Development and characterization of a double-layer smart packaging system consisting of polyvinyl alcohol electrospun nanofibers and gelatin film for fish fillet.

This study aimed to develop a double-layer film composed of an intelligent, gelatin-based film integrated with active polyvinyl alcohol electrospun nanofibers (PVANFs). Eggplant skin extract (ESE), a colorimetric indicator, was incorporated into the gelatin-based film at varying concentrations ranging from 0 % to 8 % w/w. The gelatin film containing 8 % ESE was identified as the optimal formulation based on its superior color indication, water barrier, and mechanical properties. Savory essential oil (SEO)-loaded PVANFs were electrospun onto the optimized gelatin film to fabricate the double-layer film. Analysis of the chemical and crystalline structures and the double-layer film's thermal properties confirmed the gelatin film's physical integration with PVANFs. Morphological examination revealed a smooth surface on the film and a uniform fibrillar structure within the PVANFs. Furthermore, the developed double-layer film effectively detected spoilage in trout fish while controlling pH, oxidation, and microbial changes during storage.

A novel gelatin composite film with melt extrusion for walnut oil packaging.

Gelatin have excellent film-forming and barrier properties, but its lack of biological activity limits its application in packaging. In this study, fish gelatin incorporated with apple polyphenol/cumin essential oil composite films were successfully prepared by melt extrusion. The cross-linking existed in gelatin and apple polyphenol improved the thermal stability and oxidation resistance of the film. The synergistic effect of apple polyphenols and cumin essential oil decreased the sensitivity of the film to water, especially the water solubility decreased from 41.60 % to 26.07 %. The plasticization of essential oil nearly doubled the elongation at break while maintaining the tensile strength of the film (11.45 MPa). Furthermore, the FG-CEO-AP film can inhibit peroxide value to extend the shelf life about 20 days in the walnut oil preservation. In summary, the apple polyphenol/cumin essential oil of FG film exhibits excellent comprehensive properties and high preparation efficiency for utilization as an active packaging material.

Clinical assessment of computed tomography for detecting ingested blister packs: A single-center retrospective study.

Objectives: Blister pack (BP) ingestion poses serious risks, such as gastrointestinal perforation, and accurate localization by computed tomography (CT) is a common practice. However, while it has been reported in vitro that CT visibility varies with the material type of BPs, there have been no reports on this variability in clinical settings. In this study, we investigated the CT detection rates of different BPs in clinical settings. Methods: This single-center retrospective study from 2010 to 2022 included patients who underwent endoscopic foreign body removal for BP ingestion. The patients were categorized into two groups for BP components, the polypropylene (PP) and the polyvinyl chloride (PVC)/polyvinylidene chloride (PVDC) groups. The primary outcome was the comparison of CT detection rates between the groups. We also evaluated whether the BPs contained tablets and analyzed their locations. Results: This study included 61 patients (15 in the PP group and 46 in the PVC/PVDC group). Detection rates were 97.8% for the PVC/PVDC group compared to 53.3% for the PP group, a significant difference (p < 0.01). No cases of BPs composed solely of PP were detected by CT. Blister packs were most commonly found in the upper thoracic esophagus. Conclusions: Even in a clinical setting, the detection rates of PVC and PVDC were higher than that of PP alone. Identifying PP without tablets has proven challenging in clinical. Considering the risk of perforation, these findings suggest that esophagogastroduodenoscopy may be necessary, even if CT detection is negative.

Monitoring fish freshness with pH-sensitive hydrogel films containing quercetin or eucalyptol.

