Barrier properties, migration into the food simulants and antimicrobial activity of paper-based materials with functionalized surface

The study investigates four paper-based materials designed for short-time wrapping of meat products by determining morpho-structure, capillary-hydroscopic, barrier and antibacterial properties, wettability and migration into food simulants. The paper-based materials are coded as RO, SP, IT and SLO. RO and SLO samples exhibit the best barrier properties against water vapors. The low solubility and contact angles of RO, IT and SLO in A simulant (distilled water) make them suitable for aqueous food storage. The extremely high solubility of SP and SLO in simulant B (acetic acid) shows that wax and hydrophobized starch, respectively are carried by the acidic media, thus these agents are unlikely to coat the paper designed to package acidic food. SLO inhibits E. coli, Salmonella enterica, Lysteria monocytogenes, Pseudomonas aeruginosa and fluorescens. Polyethylene coated on RO and IT surface and wax impregnated on SP have a lower antimicrobial activity in comparison with hydrophobized starch coated on SLO

Three Eruptions Observed by Remote Sensing Instruments Onboard Solar Orbiter

On February 21 and March 21 – 22, 2021, the Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter observed three prominence eruptions. The eruptions were associated with coronal mass ejections (CMEs) observed by Metis, Solar Orbiter’s coronagraph. All three eruptions were also observed by instruments onboard the Solar–TErrestrial RElations Observatory (Ahead; STEREO-A), the Solar Dynamics Observatory (SDO), and the Solar and Heliospheric Observatory (SOHO). Here we present an analysis of these eruptions. We investigate their morphology, direction of propagation, and 3D properties. We demonstrate the success of applying two 3D reconstruction methods to three CMEs and their corresponding prominences observed from three perspectives and different distances from the Sun. This allows us to analyze the evolution of the events, from the erupting prominences low in the corona to the corresponding CMEs high in the corona. We also study the changes in the global magnetic field before and after the eruptions and the magnetic field configuration at the site of the eruptions using magnetic field extrapolation methods. This work highlights the importance of multi-perspective observations in studying the morphology of the erupting prominences, their source regions, and associated CMEs. The upcoming Solar Orbiter observations from higher latitudes will help to constrain this kind of study better

Nano Food Packages: from Food Preservation Efficiency to Consumer Legal Protection

The paper explores some aspects related to the application of nanomaterials in food packaging. Therefore, the paper is structured into two sections. In the first section, aspects that could restrict/restrain the application of nanomaterials in food packaging industry in terms of environmental and human risks, the consumer`s rights to be informed regarding the utilization of nano-packages and regulation issues in the field of large scale application of food nano-packages are discussed. In the second section, the efficiency of a nano-package based on Ag/TiO2 to preserve for a longer time (6 days) the physical attributes of wheat bread (moisture, specific volume, porosity) by comparison with shorter ranges allowed by the common polyethylene bag (3 days) and non-packaging respectively (1 day) is demonstrated

Attempts to Obtain Material Based on Polyvinyl Alcohol with Barrier Properties against Water Vapor

The purpose of this study was to obtain a biodegradable film based on polyvinyl alcohol with reduced water vapor permeability. The hydrophobic character of the films was achieved by incorporating beeswax, vegetable bio-surfactant, citric acid as a cross-linking agent, and glycerol to provide elasticity, along with the application of thermal treatment. Water vapor permeability was determined gravimetrically. The results indicated that all films produced had lower water vapor permeability compared to unmodified or untreated polyvinyl alcohol films. The barrier to water vapor varied directly with the mass of beeswax used, and the homogeneous dispersion of beeswax in the polyvinyl alcohol matrix was essential for achieving an efficient hydrophobic film. The best performing-material exhibited a water vapor permeability 5.15 times lower than that of the neat polyvinyl alcohol and 15 times higher than that of polyethylene. Considering the fact that the water vapor barrier property of neat polyvinyl alcohol was 78 times lower than that of polyethylene, the combination of beeswax, citric acid, and vegetable bio-surfactant—along with thermal treatment—can be a viable solution to reduce the hygroscopicity of polyvinyl alcohol-based films

Polylactic Acid-Based Film Modified with Nano-Ag-Graphene-TiO2: New Film versus Recycled Film

The increase in the polymer-based materials needs has induced along the waste accumulation, thus argued higher interest in recycling. The study aims to assess the structural, morphological, mechanical resistance, physical–chemical and biochemical characteristics, as well as the preservative role during the curd cheese storage of a recycled polylactic acid (PLA)-based film modified with Ag-graphene-TiO2 nanostructured composite, obtained by recovering the composite from the used film, followed by its incorporation in new PLA. The breaking load of the recycled film was 24% lower than that of the new film and 10% higher than of the neat PLA. Differential scanning calorimetry (DSC) showed changes of the recycled PLA’s surface tension and crystallization degree in a greater extent than in the newly prepared film, revealing better incorporation of the recovered composite into the PLA matrix. Fourier transformed infrared spectroscopy showed the formation of C–O–Ti bridges between composite and PLA both in new and recycled film. Oxygen transmission rate (OTR) of the new and recycled film decreased by 33% and 45%, respectively, in comparison with reference PLA. The curd cheese was successfully stored in the recycled packaging; the organoleptic characteristics of cheese wrapped in recycled film were superior in comparison with the new film. The variation of fat and protein contents and mass loss was the lowest when the recycled film was used as packaging material. The study successfully showed the possibility to recover and recycle the used PLA-based films modified with inorganic nanocomposites

Recovery and Characterization of Nano-Ag-graphene-TiO2: Active Compound from Polylactic Acid (PLA)-Based Film.

The recover of the used Ag-graphene-TiO2 composite extracted from the polylactic acid (PLA) film and its characterization in comparison with the newly prepared composite was the aim of this study. The proposed recovery procedure will reduce the amount of inorganic nanostructured material released into the environment as used food packaging. Morpho-structural, environmental and photocatalytical characteristics of Ag-graphene-TiO2 composite recovered from an used PLA-based film in comparison with those of the new prepared composite are reported. The recovered Ag-graphene-TiO2 composite displayed color, consistence, appearance, homogeneity and dispersion of nano-Ag similar with the new prepared compound. The FTIR spectroscopy showed the presence of Ti–O–C bonds suggesting the cross-linking between TiO2 and graphene both in new and recovered composite. The gap energy (Eg) of the recovered composite is 1.4 times and 2.3 times lower than that of new composite and TiO2, respectively. The anatase`s content decreased by 70% during the recovering, while that of rutile rised with the same magnitude. The photocatalytic activity of the recovered composite decreased only by 30% in comparison with the new composite. Additionally, the Life-Cycle Analysis (LCA) showed that the recovering procedure had a considerably lower environmental impact than the preparation of the new composite in terms of human health, ecosystem quality, climate change and resources. In conclusion, the recovering of the nanostructed composites from the active PLA-based films should be promising way to imporve the waste management