Recent progress in PBAT-based films and food packaging applications: A mini-review

Cytocompatible 2D Graphitic Carbon Nitride-Modified Polybutylene Adipate Terephthalate/Polylactic Acid Hybrid Nanobiocomposites

Polymer nanobiocomposites (PNCs) prepared with graphitic carbon nitride (GCN) nanosheets in polybutylene adipate terephthalate (PBAT)/polylactic acid (PLA) bioblends were processed using a three-step processing technique that involved: (1) a solution-based GCN exfoliation step; (2) a masterbatching step of GCN in PBAT by solution processing; and (3) a melt-compounding step where the masterbatch was mixed with pristine PLA to delaminate the 2D GCN layers by extrusion high-shear mixing and to deposit them onto the biphasic PLA/PBAT morphology. Due to the partial exfoliation of GCN, this process led to a concurrent presence of three distinct morphologies within the PNCs' microstructure: (1) Type 1, characterized by an unaltered interface and PLA matrix, with minimal GCN deposition within the PBAT phase; (2) Type 2, distinguished by a diffused and stiff interface with GCN distribution in both the dispersed (PBAT) and matrix (PLA) phases; and (3) Type 3, featuring unmodified interfaces and GCN localization across both PLA and PBAT phases with a stair-like morphological texture. Such a morphological combination generates distinct crack propagation micromechanics, thereby influencing the variability of the plastic deformational behavior of their PNCs. Particularly, the Type 1 morphology enables GCN to act as a secondary stress-dissipating agent, whereas the PBAT domains serve as the primary stress-absorbing sites, contributing to enhanced crack propagation energy requirements. Contrarily, Type 3 (slightly) and Type 2 (predominantly) morphologies invert GCN's role from stress dissipation to stress concentration due to its localization within the PLA matrix. Differential scanning calorimetry revealed a crystallinity increase in the PNCs until 0.1 wt % GCN, followed by a decline, likely due to agglomeration at higher contents. Thermogravimetric analysis showed that GCN addition improved the thermostability of the bioblends, attributed to the GCN's nanophysical and pyrolytic barrier effect. Moreover, using both direct and indirect methods, GCN did not impair the biocompatibility of the bioblends as confirmed via cytocompatibility assays.

Dynamic responses of soil microbial communities to long-term co-contamination with PBAT and cadmium

The co-contamination of plastics and heavy metals poses novel challenges to agricultural soil ecosystems. However, research into the long-term effects of such co-contamination on soil microbial communities remains limited. This study, through a 540-day incubation experiment, investigated the impacts of poly(butylene adipate-co-terephthalate) (PBAT) and cadmium (Cd) co-contamination on the structure and function of soil microbial communities. The findings revealed that co-contamination significantly altered soil nitrate and ammonium nitrogen levels. Furthermore, the co-contamination continuously and significantly reduced bacterial diversity, producing a more pronounced negative impact compared to single pollution. Key microbial groups such as Proteobacteria, acting as core microorganisms, were significantly enriched under co-contamination conditions, with their relative abundance increasing significantly by 40.0 %. This indicates their potential role in plastic degradation and heavy metal resistance. In addition, the co-contamination also drove the shift of bacterial and fungal community assembly from deterministic processes to stochastic processes. These insights not only fill the research gap regarding the effects of long-term co-contamination on soil microorganisms but also provide a scientific foundation for the development of targeted soil management and remediation strategies, especially in regions where plastic and heavy metal pollution coexist.

Efficient preparation and properties of PBAT/starch covalent a daptable network composites

Poly (butylene adipate-co-terephthalate) (PBAT)/starch composites have captured great attentions due to their favorable biodegradability and cost-effectiveness. However, it is still a challenge to prepare PBAT/starch composites with superior mechanical performance, solvent and creep resistance, and gas barrier. This study used a chain breaking-crosslinking strategy to prepare covalent adaptable network (CAN) composites from PBAT and unmodified starch via reactive extrusion. In the chain breaking stage, dipentaerythritol was used to break PBAT via transesterification and capped more hydroxyl groups on PBAT, achieving favorable compatibility with unmodified starch, which is confirmed via infrared spectroscopy analysis and scanning electron microscopy among other experimental methods. In the crosslinking stage, the hydroxyl groups of chain broken PBAT and starch were reacted with styrene-maleic anhydride copolymer (SMA) to form CAN composites. The superior compatibility and network feature gave the composites excellent thermal properties, strength and modulus, creep resistance, solvent resistance and gas barrier performance. Moreover, fast stress relaxation can be achieved based on the transesterification, allowing for extrusion processing and thermal compression molding, demonstrating excellent reprocessing recyclability of the PBAT/starch CAN composites. Overall, this work provides a simple, green and efficient method for preparing high-performance PBAT/starch CAN composites, which should also be suitable for other polymer/filler composites.

