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The Barrier Properties of Sustainable Multiphase and Multicomponent Packaging Materials: A review
... Research shows that barrier properties, especially those related to gas and moisture of such polymers are among the most important characteristics in designing films and coatings. It should be highlighted that the barrier properties of these polymers can be influenced by various factors including, among others, polarity and chemical structure (Trinh, Chang, & Mekonnen, 2023;Tyagi et al., 2021). For example, due to its poor O 2 and moisture permeability, PS is occasionally used in packaging fresh products. ...
... Some of the most studied intelligent sensors are centred on detecting changes in food pH, fluctuations in storage temperature, and accumulation of volatile compounds containing nitrogen (Azman et al., 2022;Duan, Li, Wang, Lin, & Wang, 2023;Yousefi et al., 2019). As a result, intelligent sensors are intended to monitor and sense changes and food conditions and display its information, significantly increasing food's shelf-life, traceability, and safety (Amin et al., 2022;Trinh et al., 2023). On the contrary, active sensors contain active compounds that will interact with food or the micro-environment of the packaging system to provide functional attributes in addition to the barrier and delay expected changes during storage. ...
... On the contrary, active sensors contain active compounds that will interact with food or the micro-environment of the packaging system to provide functional attributes in addition to the barrier and delay expected changes during storage. A vast diversity of compounds with antioxidant and/or antimicrobial have been explored in food areas along with absorbers of volatile components (humidity, oxygen, or ethylene, for instance) or release of gases, such as carbon dioxide (Azman et al., 2022;Trinh et al., 2023). ...
Background
Non-biodegradable food packaging (mainly plastic) and food waste are two major concerns that cause severe environmental and economic challenges as well as potential human health and food insecurity risks. Therefore, intensive efforts are being devoted to transforming food production and consumption patterns and developing alternative technological solutions to alleviate such issues.
Scope and approach
This review intends to discuss the interplay between food packaging, food waste, and sustainability. Some common strategies used in food packaging are briefly summarised. The significance of nanobiotechnology, smart sensors, and other fourth industrial revolution (Industry 4.0) innovations is emphasized, focusing of the role of these smart technologies in the emergence of novel prospects, such as the development of active and intelligent packaging systems. In addition, insights on consumer acceptance of novel packaging materials/technologies are given and conclusions are drawn.
Key findings and conclusions: Several innovative food packaging solutions based on Industry 4.0 technologies are being developed, changing the way food is packed and consumed. Indeed, growing evidence shows that digital technologies (particularly artificial intelligence, big data, blockchain, and 3D printing) will have a greater impact on food packaging in the sense of “Packaging 4.0”. However, more research is still needed to fully harness the benefit of advanced technologies, enabling them to overcome current barriers and achieve a healthier and more sustainable food future.
... These nanocomposites are created by dispersing nanofillers into a polymeric matrix. In the literature, layered materials (clays, silicate nanoplatelets, graphene), carbon nanotubes, starch nanocrystals, cellulose nanofibers and nanocrystals, and chitosan nanoparticles, among other nanomaterials, have been reported as examples of polymeric nanocomposites that can be filled [68][69][70][71][72]. The incorporation of nanoparticles such as carbon-based nanofillers, silicon-based nanofillers, metal oxide nanofillers, and hybrid nanofillers, into polymer matrices is an approach to improve the performance of the matrices by exploiting the properties of nanofillers. ...
... These nanocomposites are created by dispersing nanofillers into a polymeric matrix. In the literature, layered materials (clays, silicate nanoplatelets, graphene), carbon nanotubes, starch nanocrystals, cellulose nanofibers and nanocrystals, and chitosan nanoparticles, among other nanomaterials, have been reported as examples of polymeric nanocomposites that can be filled [68][69][70][71][72]. ...
Nanotechnology plays a crucial role in food preservation, offering innovative solutions for food monitoring and enabling the creation of packaging with unique functional properties. The nanomaterials used in the packaging can extend the shelf life of foods, enhance food safety, keep consumers informed about contamination or food spoilage, repair packaging damage, and even release preservatives to prolong the durability of food items. Therefore, this review aims to provide an overview of the diverse applications of nanotechnology in food packaging, highlighting its key advantages. Safety considerations and regulations related to nanotechnology packaging are also addressed, along with the evaluation of potential risks to human health and the environment, emphasizing that this field faces challenges in terms of safety considerations and regulations. Additionally, the development of nanotechnology-based packaging can drive advancements in food preservation by creating safer, more sustainable, and higher-quality packaging. Thus, nanotechnology offers the potential to enhance the efficiency and functionality of packaging, delivering substantial benefits for both manufacturers and consumers.
... Also, based on the homogeneity, the application of the biopolymer nanocomposite is determined. The nanomaterials that may be used as additives in the biopolymer matrices include silver nanoparticles, carbon nanotubes, nanoclay, nano-zinc oxide, cellulose nanocrystals, chitosan nanoparticles, etc. [12][13][14][15][16][17]. ...
Biodegradable polymer nanocomposites have gained attention in recent years owing to their antimicrobial activity. The article summarizes recent developments in improving antimicrobial, mechanical and barrier properties of biodegradable polymers chitosan, cellulose, gelatin and starch. ZnO, TiO 2 , reduced graphene oxide and silver reinforced biodegradable polymer nanocomposites exhibit improved tensile strength due to intercalation of nanomaterials into the polymer matrices. Silver nanoparticle reinforced polymer nanocomposites have shown significant antimicrobial properties against various strains of bacteria and fungi. Although, development of antimicrobial nanomaterials embedded packaging films has helped to augment shelf-life of food, leakage of nanomaterials into the packaged food remains an area of concern.
... This can be improved slightly by using water insoluble biopolymers, like chitosan (Cht), although the moisture barrier properties of Cht coated paper could be insufficient for, e.g., food packaging applications (Fernandes et al. 2010). Many recent studies have thus been performed by using Cht based emulsions in combination with fatty-acids or waxes, or by the addition of clay to improve hydrophobicity and reduce water vapour transmission rates (WVTR), although often reducing the mechanical properties of the paper (Reis et al. 2011;Trinh et al. 2023). Cht was also applied as a pre-coating on a paper, to provide better bonding and a more uniform surface for other processing steps, such as the subsequent application of a water-insoluble biopolymer by extrusion coating (Koppolu et al. 2019;Kuusipalo et al. 2005). ...
Cellulose nanocrystals (CNCs) and chitosan (Cht) have been studied extensively for oxygen and water vapour barrier coatings in biodegradable, compostable or recyclable paper packaging. However, rare studies have been performed by using scalable, inexpensive, and fast continuous slot-die coating processes, and none yet in combination with fast' and high-throughput near-infrared (NIR) light energy drying. In this frame, we studied the feasibility of a moderately concentrated (11 wt%) anionic CNC and (2 wt%) cationic Cht coating (both containing 20 wt% sorbitol related to the weight of CNC/Cht), by using plain and pigment pre-treated papers. The effect of coating parameters (injection speed, dry thickness settings) were investigated on coating quantity (dry weight, thickness) and homogeneity (coverage), papers' structure (thickness, grammage, density), whiteness, surface wettability, barrier (air, oxygen and water vapour) properties and adhesion (surface strength). The coating homogeneity was dependent primarily on the suspensions' viscosity, and secondarily on the applied coating parameters, whereby CNCs could be applied at 1–2 times higher injection speeds (up to 80 mL/min) and versatile coating weights, but required a relatively longer time to dry. The CNCs thus exhibited outstanding air (4.2–1.5 nm/Pa s) and oxygen (2.7–1.1 cm³ mm/m² d kPa) barrier performance at 50% RH and 22–33 g/m² deposition, whereas on top deposited Cht (3–4 g/m²) reduced its wetting time and improved the water vapour barrier (0.23–0.28 g mm/m² d Pa). The balanced barrier properties were achieved due to the polar characteristic of CNCs, the hydrophobic nature of Cht and the quantity of the applied bilayer coating that can provide sustainable paper-based packaging.
... Furthermore, the improved optical and catalytic characteristics, among others, of bimetallic nanoparticles (BMNPs) relative to monometallic nanostructures have recently been investigated [21,22]. It has been determined that BMNPs can contribute to the achievement of several of the UN SDGs, such as excellent health and wellbeing, clean water and sanitation, and responsible consumption and production, with a focus on problems and solutions [23][24][25]. While there is research that suggests that metallic nanoparticles could be useful in Sustainability Agenda initiatives, no reviews exist that establish a direct correlation between these nanostructures and the UN SDGs [26][27][28][29]. ...
The synergistic impact of nanomaterials is critical for novel intracellular and/or subcellular drug delivery systems of minimal toxicity. This synergism results in a fundamental bio/nano interface interaction, which is discussed in terms of nanoparticle translocation, outer wrapping, embedding, and interior cellular attachment. The morphology, size, surface area, ligand chemistry and charge of nanoparticles all play a role in translocation. In this review, we suggest a generalized mechanism to characterize the bio/nano interface, as we discuss the synergistic interaction between nanoparticles and cells, tissues, and other biological systems. Novel perceptions are reviewed regarding the ability of nanoparticles to improve hybrid nanocarriers with homogeneous structures to enhance multifunctional biomedical applications, such as bioimaging, tissue engineering, immunotherapy, and phototherapy.
... Packaging films must possess high barrier attributes to satisfy the strict protective standard in food packaging applications. Fruit, vegetable, salads and bakery products are the less restrictive foods in terms of water vapour transmission rate requirements (Trinh et al., 2023) and the 27.9 ± 0.6 b 14.9 ± 0.2 a 20Gly20AR ...
... Nanotechnology enables fine control over material characteristics and may be adjusted to satisfy specific packaging needs such as oxygen or moisture barrier requirements [61]. This level of personalization guarantees that packaging options are suited for the preservation and protection of varied items. ...
This comprehensive review investigates a variety of creative approaches in the field of sustainable food packaging biomaterials in response to growing environmental concerns and the negative effects of traditional plastic packaging. The study carefully looks at new developments in biomaterials, such as biodegradable polymers, ceramics, composites, and metal alloys, in response to the growing need for environmentally suitable substitutes. It highlights how they might replace conventional plastic packaging and lessen environmental damage. Moreover, the incorporation of nanotechnology into packaging is closely examined due to its crucial function in J o u r n a l P r e-p r o o f improving barrier qualities, introducing antimicrobial properties, and introducing smart packaging features. The investigation includes edible coatings and films made of biodegradable polymers that offer new sensory experiences in addition to prolonging the shelf life of products. The review emphasizes the use of biomaterials derived from food processing and agricultural waste, supporting environmentally responsible methods of producing materials while simultaneously using less resources and waste. As a strong defense against plastic pollution, the report highlights the food industry's increasing use of recyclable and biodegradable packaging, which is in line with the concepts of the circular economy. A movement in consumer tastes and regulatory pressures toward sustainable food packaging is evident in global market patterns. Notwithstanding these encouraging trends, there are still issues to be resolved, including cost-effectiveness, technological constraints, and the scalability of biomaterial production. This thorough analysis concludes by highlighting the critical role biomaterials have played in guiding the food industry toward sustainability and emphasizing the need for ongoing research and development to adequately address environmental issues on a worldwide scale and satisfy the growing demand for environmentally friendly packaging options. Biomaterials show great promise as catalysts for the food industry's transition to a sustainable future.
... Conventional petrochemical-derived synthetic polymers such as polypropylene, polyethylene, polyethylene terephthalate, polyamide, and so on exhibit excellent barrier properties that give rise to exceptional resistance towards moisture/water, gaseous (mainly oxygen), chemical and biological entities that made them a popular choice in industrial applications. This robustness and stability, in turn, make them nonbiodegradable, and they end up in landfills after a single use and also pose a threat of leaching harmful chemicals like Bisphenol A, micro/nanoplastics, etc., into nature 82 . That makes it essential to find or create sustainable bio-based alternatives with equal or better efficiency and affordability for their usage in commercial applications. ...
