Nusrat Sharmin

Cold-water fish gelatin (FG, 5% w/v) was combined with sodium alginate (SA) and gellan (GL) at concentrations of 0.01, 0.05, and 0.1% (v/v) to prepare composite FG films using casting method. The mechanical and barrier (water vapor transmission rate) properties of resulting films were characterized while the film-forming solutions were analyzed using a rheometer and Fourier transform infrared spectroscopy (FTIR). The addition of GL and SA, regardless of concentration, improved barrier properties. GL increased the tensile strength (TS) without affecting the elongation at break (EB), whereas a high concentration of SA (0.1% v/v) led to an improvement in the EB. The viscoelastic behavior of FG film-forming solutions improved with the addition of GL at 0.05 and 0.1% (v/v), whereas SA showed only negligible effects. The FTIR analysis showed a shift in amide I peak to a higher wavenumber in the presence of GL (0.05 and 0.1% v/v), indicating changes in the secondary structures of FG mixtures and their effects on film properties.

The new packaging regulations mandate that all food packaging material must include at least 10% recycled polymer by 2030. As a large portion of food packaging is composed of polyolefins (POs), it is essential to understand the requirements for using PO in food packaging and the actions required to enhance its recycling. Although POs have inferior barrier properties compared to many other polymers, their low weight, low water vapor permeability, and resistance to oils have made them a preferred choice for many food packaging applications, ranging from fresh produce to dairy products. Recent studies suggest that PO mono‐material packaging could serve as an alternative to conventional multi‐material packaging with an appropriate packaging design. Therefore, new packaging design and utilization of the regulations and guidelines can help with efficient recycling of PO. This current article gives an overview of the properties and processing methods of various PO grades, their applications in food packaging, and the current EU regulations on PO recycling. In addition, the article also detailed the actions required for increased recycling of PO.

Cellulose‐based materials face limitations in fresh meat packaging applications, which require resistance to moist and fatty foods and high environmental humidity, as well as sufficient gas barrier properties for modified atmosphere packaging (MAP). Even with conventional plastic coating, these materials encounter practical challenges such as sealability and structural stability during storage. This study aimed to evaluate the suitability of recyclable cellulose‐based trays coated with polyethylene (PE)/ethylene vinyl alcohol (EVOH)/PE (cellulose/PE/EVOH) for MAP (60% CO ₂ /40% N ₂ and 75% O ₂ /25% CO ₂ ) of selected fresh foods of animal sources: salmon, chicken, and beef, against polyethylene terephthalate (PET) trays as control. Headspace gas levels, appearance, and compression strength of packages were assessed during storage, and food quality was analyzed in terms of drip loss, microbiology, and odor. The structure and compression strength of the cellulose‐based trays were greatly affected by the food contact, and the greatest impact was observed during contact with salmon. The compression strength of the cellulose‐based trays was 115 N initially and decreased down to 72 N after contact with food, compared to 95 N for the ones without food contact under similar storage conditions. However, the cellulose‐based trays effectively maintained headspace gas levels comparable to PET trays and did not show negative effects on the quality of the food studied. While combining cellulose‐based trays with PE/EVOH allows for fresh food packaging without compromising food quality, changes in functional material properties during storage may pose challenges to the applicability of such materials throughout the food value chain. Practical Applications: There is a need for more sustainable food packaging solutions, reducing our abundance of conventional plastics. Hybrid solutions combining cellulose‐based materials with less plastic offer an alternative for challenging food packaging applications in terms of food preservation, but other functionalities must be addressed.

Cold-water fish gelatin (FG, 5% w/v) was combined with sodium alginate (SA) and gellan (GL) at concentrations of 0.01, 0.05, and 0.1% (v/v) to prepare composite FG films using casting method. The mechanical and barrier (water vapor transmission rate) properties of resulting films were characterized while the film-forming solutions were analyzed using a rheometer and Fourier transform infrared spectroscopy (FTIR). The addition of GL and SA, regardless of concentration, improved barrier properties. GL increased the tensile strength (TS) without affecting the elongation at break (EB), whereas a high concentration of SA (0.1% v/v) led to an improvement in the EB. The viscoelastic behavior of FG film-forming solutions improved with the addition of GL at 0.05 and 0.1% (v/v), whereas SA showed only negligible effects. The FTIR analysis showed a shift in amide I peak to a higher wavenumber in the presence of GL (0.05 and 0.1% v/v), indicating changes in the secondary structures of FG mixtures and their effects on film properties.