Enhancing the compatibility and performance of poly (lactic acid) and thermoplastic polyolefin elastomer blends through a dual compatibilization strategy

Application of biodegradable polylactic acid (PLA) is limited by its poor toughness. This research focuses on modifying PLA using thermoplastic elastomers (TPO), primarily due to their dual advantages of enhancing performance and reducing application costs. Two thermoplastic polyolefin elastomers (TPO) (NS06, Versify2300) were blended to prepare a superior elastomer TPO(NV) (NS06:Versify2300 = 80:20). This improved TPO(NV) was then used as a toughening agent to enhance the toughness of polylactic acid (PLA). To enhance the compatibility between PLA and TPO(NV), TPO(NV)-g-(GMA-co-St) graft copolymer and dibutyl itaconate (DBI) were introduced into the PLA/TPO(NV) blend system. The effects of different compatibilizers on the compatibility, crystallization behavior, rheological properties, mechanical properties, and microstructure of the PLA/TPO(NV) blends were systematically studied. The results indicated that glycidyl methacrylate (GMA) and styrene (St) were successfully grafted onto the TPO(NV) molecular chains. The epoxy groups in GMA within the graft copolymer could react with the end groups of the PLA resin, while the double bonds in DBI could react with the main chains of either PLA or TPO(NV) elastomer. This effectively connected the PLA and TPO(NV) molecular chains, collectively enhancing the compatibility between TPO(NV) elastomer and PLA. The non-isothermal crystallization ability of TPO(NV) decreased after blending with PLA, and this effect was further amplified with the introduction of the TPO(NV)-g-(GMA-co-St) graft copolymer or DBI. However, the plasticizing effect of DBI increased the mobility of the polymer molecular chains, thereby enhancing the crystallization ability. Therefore, when DBI was used alone to enhance the compatibility of PLA/TPO(NV) blends, the crystallinity of the blend did not change significantly. In contrast, when the TPO(NV)-g-(GMA-co-St) graft copolymer was used alone or in combination with DBI, the crystallinity of the blend decreased significantly. Mechanical property tests indicated that the addition of either the TPO(NV)-g-(GMA-co-St) graft copolymer or DBI improved the compatibility of PLA/TPO(NV) blends, thereby enhancing their mechanical properties. However, the combined addition of both the TPO(NV)-g-(GMA-co-St) graft copolymer and DBI resulted in a more pronounced effect. The notched impact strength and elongation at break reached optimal values, which were 1.9 times and 10.4 times those of the PLA/TPO(NV) blend, respectively. At this point, the fracture surface of the blend exhibited significant plastic flow, indicating characteristics of ductile fracture.

Microplastics in the marine environment: Challenges and the shift towards sustainable plastics and plasticizers

The United Nations (UN) estimate that around 75-199 million tons of plastic is floating in the world's oceans today. Continuous unintentional disposal of plastic waste in marine environments has and continues to cause significant biological impacts to various marine organisms ranging from mild difficulties in swimming or superficial damage to critical organ malfunctions and mortality. Over time, plastics in these environments degrade into microplastics which are now acknowledged as a pervasive harmful pollutant found in the cryosphere, atmosphere and hydrosphere. In response to this issue, the production of bespoke biodegradable bioplastics derived from renewable resources, such as vegetable oils, starch and plant fibres, is emerging to mitigate our reliance on environmentally persistent conventional fossil fuel-based plastics. While bioplastics degrade more readily than conventional plastics, they present new challenges, including leaching of toxic chemical additives and plasticizers into the environment. Consequently, various techniques have been explored in the search for sustainable plasticizers, from cheap, non-toxic compounds, such as vegetable oils and sugars to hyperbranched structures with limited migration. This article seeks to explain the intricate relationship between the problem of microplastics in marine environments and the strategies that have been investigated to address it thus far.

