In situ synthesis of multi-functional gelatin/resorcinol/silver nanoparticles composite films

Silver nanoparticles (AgNP) were synthesized in situ by reducing AgNO₃ using resorcinol and gelatin to prepare functional gelatin/resorcinol/AgNP nanocomposite films (Gel/Res/AgNP). The nanocomposite film exhibited a characteristic light absorption peak of AgNP at 420 nm and improved UV-light barrier property. X-ray diffraction (XRD) results also showed a characteristic reflection peak of crystalline AgNP around 2θ = 38° corresponding to the (111) diffraction plane of AgNP. The water vapor permeability (WVP), water contact angle (WCA), surface morphology and thermal stability of the composite films were not affected, but the tensile strength (TS) of the composite film decreased and the elongation at break (E) increased by the formation of AgNP. The Gel/Res/AgNP nanocomposite film showed a strong antioxidant property with high DPPH and ABTS free radical scavenging activity. Also, the Gel/Res/AgNP nanocomposite films exhibited strong antimicrobial activity against foodborne pathogenic bacteria, Escherichia coli and Listeria monocytogenes. The developed Gel/Res/AgNP composite films with potent antimicrobial and antioxidant activities have a high potential to be used in food packaging to increase the shelf life of packaged food.