The demand for biodegradable materials across various industries has recently surged due to environmental concerns and the need for the adoption of renewable materials. In this context, lignin has emerged as a promising alternative, garnering significant attention as a biogenic resource that endows functional properties. This is primarily ascribed to its remarkable origin and structure that explains lignin's capacity to bind other molecules, reinforce composites, act as an antioxidant, and endow antimicrobial effects. This review summarizes recent advances in lignin-based composites, with particular emphasis on innovative methods for modifying lignin into micro and nanostructures and evaluating their functional contribution. Indeed, lignin-based composites can be tailored to have superior physicomechanical characteristics, biodegradability, and surface properties, thereby making them suitable for applications beyond the typical, for instance, in ecofriendly adhesives and advanced barrier technologies. Herein, we provide a comprehensive overview of the latest progress in the field of lignin utilization in emerging composite materials.
... Naturally derived, compostable, and biodegradable polymers are suitable alternatives to single-use plastics in packaging and coating applications. However, Trinh et al. [114] observed that most sustainable polymer alternatives cannot compete with traditional plastics in gas and moisture barrier properties. Recently, improved moisture barrier properties were obtained by the encapsulation of nanoclay platelets into epoxy resin [93,95,106,[115][116][117]. ...
Phyllosilicates are common minerals that include the most widely known micas and clay minerals. These minerals are found in several natural environments and have unique physical-chemical features, such as cation exchange capacity (CEC) and surface charge properties. When phyllosilicates are nano-sized, their physical-chemical properties are enhanced from those of the micro-sized counterpart. Because of their unique crystal chemical and physical-chemical features, kinetics, and particle size, nano-sized clay minerals (i.e., kaolinite, montmorillonite/illite) and micas (i.e., muscovite) are of great interest in several fields spanning from environmental applications to engineered materials. This paper aims to overview the recent developments of environmental protection and technological applications employing nano-sized natural micas and clay minerals. Emphasis is given to the role that the unique physical-chemical properties of montmorillonite, vermiculite, kaolinite, and muscovite play in nanoparticle formulations, manufacture, and technical performance.
... It is obvious that the CNC free CS/PVA blend lm exhibited ductile behavior, low modulus of elasticity and tensile strength, which precludes its usage as a packaging material requiring then high strength and stiffness. 52 A rise in tensile modulus from 202.32 to 412.46 MPa and tensile strength from 13.72 to 18.60 MPa, a decrease in elongation at break from 71.37 to 40.88% were seen in CS/PVA/CNC lms aer CNC incorporation at a weight percentage up to 5%. The increase is related to the establishment of a more adhesive bond that relies on a powerful electrostatic interaction as well as hydrogen linkage occurring between CNC and the CS/PVA blend, while the elongation at break's decrease indicates that the reinforcement affects the resulting composite's ductility. ...
Hemp is known for its swift growth and remarkable sustainability, requiring significantly less water, an adaptable cultivation to a wide range of climates when compared to other fibers sources, making it a practical and environmentally friendly choice for packaging materials. The current research seeks to extract cellulose nanocrystals (CNCs) from hemp fibers using alkali treatment followed by acid hydrolysis and assess their reinforcing capacity in polyvinyl alcohol (PVA) and chitosan (CS) films. AFM analysis confirmed the existence of elongated, uniquely nanosized CNC fibers. The length of the isolated CNCs was approximately 277.76 ± 61 nm, diameter was 6.38 ± 1.27 nm and its aspect ratio was 44.69 ± 11.08. The FTIR and SEM analysis indicated the successful removal of non-cellulosic compounds. Furthermore, the study explored the impact of adding CNCs at varying weight percentages (0, 0.5, 1, 2.5, and 5 wt%) as a strengthening agent on the chemical composition, structure, tensile characteristics, transparency, and water solubility of the bionanocomposite films. Adding CNCs to the CS/PVA film, up to 5 wt%, resulted in an improvement in both the Young's modulus and tensile strength of the bionanocomposite film, which are measured at (412.46 ± 10.49 MPa) and (18.60 ± 3.42 MPa), respectively, in contrast to the control films with values of (202.32 ± 22.50 MPa) and (13.72 ± 2.61 MPa), respectively. The scanning electron microscopy (SEM) images reveal the creation of a CS/PVA/CNC film that appears smooth, with no signs of clumping or clustering. The blending and introduction of CNCs have yielded transparent and biodegradable CS/PVA films. This incorporation has led to a reduction in the gas transmission rate (from 7.013 to 4.159 cm³ (m² day·0.1 MPa))⁻¹, a decrease in transparency (from 90.23% to 82.47%), and a lowered water solubility (from 48% to 33%). This study is the inaugural effort to propose the utilization of hemp-derived CNC as a strengthening component in the development of mechanically robust and transparent CS/PVA-CNC bio-nanocomposite films, holding substantial potential for application in the field of food packaging.
... Tailoring particle shape during synthesis could greatly enhance oxygen barrier performance. A lamellar morphology proves more effective in improving barrier properties than spherical particle [71,72]. This also suggests a promising approach for enhancing oxygen barrier stability Gels 2023, 9, 740 9 of 21 in high-humidity environments [73]. ...
Growing environmental concerns drive efforts to reduce packaging waste by adopting biodegradable polymers, coatings, and films. However, biodegradable materials used in packaging face challenges related to barrier properties, mechanical strength, and processing compatibility. A composite gel was developed using biodegradable compounds (prolamin, d-mannose, citric acid), as a coating to increase the oxygen barrier of food packaging materials. To improve gel stability and mechanical properties, the gels were physically cross-linked with particles synthesized from tetraethyl orthosilicate and tetramethyl orthosilicate precursors. Additionally, biocompatibility assessments were performed on human keratinocytes and fibroblasts, demonstrating the safety of the gels for consumer contact. The gel properties were characterized, including molecular structure, morphology, and topography. Biocompatibility of the gels was assessed using bioluminescent ATP assay to detect cell viability, lactate dehydrogenase assay to determine cell cytotoxicity, and a leukocyte stimulation test to detect inflammatory potential. A composite gel with strong oxygen barrier properties in low-humidity environments was prepared. Increasing the silane precursor to 50 wt% during gel preparation slowed degradation in water. The addition of citric acid decreased gel solubility. However, higher precursor amounts increased surface roughness, making the gel more brittle yet mechanically resistant. The increase of precursor in the gel also increased gel viscosity. Importantly, the gels showed no cytotoxicity on human keratinocytes or fibroblasts and had no inflammatory effects on leukocytes. This composite gel holds promise for oxygen barrier food packaging and is safe for consumer contact. Further research should focus on optimizing the stability of the oxygen barrier in humid environments and investigate the potential sensitizing effects of biodegradable materials on consumers.
... For example, a shift in the pH level and temperature difference changes the existence of metal nanomaterial in the solution, which also increases the leaching rate [2]. The food conservation mechanism may also have an impact on nanoparticle leaching [75]. Humans might potentially be subjected to nanoparticles through food containers encased with nanomaterials. ...
The current review focuses on the role of bio-composites, natural fibres, and clays in active and intelligent food
packaging. Because of their biodegradability, sustainability, and regenerative nature, these materials present a
potential solution to increasing environmental problems. Natural fibres, clays, and bio-composites considerably
enhance packaging material’s mechanical characteristics, thermal stability, and barrier performance, allowing
for improved food preservation. Natural fibres, such as starch-based, wool-based, silk-based, and protein-based
fibres, actively interact with packed food, improving shelf life and quality. Moreover, their incorporation into
intelligent packaging systems aids in monitoring food safety factors in real-time. Natural clays aid in the
controlled release of active chemicals such as antibacterial agents and antioxidants due to their layered structure
and high absorption capability. The ongoing research in this field hints at the significant potential of these
materials, moving towards a more sustainable and environmentally conscious future for food packaging.
... In the 21st century, along with rapid industrial and technological developments, plastic usage has been increasing significantly owing to its outstanding properties and low prices. [1] However, as they are mainly produced from fossil fuels, greenhouse gases emitted during manufacturing would exacerbate climate change. [2,3] In addition, because of its non-degradable nature (requiring more than 100 years for complete decomposition), [4,5] plastic waste has been a major environmental concern, [6][7][8] causing pollution in the atmosphere, hydrosphere, and pedosphere. ...
Plastic waste is a global issue because it causes overflowing landfills and pollution, leading to environmental concerns. To address this crisis, materials that can be decomposed in the natural environment are introduced to replace conventional plastics. Poly-ε-caprolactone (PCL) is a commonly used plastic that can degrade in natural environments. However, owing to its hydrophobicity, its natural decomposition rate is low. In this study, PCL is modified with maleic anhydride (MA) (PCL-g-MA) to increase hydrophilicity and amorphous region for faster decomposition. To assess the hydrolysis in seawater, lipase hydrolysis is performed to compare the decomposition of PCL-g-MA and PCL. Consequently, in a Pseudomonas lipase-containing PBS solution, it takes 72 and 120 h for complete hydrolyze of PCL-g-MA and PCL, respectively. MA grafted onto PCL increases the amorphous region, where lipase can easily diffuse into PCL-g-MA. Morphological (FESEM and POM images), thermal (TGA and DSC), and structural (FTIR, XRD, and XPS) analyzes support the hydrolysis reaction. The mechanisms proposed in this study confirm that lipase hydrolysis starts in the amorphous regions and then transfers to the crystal regions. This hydrolysis progress is expected to facilitate the creation of eco-friendly low-cost PCL-g-MA composites with high-rate hydrolysis, such as bio-plastics and bio-fibers.
... The internal space present inside the polymer, which is referred to as "free volume", allow the molecular chain mobility. The large amount of open spaces within polymer matrices can act as the extra room for transportation of penetrant molecules across polymeric films and coatings [13]. The addition of nanofillers and additives to packaging coatings and films can significantly improve the overall barrier performance by filling the free volume and thereby reducing porosity and providing a winding pathway for the diffusion of permeants [14]. ...
Nanocellulose has received immense consideration owing to its valuable inherent traits and impressive physicochemical properties such as biocompatibility, thermal stability, non-toxicity, and tunable surface chemistry. These features have inspired researchers to deploy nanocellulose as nanoscale reinforcement materials for bio-based polymers. A simple yet efficient characterization method is often required to gain insights into the effectiveness of various types of nanocellulose. Despite a decade of continuous research and booming growth in scientific publications, nanocellulose research lacks a measuring tool that can characterize its features with acceptable speed and reliability. Implementing reliable characterization techniques is critical to monitor the specifications of nanocellulose alone or in the final product. Many techniques have been developed aiming to measure the nano-reinforcement mechanisms of nanocellulose in polymer composites. This review gives a full account of the scientific underpinnings of techniques that can characterize the shape and arrangement of nanocellulose. This review aims to deliver consolidated details on the properties and characteristics of nanocellulose in biopolymer composite materials to improve various structural, mechanical, barrier and thermal properties. We also present a comprehensive description of the safety features of nanocellulose before and after being loaded within biopolymeric matrices.
Barrier coatings derived from synthetic polymers have been widely used as protective layers in packaging applications. In this work, water dispersions of suberin, a natural polyester of birch bark with inherent hydrophobicity properties, were revealed as a sustainable and green alternative barrier layer in fiber-based packaging. Suberin fractions were isolated from birch outer bark using a lab-scale and pilot-scale alkaline ethanol–water fractionation process, and their properties were analyzed in detail. Thermomechanical dispersing (55–75 °C) was then used to produce stable aqueous dispersions of suberin, which were further used in the coating of paper and paperboard substrates using a pilot-scale coating line. The impact of pH, temperature, addition level of stabilizer, and Ultra Turrax post-treatment on the dispersion stability, particle size, and rheology were assessed. Results showed that the suberin aqueous dispersion exhibited homogeneous particle size distribution in the range of 1–100 μm, and its shear-thinning behavior benefits the pilot-scale coating process. Most importantly, the resulting suberin-coated paperboard sample showed an excellent barrier against water vapor (18 g/m2/day), heptane vapor (below the detection limits), grease resistance (KIT number of 12), and oil penetration (24–168 h). The results indicate that the suberin aqueous dispersion is a promising coating material for fiber-based barrier packaging applications and its barrier performance is comparable to commercial barrier dispersions.