Use of Natamycin for the Development of Polymer Systems with Antifungal Activity for Packaging Applications

Recently, there has been a rapid growth in the use of biodegradable polymers as alternatives to petroleum-based polymers, particularly in the packaging sector, to reduce environmental pollution. In this scenario, the aim of this work was to study the use of different amounts of Natamycin on two polymer systems: one that is non-biodegradable but widely known in the field of packaging and one that is biodegradable and is emerging as a possible replacement, in order to accelerate progress toward the achievement of the sustainable development goals. Both systems were produced through melt mixing followed by compression moulding. Subsequently, they were fully characterized by rheological, morphological, mechanical, thermal, and wettability analyses. Natamycin release was evaluated in water at 4 °C by UV-Vis measurements. The antifungal activity of both polymeric systems containing Natamycin was assessed in vitro against three strains of undesirable filamentous fungi of food interest. The results show that PCL with 5% Natamycin represents an effective biodegradable alternative to EVA for inhibiting undesirable filamentous fungi. More specifically, both systems at 5% showed comparable inhibition zones of about 30 mm.

Chemical safety and risk assessment of bio-based and/or biodegradable polymers for food contact: A review

Bio-based and/or biodegradable polymers are being developed and applied as a sustainable and innovative alternative to conventional petroleum-based materials for food packaging applications. From the chemical standpoint, bio-based and/or biodegradable polymers present a complex chemical composition that includes additives, monomers, and other starting substances, but also, oligomers, impurities, degradation products, etc. All these compounds may migrate into the food and can be a hazard to the consumers' health. Thus, identifying potential migrants is crucial to assess the safety of these materials. The analytical methods applied to investigate migrants in bio-based and/or biodegradable polymers are reviewed and commented on. Mostly, gas chromatography or liquid chromatography coupled to mass spectrometry and specifically high-resolution mass spectrometry are the techniques of choice. In addition, a summary of recently published migration studies of chemicals from bio-based and/or biodegradable polymers into food simulants and food is provided. Moreover, current approaches to risk assessment of packaging materials are presented and illustrated with examples. Therefore, this review aims to highlight the chemical safety issues raised by biopolymers for food contact applications, that are often overlooked.

Tailoring the morphology and antibacterial activity of PBAT and thermoplastic cassava starch blown films with phosphate derivatives

Phosphate derivatives contain a high number of reactive groups that interact functionally with various polymers. Tetrasodium pyrophosphate (Na₄P₂O₇), sodium tripolyphosphate (Na₅P₃O₁₀), and sodium hexametaphosphate (Na₆(PO₃)₆) were incorporated into bioplastic polybutylene-adipate-terephthalate (PBAT) blended with thermoplastic cassava starch (TPS) in blown films. Their physicochemical, morphological, thermal, and antimicrobial properties were investigated. PBAT/TPS blended films were compounded via blown film extrusion to produce functional packaging. Infrared spectra indicated starch modification through the disruption of anhydroglucose monomer units, analyzed by ATR-FTIR, providing a more amorphous fraction and altering the properties of the films. PBAT/TPS films containing phosphate compounds exhibited non-homogeneous structures, with dispersed clumps within the film matrices that decreased tensile strength. The incorporation of phosphate compounds modified the storage modulus and relaxation temperature of PBAT/TPS films, influencing molecular mobility, decreasing heat transfer efficiency in seal strength, and enhancing stiffness due to starch disruption and interaction between the phosphate compound and the PBAT/TPS matrix. Wettability and permeability of PBAT/TPS films were modified by changes in polymer structure.