This research developed pH-sensitive smart films using carboxymethyl cellulose (CMC) and collagen (COL), combined with either quercetin (QCT) or eucalyptol (EUC), to prevent fish meat spoilage. COL, extracted from isinglass, was confirmed as type I through SDS-PAGE. The films were characterized using FESEM, FTIR, and TGA. The addition of QCT or EUC enhanced antioxidant levels to 60.16% and 70.83%, respectively, up from a baseline of 10.4%. It also increased tensile strength from 3.32 ± 0.22 to 11.8 ± 0.25 and 13.2 ± 0.27 MPa, and enhanced elongation at break from 5 ± 3.1% to 27.7 ± 1.1% and 30.15 ± 2.1%. Fish meat packaged with QCT showed a lower spoilage rate due to the antibacterial and antioxidant effects of EUC and QCT (TVBN = 7.37 ± 0.01), compared to CMC/COL film (TVBN = 10.11 ± 0.02) and non-packaged fish (TVBN = 11.23 ± 0.01). The films exhibit >80% transparency, highlighting their suitability for food packaging. CMC/COL/QCT is preferred for fish packaging because it offers better mechanical properties and lower TVB-N levels.

Life cycle assessment of recycling metallised food packaging plastics using mechanical, thermal and chemical processes.

Single treatment of metallised food packaging plastics waste (MFPW) has shown disappointing results with recycling rate <20 % due to its complex structure consisting of 10 % aluminium (Al) and 90 % mixed plastic films made of PE, PP, PS, PET, etc. Besides, it is generating many emissions and residues that must be landfilled making it difficult to integrate them into the circular economy. Therefore, a multi-stage recycling (MSR) approach has recently been developed using several sequential mechanical, thermal and chemical processes to recover energy and Al from MFPW with additional revenue for recycling plant operators. The thermal treatment helps to decompose the plastic fraction into wax or oil, gaseous, and solid residue (SR) composed of Al and coal, while the mechanical process can be used as a pre-treatment of MFPW feedstock and SR. Finally, the chemical treatment (leaching and functionalization) can be used to extract Al from SR and to refine coal into carbon microparticles (CPs), respectively. In order to investigate the environmental performance of the proposed MSR system, this research was developed. The investigation was performed using SimaPro life cycle analysis (LCA) tool according to ISO 14040/44 Standards and the impact assessment method is ReCiPe 2016. Five different scenarios were proposed in the constructed LCA layout, namely, conversion of MFPW to a) wax and gas (pyrolysis), b) wax, gas, and aluminium chloride (AlCl3) (pyrolysis and leaching), c) wax, gas, AlCl3, and CPs (pyrolysis, leaching, and functionalization), and d) oil, gas, AlCl3, and CPs (catalytic pyrolysis, leaching, and functionalization). Besides, the oil produced from catalytic pyrolysis is used for generation of electricity (scenario e). The results showed that wax and gas recovery scenario (a) has better environmental potential and environmental benefits compared to incineration practice. The results did not change much after extraction of Al and CPs (scenario b, c), with a few increasing by 2-4% in the total score. While a lot of environmental burdens from upgrading and utilization (Scenario d, e) were recorded, reaching 79 % due to the huge amount of the catalyst was used. Thus, MSR systems have bigger environmental benefits, however, the chemical and catalytic processes still need to be further improved to reduce the effect of terrestrial acidification.

Youth and young adult flavour expectancies for new 'non-menthol' cigarettes introduced following California's ban on flavoured tobacco products.