The escalating plastic pollution and potential energy crisis necessitate upcycling plastic waste into high-value-added chemicals and fuels. Combining the hydrogen evolution reaction (HER) with a thermodynamically feasible and sustainable anodizing...
In future, global demand for low-cost-sustainable materials possessing good strength is going to increase tremendously, to replace synthetic plastic materials, thus motivating scientists towards green composites. The PLA has been the most promising sustainable bio composites, due to its inherent antibacterial property, biodegradability, eco-friendliness, and good thermal and mechanical characteristics. However, PLA has certain demerits such as poor water and gas barrier properties, and low glass transition temperature, which restricts its use in food packaging applications. To overcome this, PLA is blended with polysaccharides such as gum and cellulose to enhance the water barrier, thermal, crystallization, degradability, and mechanical properties. Moreover, the addition of these polysaccharides not only reduces the production cost but also helps in manufacturing packaging material with superior quality. Hence this review focuses on various fabrication techniques, degradation of the ternary composite, and its application in the food sector. Moreover, this review discusses the enhanced barrier and mechanical properties of the ternary blend packaging material. Incorporation of gum enhanced flexibility, while the reinforcement of cellulose improved the structural integrity of the ternary composite. The unique properties of this ternary composite make it suitable for extending the shelf life of food packaging, specifically for fruits, vegetables, and fried products. Future studies must be conducted to investigate the optimization of formulations for specific food types, explore scalability for industrial applications, and integrate these composites with emerging technologies (3D/4D printing).
Petroleum-derived packaging materials commonly lack biodegradability, posing significant environmental and health concerns. As a result, there is a growing focus among researchers on developing innovative, biodegradable, and safe food packaging films. In this study, films based on a natural biopolymer gellan gum (GG) reinforced with chitosan nanoparticles (CNPs) were developed using a solvent casting technique. The CNPs, with an average size of 34 nm, were synthesized via ionic gelation using sodium tripolyphosphate (TPP) as a gelating agent. The structure–property relationship of these bionanocomposite films was examined by analyzing their microstructure, thermal behavior, mechanical strength, UV resistance, optical properties, and water barrier characteristics. Compared to pure GG films, the composite films exhibited improved thermal stability, mechanical strength, and barrier properties against water and UV radiation. Increasing the CNPs loading from 0 to 9 wt% resulted in decreased transparency and optical band gaps, from 87.73 to 42.15 and from 5.6048 to 5.3706 eV, respectively. Notably, GG films loaded with 1 wt% CNPs demonstrated the highest tensile strength and thermal stability. Moreover, water absorption, water vapor permeability, and equilibrium moisture content decreased as CNPs loading increased from 0 to 9 wt%. These findings suggest the potential of GG/CNP bionanocomposite films as sustainable packaging materials for the food industry.
The article presents the results of the analysis of the rate of mayonnaise resistance to oxidative poisoning, depending on the combination of polymer films used in doy-pack packaging, and its storage modes. The object of the study was mayonnaise with a mass fraction of fat of 67%. In the course of the studies, packaging with a combination of PET12/PE90 films was used; PET12/PE100; PET12/PE110; PET12/PE120; PET12/PE130; PET12/RE_VBS120; PETp12/PE120; RETFp12/RE_VBS120, including those with a "transparent window". The rate of oxidative poisoning was controlled using the indicator "Peroxide number", the values of which were determined by the standard method for 120 days of storage with a frequency of 15 days. Resistance to oxidative poisoning of mayonnaise was determined in the temperature range from +10 to +15°C; from +15 to +25°С and from +25 to +30°С. The results of the study showed that the resistance of mayonnaise to oxidative poisoning is directly dependent on the thickness of the packaging material - the smaller the thickness of the polyethylene, the higher the peroxide value. The combination of PET12/PE120 films used for packaging mayonnaise is able to ensure compliance with the regulated standards in terms of "Peroxide number" in all three studied temperature ranges with different durations: in the range from +25 to +30°C for 45 days, from +15 up to +25°С - for 60 days, and at a temperature from +10 to +15°С for 90 days. The use of high-barrier materials for packing mayonnaise makes it possible to reduce the intensity of the oxidative poisoning process by a factor of 2 or more and thereby increase its shelf life. The presence of a “transparent window” in the design of the packaging material does not significantly affect the intensity of oxidative processes and the shelf life of mayonnaise.
In recent years, the increase in the generation of agro-food processing waste, coupled with uncontrolled disposal and inefficient recovery methods, has raised concerns among society, industries, and the research community. This issue is compounded by the accumulation of conventional synthetic packaging. Owing to their significant environmental and economic impacts, the development of sustainable, biocompatible, and biodegradable materials has become an urgent target. In this context, research efforts have been directed toward developing new packaging materials based on renewable sources, such as agro-food waste, contributing to the circular economy concept. However, despite significant advances, novel agro-food-waste-based packaging solutions still largely remain at a laboratory scale. This situation highlights the urgent need for further understanding and thorough investigation into how to upscale these products, thereby promoting engagement, investment, and awareness across various fields. This review aims to discuss the current advances in food packaging development using agro-food waste. It covers the main agro-food wastes and by-products currently recovered for sustainable packaging systems through various approaches, such as the extraction of valuable compounds or waste treatments for incorporation into packaging materials, techniques for their valorization, and recent applications of agro-food waste materials in films and coatings. It also addresses the toxicological and safety approaches, challenges, and future perspectives. After an extensive review, we conclude that current research faces challenges in transitioning novel findings to commercial scale, primarily due to safety factors, high production costs, performance deficits, legislative ambiguities, lack of consumer awareness, and inadequate governmental regulations. Consequently, significant investments in research and development appear to be mandatory in the coming years, aiming for optimized, safe, and cost-effective solutions.
The circular economy and sustainable development are critical issues today, given the growing environmental pollution caused by solid waste, especially plastics. Furthermore, plastic waste has raised significant social concerns and alerted plastic product designers. Therefore, developing or redesigning plastic products in the flexible packaging industry is imperative to ensure their recyclability at the end of their life cycle. It is necessary to ensure that the mechanical and barrier properties of the ecological plastic packaging remain intact for specific uses. The current study aims to redesign flexible packaging, focusing on providing the mechanical and barrier properties of the packaging suitable for food industry applications, thus offering a solution through new design proposals that allow the development of sustainable and flexible packaging, emphasizing material reduction and recyclability. This study assessed and compared the mechanical properties of the proposed packaging with those of existing products. The results demonstrated the feasibility of reducing plastic film thickness or eliminating layers in a tri-laminated structure and transitioning to a bi-laminated structure. This adjustment did not compromise the mechanical and barrier properties; the oxygen barrier remained at 35.39 cc/m2*day, and the humidity stood at 0.57 mg/m2*day. This investigation led to a 26.48% reduction in the raw material consumption of laminated coils and 12.68% in Doypack type packaging used in food applications. Consequently, the decreased material usage and adoption of monomaterial structures significantly minimized the environmental impact of plastic waste contamination due to the possibility of mechanically recycling the final product.
Although bioactive compounds (BCs) have many important functions, their applications are greatly limited due to their own defects. The development of nanocarriers (NCs) technology has gradually overcome the defects of BCs. NCs are equally important as BCs to some extent. Self‐assembly (SA) methods to build NCs have many advantages than chemical methods, and SA has significant impact on the structure and function of NCs. However, the relationship among SA mechanism, structure, and function has not been given enough attention. Therefore, from the perspective of bottom‐up building mechanism, the concept of SA‐structure‐function of NCs is emphasized to promote the development of SA‐based NCs. First, the conditions and forces for occurring SA are introduced, and then the SA basis and molecular mechanism of protein, polysaccharide, and lipid are summarized. Then, varieties of the structures formed based on SA are introduced in detail. Finally, facing the defects of BCs and how to be well solved by NCs are also elaborated. This review attempts to describe the great significance of constructing artificial NCs to deliver BCs from the aspects of SA‐structure‐function, so as to promote the development of SA‐based NCs and the wide application of BCs.
Sustainable packaging has been steadily gaining prominence within the food industry, with biobased materials emerging as a promising substitute for conventional petroleum-derived plastics. This review is dedicated to the examination of innovative biobased materials in the context of bread packaging. It aims to furnish a comprehensive survey of recent discoveries, fundamental properties, and potential applications. Commencing with an examination of the challenges posed by various bread types and the imperative of extending shelf life, the review underscores the beneficial role of biopolymers as internal coatings or external layers in preserving product freshness while upholding structural integrity. Furthermore, the introduction of biocomposites, resulting from the amalgamation of biopolymers with active biomolecules, fortifies barrier properties, thus shielding bread from moisture, oxygen, and external influences. The review also addresses the associated challenges and opportunities in utilizing biobased materials for bread packaging, accentuating the ongoing requirement for research and innovation to create advanced materials that ensure product integrity while diminishing the environmental footprint.
The world faces threats that the United Nations has classified into 17 categories with different objectives as solutions for each challenge that are enclosed in the Sustainable Development Goals (SDGs). These actions involved the widespread use of science and technology as pathways to ensure their implementation. In this regard, sustainability science seeks the research community's contribution to addressing sustainable development challenges. Specifically, nanotechnology has been recognized as a key tool to provide disruptive and effective strategies to reach the SDGs. This review proposes the application of bimetallic nanoparticle substances capable of providing possible solutions to achieve target SDG 3: good health and well-being, SDG 6: clean water and sanitation, and SDG 12: responsible consumption and production. Furthermore, the term green nanotechnology is introduced in each section to exemplify how green synthesized bimetallic nanoparticles have been used to resolve each target SDG. This review also outlines the current scenario regarding the utilization of metallic nanomaterials in the market, together with the upscaling challenges and the lack of understanding of the long-term effects and hazards to the environment regarding bimetallic nanoparticles.
Medications have been a part of space travel dating back to the Apollo missions. Currently, medical kits aboard the International Space Station (ISS) contain medications and supplies to treat a variety of possible medical events. As we prepare for more distant exploration missions to Mars and beyond, risk management planning for astronaut healthcare should include the assembly of a medication formulary that is comprehensive enough to prevent or treat anticipated medical events, remains safe and chemically stable, and retains sufficient potency to last for the duration of the mission. Emerging innovation and technologies in pharmaceutical development, delivery, quality maintenance, and validation offer promise for addressing these challenges. The present editorial will summarize the current state of knowledge regarding innovative formulary optimization strategies, pharmaceutical stability assessment techniques, and storage and packaging solutions that could enhance drug safety and efficacy for future exploration spaceflight missions.
