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The migration study of nano‐Ag migration from polylactic acid (PLA) films was studied. Samples treated by high‐pressure food processing (0, 100, 200, 300, and 400 MPa pressure) were soaked in acetic acid solution and incubated at 20 °C for 90 days. At the end of storage, nano‐Ag particles (AgNPs) migration from the PLA/AgNPs composite film treated under 200 MPa high pressure was the lowest. However, AgNPs migration was accelerated under 400 MPa high pressure. High‐pressure processing (200 MPa) could cause denser structure and higher crystallinity degree in films than other treatments. Lower amount of AgNPs induced a decline in the intensity of specific characteristic peaks. The diffraction peak intensity of α‐crystal for the film sample treated with 400 MPa was the lowest on day 60. The crystallization index of the PLA matrix changed with different high‐pressure processing. The result indicated that appropriate high‐pressure food processing could effectively suppress AgNPs migration from PLA‐based film while contacting with acidic acid food simulant. Practical Application: The release of nanoparticles from food packaging material is a very important matter when the migration is concerned with regulatory and toxicity issues. The study described the migration kinetic of AgNPs from PLA nanocomposite film into acidic food simulant after different high‐pressure food processing. The results indicated that the PLA/AgNPs nanocomposite film was safe for acidic food after high‐pressure treatment. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) is the most suitable for biodegradable packaging film because of its excellent integrated property, but the poor gas barrier property is its weakness. In this study, a nanocomposite film based on PLA incorporated with 0‐, 1‐, 3‐, 5‐, 10‐, or 15‐wt% nano‐Ag was developed. Effect of multiscale structure on the barrier properties of PLA/nano‐Ag films was studied. The PLA nanocomposite film with 5‐wt% nano‐Ag had the lowest water vapor permeability (WVP) value. Oxygen transmission rate (OTR) value for PLA nanocomposites with 3‐wt% nano‐Ag was found to be the lowest among all the samples. Multiscale structure was demonstrated by the scanning electron microscopy, Fourier transform‐infrared spectroscopy, X‐ray diffraction measurement, and differential scanning calorimetry results. The crystallinity of the PLA phase increased with the content of nano‐Ag in the PLA composites. The evolution of the PLA phase crystallinity could improve the barrier properties of PLA/nano‐Ag composite films for food packaging applications. From the view of multiscale structure, it is better to achieve a balance among short‐range conformation in the amorphous region, long‐range‐ordered structure, and ordered aggregated structure to improve the barrier properties of PLA/nano‐Ag composite films. [ABSTRACT FROM AUTHOR]

Effects of high pressure treatment (0, 200 and 400 MPa) on water vapour barrier, microstructure, thermal, and mechanical properties of poly (lactic acid) (PLA)/Ag nanocomposite films were investigated. The migration behavior of nano-Ag from the nanocomposite films in the presence of 50% (v/v) ethanol as a food simulant was also studied. The water vapour barrier properties increased as pressure was applied to film-forming solutions. High pressure treatment enhanced the mutual effect between PLA and nanoparticles, leading to a more compact network structure in PLA/Ag nanocomposite films. Furthermore, PLA/Ag nanocomposite films treated by high pressure were significantly affected by microstructure, thermal, and mechanical properties when, compared with untreated samples. High pressure treatment at 200 to 400 MPa significantly (p < 0.05) reduced the migration of nano-Ag from the films. Overall, high pressure treatment on film-forming solutions showed potential in improving the functional properties of nanocomposite films, especially in relation to water vapour barrier properties. [ABSTRACT FROM AUTHOR]

The effects of nano-Ag content, high pressure treatment, and migration time on nano-Ag migration and properties of polylactide (PLA)/nano-Ag composite films were investigated. The PLA films incorporated with 1 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt% nano-Ag were treated by 100, 200, 300, and 400 MPa high pressure for 10, 20, and 30 min, respectively, and then soaked in isooctane food simulant at 40 °C for 49 days. The migration of nano-Ag in the PLA nanocomposite films increased by the addition of nano-Ag, the pressure of high pressure treatment, and migration time. Thermal and mechanical properties showed that high pressure and migration time would make the films rougher and increase the crystallization temperature of the PLA nanocomposite films. Moreover, the addition of nano-Ag could improve the barrier properties of the PLA nanocomposite films. However, the longer the migration time, the worse the barrier property. The results indicated that the migration amount of nano-Ag and performance of the PLA/nano-Ag composite films were greatly affected by the migration time. • This paper applied high pressure technology to the preparation of composite film materials. • The addition of nano-Ag could increase the crystallinity of the composite films. • The migration of the nano-Ag/PLA composite films in the oily food simulating liquid was safe. • As the migration time increased, the barrier and mechanical properties of the composite films deteriorated. • The results indicated that the migration of nano-Ag in the composite films increased as the initial addition quantity of nano-Ag. [ABSTRACT FROM AUTHOR]

Highlights • A film was prepared by adding TiO 2 and Ag nanoparticles into PLA matrix. • Weight loss in PLA nanocomposite group was lower than that for PLA and PLA/BEO group. • The PLA nanocomposite films provided better retention in firmness, color, and Vit C. • The PLA nanocomposite films had an obvious inhibition on the microorganism growth. • Mango sample packed by the PLA nanocomposite films achieved a shelf-life of 15 days. Abstract The effects of polylactic acid (PLA) film, PLA/bergamot essential oils (BEO) film, and PLA nanocomposite film (PLA/BEO/nano-TiO 2 film and PLA/BEO/nano-TiO 2 +nano-Ag film) on the physicochemical and microbial quality of mangoes stored at room temperature for 15 days was evaluated. The measured properties of mangoes included weight loss, fruit firmness, color, total soluble solids content, total acidity, vitamin C, microbial property, and sensory quality. The weight loss of mangoes packed by PLA nanocomposite films was significantly (p < 0.05) lower than that for PLA and PLA/BEO groups from day 9 to day 12. The PLA nanocomposite films could effectively delay the loss of mango firmness during the entire storage period. The PLA nanocomposite films could also retard the harmful changes in color, total acidity, vitamin C, and microbial property when compared with PLA and PLA/BEO films. The overall acceptability of mangoes packed by the PLA nanocomposite films was still higher than 5 scores and within limit of marketability at the end of storage period. The result indicated that the PLA nanocomposite films could be used to maintain the quality of fresh mango and extend its postharvest life to 15 days. [ABSTRACT FROM AUTHOR]