Preparation of a Novel Carbon Dot/Polyvinyl Alcohol Composite Film and Its Application in Food Preservation

Abstract

Carbon dots (CDs) were synthesized with the facile hydrothermal method to produce CDs/polyvinyl alcohol (PVA) active food packaging films. The CDs had a diameter ranging from 2.01 to 5.61 nm and were well-dispersed. The effects of different concentrations of CDs on mechanical strength, water resistance, morphology, optical, and thermal performance of the CDs/PVA films were discussed. The incorporation of CDs in the PVA film improved its mechanical properties, water resistance properties, UV blocking properties, and thermal stability and endowed the composite film with antioxidant and antimicrobial properties. The maximum scavenging rates of 2,2-diphenyl-1-picrylhydrazyl and ABTS free radicals by the 0.50% CDs/PVA film were 72.81 and 97.08%, respectively. The inhibition zone diameters of the 0.50% CDs/PVA solution against Staphylococcus aureus (S. aureus), Bacillus subtilis (B. subtilis), and Escherichia coli (E. coli) were 9.52, 8.21, and 9.05 mm, respectively. Using the 0.50% CDs/PVA film as active packaging, the shelf life of banana, jujube, and fried meatballs was observed to be extended significantly. These results demonstrate the viability of the CDs/PVA composite film as a promising active food packaging material.

Halogen Bond-Driven Aggregation-Induced Emission Skeleton: N-(3-(Phenylamino)allylidene) Aniline Hydrochloride

“…Because of their strong fluorescence emission, 1 wt % PA-derivatives were mixed with PVA aqueous solution to prepare various light-emitting films by a solution-casting method . Here, PVA was selected as the substrate material due to its biodegradability, flexibility, and film-forming ability . As shown in Figure a, yellow, colorless, and brown films were obtained by using PA-Br, PA-COOH, PA-CH 3 O, and PA-CF 3 as the phosphors, respectively, which emitted bright green or brown fluorescence under 365 nm UV light irradiation.…”

“…60 Here, PVA was selected as the substrate material due to its biodegradability, flexibility, and film-forming ability. 61 As shown in Figure 6a, yellow, colorless, and brown films were obtained by using PA-Br, PA-COOH, PA-CH 3 O, and PA-CF 3 as the phosphors, respectively, which emitted bright green or brown fluorescence under 365 nm UV light irradiation. The CLSM image (Figure 6a, photo 9) shows uniform green fluorescence of PA-CF 3 film at the micro scale, indicating that PA-CF 3 was uniformly embedded in the film matrix.…”

Carbon dots for food packaging applications

“…UV radiation affects the oil in food, which can lead to oxidation, change in the food's color, and reduce vitamin C and vitamin D in food. 55,56 Carbon dots have good scattering and adsorption properties in that they immediately convert UV photons into heat, which means they can be used to protect food from UV radiation. Fig.…”

Prospective Nanomaterials for Food Packaging and Safety

“…They can be manufactured from environmentally friendly sources at a low price, such as microorganisms, food by-products, and waste streams, or they may be generated in foods during normal processing operations, such as cooking. CDs /polyvinyl alcohol (PVA) films can be used as active food packaging materials [34]. The incorporation of CDs in the PVA film enhances the water resistance properties, antimicrobial and antioxidant properties, mechanical properties, thermal stability, and UV blocking properties, illustrated in Fig.…”