Over the last decades, food packaging has advanced significantly, which is crucial in maintaining food safety and minimizing waste. However, most traditional food packaging materials in the market are typically made of inexpensive synthetic plastics with a limited scope of providing physical containment and an effective barrier against moisture and gases. In contrast, sustainable active packaging offers a promising solution to extend the shelf-life of food by effectively decreasing the rate of oxidative deterioration and microbial growth while reducing the environmental impact of petrochemical-derived plastics. As a result, there is a significant interest in developing sustainable and active food packaging materials with a low carbon footprint. Natural resource-derived antioxidant and antimicrobial agents are better alternatives to traditional synthetic agents when combined with any biodegradable polymer as it enhances the sustainability portfolio. This review critically evaluates recent trends in developing natural resource-derived antioxidant and antimicrobial agents for active food packaging applications. Various active biobased antioxidant and antimicrobial agents are critically reviewed and discussed, including their structure, physico-chemical properties, and various attributes in food packaging applications. Finally, this review presents an outlook on the future of sustainable and active food packaging materials and highlights the potential challenges in their development and implementation
A solid skin layer inevitably forms on the foam surface for supercritical carbon dioxide (sc-CO2) foaming technology, leading to deterioration of some inherent properties of polymeric foams. In this work, skinless polyphenylene sulfide (PPS) foam was fabricated with a surface-constrained sc-CO2 foaming method by innovatively constructing aligned epoxy resin/ferromagnetic graphene oxide composites (EP/GO@Fe3O4) as a CO2 barrier layer under a magnetic field. Introduction of GO@Fe3O4 and its ordered alignment led to an obvious decrease in the CO2 permeability coefficient of the barrier layer, a significant increase of the CO2 concentration in the PPS matrix, and a decrease of desorption diffusivity in the depressurization stage, suggesting that the composite layers effectively inhibited the escape of CO2 dissolved in the matrix. Meanwhile, the strong interfacial interaction between the composite layer and the PPS matrix remarkably enhanced the heterogeneous nucleation of cells at the interface, resulting in elimination of the solid skin layer and formation of an obvious cellular structure on the foam surface. Moreover, by the alignment of GO@Fe3O4 in EP, the CO2 permeability coefficient of the barrier layer became much lower, and the cell density on the foam surface further increased with decreasing cell size, which was even higher than that of the cross section of foam, attributed to stronger heterogeneous nucleation at the interface than the homogeneous nucleation in the core region of the sample. As a result, the thermal conductivity of the skinless PPS foam reached as low as 0.0365 W/m·k, decreasing by 49.5% compared with that of regular PPS foam, showing a remarkable improvement in the thermal insulation properties of PPS foam. This work provided a novel and effective method for fabricating skinless PPS foam with enhanced thermal insulation properties.
Bio-based packaging materials reduce the interactions of foods with their environment, which improves their quality, safety, and shelf life. Simple blending and layer-by-layer (LBL) deposition methods are commonly used film preparation methods. However, it is not clear which method has a better preservation effect. In this study, differences in the structures and properties of tyrosinase-crosslinked sodium caseinate (SC)-epigallocatechin gallate (EGCG)-carboxymethyl chitosan (CMC) composite packaging materials (coatings and films) prepared by these two methods were compared. Fruit preservation experiments were carried out by applying blend or LBL coatings to banana or strawberry. The structural properties of films prepared by the blend and LBL methods were analyzed to provide insights into their different performances. The adsorption of the coating solution onto the fruit surfaces, as well as the microstructure and properties of the coatings formed, were the main factors affecting fruit preservation. Strawberry or banana coated by blend coatings exhibited a good appearance after 7 or 14 days. Overall, the water vapor barrier properties of the blend films were better than those of the LBL films. Moreover, the mechanical and EGCG-release properties of the blend films were also good. In summary, the properties of the coatings/films prepared by the blending and LBL methods were compared. This study helps to facilitate the rational design of edible packaging materials for different applications.
Many jurisdictions across the globe consider circular economy as their principal strategy in their climate action plan, which aims to reduce emissions in the short-term and eventually reach to net-zero emissions. The creation of a sustainable and resilient future requires the adoption of clean technologies and resource efficient technology development that underpin a circular economy as opposed to the current linear economy. The food packaging market is saturated with inexpensive, single-use, and petroleum-based polymers. Only a small fraction of such packaging materials are recycled, which leads to spillover in the environment and accumulation in landfills, causing a substantial ecological challenge. Thus, increased environmental concerns in combination with consumer demands for greater quality and longer shelf-life of food products spurs the need for the development of biodegradable, compostable, or recyclable packaging materials. In this space, paper packaging is the front runner. Unfortunately, the replacement of plastic packaging with regular paper designs typically reduces the shelf stability due to its inadequate barrier performance. Hence, surface coating with bio-based polymers is an emerging approach to confer the desired barrier properties to papers. This review aims to provide a critical and comprehensive overview of the most impactful and important advancements in improving the barrier properties of sustainable polymer-coated paper packaging systems. Also, developing active paper packaging materials by incorporating antimicrobial agents in coatings as an attractive option for protecting food from spoilage and extending shelf-life is outlined. Biodegradability aspects, as well as future trends and opportunities of sustainable paper packaging platforms are also emphasized.
Nanocellulose films have been extensively studied for their excellent oxygen barrier properties. However, in the presence of moisture and higher humidity, the oxygen barrier performance decreases rapidly. In this work, natural rubber latex (NRL) was used as a compounding material to improve the hydrophobic properties of 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidized nanocellulose fibers (TOCNF) due to the ability of its naturally occurring phospholipid-protein surface to avoid the interfacial compatibility problems that exist in most hydrophobic polymers when mixed in aqueous solutions. The exposure of the internal hydrophobic isoprene molecular chains of NRL during the drying process allows the composite film to have greatly improved water resistance and excellent water vapor and oxygen barrier properties. The water vapor permeability (WVP) and oxygen permeability (OP) of the films were as low as 6.07×10 − 10 g·mm/m ² ·s·pa and 3.11×10 − 15 cm ³ ·cm/cm ² ·s·Pa, respectively. And the good water resistance of the composite film makes the wet tensile strength of the film up to 15.87 MPa, which reaches 71.69% of the dry tensile strength. In addition, the high ductility of NRL makes the laminate film good toughness, and its elongation at break can reach about three times that of most nanocellulose-based films. Experiments on strawberry preservation with composite films have shown that it can effectively slow down the deterioration of strawberries and extend their shelf life from two days to seven days. This study highlights the exceptional promise of these innovative films for use in food packaging applications.
This work reports the design of a single-layer robust and good barrier sustainable films by using graft polymer compatibilizers. A starch-graft-poly(lactic acid) (St-PLA) copolymer was synthesized and its efficacy as a compatibilizer of thermoplastic starch (TPS)/PLA blends was studied in detail. The St-PLA copolymer is synthesized using a tin(ii) 2-ethylhexanoate initiator, employing ring-opening surface graft polymerization. The microstructure and morphology development of the blends are studied using a polarized optical microscope (POM), scanning electron microscope (SEM), differential scanning calorimetry (DSC), and rheology investigations. Results indicate that the addition of the St-PLA at 2.5 wt% and 5 wt% in the TPS/PLA blend via a melt extrusion process has tremendously improved the compatibility of TPS/PLA blends. Moreover, the PLA crystal spherulite size demonstrates considerable reduction with the addition of the St-PLA compatibilizer despite maintaining similar melt processing parameters. As a result of the improvement in microstructure and morphology changes, the compatibilized blends exhibit outstanding oxygen barrier and thermomechanical properties. Thus, the compatibilization effects provided by St-PLA offer a non-reactive approach to improve the overall morphology and physical properties of the immiscible TPS–PLA blends. Such blend can be used as a single layer flexible packaging material and allows repeated recycling.
This review describes the state-of-the-art of material derived from the forest sector with respect to its potential for use in the packaging industry. Some innovative approaches are highlighted. The aim is to cover recent developments and key challenges for successful introduction of renewable materials in the packaging market. The covered subjects are renewable fibers and bio-based polymers for use in bioplastics or as coatings for paper-based packaging materials. Current market sizes and forecasts are also presented. Competitive mechanical, thermal, and barrier properties along with material availability and ease of processing are identified as fundamental issues for sustainable utilization of renewable materials.
There is a dire need to cut post-harvest food loss to improve global food security, public health, and sustainable natural resource use. Fruits and vegetables constitute one of the most perishable food items and typically require cold storage systems, adequate packaging, and efficient transport and road systems to reduce their loss. This research showed that by stabilizing cornstarch and beeswax emulsion with cellulose nanocrystals, a sustainable and edible coating that substantially reduces the spoilage of fruits and other produce could be obtained. Native and aliphatic succinic anhydride-modified CNCs were employed as Pickering emulsifiers. The effect of emulsion stabilizers concentrations on the enhancement of physical properties, reduction of water vapor loss, and oxygen permeability was investigated, and 2 wt.% modified CNC was selected as the optimal Pickering emulsion stabilizer. Fresh bananas, strawberries, and fresh-cut apples that were dip-coated with the formulated edible coating displayed magnificent color and freshness preservation by reducing oxygen activities and preventing moisture losses. Overall, the studied emulsion is edible and inexpensive, making it an exciting material that can be used to combat fresh produce waste caused by oxidative and enzymatic over-ripening.
The health and environmental concerns of the usage of non-biodegradable plastics have driven efforts to explore replacing them with renewable polymers. Although starch is a vital renewable polymer, poor water resistivity and thermo-mechanical properties have limited its applications. Recently, starch/synthetic biodegradable polymer blends have captured greater attention to replace inert plastic materials; the question of ‘immiscibility’ arises during the blend preparation due to the mixing of hydrophilic starch with hydrophobic polymers. The immiscibility issue between starch and synthetic polymers impacts the water absorption, thermo-mechanical properties, and chemical stability demanded by various engineering applications. Numerous studies have been carried out to eliminate the immiscibility issues of the different components in the polymer blends while enhancing the thermo-mechanical properties. Incorporating compatibilizers into the blend mixtures has significantly reduced the particle sizes of the dispersed phase while improving the interfacial adhesion between the starch and synthetic biodegradable polymer, leading to fine and homogeneous structures. Thus, Significant improvements in thermo-mechanical and barrier properties and water resistance can be observed in the compatibilized blends. This review provides an extensive discussion on the compatibilization processes of starch and petroleum-based polymer blends.
Fresh fruits and vegetables are perishable commodities requiring technologies to extend their postharvest shelf life. Edible coatings have been used as a strategy to preserve fresh fruits and vegetables in addition to cold storage and/or controlled atmosphere. In recent years, nanotechnology has emerged as a new strategy for improving coating properties. Coatings based on plant-source nanoemulsions in general have a better water barrier, and better mechanical, optical, and microstructural properties in comparison with coatings based on conventional emulsions. When antimicrobial and antioxidant compounds are incorporated into the coatings, nanocoatings enable the gradual and controlled release of those compounds over the food storage period better than conventional emulsions, hence increasing their bioactivity, extending shelf life, and improving nutritional produce quality. The main goal of this review is to update the available information on the use of nanoemulsions as coatings for preserving fresh fruits and vegetables, pointing to a prospective view and future applications.
Among commercial biodegradable polyesters, poly(glycolic acid) (PGA) has been rarely investigated for packaging applications, despite its unique advantages such as 100% compostability, high degree of crystallinity, high thermal stability and high gas barrier properties. The application of PGA has been limited by its mechanical brittleness, moisture sensitivity, and high melting temperature (~240°C), restricting its processing and applications for film packaging. In this study, PGA was modified by blending with poly (butylene adipate‐co‐terephthalate) (PBAT) via melt‐extrusion. A commercial terpolymer of ethylene, acrylic ester and glycidyl methacrylate (EMA‐GMA) was selected for compatibilization. The phase morphology, rheology, thermal, mechanical and gas barrier properties of the blends were investigated. With addition of 20 wt. % EMA‐GMA, the elongation of PGA/PBAT (50/50 wt. %) blends was improved from 10.7% to 145%, the oxygen permeability was reduced from 125 to 103 (cm³ mm)/(m² 24 h atm), and the water vapor barrier performance was improved by ~47%. The enhancement in ductility, oxygen and water vapor barrier properties of the flexible blends were ascribed to the interfacial bonding between PBAT and PGA enabled by EMA‐GMA. The compatibilized PGA/PBAT blends with high thermal stability up to 300°C are preferable for high temperature or hot food packaging.