A state-of-the-art review of environmental behavior and potential risks of biodegradable microplastics in soil ecosystems: Comparison with conventional microplastics

As the use of biodegradable plastics becomes increasingly widespread, their environmental behaviors and impacts warrant attention. Unlike conventional plastics, their degradability predisposes them to fragment into microplastics (MPs) more readily. These MPs subsequently enter the terrestrial environment. The abundant functional groups of biodegradable MPs significantly affect their transport and interactions with other contaminants (e.g., organic contaminants and heavy metals). The intermediates and additives released from depolymerization of biodegradable MPs, as well as coexisting contaminants, induce alterations in soil ecosystems. These processes indicate that the impacts of biodegradable MPs on soil ecosystems might significantly diverge from conventional MPs. However, an exhaustive and timely comparison of the environmental behaviors and effects of biodegradable and conventional MPs within soil ecosystems remains scarce. To address this gap, the Web of Science database and bibliometric software were utilized to identify publications with keywords containing biodegradable MPs and soil. Moreover, this review comprehensively summarizes the transport behavior of biodegradable MPs, their role as contaminant carriers, and the potential risks they pose to soil physicochemical properties, nutrient cycling, biota, and CO2 emissions as compared with conventional MPs. Biodegradable MPs, due to their great transport and adsorption capacity, facilitate the mobility of coexisting contaminants, potentially inducing widespread soil and groundwater contamination. Additionally, these MPs and their depolymerization products can disrupt soil ecosystems by altering physicochemical properties, increasing microbial biomass, decreasing microbial diversity, inhibiting the development of plants and animals, and increasing CO2 emissions. Finally, some perspectives are proposed to outline future research directions. Overall, this study emphasizes the pronounced effects of biodegradable MPs on soil ecosystems relative to their conventional counterparts and contributes to the understanding and management of biodegradable plastic contamination within the terrestrial ecosystem.

Bio-Based and Biodegradable Polymeric Materials for a Circular Economy

Nowadays, plastic contamination worldwide is a concerning reality that can be addressed with appropriate society education as well as looking for innovative polymeric alternatives based on the reuse of waste and recycling with a circular economy point of view, thus taking into consideration that a future world without plastic is quite impossible to conceive. In this regard, in this review, we focus on sustainable polymeric materials, biodegradable and bio-based polymers, additives, and micro/nanoparticles to be used to obtain new environmentally friendly polymeric-based materials. Although biodegradable polymers possess poorer overall properties than traditional ones, they have gained a huge interest in many industrial sectors due to their inherent biodegradability in natural environments. Therefore, several strategies have been proposed to improve their properties and extend their industrial applications. Blending strategies, as well as the development of composites and nanocomposites, have shown promising perspectives for improving their performances, emphasizing biopolymeric blend formulations and bio-based micro and nanoparticles to produce fully sustainable polymeric-based materials. The Review also summarizes recent developments in polymeric blends, composites, and nanocomposite plasticization, with a particular focus on naturally derived plasticizers and their chemical modifications to increase their compatibility with the polymeric matrices. The current state of the art of the most important bio-based and biodegradable polymers is also reviewed, mainly focusing on their synthesis and processing methods scalable to the industrial sector, such as melt and solution blending approaches like melt-extrusion, injection molding, film forming as well as solution electrospinning, among others, without neglecting their degradation processes.

Preparation and Performance of PBAT/PLA/CaCO3 Composites via Solid-State Shear Milling Technology

Replacing traditional disposable, non-biodegradable plastic packaging with biodegradable plastic packaging is one of the key approaches to address the issue of "white pollution". PBAT/PLA/inorganic filler composites are widely utilized as a biodegradable material, commonly employed in the field of packaging films. However, the poor dispersion of inorganic fillers in the polymer matrix and the limited compatibility between PBAT and PLA have led to inferior mechanical properties and elevated costs. In this work, we propose a simple and effective strategy to improve the dispersion of nano-CaCO3 in a PBAT/PLA matrix through solid-state shear- milling (S3M) technology, combined with mechanochemical modification and in situ compatibilization to enhance the compatibility between PBAT and PLA. The impact of varying milling conditions on the structure and performance of the PBAT/PLA/CaCO3 composites was investigated. During the milling process, PBAT and PLA undergo partial molecular chain fragmentation, generating more active functional groups. In the presence of the chain extender ADR during melt blending, more branched PBAT-g-PLA is formed, thereby enhancing matrix compatibility. The results indicate that the choice of milling materials significantly affects the structure and properties of the composite. The film obtained by milling only PBAT and CaCO3 exhibited the best performance, with its longitudinal tensile strength and fracture elongation reaching 22 MPa and 437%, respectively. This film holds great potential for application in the field of green packaging.

