin gelatin.