Incorporation of Prosopis cineraria Extract Improved the Mechanical, Barrier and Antioxidant Properties but Not the Antibacterial Activity of Tigertooth croaker Fish Scale Gelatin Film

Scale gelatin films derived from croaker fish and infused with Prosopis (Prosopis cineraria) extract (PE) at concentrations of 0.3% and 0.7% were produced. A control film, void of extract, was employed for comparative purposes. The thickness of each film was found to be statistically insignificant (p > 0.05). The results show that the highest solubility (78.57 ± 3.57) was found for the glycerol film, and the least permeability was found for the water vapor (0.74 ± 0.09); however, the water vapor permeability (WVP) and water solubility (WS) of the films that contained PE were considerably lower than those of the control film (p < 0.05). In contrast to the control film, those infused with 0.7% PE exhibited exceptional UV-barrier properties (>99%) and favorable thermal characteristics. The highest and lowest anti-oxidant activities were found for the 7% Prosopis cineraria extract (56.96 ± 2.6) and the glycerol film (40.66 ± 2.46), respectively. No antibacterial activity was observed in these films. Microscopic pictures showed that all three films had a uniform and plain surface. Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR–ATR) analysis revealed distinct amide bands and protein–polyphenol interactions within the films that contained the extract.