Effect of extraction methods on the structural characteristics, functional properties, and emulsion stabilization ability of Tilapia skin gelatins

The application of fish gelatins in emulsions has attracted much attention and their stabilization mechanisms remain unclear. This work explores the effect of extraction methods on the structural characteristics, functional properties, and emulsion application of Tilapia skin gelatins. The creaming stability of Tilapia skin gelatin-stabilized emulsions are dependent on gelatin secondary structure, gelatin fat-binding capacity, the presence of NaCl, and storage temperatures. The emulsion creaming velocities are: acetic acid-extracted gelatin (AAG) ≈ hot water-extracted gelatin (HWG) > pepsin enzyme-extracted gelatin (PEG). The emulsion creaming velocities in the presence of NaCl are: AAG < HWG ≈ PEG. The stability mechanisms are involved with a "protein secondary structure - molecular interaction - emulsion droplet structure - emulsion stability" route. This work provides useful information for understanding the relationships between the structural characteristics and emulsion stability of gelatins. The fish oil-loaded Tilapia skin gelatin-stabilized emulsions also show promising prospective applications in food beverages.