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Packaging materials play an essential role in the preservation and marketing of food and other products. To improve their conservation capacity, antimicrobial agents that inhibit bacterial growth are used. Biopolymers such as starch and chitosan are a sustainable alternative for the generation of films for packaging that can also serve as a support for preservatives and antimicrobial agents. These substances can replace packaging of synthetic origin and maintain good functional properties to ensure the quality of food products. Films based on a mixture of corn starch and chitosan were developed by the casting method and the effect of incorporating cellulose nanocrystals (CNC) at different concentrations (0 to 10% w/w) was studied. The effect of the incorporation of CNC on the rheological, mechanical, thermal and barrier properties, as well as the antimicrobial activity of nanocomposite films, was evaluated. A significant modification of the functional and antimicrobial properties of the starch–chitosan films was observed with an increase in the concentration of nanomaterials. The films with CNC in a range of 0.5 to 5% presented the best performance. In line with the physicochemical characteristics which are desired in antimicrobial materials, this study can serve as a guide for the development this type of packaging for food use.

Conducted under the project “MobFood-Mobilizing scientific and technological knowledge in response to the challenges of the agri-food market” (POCI-01-0247-FEDER-024524), by “Mob Food” Consortium, and financed by European Regional Development Fund (ERDF), through the Incentive System to Research and Technological development, within the Portugal2020 Competi tiveness and Internationalization Operational Program. IPC researchers acknowledge also funding by National Funds through FCT-Portuguese Foundation for Science and Technology, References UIDB/05256/2020 and UIDP/05256/2020.

Particulate matter (PM), usually formed as aerosols suspended in atmosphere, is becoming a carrier of viruses and bacteria, accelerating the spread of respiratory diseases. Hence, air filtration devices are widely utilized for removing PM. In this study, a regenerated cellulose (RC) film was prepared with the properties of good mechanical strength, antibacterial, and highly efficient filtration (EF) properties, through cellulose dissolution and further crosslinking with P(AGE-DMDAAC)/ZnO. Results exhibited that the Young's modulus of the composite membrane was nearly 4.3 GPa. Additionally, the antibacterial performance against Escherichia coli and Staphylococcus aureus, was up to 99.89% and 99.67%, respectively. Meanwhile, RC composite filter exhibited a high PM 2.5 capture efficiency (over 99.91%). This study introduces an interesting approach to produce antibacterial films with the characteristics of notably good mechanical performance and high fine particle EF that can be utilized in a high humidity environment.

In this study, an ecofriendly multifunctional (antibacterial, antifungal, and antioxidant) and versatile packaging material based on methylcellulose (MC)/chitosan nanofibers (CNFs) loaded with zinc oxide nanoparticles (ZNPs), quercetin (Qu) and natamycin (NAT) was successfully developed and characterized by physicomechanical, optical, crystallinity, morphology, interactive, and thermal characteristics, as well as, antibacterial, antioxidant, antifungal and biodegradability properties. The results revealed great compatibility of film components, and considerable functional, and degradability properties. The addition of ZNPs, Qu and NAT within the MC/CNFs film matrix significantly reduced solubility in water from 44.5 to 37%. Likewise, water vapor permeability (WVP) value of MC/CNFs/ZNPs/Qu/NAT nanocomposite film (1.85 × 10 − 10  g. m/m 2 . s. Pa) significantly was lower than MC film (6 × 10 − 10  g. m/m 2 . s. Pa). In addition, incorporation of active agents led to an increase in the water contact angle (WCA) from 44.6° to 97.6° in the MC/CNFs/ZNPs/Qu/NAT film. Nevertheless, MC/CNFs/ZNPs/Qu/NAT film had the highest tensile strength (66.65 MPa) with fairly acceptable flexibility (9.8%). Moreover, MC/CNFs/ZNPs/Qu/NAT film exhibited remarkable antimicrobial activity against Escherichia. coli (18.6 mm), Staphylococcus. aureus (19.4 mm), Aspergillus sp. (13.7 mm) and Penicillium sp. (16.0 mm) with a great antioxidant capacity (84.15%). As a result, this green multifunctional packaging film can be introduced as an ideal alternative for food packaging to plastics on the industrial scale.