The recent surge in environmental awareness and consumer demand for stable, healthy, and safe foods has led the packaging and food sectors to focus on developing edible packaging materials to reduce waste. Edible films and coatings as a modern sustainable packaging solution offer significant potential to serve as a functional barrier between the food and environment ensuring food safety and quality. Whey protein is one of the most promising edible biopolymers in the food packaging industry that has recently gained much attention for its abundant nature, safety, and biodegradability and as an ecofriendly alternative of synthetic polymers. Whey protein isolate and whey protein concentrate are the two major forms of whey protein involved in the formation of edible films and coatings. An edible whey film is a dry, highly interacting polymer network with a three-dimensional gel-type structure. Films/coatings made from whey proteins are colorless, odorless, flexible, and transparent with outstanding mechanical and barrier properties compared with polysaccharide and other-protein polymers. They have high water vapor permeability, low tensile strength, and excellent oxygen permeability compared with other protein films. Whey protein-based films/coatings have been successfully demonstrated in certain foods as vehicles of active ingredients (antimicrobials, antioxidants, probiotics, etc.), without considerably altering the desired properties of packaging films that adds value for subsequent industrial applications. This review provides an overview of the recent advances on the formation and processing technologies of whey protein-based edible films/coatings, the incorporation of additives/active ingredients for improvement, their technological properties, and potential applications in food packaging.
Nowadays the issues related to the end of life of traditional plastics are very urgent due to the important pollution problems that plastics have caused. Biodegradable plastics can help to try to mitigate these problems, but even bioplastics need much attention to carefully evaluate the different options for plastic waste disposal. In this Minireview, three different end‐of‐life scenarios (composting, recycling, and upcycling) were evaluated in terms of literature review. As a result, the ability of bioplastics to be biodegraded by composting has been related to physical variables and materials characteristics. Hence, it is possible to deduce that the process is mature enough to be a good way to minimize bioplastic waste and valorize it for the production of a fertilizer. Recycling and upcycling options, which could open up many interesting new scenarios for the production of high‐value materials, are less studied. Research in this area can be strongly encouraged.
Here we introduce a new method aiming the immobilization of bioactive principles onto polymeric substrates, combining a surface activation and emulsion entrapment approach. Natural products with antimicrobial/antioxidant properties (essential oil from Syzygium aromaticum—clove and vegetal oil from Argania spinosa L—argan) were stabilized in emulsions with chitosan, a natural biodegradable polymer that has antimicrobial activity. The emulsions were laid on poly(lactic acid) (PLA), a synthetic biodegradable plastic from renewable resources, which was previously activated by plasma treatment. Bioactive materials were obtained, with low permeability for oxygen, high radical scavenging activity and strong inhibition of growth for Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli bacteria. Clove oil was better dispersed in a more stable emulsion (no separation after six months) compared with argan oil. This leads to a compact and finely structured coating, with better overall properties. While both clove and argan oils are highly hydrophobic, the coatings showed increased hydrophilicity, especially for argan, due to preferential interactions with different functional groups in chitosan. The PLA films coated with oil-loaded chitosan showed promising results in retarding the food spoilage of meat, and especially cheese. Argan, and in particular, clove oil offered good UV protection, suitable for sterilization purposes. Therefore, using the emulsion stabilization of bioactive principles and immobilization onto plasma activated polymeric surfaces we obtained a bioactive material that combines the physical properties and the biodegradability of PLA with the antibacterial activity of chitosan and the antioxidant function of vegetal oils. This prevents microbial growth and food oxidation and could open new perspectives in the field of food packaging materials.
To improve the mechanical properties of zein films, glycerol (GLY) and glutaraldehyde (GDA) were, respectively, selected as plasticizer and cross-linking agent to fabricate modified zein films by casting method. It was generally believed that the tensile strength (TS) of the modified film was improved with more GDA content. However, there was an interesting phenomenon that above 1 wt% GDA would reduce the TS value. Optimum films were obtained by using 25 wt% GLY and 1 wt% GDA, given dry state properties of tensile strength (TS), elongation at break (EAB %), oxygen transmission rate as 15.22 MPa, 4.25%, 15.5061 cm³/(m²·24 h·0.1 MPa). Circular dichroism (CD) spectroscopy and rheological properties of the film-forming solutions were evaluated. The films were further characterized through using Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), oxygen-permeability coefficient (OTR), transmittance (T%) and water contact angle (CA). The cross-linking mechanism of zein films was demonstrated that GLY was effective to fully “lubricate” between the zein molecular chains, GDA was beneficial to obtain the network structure through intra- and intermolecular cross-linking reactions of zein protein. Improving the understanding of this cross-linking mechanism can be useful to develop an environment-friendly, biodegradable polymer which has a strong potential in the packaging industrial applications.
Over recent years, keratin has gained great popularity due to its exceptional biocompatible and biodegradable nature. It has shown promising results in various industries like poultry, textile, agriculture, cosmetics, and pharmaceutical. Keratin is a multipurpose biopolymer that has been used in the production of fibrous composites, and with necessary modifications, it can be developed into gels, films, nanoparticles, and microparticles. Its stability against enzymatic degradation and unique biocompatibility has found their way into biomedical applications and regenerative medicine. This review discusses the structure of keratin, its classification and its properties. It also covers various methods by which keratin is extracted like chemical hydrolysis, enzymatic and microbial treatment, dissolution in ionic liquids, microwave irradiation, steam explosion technique, and thermal hydrolysis or superheated process. Special emphasis is placed on its utilisation in the form of hydrogels, films, fibres, sponges, and scaffolds in various biotechnological and industrial sectors. The present review can be noteworthy for the researchers working on natural protein and related usage.
The consumption of minimally processed fresh vegetables has increased by the consumer’s demand of natural products without synthetic preservatives and colorants. These new consumption behaviors have prompted research on the combination of emulsion techniques and coatings that have traditionally been used by the food industries. This combination brings great potential for improving the quality of fresh-cut fruits and vegetables by allowing the incorporation of natural and multifunctional additives directly into food formulations. These antioxidant, antibacterial, and/or antifungal additives are usually encapsulated at the nano- or micro-scale for their stabilization and protection to make them available by food through the coating. These nano- or micro-emulsions are responsible for the release of the active agents to bring them into direct contact with food to protect it from possible organoleptic degradation. Keeping in mind the widespread applications of micro and nanoemulsions for preserving the quality and safety of fresh vegetables, this review reports the latest works based on emulsion techniques and polysaccharide-based coatings as carriers of active compounds. The technical challenges of micro and nanoemulsion techniques, the potential benefits and drawbacks of their use, the development of polysaccharide-based coatings with natural active additives are considered, since these systems can be used as alternatives to conventional coatings in food formulations.
A high-barrier, strong, and antibacterial paper was fabricated by coating the acetylated cellulose solution with different contents of cinnamaldehyde (CIN) on Kraft paper. The antibacterial, antioxidant, mechanical, and barrier properties of coated paper were investigated. When the amount of CIN added in coating reached 6% v/v, the coated paper exhibited excellent antioxidant activity and antibacterial activity against Escherichia coli and Staphylococcus aureus. Notably, the dry and wet tensile strength of paper after coating was increased by 26.4 and 10.6 MPa, respectively. Furthermore, the coated papers' barrier properties against oil, water, water vapor, and oxygen were dramatically improved, especially for the water barrier rate up to 96.4%. Our coated papers with over 6% v/v CIN could extend beef's shelf-life for at least 4 days, which exhibited a promising prospect in eco-friendly antibacterial packaging.
Graphical abstract
Cellulose-based film material, due to its remarkable physicochemical properties, environmentally friend and low cost, has been widely applied in many high-end areas. However, the lack of functional properties (e.g., flame resistance) expect poor mechanical performance severely hinders their further applications. Herein, bamboo-based phosphorylated cellulose nanofibrils (B-PCNFs) were prepared through a simple two-step method composed of phosphorylation and mechanical grinding process. The resultant film prepared via solvent casting process shows an excellent mechanical strength of 115.9 MPa, remarkable elongation at break of 53.1%, high Young's modulus of 2.5 GPa and impressive work of fracture up to 41.8 MJ m⁻³, respectively, which should be contributed to formation of the dense and homogeneous polymer networks reinforced by enhanced multiple interactions. When burned against the flame of alcohol lamp (700–800 °C), BHL-PCNF film also delivers appealing structural stability even over 25s, demonstrating a prominent flame resistance. Meanwhile, compared to original one, the peak heat release rate (PHRR) and total heat released (THR) of BHL-PCNF film produce dramatical reduction, i.e., 87.3% and 86.6% for PHRR and THR, respectively. Based on the evolution of morphological and chemical structure, the highly improved flame resistance is strongly contributed to the synergy of phosphorus containing group and lignin, resulting in a protective layer composed of PxOy compound and carbon layer. The proposed mechanism for the enhanced flame retardant property is also declared and clarified. Thereby, this cellulose-based film that integrates outstanding mechanical performance and excellent intrinsically flame resistance holds promising potential candidate in practical applications, such as flame-retardant packaging materials.
Carbon-based nanomaterials (CBN) are currently used in many biomedical applications. The research includes optimization of single grain size and conglomerates of pure detonated nanodiamond (DND), modified nanodiamond particles and graphene oxide (GO) in order to compare their bactericidal activity against food pathogens. Measurement of grain size and zeta potential was performed using the Dynamic Light Scattering (DLS) method. Surface morphology was evaluated using a Scanning Electron Microscope (SEM) and confocal microscope. X-ray diffraction (XRD) was performed in order to confirm the crystallographic structure of detonation nanodiamond particles. Bacteriostatic tests were performed by evaluating the inhibition zone of pathogens in the presence of carbon based nanomaterials. Raman spectroscopy showed differences between the content of the diamond and graphite phases in diamond nanoparticles. Fluorescence microscopy and adenosine-5′-triphosphate (ATP) determination methods were used to assess the bactericidal of bioactive polymers obtained by modification of food wrapping film using various carbon-based nanomaterials. The results indicate differences in the sizes of individual grains and conglomerates of carbon nanomaterials within the same carbon allotropes depending on surface modification. The bactericidal properties depend on the allotropic form of carbon and the type of surface modification. Depending on the grain size of carbon-based materials, surface modification, the content of the diamond and graphite phases, surface of carbon-based nanomaterials film formation shows more or less intense bactericidal properties and differentiated adhesion of bacterial biofilms to food films modified with carbon nanostructures.
Reported herein is an economical, plastic‐ and fluorine‐free coating approach for oil and water repellent paper substrates using blends of poly(vinyl alcohol) and chitosan‐graft‐polydimethylsiloxane copolymer. The obtained coated paper showed good water‐resistance, as evidenced by its low Cobb60 values of ~20 ± 2.1 g/m² and high water contact angles of 119 ± 6.3 °. The kit rating of the coated paper was 7.6/12, indicating decent grease‐resistant properties as compared to the kit value of 0/12 for the uncoated paper. The coated paper is also repulpable as demonstrated by the complete washing off the coating from the coated paper. Giving the cost‐effective nature of the coating materials and good water and oil‐resistant properties of the coated paper, the approach developed here is commercially viable, and will offer a multitude of environmental benefits such as the elimination of microplastic‐ and PFAS problems associated with existing paper coatings.
The emergence of many new food products on the market with need of consumers to constantly monitor their quality until consuming, in addition to the necessity for reducing food corruption during preservation time, have led to the development of some modern packaging technologies such as intelligent packaging (IP) and active packaging (AP). The benefits of IP are detecting defects, quality monitoring and tracking the packaged food products to control the storage conditions from the production stage to the consumption stage by using various sensors and indicators such as time-temperature indicators (TTIs), gas indicators, humidity sensors, optical, calorimetric and electrochemical biosensors. While, AP helps to increase the shelf-life of products by using absorbing and diffusion systems for various materials like carbon dioxide, oxygen, and ethanol. However, there are some important issues over these emerging technologies including cost, marketability, consumer acceptance, safety and organoleptic quality of the food and emphatically environmental safety concerns. Therefore, future researches should be conducted to solve these problems and to prompt applications of IP and AP in the food industry. This paper reviews the latest innovations in these advanced packaging technologies and their applications in food industry. The IP systems namely indicators, barcoding techniques, radio frequency identification systems, sensors and biosensor are reviewed and then the latest innovations in AP methods including scavengers, diffusion systems and antimicrobial packaging are reviewed in detail.