BACKGROUND: Following California's statewide law prohibiting the sale of flavoured tobacco products, some cigarette brands introduced new variants advertised as non-menthol, yet featuring design and text commonly found in menthol cigarette marketing. METHODS: Data are from the February-May 2023 wave of the Tobacco Epidemic Evaluation Network (TEEN+) national probability-based survey (aged 13-25 years). Respondents (N=10 217) were shown images of two (of four) 'new non-menthol' brand ads or packaging and two comparators ('classic' non-menthol and menthol cigarette brands). Respondents reported expected taste of each (no or any minty/menthol taste; 'don't know'). Multinomial regression models tested associations between predictors (age, gender identity, race and ethnicity, perceived financial situation, smoking status) and expectation of minty/menthol taste. RESULTS: Younger age was associated with expectations of minty/menthol taste, controlling for covariates. Respondents aged 13-17 years had greater odds of expecting minty/menthol taste than no minty/menthol taste for all tested new non-menthol brands (Camel Crush Oasis adjusted OR (aOR): 1.30, p<0.05; Camel Crisp aOR: 1.47, p<0.001; Kool Non-Menthol Blue aOR: 1.27, p<0.05; Kool Non-Menthol Green aOR: 1.43, p<0.01), compared to respondents aged 21 and older. Respondents aged 18-20 years had greater odds of reporting minty/menthol expectancies than no minty/menthol expectancies for Camel Crush Oasis (aOR: 1.35, p<0.05) and Kool Non-Menthol Green (aOR: 1.29, p<0.05) compared to those aged 21-25 years. Compared to non-Hispanic white respondents, non-Hispanic Asian respondents had greater odds of expecting minty/menthol taste than no minty/menthol taste for Camel Crush Oasis (aOR: 1.89, p<0.01), Kool Non-Menthol Blue (aOR: 1.88, p<0.01) and Kool Non-Menthol Green (aOR: 1.72, p<0.05). DISCUSSION: Younger age was associated with expectations of new non-menthol cigarettes having a minty/menthol taste. Results raise concerns regarding the potential appeal of these products to youth and young adults.

Using palm oil residue for food nutrition and quality: from palm fatty acid distillate to vitamin E toward sustainability.

Increasing global palm oil production yields a valuable palm fatty acid distillate (PFAD) - a rich vitamin E (Vit-E) source and multifunctional ingredient in the food agro-industry - that can be utilized to achieve sustainability. This article reviews trends in the use and role of PFAD and its Vit-E in the food sector and proposes an integrated agro-industrial concept toward sustainability. Vit-E can be separated from PFAD with diverse and impactful pharmaceutical activities, including antioxidant, anti-inflammatory, anticancer and anti-ultraviolet effects. Based on in vivo experimental tests, PFAD and Vit-E supplementation can enhance the productivity and quality of livestock-based food products. PFAD is a plasticizer and antistatic packaging material in food packaging systems, and its derivatives can be used as food additives. Meanwhile, the Vit-E molecule in packaging can extend food shelf life by maintaining color stability, reducing lipid oxidation and rancidity, adding antimicrobial properties, and influencing changes in packaging properties such as water vapor, tensile strength, melting point and other physical properties. Toward sustainability, an integrated agro-industrial design has been proposed to implement clean production, increase the added value of palm oil industry residues, minimize environmental risks and increase profits to achieve long-term social welfare. In conclusion, PFAD residues and their Vit-E content have shown broad benefits in the food sector and prospects toward sustainability. © 2024 Society of Chemical Industry.

An analysis of flavor descriptors on tobacco products in the Philippines: Regulatory implications and lessons for low- and middle-income countries.

BACKGROUND: Historically, tobacco companies have used flavored tobacco products to enhance the appeal of tobacco consumption, encourage initiation and experimentation of tobacco use, and contribute to sustained tobacco use. While flavored tobacco products are regulated in several countries, there is no existing regulation on flavored tobacco products in the Philippines, specifically for cigarettes and cigars. This study aims to update evidence on the flavored tobacco product landscape in the Philippines by assessing both the flavor descriptors and flavor imagery featured on cigarette and cigar packaging. RESULTS: We collected 106 cigarette and cigar products from four major cities in the National Capital Region, Balanced Luzon, Visayas, and Mindanao. Of these 106 cigarette and cigar products, 62 (58.49%) had flavor descriptors. Three crushable capsule products did not feature any flavor descriptor but were included for flavor imagery examination. We identified five categories of flavor descriptors: menthol, concept descriptors, tobacco, beverages, and other flavors. Out of 62 packs, ten featured more than one flavor descriptor on the packaging. Menthol flavor descriptors comprised the majority of flavor descriptors. Imagery and other graphic elements closely resonate with and enhance the flavor descriptors found on these packs. CONCLUSIONS: This study aimed to update the evidence on the flavored tobacco product landscape in the Philippines and address their absence of regulation. Regulating flavored tobacco products requires a comprehensive policy approach complemented by complete enforcement. Flavor substances, flavor descriptors, and flavor imagery must be regulated altogether; however, it is ideal to enforce a ban on flavored tobacco products in compliance with the WHO FCTC, to which the Philippines is a signatory. Policymakers should consider plain packaging as an intervention to eliminate the appeals associated with flavored tobacco products.

