Active Double-Layered Films Enriched with AgNPs in Great Water Dock Root and Pu-Erh Extracts

Abstract

A novel, eco-friendly, and biocompatible method was applied to form silver nanoparticles (AgNPs) in great water dock (Lapathi radix) (KB) and pu-erh (Camellia sinensis) (PE) extracts. The surface plasma resonance peak of green synthesized AgNPs at 451.8 nm for AgNPs+KB and 440.8 nm for AgNPs+PE was observed via spectral analysis of UV absorbance. In this study, double-layered biopolymer films (FUR/CHIT+HGEL) with AgNPs incorporated in KB solution (AgNPs+KB) and AgNPs in PE solution (AgNPs+PE), were successfully prepared using the casting method. The SEM, XRD, zeta potential and size analyses confirmed the presence of AgNP in the films. The addition of AgNPs in plant extracts improved antimicrobial and antioxidant activity and thermal stability, whereas WVTR experienced a decrease. The nanocomposite films’ orange-brown colour may aid in the protection of food products against UV rays. The composite films demonstrated antibacterial activity against food-borne pathogens and may offer potential in food packaging applications.

Double-Layered Films Based on Furcellaran, Chitosan, and Gelatin Hydrolysates Enriched with AgNPs in Yerba Mate Extract, Montmorillonite, and Curcumin with Rosemary Essential Oil

“…The antimicrobial potential of the presented films may result from the presence of curcumin extract and AgNPs in the plant extracts. In previous works, we indicated the high antimicrobial potential of AgNPs in plant extracts [ 30 ] and curcumin extract with lemongrass essential oil [ 48 ]. Packaging that shows antimicrobial activity can be used as a material for extending the shelf life of food products.…”

“…The procedure for preparing the AgNPs in the extract was performed according to Jamróz et al [ 30 ], with slight modifications. From the prepared solution, 5 mL of plant extract was taken, and 15 mL of distilled water was added.…”

“…The surface color of the film was measured, and the method was described previously [ 30 ], where the material was evaluated via the reflection method using a Color i5 spectrometer (X-Rite, Grand Rapids MI, USA, illuminant D65). The results are presented as L* (lightness), a* (red–green), and b* (yellow–blue).…”

“…The water vapor transmission rate (WVTR) was measured by a method described previously [ 30 ]. A glass vessel was filled with silica gel, which was then covered with the film under analysis.…”

“…The water contact angle (WCA) measurement method has been described previously [ 30 ]. The contact angle, with regard to the water contents of the films under study, was determined using the sessile drop method with a video-based measuring system for assessing the contact angle (OCA, Dataphysics, Filderstadt, Germany).…”