Antimicrobial nanocomposite films containing oregano essential oil (EO) were prepared by solvent casting. Film matrix was composed of supramolecular poly(lactic acid)–cellulose nanocrystals (PLA–CNC) nanocomposite. Bioactive PLA–CNC–oregano films were prepared by incorporating oregano EO as an antimicrobial agent. Resulting films were then converted into packaging applied on mixed vegetables as a food model and stored for 14 days at 4 °C to determine their antimicrobial capacity against Listeria monocytogenes, their physico-chemical/structural properties and their total phenols (TP) release during storage, in order to evaluate the effect of oregano EO. It was observed the addition of oregano EO did not affect the water vapor permeability (WVP) of films, but increased their elongation at break (Eb) and reduced their tensile strength (TS) and tensile modulus (TM) at day 0. However, TS, TM, Eb and WVP values of control and bioactive films were increased slightly after 14 days of storage. FTIR analysis allowed characterizing the molecular interactions of oregano EO with PLA–CNC matrix via the identification and interpretation of their respective vibration bands. Microbiological analysis of mixed vegetables inoculated with L. monocytogenes (3 log CFU g⁻¹) indicated that PLA–CNC–oregano films induced a quasi-total inhibition of bacteria in vegetables at day 14 and therefore demonstrated a strong antimicrobial capacity in situ. The percentage of TP release from bioactive films was determined by Folin–Ciocalteu’s method and results showed that TP release increased continuously from day 0 to day 14, up to 16.6 % at day 14. These results allowed demonstrating the strong antimicrobial capacity of PLA–CNC–oregano films for food packaging applications in vegetable produce.

Pectin recovered via hydrodynamic cavitation (IntegroPectin) from lemon and grapefruit agri-food waste intrinsically containing antimicrobial bioactive substances (flavonoids, phenolic acids, terpenes, and terpenoids) was used to generate innovative and eco-compatible films that efficiently inhibit the growth of Gram-negative pathogens. Extensive characterization of films confirmed the presence of these substances, which differently interact with the polysaccharide polymer (pectin), plasticizer (glycerol), surfactant (Tween 60), and cross-linker (Ca 2+ ), conferring to these films a unique structure. Besides, IntegroPectin-based films constitute versatile systems for the sustained, controlled, and slow-release (up to 72 h) of bioactive substances in an aqueous environment. This feature is crucial for the good in vitro antimicrobial activity exerted by IntegroPectin films against three Gram-negative bacteria (two indicator pathogen strains Pseudomonas aeruginosa ATCC 10145, P. aeruginosa PAO1, and the clinical isolate Klebsiella pneumoniae ) that are involved in the global emergence of the antimicrobial resistance. Graphical abstract

Biodegradable packaging in food materials is a green technology based novel approach to replace the synthetic and conventional packaging systems. This study is aimed to formulate the biodegradable cassava starch based films incorporated with cinnamon essential oil and sodium bentonite clay nanoparticles. The films were characterized for their application as a packaging material for meatballs. The cassava starch films incorporated with sodium bentonite and cinnamon oil showed significant antibacterial potential against all test bacteria; Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. Antibacterial effect of films increased significantly when the concentration of cinnamon oil was increased. The cassava starch film incorporated with 0.75% (w/w) sodium bentonite, 2% (w/w) glycerol and 2.5% (w/w) cinnamon oil was selected based on physical, mechanical and antibacterial potential to evaluate shelf life of meatballs. The meatballs stored at ambient temperature in cassava starch film incorporated with cinnamon oil and nanoclay, significantly inhibited the microbial growth till 96 h below the FDA limits (106 CFU/g) in foods compared to control films that exceeded above the limit within 48 h. Hence cassava starch based film incorporated with essential oils and clay nanoparticles can be an alternate approach as a packaging material for food industries to prolong the shelf life of products.