Evaluation of new safety decontamination approaches at lab scale for recycled highdensity polyethylene (rHDPE) intended for food contact.

BACKGROUND: The increasing use of plastic packaging materials generates concerns related to the environmental problem generated by their waste. As a result, the search for new recycling methodologies to extend the lifecycle of plastic packaging is becoming more important, without forgetting to ensure the safety of these materials. Currently, the use of recycled polyolefins as food contact materials is not widespread yet. This is because the decontamination processes currently available are insufficient to produce clean, safe materials suitable for such applications. This work is focused on the evaluation of the safety of recycled high-density polyethylene (rHDPE), and the search for strategies to achieve its decontamination. RESULTS: To this end, three batches of flakes and three batches of pellets of rHDPE coming from the mechanical recycling of post-consumer milk bottles were analyzed. The analysis of the volatile and semi-volatile compounds present in the samples was carried out using gas chromatography-mass spectrometry (GC-MS), finding a total of 67 compounds. The strategy to achieve the decontamination of flakes and pellets of this material has been based on the application of high temperature and vacuum at lab scale, obtaining a clear decrease in volatile compounds, below 50% of the initial value in most cases when applying 120 °C during 5 h. The migration test performed in the samples (treated and untreated) to different food simulants (10 % ethanol and 3 % acetic acid, 95 % ethanol) revealed also a clear decrease of concentrations of volatiles. SIGNIFICANCE: The findings are highly encouraging, demonstrating substantial progress toward the safe and effective use of rHDPE in specific food packaging applications. This indicates a significant step forward in the potential uses of rHDPE. Nevertheless, the lack of toxicity data for many migrants necessitates additional toxicological testing to obtain a more precise risk assessment.

The potential of nanofibrillated cellulose from Hevea brasiliensis to produce films for bio-based packaging.

Cellulose micro/nanofibril (MNFC) films are an interesting alternative to plastic-based films for application in biodegradable packaging. In this study, we aimed to produce and characterize MNFC films obtained from alkaline-pretreated rubberwood (Hevea brasiliensis) waste and Eucalyptus sp. commercial pulp. MNFC and films were evaluated regarding microstructure; crystallinity; stability; and physical, optical, mechanical, and barrier properties. A combined quality index (QI) was also calculated. Eucalyptus MNFC suspensions were more stable than H. brasiliensis. Both films had a hydrophobic surface (>90°) and high grease resistance (oil kit 12). H. brasiliensis films had lower transparency (26.4 %) and high crystallinity (∼89 %), while Eucalyptus films had lower permeability and higher mechanical strength. The QI of MNFC was 51 ± 5 for H. brasiliensis and 55 ± 4 for Eucalyptus, showing that both types of raw material have potential for application in the packaging industry and in the reinforcement of composites, as well as for high value-added applications in products made from special materials.

Development of antifouling antibacterial polylactic acid (PLA) -based packaging and application for chicken meat preservation.

Microbial contamination is the leading cause of food spoilage and food-borne disease. Here, we developed a multifunctional surface based on polylactic acid (PLA) bioplastic with antifouling and antibacterial properties via a facile dual-coating approach. The surface was designed with hierarchical micro/nano-scale roughness and low surface energy. Bactericidal agent polyhexamethylene guanidine hydrochloride (PHMG) was incorporated to endow the film with bactericidal activity. The film had good superhydrophobic, antifouling and antibacterial performance, with a water contact angle of 154.3°, antibacterial efficiency against E. coli and S. aureus of 99.9 % and 99.6 %, respectively, and biofilm inhibition against E. coli and S. aureus of 63.5 % and 68.9 %, respectively. Synergistic effects of antibacterial adhesion and contact killing of bacteria contributed to the significant antibacterial performance of the film. The biobased biodegradable film was highly effective in preventing microbial growth when applied as antibacterial food packaging for poultry product, extending the shelf life of fresh chicken breast up to eight days.