Biocompatible film based on protein/polysaccharides combination for food packaging applications: A comprehensive review

Protein and polysaccharides are the mostly used biopolymers for developing packaging film and their combination-based composite produced better quality film compared to their single counterpart. The combination of protein and polysaccharides are superior owing to the better physical properties like water resistance, mechanical and barrier properties of the film. The protein/polysaccharide-based composite film showed promising result in active and smart food packaging regime. This work discussed the recent advances on the different types of protein/polysaccharide combinations used for making bio-based sustainable packaging film formulation and further utilized in food packaging applications. The fabrication and properties of various protein/polysaccharide combination are comprehensively discussed. This review also presents the use of the multifunctional composite film in meat, fish, fruits, vegetables, milk products, and bakery products, etc. Developing composite is a promising approach to improve physical properties and practical applicability of packaging film. The low water resistance properties, mechanical performance, and barrier properties limit the real-time use of biopolymer-based packaging film. The combination of protein/polysaccharide can be one of the promising solutions to the biopolymer-based packaging and thus recently many works has been published which is suitable to preserve the shelf life of food as well trace the food spoilage during food storage.

Bioinspired Nanolayered Structure Tuned by Extensional Stress: A Scalable Way to High-Performance Biodegradable Polyesters

The nacre-inspired multi-nanolayer structure offers a unique combination of advanced mechanical properties, such as strength and crack tolerance, making them highly versatile for various applications. Nevertheless, a significant challenge lies in the current fabrication methods, which is difficult to create a scalable manufacturing process with precise control of hierarchical structure. In this work, a novel strategy is presented to regulate nacre-like multi-nanolayer films with the balance mechanical properties of stiffness and toughness. By utilizing a co-continuous phase structure and an extensional stress field, the hierarchical nanolayers is successfully constructed with tunable sizes using a scalable processing technique. This strategic modification allows the robust phase to function as nacre-like platelets, while the soft phase acts as a ductile connection layer, resulting in exceptional comprehensive properties. The nanolayer-structured films demonstrate excellent isotropic properties, including a tensile strength of 113.5 MPa in the machine direction and 106.3 MPa in a transverse direction. More interestingly, these films unprecedentedly exhibit a remarkable puncture resistance at the same time, up to 324.8 N mm-1, surpassing the performance of other biodegradable films. The scalable fabrication strategy holds significant promise in designing advanced bioinspired materials for diverse applications.

PBAT/lignin-ZnO composite film for food packaging: Photo-stability, better barrier and antibacterial properties

When PBAT used as film, stability deteriorates under sunlight exposure, the poor barrier and antibacterial properties are also limiting its application. In this work, lignin-ZnO nanoparticles were prepared by hydrothermal method, as additives to fill the PBAT matrix. In addition, PBAT-lignin-ZnO composite films were successfully prepared by melting and hot-pressing method. It is found that lignin could well dispersed the ZnO when its implantation into PBAT films, and lignin-ZnO not only maintaining tensile strength and thermal stability, but also could prompt PBAT's crystallinity. Especially, P-L-ZnO-2 composite films have good photostability. After 60 h aging, it can still maintain good molecular weight, chemical structure and mechanical properties. Besides, these composite films have improved hydrophobicity, barrier and antibacterial properties, could prevent mildew and significantly reduce the weight loss rate, color difference and hardness changes of strawberries during storage. This work provides a potential film material for outdoor applications and food packaging.

PBAT is biodegradable but what about the toxicity of its biodegradation products?

CONTEXT

Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable plastic. It was introduced to the plastics market in 1998 and since then has been widely used around the world. The main idea of this research is to perform quantum chemical calculations to study the potential toxicity of PBAT and its degradation products. We analyzed the electron transfer capacity to determine its potential toxicity. We found that biodegradable products formed with benzene rings are as good electron acceptors as PBAT and OOH•. Our results indicate that the biodegradation products are potentially as toxic as PBAT. This might explain why biodegradation products alter the photosynthetic system of plants and inhibit their growth. From this and other previous investigations, we can think that biodegradable plastics could represent a potential environmental risk.

METHODS

All DFT computations were performed using the Gaussian16 at M062x/6-311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as response functions.

