Enhanced edible films with Ferulic acid nanoemulsion: Fabrication, characterization, and preservation effects on fresh-cut Chinese water chestnuts

Abstract

The cavitation produced by ultrasonication can generate strong shear forces and shock waves in the liquid medium, forming nanometer-sized droplets. In this study, ferulic acid (FA) nanoemulsions were prepared using ultrasonication for different durations. The FA nanoemulsion sonicated for 2.5 min exhibited the smallest droplet size (34.44 ± 3.38 nm) and the highest system stability. The compatibility of FA nanoemulsion with gelatin/starch edible films was further analyzed using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results indicated that the film containing the FA nanoemulsion sonicated for 2.5 min (G/S/FA2.5) demonstrated better film-forming ability, mechanical properties, and barrier performance. Moreover, due to its smallest droplet size and uniform distribution within the film matrix, the G/S/FA2.5 film also showed excellent antioxidant and antibacterial capabilities. Furthermore, the Rheological properties results of the film-forming solution indicate that G/S/FA2.5 possesses a better internal network structure and the most suitable viscosity value for application in food coatings. Finally, the film was applied to fresh-cut water chestnut stored at low temperatures (10 °C). The preservation experiment results showed that the FA nanoemulsion film can suppress up to 50.13% of the yellowing in fresh-cut Chinese water chestnuts by the 8 day of storage, effectively inhibiting the wrinkling on their surface. It significantly reduced the weight loss and spoilage of the water chestnut fruits, thereby extending their shelf life.