Advances in chlorogenic acid derived nanomaterials: designs and applications.

Chlorogenic acid (CGA) that exhibits various bioactivities holds promise as a natural and safe medicinal agent or food supplement for promoting human health. However, the direct formulation for treatment is severely limited by its low water solubility, poor bioavailability, low plasma stability, and side effects caused by high doses. Fortunately, nanotechnology is widely applied for drug delivery to overcome the partial disadvantages of traditional drug molecules or naturally active components. The properties of CGA containing multiple hydroxyl groups as a green reductant and stabilizer have made the development of CGA-loaded nanomaterials possible. In this review, recent advancements in the design of CGA-loaded nanomaterials based on organic or inorganic nanomaterials were discussed, and the positive effects of nanomaterials on the release properties of active molecules and their targeted distribution in biological systems were indicated. These nanomaterials enhance the physiological activity of CGA in the treatment of various diseases. Moreover, in the field of food, CGA-loaded nanocomposites have been found to optimize the mechanical properties of nano-food packaging, leading to an extended shelf life of food products. The findings of this review provide a valuable foundation and reference for the development of novel CGA-loaded nanomedicines and nano-food packaging.

Development and investigation of a polysaccharide ternary nanocomposite based on basil seed gum/graphene oxide/anthocyanin for intelligent food packaging.

A new pH-sensitive intelligent packaging system was developed composed of extracted and purified basil seed gum (BG) containing aqueous malva sylvestris extract (MS) and varying amounts of synthesized graphene oxide (GO). In the following, the characteristics of prepared films including spectroscopic, physio-mechanical, thermogravimetry, fracture-surface morphology, anthocyanin release, and pH and TVB-N sensitivity, were investigated. Our results revealed that the addition of 0.5 wt % MS into the BG matrix induced pH sensitivity to the film and resulted in a visible color change from pH 2.0 to 14.0; however, it reduced the thermal and physio-mechanical properties. In this regard, the effective presence of the optimum concentration of GO (0.25 wt%) in enhancing the mechanical and thermal properties of the BG-MS films was shown. Moreover, inspecting the release kinetics demonstrated a controllable release for BG-MS-GO film compared to the BG-MS film in 48 h. Furthermore, the total volatile basic nitrogen (TVB-N) content and pH value were shown to be highly correlated with the color changes of the freshness indicator film during the storage of salmon fillets at 25 °C for 36 h. Therefore, it was shown that BG-MS-GO film can be used as a highly effective freshness/spoilage indicator of proteinic products.

Enhancing biodegradable smart food packaging: Fungal-synthesized nanoparticles for stabilizing biopolymers.

The increasing global concern over environmental plastic waste has propelled the progress of biodegradable supplies for food packaging. Biopolymer-based packaging is undergoing modifications to enhance its mechanical properties, aligning with the requirements of smart food packaging. Polymer nanocomposites, incorporating reinforcements such as fibers, platelets, and nanoparticles, demonstrate significantly improved mechanical, thermal, optical, and physicochemical characteristics. Fungi, in particular, have garnered significant interest for producing metallic nanoparticles, offering advantages such as easy scaling up, streamlined downstream handling, economic feasibility, and a large surface area. This review provides an overview of nano-additives utilized in biopackaging, followed by an exploration of the recent advancements in using microbial-resistant metal nanoparticles for food packaging. The mycofabrication process, involving fungi in the extracellular or intracellular synthesis of metal nanoparticles, is introduced. Fungal functionalized nanostructures represent a promising avenue for application across various stages of food processing, packaging, and safety. The integration of fungal-derived nanostructures into food packaging materials presents a sustainable and effective approach to combatting microbial contamination." By harnessing fungal biomass, this research contributes to the development of economical and environmentally friendly methods for enhancing food packaging functionality. The findings underscore the promising role of fungal-based nanotechnologies in advancing the field of active food packaging, addressing both safety and sustainability concerns. The study concludes with an investigation into potential fungal isolates for nanoparticle biosynthesis, highlighting their relevance and potential in advancing sustainable and efficient packaging solutions.