Enzymatic Degradation Behavior of Self-Degradable Lipase-Embedded Aliphatic and Aromatic Polyesters and Their Blends

Over the past decade, the preparation of novel materials by enzyme-embedding into biopolyesters has been proposed as a straightforward method to produce self-degrading polymers. This paper reports the preparation and enzymatic degradation of extruded self-degradable films of three different biopolyesters: poly(lactic acid) (PLA), poly(butylene adipate-co-terephthalate) (PBAT), and poly(butylene succinate) (PBS), as well as three binary/ternary blends. Candida antarctica lipase B (CalB) has been employed for the enzyme-embedding procedure, and to the best of our knowledge, the use of this approach in biopolyester blends has not been reported before. The three homopolymers exhibited differentiated degradation and suggested a preferential attack of CalB on PBS films over PBAT and PLA. Moreover, the self-degradable films obtained from the blends showed slow degradation, probably due to the higher content in PLA and PBAT. These observations pave the way for exploring enzymes capable of degrading all blend components or an enzymatic mixture for blend degradation.

A study on the performance, structure, composition, and release behavior changes of polybutylene adipate terephthalic acid (PBAT) film during food contact

Polybutylene adipate terephthalic acid (PBAT) is an emerging biodegradable material in food packaging. However, concerns have been raised regarding the potential hazards it could pose to food safety. In this study, the changes of PBAT films during food contact and the release of small molecules were inestigated by a multiscale approach. On a macro-scale, the surface roughness of the films increased with the reduction in the concentration of food simulants and the increase in contact temperatures, especially after immersion in acidic food environments. On a micro-scale, the crystallinity (Xc) and degradation indexes (DI) of the films increased by 5.7-61.2% and 7.8-48.6%, respectively, which led to a decrease in thermal stability. On a scale approaching the molecular level, 2,4-di-tert-butylphenol (2,4-DTBP) was detected by gas chromatography-mass spectrometry (GC-MS/MS) with the highest migration content, and the release behavior of 2,4-DTBP was further investigated by migration kinetics. In addition, terephthalic acid (TPA), a hydrolysis product of PBAT, was detected in acidic food environments by liquid chromatography-mass spectrometry (LC-MS/MS). The results of this study could provide practical guidance and assistance to promote sustainable development in the field of food packaging.

Cellulose-based biomass composite films for plastic replacement: Synergistic UV shielding, antibacterial and antioxidant properties

With the gradual increase in environmental awareness and the growing demand for food safety, sustainable and environmentally friendly cellulose-based materials have become a promising alternative to petroleum-based plastics. However, in practice, packaging materials prepared from cellulose-based materials still have some unsatisfactory properties, such as monofunctionality, low transparency, and lack of UV shielding, antibacterial or antioxidant properties. Herein, a novel synthetic strategy is proposed in this paper, specifically, tannic acid (TA), a green natural extract with antibacterial and antioxidant properties, is used as a plasticizer and cross-linker, and oxidized cellulose nanocellulose (TOCN) modified with folic acid (FA) grafting is blended with TA, and cellulose-based biomass thin films with ultraviolet (UV) shielding, antibacterial, and antioxidant properties have been successfully prepared by using a simple vacuum-assisted filtration. The experimental results showed that the films could completely block ultraviolet light at wavelengths of 200-400 nm while providing 81.47 % transparency in the visible spectrum, while the introduction of TA conferred excellent antibacterial and antioxidant capabilities with antioxidant activity of up to 95 %, and also resulted in films with excellent mechanical properties. Therefore, this work provides ideas for the design and manufacture of competitive biomass green packaging materials, laying the foundation for future applications in food packaging.

Unveiling the Future of Meat Packaging: Functional Biodegradable Packaging Preserving Meat Quality and Safety

Meat quality and shelf life are important parameters affecting consumer perception and safety. Several factors contribute to the deterioration and spoilage of meat products, including microbial growth, chemical reactions in the food's constituents, protein denaturation, lipid oxidation, and discoloration. This study reviewed the development of functional packaging biomaterials that interact with food and the environment to improve food's sensory properties and consumer safety. Bioactive packaging incorporates additive compounds such as essential oils, natural extracts, and chemical substances to produce composite polymers and polymer blends. The findings showed that the incorporation of additive compounds enhanced the packaging's functionality and improved the compatibility of the polymer-polymer matrices and that between the polymers and active compounds. Food preservatives are alternative substances for food packaging that prevent food spoilage and preserve quality. The safety of food contact materials, especially the flavor/odor contamination from the packaging to the food and the mass transfer from the food to the packaging, was also assessed. Flavor is a key factor in consumer purchasing decisions and also determines the quality and safety of meat products. Novel functional packaging can be used to preserve the quality and safety of packaged meat products.

