Effects of antimicrobial nanocomposite films packaging on the postharvest quality and spoilage bacterial communities of mushrooms (Chanterelles).

Poly (lactic acid) (PLA) composite films with the addition of mesoporous silica nanoparticles MSN (0, 2, 4 and 6 wt%) loaded with 10 wt% citral (CIT) were prepared for application in Chanterelles packaging. Composite films with added MSN/CIT showed good mechanical properties, especially 4MSN/CIT/PLA. Changes in physicochemical properties and bacterial flora of Chanterelles during packaging and storage were tested. Compared with CIT/PLA, Chanterelles packed with 4MSN/CIT/PLA showed about 1.62-times lower browning value, 1.53-times lower electrolyte permeability, and 1.83- and 1.78-times lower PPO and POD, respectively, at 12 day. Better physicochemical properties of Chanterelles can be maintained. For bacterial flora changes, Chanterelles packaged with 4MSN/CIT/PLA had more stable flora (p < 0.05) and lower species diversity during storage (p < 0.05), effectively controlling the growth and reproduction of their dominant spoilage bacteria (Enterobacteriaceae spp). In conclusion, the composite membranes obtained by the addition of MSN/CIT to PLA have great potential in the storage of Chanterelles.

Active and Intelligent Biodegradable Packaging Based on Anthocyanins for Preserving and Monitoring Protein-Rich Foods.

Currently, active and intelligent packaging has been developed to solve the spoilage problem for protein-rich foods during storage, especially by adding anthocyanin extracts. In such a film system, the antioxidant and antibacterial properties were dramatically increased by adding anthocyanins. The physicochemical properties were enhanced through interactions between the active groups in the anthocyanins and reactive groups in the polymer chains. Additionally, the active and intelligent film could monitor the spoilage of protein-rich foods in response to pH changes. Therefore, this film could monitor the sensory acceptance and extend the shelf life of protein-rich foods simultaneously. In this paper, the structural and functional properties of anthocyanins, composite actions of anthocyanin extracts and biomass materials, and reinforced properties of the active and intelligent film were discussed. Additionally, the applications of this film in quality maintenance, shelf-life extension, and quality monitoring for fresh meat, aquatic products, and milk were summarized. This film, which achieves high stability and the continuous release of anthocyanins on demand, may become an underlying trend in packaging applications for protein-rich foods.

Development of a Sodium Alginate-Based Active Package with Controlled Release of Cinnamaldehyde Loaded on Halloysite Nanotubes.

The worsening environment and the demand for safer food have accelerated the development of new food packaging materials. The objective of this research is to prepare antimicrobial food packaging film with controlled release by loading cinnamaldehyde (CIN) on etched halloysite nanotubes (T-HNTs) and adding it to sodium alginate (SA) matrix. The effects of T-HNTs-CIN on the physical functional properties and antibacterial activity of the film were systematically evaluated, and the release of CIN in the film was also quantified. Transmission electron microscopy and nitrogen adsorption experiments showed that the halloysite nanotubes had been etched and CIN was successfully loaded into the T-HNTs. The addition of T-HNTs-CIN significantly improved the water vapor barrier properties and tensile strength of the film. Similarly, the presence of T-HNTs-CIN in the film greatly reduced the negative effects of ultraviolet rays. The release experiment showed that the diffusion time of CIN in SA/T-HNTs-CIN film to fatty food simulation solution was delayed 144 h compared with that of SA/CIN film. Herein, the antibacterial experiment also confirmed the controlled release effect of T-HNTs on CIN. In conclusion, SA/T-HNTs-CIN film might have broad application prospects in fatty food packaging.

Migration kinetic of silver from polylactic acid nanocomposite film into acidic food simulant after different high-pressure food processing.

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.

Structural changes and nano-TiO2 migration of poly(lactic acid)-based food packaging film contacting with ethanol as food simulant.

The poly(lactic acid) (PLA)/nano-TiO2 composite films with different nano-TiO2 loading (0 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt%) were prepared and contacted with 50% (v/v) ethanol solution as food simulant to study the behavior of nano-TiO2 migration. The structural changes and intermolecular interactions were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The migration amount increased with the increase of initial nano-TiO2 content. SEM images demonstrated that the microstructure of PLA nanocomposite films became rougher as exposure to ethanol solution in a few days. XRD spectra indicated that a decrease in the intensity of specific diffraction peak occurred as the decrease in nano-TiO2 content of PLA nanocomposite films during exposure to ethanol simulant. DSC analysis confirmed that the higher crystallinity percentage obtained during the different degradation times. The reasonable food packaging application of the nano-TiO2 composite films with restrained nano-TiO2 migration could be accomplished by controlling the nano-TiO2 loading.

The Quality Evaluation of Postharvest Strawberries Stored in Nano-Ag Packages at Refrigeration Temperature.

Different percentages (0%, 1%, 5%, and 10%) of nano-Ag particles were added to polylactic acid (PLA) to make an active nanocomposite packaging film. Strawberries were packaged by the nanocomposite films and stored at 4 ± 1 °C for 10 days. The freshness of strawberries was assessed by regularly measuring the physicochemical properties of the strawberries in each packaging film. The difference in the freshness of strawberries was evaluated by determining the following parameter changes: weight loss, hardness, soluble solids, titratable acid, color, vitamin C, total phenol, free radical scavenging activity, peroxidase activity, and sensory evaluation. The results revealed that the active nanocomposite packaging film has better preservation effect when compared with pure PLA film. Its preservation effect is mainly reflected in the more effective reduction of vitamin C loss, delaying the decline of total phenols and 1-Diphenyl-2-picrylhydrazyl (DPPH) in strawberries. It also showed better physical properties. The results showed that the PLA nanocomposite packaging film could effectively preserve freshness of strawberries.