Recent functionality developments of carboxymethyl chitosan as an active food packaging film material.

In recent years, environmental concerns regarding the persistence of petroleum-based plastic food packaging have increased, prompting the exploration of biopolymer alternatives. Carboxymethyl chitosan (CMCS), a derivative of chitosan, exhibits superior water-soluble film properties, making it an ideal material for degradable food packaging applications. This study comprehensively examines the synthesis methods and properties of CMCS, with a particular emphasis on recent advancements in CMCS-based food packaging films. Various functionalized CMCS-based food packaging films, including coblended, nanoparticle composite, plant extract composite, and cross-linked films, were reviewed. The practical applications of CMCS-based food packaging films and edible coatings in food preservation are also showcased. This study emphasizes that the notable compatibility of CMCC with a range of polymers and additives has facilitated the development of multifunctional packaging films. These innovations, including antibacterial, antioxidant, and smart-indicating variants, have demonstrated remarkable efficacy in preserving fruits, aquatic products, poultry, and other perishable goods.

Mechanistic Insights Into an Ancient Adenovirus Precursor Protein VII Show Multiple Nuclear Import Receptor Pathways.

Adenoviral pVII proteins are multifunctional, highly basic, histone-like proteins that can bind to and transport the viral genome into the host cell nucleus. Despite the identification of several nuclear localization signals (NLSs) in the pVII protein of human adenovirus (HAdV)2, the mechanistic details of nuclear transport are largely unknown. Here we provide a full characterization of the nuclear import of precursor (Pre-) pVII protein from an ancient siadenovirus, frog siadenovirus 1 (FrAdV1), using a combination of structural, functional, and biochemical approaches. Two strong NLSs (termed NLSa and NLSd) interact with importin (IMP)ß1 and IMPα, respectively, and are the main drivers of nuclear import. A weaker NLS (termed NLSb) also contributes, together with an additional signal (NLSc) which we found to be important for nucleolar targeting and intranuclear binding. Expression of wild-type and NLS defective derivatives Pre-pVII in the presence of selective inhibitors of different nuclear import pathways revealed that, unlike its human counterpart, FrAdV1 Pre-pVII nuclear import is dependent on IMPα/ß1 and IMPß1, but not on transportin-1 (IMPß2). Clearly, AdVs evolved to maximize the nuclear import pathways for the pVII proteins, whose subcellular localization is the result of a complex process. Therefore, our results pave the way for an evolutionary comparison of the interaction of different AdVs with the host cell nuclear transport machinery.

Chitosan-gallic acid conjugate edible coating film for perishable fruits.

Approximately 30 % of global agricultural land is used to produce food that is ultimately lost or wasted, making it imperative to explore strategies for mitigating this waste. This study explored the potential of chitosan (CS) derivatives as edible coatings to extend food shelf life. Although soluble CS derivatives such as glycol CS are suitable coatings, their antimicrobial properties often diminish with increased solubility. To address this issue, gallic acid (GA), a polyphenol, was conjugated with CS using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS) chemistry to create edible coating solutions. The resulting CS-GA films exhibited remarkable solubility, mechanical strength, UV-blocking properties, and superior antioxidant and antimicrobial properties. Furthermore, these films exhibited a high affinity for hydrophobic fruit surfaces while also facilitating easy washing, making them an alternative for consumers who are averse to film-coated products. The CS-GA-coated fruits exhibited minimal surface spoilage, decreased mass loss, and increased firmness. Therefore, these CS-GA conjugate coatings hold significant potential as eco-friendly, edible, and washable food packaging coatings.