The present study aimed to develop magnetically and electrically responsive films based on Balangu seed mucilage-gelatin reinforced with Fe₃O₄ nanoparticles (5% and 10%) and TiO₂ nanoparticles (3% and 6%). Results indicated that the incorporation and increased concentration of nanoparticles enhanced film thickness by up to 83%, improved tensile strength and elastic modulus by 29% and 48%, respectively, increased opacity by 471%, and ultimately reduced water vapor and oxygen permeability by 47% and 37%, respectively. Although increasing the nanoparticle concentration reduced the films’ flexibility and biodegradability rate, they retained sufficient flexibility and degraded by more than 75% after 60 days. Enhanced electrical conductivity, antioxidant activity, and antimicrobial properties were also demonstrated, indicating improved functional characteristics of the films upon integration with nanoparticles. FTIR results indicated increased cross-linking and strong molecular interactions between the nanoparticles and the film matrix. Furthermore, XRD results confirmed that the film’s overall crystallinity increased with higher nanoparticle concentrations, in contrast to the control film’s amorphous nature. The interactions between nanoparticles and the biopolymer matrix, along with the hydrophobic nature of the nanoparticles, improved the thermal stability of the films, reduced water solubility, moisture content, and swelling ratio, and rendered the film surface more hydrophobic. FESEM analysis revealed that the film surfaces became slightly rougher and somewhat uneven with the incorporation of nanoparticles. Surface and cross-sectional FESEM images also showed a relatively compact structure with evidence of nanoparticle clustering, which was corroborated by energy-dispersive X-ray spectroscopy (EDX) results. These findings demonstrate the potential of Balangu seed mucilage-gelatin films reinforced with Fe₃O₄ and TiO₂ nanoparticles for advanced applications, including active food packaging, biomedical materials, and intelligent packaging systems.

This study aims to produce a biodegradable active packaging film that is pH sensitive, and has a good antioxidant and antimicrobial activity. To do this, a novel phenolic extract was interfacially assembled onto a cellulose film, resulting in a film with a pH-triggered release mechanism of the active polyphenol agent. First, an aqueous extraction of cashew nut testa (CTE) was performed and subsequently, the CTE was characterized. The disc diffusion assay showed that CTE exhibited antimicrobial activity towards the food pathogens Escherichia coli (6 mm) and Staphylcoccus aureus (12 mm). CTE was also cytotoxic against cancer HepG2 and HEK293 cells, reducing the viability to 52% and 47%, respectively. It was incorporated into a cellulose-based packaging film, prepared from the by-product, sugarcane bagasse (SC) through interfacial assembly. The incorporation of CTE resulted in a film with good antimicrobial activity, excellent antioxidant content (91%), and has extremely high thermal stability (290 °C). FTIR indicated the formation of hydrogen bond between the SC cellulose-based film and CTE. The hydrogen bonds formed between the cellulose film and CTE became the driving force behind the pH-triggered release mechanism. It was found that the active agent, tannic acid, could be controllably released from the film, depending on the pH of the environment. Our strategy to produce a cellulose-based film impregnated with a phenolic extract, using interfacial assembly, resulted in an active packaging film with pH-triggered release mechanism. This film could be useful to extend the shelf life of perishable food items.

A linear polycation, poly(diallyldimethylammonium chloride), electrostatically interacts with anionic latex particles from a carboxylated butadiene–styrene copolymer in aqueous solution thus forming an interpolyelectrolyte complex. A mutual neutralization of oppositely charged latex and polycation groups occurs at W = latex/polycation = 50 w/w ratio. At W = 27, an ultimate polycation adsorption is reached, resulting in the formation of positive polycomplex particles, while at W ˂ 27, two-component systems are formed composed of positive polycomplex particles and free polycation. A film created from the W = 12 formulation shows a high toxicity to Gram-positive and Gram-negative bacteria and yeast. Repeated washing the film leads to partial removal of polycation and a 50% decrease in the activity of the film only towards Gram-negative Pseudomonas aeruginosa. The results indicate the potential for use of the mixed polymer formulations for the fabrication of antimicrobial films and coatings.