Improving foaming properties of fish gelatin by neutral protease and gum arabic

Neutral protease and gum arabic (GA) were combined to enhance foaming ability (FA) and foaming stability (FS) of fish gelatin. Meanwhile, structural changes of pure, single-modified and combined-modified fish gelatins were evaluated in detail to investigate the mechanism. FA and FS of combined-modified fish gelatin were boosted to the maximum of 158% and 55%, respectively. The enzymolysis enhanced the surface hydrophobicity (increased by 40%) and destroyed the microstructure. On the basis, hydrogen bond and electrostatic forces of combined-modified fish gelatin were strengthened by GA, which elevated viscosity and interfacial protein adsorption content (6 mg/g), enhancing FS and FA. The redshift of amide I and II wavenumbers indicated more stable secondary structure of combined-modified fish gelatin, reflected in the SEM-verified denser foam. The underlying mechanism for improving foaming properties of fish gelatin was related to the opened structure by neutral protease and further noncovalent interaction by GA. New insights for the development of sustainable foaming agents were provided by these findings.