Poly(3-hydroxybutyrate) production for food packaging from biomass derived carbohydrates by cupriavidus necator DSM 545.

The extensive utilization of conventional plastics has resulted in a concerning surge in waste. A potential solution lies in biodegradable polymers mostly derived from renewable sources. Cupriavidus necator DSM 545 is a microorganism capable, under stress conditions, of intracellularly accumulating Poly(3-hydroxybutyrate) (PHB), a bio-polyester. This study aimed to identify optimal conditions to maximize the intracellular accumulation of PHB and its global production using natural media obtained by processing lignocellulosic residues of cardoon, a low-cost feedstock. An intracellular PHB accumulation was observed in all of the tested media, indicating a metabolic stress induced by the lack of macronutrients. Increasing C/N ratios led to a significant decrease in cellular biomass and PHB production. Furthermore C. necator DSM 545 was incapable of consuming more than 25 g/L of supplied monosaccharides. Surprisingly, in the samples supplied with 60 % of the pentose-rich liquid fraction, complete consumption of xylose was observed. This result was also confirmed by subsequent tests using Medium 1 growth media containing xylose as the sole carbon source. Using a diluted medium with a C/N ratio of 5, a PHB production of 5.84 g/L and intracellular PHB accumulation of 77 % w/w were respectively achieved. Finally, comparative shelf-life tests conducted against conventional pre-packaging materials in PP suggested that PHB films performed similarly in preserve ready-to-eat products.

Can pure cellulose nanofibril films replace polyolefins as water vapor barriers in packaging?

Despite significant research into cellulose nanofibril (CNF) films as substitutes to synthetic plastic materials, commercial applications remain very limited. One major hindrance is the poor water vapor barrier properties of CNF films compared to polyolefins, a critical property for product protection, such as food safety and preservation. To date, it is unknown whether full moisture barrier properties can be achieved with materials made by the assembly of nanofibers and fibrils. A comprehensive understanding of the effect of film structure on water vapor transport properties is required. Here, over 200 films were produced with a wide range of grammages from 30 g/m2 to 580 g/m2 by casting and spray deposition. Their structures were quantified by µCT and SEM and related to their water vapor transmission rates (WVTRs). Porosity and pore connectivity decreased with increasing film grammage, which correlates with the exponential decrease in WVTR. However, the WVTR plateaued at 30 g/m2day, indicating that the known open space and adsorption diffusion mechanisms cannot be fully eliminated by producing high grammage films. Pure cellulose nanofibril films therefore cannot replace polyolefins in packaging applications, requiring modifications such as coating and nanofillers.

Effect of dialdehyde nanocellulose-tannin fillers on antioxidant, antibacterial, mechanical and barrier properties of chitosan films for cherry tomato preservation.

In this study, bio-based composite films from nanocellulose, tannin and chitosan were fabricated. First, tannin was covalently immobilized onto dialdehyde CNCs (DACNCs) through the nucleophilic reaction to obtain TA-CNCs. TA-CNCs were then added into chitosan matrix as the nanofillers to obtain chitosan-TA-CNC (CS-TA-CNC) films. Compared with pure chitosan film, the water solubility, swelling ratio, water vapor and oxygen barrier properties of CS-TA-CNC films decreased, indicating the improved water-resistant and barrier properties. The composite films exhibited high UV blocking, antioxidant capacity and antimicrobial properties against both E. coli and S. aureus. CS-TA-CNC film with a TA-CNC content of 10 % exhibited the highest tensile strength (77.57 MPa) and toughness (23.51 MJ/m3), 2.23 and 2.5 times higher than that of pure chitosan film, respectively. The composite films extended postharvest life of tomato cherries compared to the pure chitosan film. Films prepared from sustainable bioresources show promising potential for use in active packaging.