In the packaging industry, the barrier property of packaging materials is of paramount importance. The enhancement of barrier properties of materials can be achieved by adding impermeable nanoparticles into thin polymeric films, known as mixed-matrix membranes (MMMs). Three-dimensional numerical simulations were performed to study the barrier property of these MMMs and to estimate the effective membrane gas permeability. Results show that horizontally-aligned thin cuboid nanoparticles offer far superior barrier properties than spherical nanoparticles for an identical solid volume fraction. Maxwell’s model predicts very well the relative permeability of spherical and cubic nanoparticles over a wide range of the solid volume fraction. However, Maxwell’s model shows an increasingly poor prediction of the relative permeability of MMM as the aspect ratio of cuboid nanoparticles tends to zero or infinity. An artificial neural network (ANN) model was developed successfully to predict the relative permeability of MMMs as a function of the relative thickness and the relative projected area of the embedded nanoparticles. However, since an ANN model does not provide an explicit form of the relation of the relative permeability with the physical characteristics of the MMM, a new model based on multivariable regression analysis is introduced to represent the relative permeability in a MMM with impermeable cuboid nanoparticles. The new model possesses a simple explicit form and can predict, very well, the relative permeability over an extensive range of the solid volume fraction and aspect ratio, compared with many existing models.
The accumulation of synthetic plastics used in packaging applications in landfills and the environment is a serious problem. This challenge is driving research efforts to develop biodegradable, compostable, or recyclable barrier materials derived from renewable sources. Cellulose, chitin/chitosan, and their combinations are versatile biobased packaging materials because of their diverse biological properties (biocompatibility, biodegradability, antimicrobial properties, antioxidant activity, non-toxicity, and less immunogenic compared to protein), superior physical properties (high surface area, good barrier properties, and mechanical properties), and they can be assembled into different forms and shapes (powders, fibers, films, beads, sponges, gels, and solutions). They can be either assembled into packaging films or used as fillers to improve the properties of other biobased polymers. Methods such as preparation of composites, multilayer coating, and alignment control are used to further improve their barrier, mechanical properties, and ameliorate their moisture sensitivity. With the growing application of cellulose and chitin-based packaging materials, their biodegradability and recyclability are also discussed in this review paper. The future trends of these biobased materials in packaging applications and the possibility of gradually replacing petroleum-based plastics are analyzed in the “Conclusions” section.
To address the increasing accumulation of water bottle waste and lack of effective recycling processes, water bottle waste was upcycled into a high value activated carbon product. This growing waste feedstock has proved to be a promising precursor for activated carbon, but it has not been investigated for use in the treatment of dye-contaminated effluent which is a very high-volume source of waste from textile industries. In this work, the production of activated carbon from water bottle waste by chemical activation using KOH was optimized and validated for the application as an adsorbent of textile dyes. The activation conditions of 800 °C for 1 h proved to be most optimal based on conversion efficiency, surface area, surface charge, and yield measurement. It was found that the product’s negative zeta potential (−40 mV) and high surface area (1124 m²/g), provided excellent adsorption capacity for the cationic methylene blue dye (335 mg/g). The adsorption of this representative dye was studied in detail and compared with cationic brilliant green dye and a mixture containing anionic methyl orange dye. Although the adsorption was found to depend on dye charge characteristics, there is potential for adsorption enhancement through pH adjustments. Additionally, the AC demonstrated the ability to treat mixed dye wastes containing anionic dyes despite its selective adsorption towards cationic dyes of over twice the amount. Overall, the product showed potential to be extended to a variety of textile dyes to provide excellent value for the textile industry while also helping to divert a significant amount of waste from landfills.
Various biomass components have attracted interest for their applications in biofuels, biochemicals, and sustainable materials. In biomass valorization, the development of green processes that provide high yield and purity of components at low cost is highly desired. In lignocellulosic biomasses, valuable components include cellulose, hemicellulose, lignin, tannins, etc. Other biomasses contain various desirable components, such as pectins, lipids, sugar, etc. Extrusion is considered a promising green process for effectively deconstructing biomasses into their components due to its high shear, continuous, and flexible operations. The process may also involve in situ reactions, known as reactive extrusion. Reactive extrusion is advantageous due to the effective combination of physical and chemical deconstruction phenomena. Its superior shear capabilities also allow for higher solid processing, reducing chemical use and its related costs. Through review of existing literature, the reactive extrusion process has been improved through the adjustment of various processing parameters and the application of other treatment methods. Newer research areas in biomass reactive extrusion processing specifically focus on the application of green solvents. However, challenges still exist regarding the industrial application of reactive extrusion due to a lack of energy and cost analysis. This review critically reviewed the use of reactive extrusion to deconstruct biomass and recover its components. The treatment of lignocellulosic biomass and the subsequent valorization of cellulose and lignin was emphasized.
Sustainable and biodegradable packaging materials are appealing alternatives to the petrochemical-derived and non-biodegradable plastics that currently dominate the market. However, their inferior barrier properties and high cost inhibit their widespread applications. In this work, pristine and esterified lignin were investigated as a functional filler of poly (butylene adipate-co-terephthalate) (PBAT) based bioplastic paper coating formulations. For this, the pristine and esterified lignin (10–50 wt%) were separately dispersed in a solvent and incorporated in PBAT solutions and applied on paper substrates. The effects of varying concentrations of pristine and esterified lignin on the rheology, mechanical, morphology, and barrier properties of the coated paper substrate were investigated. Comprehensive characterization of esterified lignin/PBAT coatings exhibited enhanced dispersion of the lignin fraction in the PBAT, resulting in excellent wet tensile properties and enhanced water, oil, and oxygen barrier performance. Overall, the studied coating formulations have appealing properties for food contact materials, such as paper wraps and paperboard applications, as a sustainable and eco-friendly alternative to the incumbent coating materials, such as petroleum sourced waxes and polyolefin-based coatings.
Canola protein derived from the canola industry byproduct is a potent biopolymer source to develop sustainable food packaging materials, but it has limitations due to its poor mechanical and barrier properties. Nanomaterials such as nanocrystalline cellulose (NCC) have shown promising potential in improving material properties. The current study aimed to enhance the functionality of canola protein-based films using TEMPO ((2,2,6,6-Tetramethylpiperidin-1-yl)oxyl) modified nanocrystalline cellulose (TM-NCC). TEMPO modification was performed using TEMPO/NaClO/NaBr based oxidation. Modified and unmodified nanocrystalline cellulose (U-NCC) were used at different weight ratios to prepare the films. TEMPO-mediated oxidation converted 19.61 ± 3.53 % of primary –OH groups into –COOH groups. The addition of U-NCC and TM-NCC significantly increased the tensile strength reporting the highest value of 8.36 ± 0.85 MPa for 5% TM-NCC, which was only 3.43 ± 0.66 MPa for control films. Interestingly, both U-NCC and TM-NCC enhanced the films' water barrier and thermal properties compared to control.
There is an increasing interest in utilizing more sustainable and inherently biodegradable materials alternatives ideally derived from renewable resources for modern material applications, especially in the area of packaging materials. This work employed the polysaccharide alpha-1,3-glucan derived from an enzymatic polymerization process as a functional additive for natural rubber (NR) latex-based coating films. Coating formulations containing NR and 9–50 wt% alpha-1,3 glucan were prepared and then applied to paper substrates at different thicknesses. The effect of coating formulations on the barrier properties (e.g., oxygen, oil, water vapor barrier), the viscosity, and dry and wet tensile properties were investigated. The NR/glucan coatings exhibited outstanding tensile properties and balanced oxygen and oil barrier performance. However, higher glucan loading could be detrimental to moisture barrier. Overall, this study indicated that the NR/glucan coating films are comparable in performance to commercial coating formulations while providing a renewable, potential to be recycled with paper, and biodegradable alternative.
Lignin being the second most abundant natural biopolymer after cellulose constitutes between 18 wt% and 35 wt % of wood. Due to its abundance, sustainability, renewability, and the ability to undergo numerous modifications through chemical reactions, there is a significant interest in lignin valorization for material applications. How-ever, its hydrophilicity, lack of melt processability, and poor dispersibility have hindered its wide scale appli-cation. Structural modifications have been reported to counter its detrimental properties effectively. Thus, in the present work, a novel silylation reaction was employed to successfully modify kraft lignin and enhance its hy-drophobicity. The modification was verified by using nuclear magnetic resonance and infrared spectroscopies. The change in the wettability and dispersibility in various solvent systems indicated the increase in hydropho-bicity due to the modifications. This enabled it to better disperse in natural rubber composites. Lignin being the hard moiety imparted mechanical strength, while, NR being the soft moiety, provided it with elastomeric characteristics in the composites. The incorporation of 5 wt% modified lignin in the hydrophobic NR matrix led to a 44.4% increase in the tensile strength. With higher loadings of filler in composites, an increase in elastic moduli and intensity of Payne effect were recorded. The hypothesized dispersibility improvement of the modified lignin in NR compared to its unmodified counterparts was also evident from the morphological analysis.
This research was conducted to assess the structure, mechanical, barrier and optical properties of three edible composite films based on chitosan nanoparticles. Films containing cinnamon-perilla essential oil (C-PEO) Pickering nanoemulsion had denser structure and better mechanical properties. In addition, films with anthocyanidins exhibited enhanced antioxidant activity. The results showed that both Pickering nanoemulsion and anthocyanidins could improve some properties of edible composite film based on chitosan nanoparticles. Finally, preservation experiments were carried out. Analysis of storage quality indices (sensory evaluation, microbiological analyses, pH, total volatile basic nitrogen, thiobarbituric acid values, color and texture) revealed the shelf life of fillets wrapped in three kinds of composite film was extended to 6–8 days. The preservation effect of plant essential oil compound anthocyanidin edible film for fillet was the best and anthocyanidins compound chitosan nanoparticles edible film was the best in appearance of protection.
Biodegradable active packaging was produced by compounding nisin (3, 6 and 9%) and nisin-ethylenediaminetetraacetic acid (EDTA) (3 and 6%) mixtures with poly(butylene adipate terephthalate) and thermoplastic starch blends (PBAT/TPS) by blown-film extrusion. Nisin and EDTA interacted with polymers, involving CO stretching of ester bonds and increased compatibility. This plasticized the films and modified the crystallinity, surface roughness and thermal relaxation behavior. Barrier properties were improved due to modified hydrophilic-hydrophobic properties, compact structures and crystallites that restricted vapor and oxygen permeation. PBAT/TPS films containing EDTA and nisin effectively inhibited lipid degradation in pork tissues corresponding with stabilizing the CO ester bond of triacylglycerol. Microbial growth was also inhibited, particularly in EDTA-containing films up to 1.4 log. Inactivation of microorganisms stabilized redness and delayed meat discoloration, preserving the quality of packaged pork. Interaction between nisin, EDTA and polymers modified the morphology and film properties and functionalized biodegradable food packaging to inactivate microorganisms.
Polybutylene adipate-co-terephthalate (PBAT) is one of the most attractive biodegradable polymers that is touted to replace single-use plastics. In this research, hemp powder (HP), a byproduct of bast hemp fiber production process was investigated as a functional additive of PBAT resins to produce biocomposites. An industrially relevant, continuous, and scaleable extrusion process was employed to effectively disperse the HP in the PBAT. Maleic anhydride grafted PBAT (mPBAT) was produced through a peroxide-initiated reactive extrusion process and used as a functional additive of the PBAT-HP biocomposites. The effect of HP compositions (10-40 wt.%) on the structure, processing, and thermo-mechanical properties of the biocomposites was investigated and reported. The mPBAT improved the interfacial interaction between the HP and PBAT that resulted in a homogeneous dispersion of the hemp particles in the PBAT matrix and a substantial increase in the tensile strength (209%), toughness (∼300%), impact resistance (∼90%), and other properties. Furthermore, the heat deflection temperature of biocomposites with 40% HP was found to be ∼60°C higher than the pristine PBAT. Overall, the biocomposites displayed appealing material properties making it attractive for a range of single-use consumer goods, such as fast-food utensils, cosmetic containers, and food containers.
