Curcumin-modified gelatin nanocomplexes as novel food foaming Agents: Impact on foamability and interfacial properties

Although polyphenol modification can enhance the foaming properties of hydrophilic gelatin, the mechanisms by which polyphenols affect gelatin interfacial and foaming behavior are not well understood. In this study, hydrophobic curcumin was used to modify gelatin (Type A), forming a nanocomplex designed as a novel foaming agent. In this study, we investigated the adsorption of curcumin/gelatin nanocomplexes at the air/water interface and the resulting foaming properties. Nanocomplexes were prepared at curcumin to gelatin mass ratios of 0, 0.05, 0.1, 0.15, and 0.2. Their bulk behavior was assessed based on particle size, zeta potential, complexation efficiency, and surface hydrophobicity. As the mass ratio of curcumin to gelatin increased from 0:1 to 0.2:1, the diameter of the nanocomplexes gradually increased from 32 nm to 279 nm, whereas their negative surface charge decreased from −3.4 mV to −1.3 mV. Additionally, surface hydrophobicity increased with curcumin addition, as indicated by the amount of bound bromophenol blue sodium, which rose from 11 μg to 30 μg. The interfacial properties were evaluated using dynamic surface pressure and dilatational rheology. The presence of curcumin increased the nanocomplex surface pressure, leading to enhanced foamability. The interfacial behavior was predominantly elastic; whereas, as the curcumin concentration increased, the elastic modulus did not improve significantly, resulting in no significant enhancement in foam stability. These findings suggest that curcumin/gelatin nanocomplexes are potential excellent foaming agents to be used in food, pharmaceutical, and other industries.