Recent Progress of Carrageenan-Based Composite Films in Active and Intelligent Food Packaging Applications

Recently, as concerns about petrochemical-derived polymers increase, interest in biopolymer-based materials is increasing. Undoubtedly, biopolymers are a better alternative to solve the problem of synthetic polymer-based plastics for packaging purposes. There are various types of biopolymers in nature, and mostly polysaccharides are used in this regard. Carrageenan is a hydrophilic polysaccharide extracted from red algae and has recently attracted great interest in the development of food packaging films. Carrageenan is known for its excellent film-forming properties, high compatibility and good carrier properties. Carrageenan is readily available and low cost, making it a good candidate as a polymer matrix base material for active and intelligent food packaging films. The carrageenan-based packaging film lacks mechanical, barrier, and functional properties. Thus, the physical and functional properties of carrageenan-based films can be enhanced by blending this biopolymer with functional compounds and nanofillers. Various types of bioactive ingredients, such as nanoparticles, natural extracts, colorants, and essential oils, have been incorporated into the carrageenan-based film. Carrageenan-based functional packaging film was found to be useful for extending the shelf life of packaged foods and tracking spoilage. Recently, there has been plenty of research work published on the potential of carrageenan-based packaging film. Therefore, this review discusses recent advances in carrageenan-based films for applications in food packaging. The preparation and properties of carrageenan-based packaging films were discussed, as well as their application in real-time food packaging. The latest discussion on the potential of carrageenan as an alternative to traditionally used synthetic plastics may be helpful for further research in this field.

New modifications of PBAT by a small amount of oxalic acid: Fast crystallization and enhanced degradation in all natural environments

Biodegradable plastics are often mistakenly thought to be capable of degrading in any environment, but their slow degradation rate in the natural environment is still unsatisfactory. We synthetized a novel series of poly(butylene oxalate-co-adipate-co-terephthalate) (PBOAT) with unchanged melting point (135 °C), high elastic modulus (140 - 219 MPa) and elongation at break (478 - 769%). Fast isothermal crystallization with a semi-crystallization time < 20 s was demonstrated by the PBOAT. In N2 and air atmospheres, the PBOAT maintained the Td,5% higher than 329 °C. They also had good thermal stability at melt processing temperature for more than 20 min. PBOAT exhibited faster hydrolysis and seawater degradation, even under natural soil burial without light, but still kept stable under low humidity conditions during the storage and the shelf-life. Moreover, the hydrolysis mechanisms were clarified based on Fukui function analysis and DFT calculation, indicating that the hydrolysis of PBOAT would be more straightforward. The mechanism of soil burial is also elucidated through detailed characterization of the structure changes. The PBOAT offered a fresh approach to the development of high-performing, naturally degradable materials.

Enhanced Preservation of Climacteric Fruit with a Cellulose Nanofiber-Based Film Coating

Bananas are a typical climacteric fruit with high respiration and ethylene production rates after harvest, and they show rapid ripening-senescence phenotypes. Here, we demonstrate that carboxymethylcellulose nanofibers (CM-CNFs) and red cabbage extracts (RCE) can be used as a unique film coating formulation for enhancement of the shelf-life of fruit. A CM-CNF suspension solution is created through a process involving chemical modification, followed by mechanical grinding. It has a high aspect ratio that allows for the creation of a thin and transparent film on the surface of bananas. The cross-linked CM-CNF hydrogel forms a dense film layer on the banana surface during dehydration and prevents respiration and weight loss. RCE contains polyphenols acting as antioxidants, which prevent the appearance of black dots on the banana peels. It serves to mitigate the browning of banana skins and also hinders the respiration process, consequently slowing the aging of bananas.