Different equilibrium modified atmosphere packaging systems (EMAP) were evaluated for cape gooseberry fruits, including a moisture adsorber. Three packages were used: cellulose trays with a cellulose film, polylactic acid (PLA) trays and film, and polyethylene terephthalate trays (PET) with a film of polypropylene (PP). The packages’ configuration, perforations, and amount of moisture adsorber were predefined by modeling the gas transfer in the packaging system. The packaged fruits were stored at 6 °C and 75% RH for 6 weeks. The fruits in the PLA trays without sachets had the maximum shelf life of 42 days, while the fruits in celulose with sachets had a shelf life of 40 days compared to 35 days with the PET/PP trays and 21 days of the control fruits. With similar equilibrium gas levels between the EMAP packages, the higher permeability to water vapor of PLA prevented the formation of condensation with lower dehydration compared to the celulose packages with sachets.
Developing renewable resource-based plastics with complete biodegradability and a minimal carbon footprint can open new opportunities to effectively manage the end-of-life plastics waste and achieve a low carbon society. Polyhydroxyalkanoates (PHAs) are biobased and biodegradable thermoplastic polyesters that accumulate in microorganisms (e.g., bacterial, microalgal, and fungal species) as insoluble and inert intracellular inclusion. The PHAs recovery from microorganisms, which typically involves cell lysis, extraction, and purification, provides high molecular weight and purified polyesters that can be compounded and processed using conventional plastics converting equipment. The physio-chemical, thermal, and mechanical properties of the PHAs are comparable to traditional synthetic polymers such as polypropylene and polyethylene. As a result, it has attracted substantial applications interest in packaging, personal care, coatings, agricultural and biomedical uses. However, PHAs have certain performance limitations (e.g. slow crystallization), and substantially more expensive than many other polymers. As such, more research and development is required to enable them for extensive use. This review provides a critical review of the recent progress achieved in PHAs production using different microorganisms, downstream processing, material properties, processing avenues, recycling, aerobic and anaerobic biodegradation, and applications.
Effects on the physical properties of a chitosan (C) based emulsion by incorporating beeswax (BW) and basil essential oil (BEO) were investigated in this study. In addition, the structural and antibacterial properties of coatings produced from these emulsions and their egg preservation abilities were studied. Dynamic light scattering experiments demonstrated that addition of 0.5% or 1% BEO decreased the droplet size of the emulsion and improved the stability of the coating. It was also observed that the coating surface produced by this emulsion was smoother using scanning electron microscopy. The FT-IR spectroscopy suggested that there was electrostatic interaction between BW and C and the interaction between BEO and both BW and C might be non-covalent. The addition of BW and BEO decreased the water vapor permeability and increased the contact angle of the C-BW-BEO composite coating. In summary, there was good compatibility between the various components of the C-BW-BEO coating emulsion. The addition of BW and 0.5% or 1% BEO enhanced the stability and water-blocking properties of the coating. Additionally, the composite coating showed antibacterial effects against the main bacteria on the eggshell surface and extended the shelf life of eggs.
Ending the fossil fuel era towards a sustainable future will require high-performing renewable materials with a low environmental impact. Carbon black, produced by partial combustion or thermal decomposition of petroleum hydrocarbons, is by far the most dominant filler of rubber composites, followed by mineral fillers (silica, talc, clay, calcium carbonate, etc.). However, the manufacture of carbon black has a considerable carbon footprint. On the other hand, the mineral fillers do not also come without a challenge including poor compatibility with rubber matrices and high density. Consequently, the need for sustainable and green fillers with low or even zero carbon footprint has dramatically increased. In recent years, plant derived green materials such as cellulose nanocrystals, natural fibers, lignin, biochar, polysaccharides, etc. are extensively investigated as a substitute or complementary fillers of rubbers. In this work, we reviewed the recent developments in the innovation and utilization of sustainable biofillers for rubber composite applications, emphasizing the effect of the filler on the structure-processing-property relationship in rubber composites. A wide range of biofillers with an array of structure, morphology, and physico-chemical properties and their various attributes in different rubbers are intensively reviewed and discussed. Effective fabrication strategies and surface modifications platforms on the different biofillers to develop a high-performance sustainable rubber biocomposites were critically reviewed. Finally, future perspectives for biofillers in rubber composite applications and challenges are discussed.
Poly(propylene carbonate) (PPC)/poly(butylene succinate‐co‐butylene adipate) (PBSA) blends are prepared via melt mixing using a twin‐screw extruder. A one‐step method based on the reaction compatibilization mechanism is used to prepare PPC/PBSA/AX8900(ethylene‐methyl acrylate‐glycidyl methacrylate random terpolymer) blends. The films of blends are prepared by an extrusion blown film machine. Fourier transform infrared spectroscopy results show that there is a strong hydrogen bonding between PPC and PBSA. The epoxy group of AX8900 can react with molecular chains of PPC and PBSA. It is shown from the rheological behavior that AX8900 can extend the molecular chains and increase the compatibility of PPC and PBSA. The films of PPC/PBSA blends exhibit more orientation structure than pure PPC film. The tensile strength of machine direction and transverse direction for 70PPC/30PBSA/1AX8900 film is higher than that for pure PPC film. The PPC/PBSA/AX8900 films have similar excellent barrier properties, compared with PPC film. The modified Maxwell theoretical model is used to predict and analyze changes in film barrier properties. Poly(propylene carbonate) (PPC)/poly(butylene succinate‐co‐butylene adipate) (PBSA)/AX8900(ethylene‐methyl acrylate‐glycidyl methacrylate random terpolymer) blends and their films are prepared by melt mixing and extrusion blown film. The addition of PBSA and AX8900 can greatly improve the mechanical and thermal properties of PPC. The films with excellent mechanical and barrier properties have good application potential in the packaging field.
The utilization of lipids is presently in the spotlight of food industry as they are one of novel renewable and sustainable raw materials. Lipids derived materials are considered as a promising alternate to petro-based polymers as they are sustainable, biorenewable, biodegradable, and environmentally benign. These unique attributes draw the attention of scientific community for the use of lipids in food packaging applications with a potential to compete with fossil fuel derived polymers. This paper reviews recent advances in the use of lipids and their effect on the barrier, antimicrobial, antioxidant, and mechanical properties of films, coating and nanocomposites for food packaging applications. Modification of lipids and its chemical interactions with other biopolymers during processing for the synthesis of different materials are also discussed. Global patents and research trend in use of lipids for the preparation of biocomposites are also described. The role of lipids in the circular economy is highlighted and life cycle assessment of lipids derived products is outlined with examples. The review is concluded with synoptic view of existing and forthcoming potential use of lipids in various food packaging applications.
The merits of temporary carbon storage are often debated for bio-based and biodegradable plastics. We employed life cycle assessment (LCA) to assess environmental performance of polyhydroxyalkanoate (PHA)-based plastics, considering multiple climate tipping as a new life cycle impact category. It accounts for the contribution of GHG emissions to trigger climate tipping points in the Earth system, considering in total 13 tipping elements that could pass a tipping point with increasing warming. The PHA was either laminated with poly(lactic acid), or metallized with aluminum or aluminum oxides to lower permeability of the resulting plastics toward oxygen, water vapor and aromas. The assessments were made accounting for potential differences in kinetics of evolution of greenhouse gases (CO2, CH4) from bioplastic degradation in the end-of-life. Results show that: (1) PHA films with high biodegradability perform best in relation to the climate tipping, but are not necessarily the best in relation to radiative forcing increase or global temperature change; (2) sugar beet molasses used as feedstock is an environmental hot spot, contributing significantly to a wide range of environmental problems; (3) increasing PHA production scale from pilot to full commercial scale increases environmental impacts, mainly due to decreasing PHA yield; and (4) further process optimization is necessary for the PHA-based plastics to become attractive alternatives to fossil-based plastics. Our study suggests that multiple climate tipping is a relevant impact category for LCA of biodegradable bioplastics.
In this study, in situ reactive extrusion of polylactide and thermoplastic starch modified with chloropropyl trimethoxysilane coupling agent (PLA/mTPS) is proposed. The success of covalent bond formation between PLA matrix and mTPS phase is clarified by two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy with ¹H¹H TOCSY mode. This chemically bound PLA with starch gives the remarkable compatibility in the PLA/mTPS film, with not only a decreased glass transition temperature (47 °C) but also an increased crystallinity of PLA (Χc of 50%). It consequently increases oxygen barrier significantly and also enhances the film flexibility as observed from the drastic increase of elongation at break (from 3% to 50%). Moreover, the PLA/mTPS 60/40 film exhibits the accelerated degradation as compared with pure PLA film.
Biodegradable polymers have emerged as a subject of enormous scientific and industrial interest due to their environmentally friendly compostability. From the perspective of market size and environmental hazards, biodegradable materials should play a more critical role in packaging materials, which accounts for 60% of the plastic products. However, various challenges remain for biodegradable polymers toward practical packaging applications. Particularly, the poor gas/moisture barrier issues are critical factors limiting the food packaging applications of current biodegradable polymers. The chain architecture tailoring, crystallinity, melt blending/multi-layer co-extrusion, nanotechnology and surface coating have been considered as effective strategies for overcoming the poor gas/moisture barrier facing biodegradable polymers, which has been extensively researched for decades. In this review, we provide an in-depth study on the oxygen/water vapor barrier of representative biodegradable polymers in mainstream research with an emphasis on theoretical models and experimental modifications to improve their barrier properties. The influence of various strategies on the barrier improvement, and the pros/cons of each method are summarized. The limitations of current methods are discussed, and potential methods to overcome these limitations are presented. Finally, we conclude this review by listing current challenges associated with the barrier properties, processing and scalability of biodegradable polymers in the food packaging market and future perspectives for these biodegradable polymers in sustainable composites field.
Multilayer films comprised of thermoplastic starch (TPS) and poly (lactic acid) (PLA) were fabricated via a reactive extrusion, compression molding, and dip coating processes. Maleic anhydride (MA) modification of TPS was employed to improve the interfacial adhesion between TPS and PLA layers of the film. The level and effect of TPS modification were evaluated using Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (H-NMR), titration, and thermogravimetric analysis (TGA). Nanoclays were incorporated in the TPS and maleated TPS (MTPS) matrices to further enhance the physico-mechanical properties of the multilayer films. The optimized multilayer film fabricated in this study, which was the nanoclays-filled maleated thermoplastic starch and PLA multilayer film (MTPS-3C/PLA) displayed good transparency and tensile properties, and excellent moisture and oxygen barrier properties. This multilayer film assembly provided 1,300% improvement in moisture barrier compared to TPS films, and 3,300% improvement in oxygen barrier properties as compared to PLA films adjusted for thickness. Moreover, these multilayer films are composed of compostable, food-grade, inexpensive, and bio-based ingredients and as such they are expected to be compostable with great cost structure and environmentally friendly.
The demands for bioplastics that provide good barrier properties against moisture and oxygen while simultaneously displaying good physical properties without compromising their biodegradability is ever-increasing. In this work, a multiphase and multilayer film assembly composed of thermoplastic starch (TPS) and its maleated counterpart (MTPS) with poly(butylene adipate-co-terephthalate) (PBAT) was constructed as a suitable barrier film with excellent mechanical properties. The bioplastic film assemblies were fabricated through reactive extrusion, compression molding, and dip-coating process. The incorporation of PBAT co-blend with TPS in the core layer enhanced the multilayer film's interfacial bond. The MTPS/PBAT film assembly provided 86.8% and 74.3% improvement in moisture barrier and oxygen barrier as compared to the baseline TPS and PBAT films, respectively. Overall, the multiphase and multilayer film assembly displayed good mechanical properties in conjuncture with excellent barrier properties indicating their potential as a biodegradable and cost effective alternative to conventional plastics used in the packaging industry.