Low‐density polyethylene (LDPE) is one of the most used polyolefins for food packaging applications. However, there are food safety concerns and challenges to recycle it back to food contact material. The present study compares the thermal, mechanical, and barrier properties, contact angle, color, and structural properties (Fourier transfer infrared) between virgin LDPE and two recycled qualities of LDPE, without and with functional barrier layers (ABA structure). In addition, migration analysis and food contact interaction study were also conducted. Thermal‐induced degradation resulting from chain scission was observed in the recycled LDPE. However, the thermal behavior of the recycled films was not affected by the quality of the recyclate. On the other hand, the quality of the recyclate had a significant effect on both the mechanical and barrier properties. The tensile strength and oxygen permeability of the films were affected by the type of recyclate. The addition of LDPE as functional barrier layers in the multilayer films increased the tensile strength, while high‐density polyethylene (HDPE) did not have any additional effect on the mechanical properties. The presence of HDPE did not have any effect as a barrier layer on the permeability, irrespective of the recyclate quality. No difference in the contact angle and structure was observed between the virgin and recycled LDPE. The effect of functional barrier layers on the migration of nonvolatile compounds was not conclusive from the chromatographic analysis. The simple odor/flavor evaluation indicated that cheese in contact with the recycled LDPE without functional barrier layers resulted in higher perception of chemical/plastic flavor compared to the virgin, and the odor was apparently lower when adding LDPE as a barrier layer, while HDPE had no additional effect.Highlights: Multilayered films were prepared from virgin and two recycled low‐density polyethylene with and without a barrier layer. The recyclate quality showed a significant effect on the mechanical and barrier properties. Recyclate quality has a significant effect on the organoleptic properties of food. Low‐density polyethylene as a functional barrier has a positive effect on the mechanical properties. The barrier layers were effective against migration of volatiles from recyclates to food contact material.

The aim of this study was to evaluate if high barrier recyclable material polyethylene/ethylene vinyl alcohol (PE/EVOH) can be an alternative non‐recyclable polyamides (PA)/PE laminate and also if high barrier is required or recyclable PE material with low barrier properties is good enough to maintain the quality of thermally processed mashed potato and ground carrot. The oxygen transmission rate (OTR) of the PA/PE and PE films decreased after heat treatment, while no change was observed for PE/EVOH films. Food contact did not impact the OTR of PA/PE and PE/EVOH films, while the OTR of PE films decreased. The water vapor transmission rate (WVTR) of PA/PE and PE/EVOH films increased after heat treatment. In general, the WVTR of films increased after food contact. The tensile strength of all films was only reduced up to 3–4 weeks of food contact. After 10 weeks, the PE film showed significantly lower hue values and a larger total color difference than the two other films. Light exposure reduced the hue values and increased total color difference after 6 weeks of storage. The odor and flavor of both mashed potatoes and ground carrots were affected by light exposure. The mashed potato showed a slight reduction in freshness‐odor for all materials with storage time. For flavor, mashed potato and ground carrot showed similar trends; flavor was scored unacceptable when packaged in PE films after 6 weeks, but when packaged in PA/PE and PE/EVOH films, the flavor was still acceptable after 10 weeks of storage.

To fulfil the European Green Deal targets and implement a circular economy, there is an urgent need to increase recycling rates of packaging materials. However, before recycled materials can be used in food contact applications, they must meet high safety standards. According to the European Food Safety Authority (EFSA), a worst-case scenario must be applied and unknown substances must be evaluated as being potentially genotoxic. The Ames test, which detects direct DNA-reactive effects, together with chromatographic analysis is very promising to complement risk assessment. This study aims to evaluate the effectiveness of functional barriers in ten different samples, including virgin and recycled LDPE foils. FT-IR analysis did not show major differences between virgin and recycled films. Light microscopy revealed differences in quality and an increased number of particles. GC-MS analysis detected and quantified 35 substances, including eight unknowns. Using a miniaturized version of the Ames test, four of ten samples tested positive in two individual migrates up to a dilution of 12.5%. All virgin LDPE materials tested negative; however, recycled material F showed an increased mutagenic activity, with an n-fold induction up to 28. Samples with functional barriers lowered migration and reduced mutagenicity. Nonetheless, further investigations are needed to identify possible sources of contamination.

Alginate films (2% w·v⁻¹) were prepared with varying concentrations (5–20% w/w) of citric acid and aqueous grape seed extract (GSE) filtrate (11.66 ± 1.32 g GAE/L) using the solvent-evaporation method. Crosslinking alginate via ester bonds (FTIR analysis) with citric acid up to 10% (w/w) led to a 33% increase in tensile strength, a 34% reduction in water vapor transmission rate (WVTR), and had no impact on elongation at break. Crosslinking alginate with citric acid in the presence of GSE increased the tensile strength by 17%, decreased WVTR by 21%, and significantly improved DPPH scavenging activity. Moreover, after incubation for 24 h at 37 °C, the film-forming solutions exhibited increased antimicrobial activity, resulting in 0.5- and 2.5-log reductions for Escherichia coli and Staphylococcus aureus, respectively, compared to the values obtained without the addition of GSE. The stronger inhibitory effect observed against Gram-positive bacteria can be attributed to the unique composition and structure of their cell walls, which creates a barrier that restricts the penetration of polyphenols into the cells. The pH adjustment of the GSE film-forming solution from 2.0 to 10.0 shifted the UV/VIS absorption spectra, resulting in a colour change from yellow to red. The findings of this study have showcased the potential of combining GSE and citric acid to enhance the functionality and bioactivity of alginate films for applications in smart food packaging.