RESUMEN
Biodegradable and eco-friendly food packaging materials have attracted attention. Novel blending films were prepared with polylactic acid (PLA) and Perilla essential oil (PEsO). The morphological features of the nanofibers were modulated by adjusting process parameters (e.g. PLA solution concentration, applied voltage and ultrasonic power). The optimal spinning concentrations, applied voltages and ultrasonic power of the PLA solutions were set at 15% (m/v), 20 kV and 640 W, respectively. Compared with the PLA films, the addition of PEsO increased the diameter of the nanofibers and solvent resistance and reduced the swelling rate of the PLA/PEsO films. The breakage elongation and the gas barrier properties significantly improved when 2% (w/w) PEsO was used. Fourier infrared spectroscopy, X-ray diffractometer, thermogravimetry and differential scanning were used in analyzing the potential interactions of the film matrices. The PLA/PEsO films had good biocompatibility and antibacterial and antioxidant properties. The PLA/PEsO (1:0.02) film loaded with 2% PEsO extended the shelf life of chilled chicken to 12 days, as indicated by the measured total volatile basic nitrogen (TVB-N), total viable count and pH value. Therefore, PLA/PEsO films have great potential as fresh-keeping packaging.
Asunto(s)
Antibacterianos/química , Biopolímeros/química , Embalaje de Alimentos , Nanofibras/química , Aceites Volátiles/química , Perilla/química , Poliésteres/química , Animales , Antibacterianos/farmacología , Fenómenos Químicos , Pollos , Conservación de Alimentos , Fenómenos Mecánicos , Nanofibras/ultraestructura , Aceites Volátiles/farmacología , Permeabilidad , Solventes , Análisis Espectral , VaporRESUMEN
In this study, antibacterial nanofiber films were prepared by electrospinning gelatin, chitosan, and 3-phenyllactic acid (PLA). The addition of PLA improved the microstructures of the nanofibers, and the nanofiber films (GCP-1 and GCP-2) had uniform and continuous structures with a diameter range of 40--70 nm when the PLA concentrations in the polymers were 1% and 2%. Under acidic conditions, chitosan and PLA interacted and formed hydrogen bonds, which decreased the crystallinity of the nanofiber films. The GCP-2 nanofiber film had the best thermal stability, water stability, and water vapor permeability. Compared with the control GCP-0 film, the four nanofiber films with PLA (GCP-1, GCP-2, GCP-3, and GCP-4) had more effective antibacterial effects, and GCP-2 film reduced approximately 4 log CFU/mL of Salmonella enterica Enteritidis and Staphylococcus aureus in 30 min. Results suggested that the GCP-2 nanofiber film mat can be used as an active food packaging.
Asunto(s)
Quitosano/química , Embalaje de Alimentos/métodos , Gelatina/química , Fenilacetatos/química , Antibacterianos/química , Antiinfecciosos/química , Nanofibras/química , Permeabilidad , Polímeros , Vapor , Agua/químicaRESUMEN
An effective antibacterial nanofiber film was prepared through the incorporation of ε-polylysine (ε-PL) into gelatin/chitosan-based polymers. All nanofiber films had uniformly disordered fibrous structure with good diameter distribution. The weight ratio of the gelatin/chitosan/ε-PL (G/C/P) influenced the solution property and nanofiber morphology. The addition of ε-PL can decrease the viscosity and increase the conductivity of solutions, which lead to a decrease in the diameter of nanofibers. The three polymers of gelatin, chitosan, and ε-PL were interacted by hydrogen bonding, and the crystallinity of nanofiber films was decreased by the electrospinning process. The addition of ε-PL can enhance the thermal stability, and decrease the water vapor permeability and oxygen permeability of the films, and ε-PL did not easily release from the nanofiber films. The G/C/P (6:1:0.125) nanofiber film was more effective to control six foodborne pathogens than the G/C nanofiber films by destroying the bacterial cell membranes. The result indicated that the gelatin/chitosan/ε-PL nanofiber films can be used as a food-packaging material to reduce the risk of foodborne pathogens.
Asunto(s)
Gelatina/química , Polilisina/química , Polilisina/farmacología , Antibacterianos/química , Quitosano/química , Escherichia coli/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Nanofibras/química , Permeabilidad , Polilisina/metabolismo , Polímeros/química , Staphylococcus aureus/efectos de los fármacosRESUMEN
Silver-coated poly(methyl acrylic acid) (PSA) core-shell colloid particles were prepared by an in situ chemical reduction method. Crystalline silver/titania composite hollow spheres were obtained by coating the as-prepared PSA/silver particles with an amorphous titania layer and subsequently calcining in Ar atmosphere. SEM and TEM investigation indicated that the size of the as-prepared PSA/silver and PSA/silver/TiO(2) core-shell particles and silver/titania composite hollow particles was fairly uniform and the wall thickness of the hollow spheres was in the range of 40-80 nm. UV-vis absorption spectra were recorded to investigate their optical properties.