Background
The perishable nature of fruits and vegetables makes their shelf-life limited. Environmental factors, transportation and preservation conditions through postharvest could decrease the storage time and quality. Therefore, prolonging supply time of fruits and vegetables by safer postharvest treatments direct the preservation methods to edible coatings. Active edible coatings incorporating different types of functional substances can be used as a preservation method to boost strategies in improving quality, safety and shelf-life of fruits and vegetables upon storage.
Scope and approach
This review attempts to present a complete overview of carboxymethyl cellulose (CMC) and pectin as a basis for edible coatings and recent developments related to their application as active coatings for preservation of fruits and vegetables quality.
Key findings and conclusion
CMC and pectin are two main polysaccharides with great potential in making edible coatings. The CMC- and pectin-based edible coatings are commonly odorless, tasteless, non-toxic, non-allergic, water-soluble, transparent and resistant to oil and fats. CMC and pectin, additionally, could be good carriers for active additives. In this sense, CMC and pectin-based active coatings could provide a great potential both for their protective effect and carrying functional compounds such as antimicrobials, antioxidants, anti-browning agents, texture enhancers and nutraceuticals into their coating matrix to prevent unwanted reactions (e.g., microbial growth, oxidation, enzymatic browning and softening) in horticultural products. Such strategy could inhibit microbial decays and enzymatic or biochemical damages and prevent physical or textural deteriorations in fruits and vegetables during storage.
Bioplastics have introduced numerous flexibilities to humankind. However, bioplastics have brought newer challenges in waste management. Approximately half of the current bioplastic market is not biodegradable, and with a larger market volume, its end-of-life allocation will be problematic for the governments and policymakers. This study aims to provide an overview of the non-biodegradable bioplastics market, including their underlined challenges, typical production methods, characterization, and possible alternative waste utilization perspective. Bioplastic production usually starts from a biological source i.e., biomass and a series of modification techniques such as pretreatment, hydrolysis, and fermentation are carried out to produce bioethanol. Then, bioethanol is converted to non-biodegradable bioplastics. The major non-biodegradable bioplastics are bio-polyethylene (bio-PE), bio-polypropylene (bio-PP), bio-polyethylene-terephthalate (bio-PET), bio-polytrimethylene terephthalate (Bio-PTT), and bio-polyamide (bio-PA). In this review article, an overview of each bioplastic is presented with flow diagrams. Also, the production method of compostable bioplastics—polylactic acid (PLA) — is briefly discussed for comparison purpose. Since the chemical structure of bio-based non-biodegradable plastics is similar to the conventional fossil-based plastics, the characterization and alternative thermochemical utilization techniques of five bioplastic wastes are discussed based on the conventional plastics characterizations. Per ultimate analysis, considering high hydrogen, low oxygen, and low fixed carbon content, bio-PE and bio-PP are recommended as potential feedstocks for the catalytic pyrolysis process to produce gasoline and diesel range liquid hydrocarbons. Alternatively, bio-PET, bio-PA, and PLA are recommended as potential feedstocks for the gasification process, considering their higher oxygen content.
This study introduces a hydrophobically modified bacterial cellulose nanofibrils (BCNF)-stabilized Pickering emulsion system, which can limit the influx of metal ions through the interface. We showed that the C18 alkyl chain-grafted BCNF (C18BCNF) can readily associate to generate a resilient thin membrane at the oil-water interface regardless of the type of oil, which is essential for the production of stable emulsion drops. The viscoelasticity of C18BCNF-armored Pickering emulsion was feasibly tunable by manipulating the grafting amount of the C18 alkyl chains, as well as controlling the C18BCNF concentration. We also demonstrated that the C18BCNF membrane formed at the interface effectively entrapped metal ions through electrostatic binding with the carboxyl groups on C18BCNF, thus maintaining original UV-absorbing capability of chemical UV filter-containing emulsions. We expect that the BCNF surfactant fabricated in this study has immense potential for the development of various complex emulsion products.
Edible films and coatings have received significant consideration in recent years because of their biodegradation, non‐toxicity, and biocompatibility as new packaging materials over synthetic films. Recent advances in transforming certain polysaccharides, proteins, natural waxes, and food and agro‐waste into flexible and functional films have paved the way for developing more ecofriendly packaging materials. Among them, the plant protein zein is a soluble corn extract with thermoplastic properties. The hydrophobic nature of zein is related to its high content of nonpolar amino acids. Zein has excellent film‐forming properties and can be used for the fabrication of biodegradable films. Zein films have relatively good water vapor barrier properties compared to other edible films. This chapter reviews recent advances in the fabrication and characterization of zein films by using different approaches such as solvent casting, co‐solvent deposition, blends with other biopolymers, and melt forming/extrusion. Functionalized zein nanoparticles or nanofibers developed for biomedical and pharmaceutical‐controlled release applications are excluded from this chapter. We also review use of zein in laminated food packaging both in conjunction with other bio‐based polymers and standard petroleum‐based food packaging films. Different packaging applications with zein films are also presented to show the benefits of this biomaterial to enhance the safety and quality of foods.
This study explores the potential use of a Thermoplastic Starch (TPS)/Polyvinyl Alcohol (PVOH) blend as an alternative center-layer material to ethylene vinyl alcohol (EVOH) in food packaging films. Multi-layer films consisting of a TPS/PVOH blend center-layer sandwiched between low-density polyethylene (LDPE) outer layers were prepared in a co-extruded blown film line. Middle-layer blend concentration of TPS was varied from 0 to 100 wt% and the barrier and mechanical properties were characterized. Films with center layer blends containing 25 and 75 wt% TPS exhibited similar oxygen barrier properties to neat EVOH. Moreover, multi-layer films containing 25 wt% TPS center-layers showed the highest tensile strength and dart impact value among all blends and this was attributed to an enhanced interaction between blend constituents. The study suggests that the blends containing either 25 or 75 wt% TPS could serve as alternative barrier layers due to their relatively low material cost, good oxygen barrier performance and adequate material properties.
This paper reports the use of cellulose nanocrystals (CNCs) and nanoclays as reinforcing fillers in starch ester (StE) films. The StE was prepared by a one-step homogenous esterification reaction to obtain a degree of substituted hydroxyl moieties of 2.8. StE films with varying concentrations (0, 0.5 wt.%, 1.5 wt.%, 3 wt.%, and 5 wt.%) of CNC and nanoclay were then fabricated using a solvent casting process and characterized using scanning electron microscopy, optical spectrometry, water absorbance, water vapor permeability, mechanical tests, and simulated compostability studies. The SEM images for the CNC-filled composites revealed aggregates of CNC in the matrix, while nanoclay showed a homogeneous dispersion. Although no apparent visible change in transparency was observed for all filled films, a decrease in light transmission was revealed by optical density measurements. The incorporation of the nanofillers improved the yield strength of the starch-ester films significantly. This improvement in the tensile strength was as much as 112 % and 173 % for 5 wt. % of CNC and 5 wt.% of nanoclay, respectively. No hydrolysis was observed for StE under the simulated composting conditions over six months. Compared to the unfilled StE films, the reinforced films showed a reduction in weight approximately equal to the amount of the filler, with a maximum degradation of 8.9 wt.% for the 5 wt. % nanoclay filled StE films.
A stiff, hydrophobic, and corrosion protective polyurethane (PU) nanocomposite coatings have been fabricated via the incorporation of surface modified cellulose nanocrystals (CNC). The modification of CNC involves surface grafting of varying levels of epoxy functionalized silane (ES). The effect of reaction time and concentration of ES on the level of grafting were evaluated using Fourier Transform Infrared Spectroscopy (FTIR), Elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), water contact angle measurement (WCA) and dispersibility test. It was found that prolonged reaction time and the high mole ratio of ES to CNC improve thermal properties and material wettability of the modified CNC. The incorporation of modified CNC in PU not only improved thermomechanical properties but also reduced the water absorption properties of the PU composites, which could be attributed to the improvement in the dispersion and enhanced interfacial adhesion between the nanoparticle and the PU matrix. Salt spray and electrochemical impendence spectroscopy (EIS) studies, which were carried out on mild steel coated with the fabricated nanocomposite (PU/ES-CNC), exhibited better anticorrosion behaviors as compared to PU. Overall, the CNC modification through silanization is a robust, eco-friendly, and scalable process, making it an appealing material for a range of polymer composite applications.
In this work, lignin was used as a heterogeneous nucleating agent to increase polylactic acid (PLA) crystallinity. To enhance the gas barrier performance of PLA/LG composite films, two graft copolymers, polylactide‐graft‐glycidyl methacrylate (PLA‐g‐GMA) and polylactide‐graft‐poly (ethylene glycol) methyl ether methacrylate (PLA‐g‐PEGMA) were successfully synthesized and separately used as compatibilizers to modify PLA/LG composite properties such as interfacial adhesion, crystallinity, and mechanical properties. Since crystallites can act as obstacles to gas diffusion, the higher the crystallinity of the polymer matrix, the better gas barrier performance of the composite film will be. The crystallinity and crystalline structure of the PLA matrix was demonstrated by wide‐angle X‐ray diffraction and differential scanning calorimetry results. Since LG particles can act as efficient heterogeneous crystal nucleating agents, a roughly 50% reduction in oxygen permeability (PO2) was obtained by adding 1 phr LG to the PLA matrix (PLA/1LG). Following addition of 10 phr PLA‐g‐GMA to the PLA/LG composite, PLA/PLA‐g‐GMA/LG composite films showed lower gas barrier properties than PLA/LG composites without added compatibilizer. Moreover, the interfacial adhesion of PLA/LG composites was significantly improved after addition of PLA‐g‐GMA. Therefore, PLA/PLA‐g‐GMA/3LG showed the highest tensile strength, 33% higher than that of neat PLA. Following addition of 10 phr PLA‐g‐PEGMA to the PLA/LG composite, the long liner side chains of PLA‐g‐PEGMA were able to act as nucleating agents for PLA to promote the crystallization of PLA. Accordingly, PLA/PLA‐g‐PEGMA/3LG with 3 phr LG showed a roughly 86% reduction in PO2 when compared with neat PLA film.
We report a modified starch-poly(butylene adipate co-terephthalate) (PBAT) film (MSPF) prepared by extrusion blowing. Polyurethane prepolymer (PUP), was modified to the starch to enhance the compatibility. Different contents of amylose was blended with PBAT for improving mechanical strength and oxygen-barrier properties of MSPF. The microstructures, crystallinity, mechanical properties, oxygen-barrier capacity of MSPF were thoroughly evaluated. The result showed that MSPF with high starch content and excellent performances was successfully prepared with the synergy of PUP modification, amylose introduction and extrusion blowing. The crystallinity, hydrophobicity, oxygen-barrier properties and mechanical properties of MSPF increased with the increasing amylose content. The maximum tensile strength and elongation at break of MSPF reached 10.6 MPa and 805.6 %, respectively, even at the high starch content of 50 %. The result demonstrated that MSPF having excellent mechanical properties and oxygen-barrier properties could be use in the biodegradable field such as packaging materials, agricultural films and garbage bags.
Polypropylene (PP) and low-density polyethylene (LDPE) are among the most converted resins; as such, they also have the largest share in municipal waste fractions. Currently, there is a great societal and industrial need to recycle these polymers using thermo-mechanical processes. However, process-induced degradation during recycling operations may lead to irreversible changes. In this study, PP was blended with 0 to 10 wt.% of LDPE was subjected to consecutive twin-screw extrusion cycles (0 to 5 times) to mimic thermo-mechanical recycling. The effect of reprocessing on the rheological, thermal, and mechanical properties of PP/LDPE blends was investigated. An increase in MFR and decrease in viscosity was observed for PP and the blends. DSC results showed that the crystal structure of PP was seriously affected and generated more disorder with reprocessing. Although tensile properties were not substantially affected, all properties had a decreasing trend. While successive thermo-mechanical processing caused chain scission of the PP phase of the blend, the overall property of the studied blend composition maintained acceptable properties. Thus, recycling of PP with low PE blend additive is a feasible option not only to reduce plastic waste but also to generate value from an otherwise waste product.