Bio-based Films Research Articles

Morphology and permeability of bio-based poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene succinate) (PBS) and linear low-density polyethylene (LLDPE) blend films control shelf-life of packaged bread

Poly(butylene adipate-co-terephthalate) (PBAT), poly(butylene succinate) (PBS) and linear low-density polyethylene (LLDPE) were blended to produce bio-based packaging via blown-film extrusion. Blend ratios modified morphology, crystallinity and relaxation temperatures (T α ) of the films. Binary mixtures caused phase separation and non-homogeneous fibrous microstructures of immiscible polymers. Bio-based blend films containing LLDPE (LLDPE/PBAT and LLDPE/PBS) gave less homogeneous structures than PBAT/PBS films. The formation of oriented fibrous networks subsequently controlled mechanical and barrier properties of the blend films. LLDPE blending modified C=O carbonyl groups in PBAT and PBS, forming voids in topographic images indicating incompatibility. PBAT and PBS blends showed good compatibility and adhesion of polymer interface, causing smooth and compact structures with minimal surface roughness. Incorporation of PBAT and PBS sharply reduced crystallinity of LLDPE/PBAT and LLDPE/PBS films. LLDPE/PBAT blends had lower T α than neat PBAT and LLDPE, while T α of PBAT/PBS blends proportionally decreased at increasing PBS which indicated diverse polymer miscibility and molecular mobility. Water vapor permeability (WVP) and oxygen permeability (OP) fitted with polynomial and exponential equations, respectively and depended on blend ratios. Films containing higher PBS had combined higher WVP and lower OP, delaying fungal growth in packaged bread due to dehydration. Ratios of PBAT, PBS and LLDPE blend films clearly affected mold growth and crumb hardness during storage. Regardless of film components, the firmness of bread crumbs increased linearly with package WVP. Conversely, mold growth had insignificant correlation with OP. Moisture loss from bread crumbs due to high WVP showed dominant effects on microbial growth. Blending PBAT and PBS modified the morphology and permeability of bio-based films and increased the shelf-life of packaged bread. • Systematic investigations for packaging properties in bio-based PBAT/PBS/PE blends. • FTIR intensity ratios effectively monitor bonding and morphology modifications. • H 2 O and O 2 permeability in PBAT/PBS/PE blends fitted to cubic and exponential model. • Hardness of packaged bread linearly increased with water vapor permeability. • Water vapor permeability majorly affected mold growth and increasing crumb hardness.

Effect of Cold Plasma Treatment on the Packaging Properties of Biopolymer-Based Films: A Review

Biopolymers, like polysaccharides and proteins, are sustainable and green materials with excellent film-forming potential. Bio-based films have gained a lot of attention and are believed to be an alternative to plastics in next-generation food packaging. Compared to conventional plastics, biopolymers inherently have certain limitations like hydrophilicity, poor thermo-mechanical, and barrier properties. Therefore, the modification of biopolymers or their films provide an opportunity to develop packaging materials with desired characteristics. Among different modification approaches, the application of cold plasma has been a very efficient technology to enhance the functionality and interfacial characteristics of biopolymers. Cold plasma is biocompatible, shows uniformity in treatment, and is suitable for heat-sensitive components. This review provides information on different plasma generating equipment used for the modification of films and critically analyses the impact of cold plasma on packaging properties of films prepared from protein, polysaccharides, and their combinations. Most studies to date have shown that plasma treatment effectively enhances surface characteristics, mechanical, and thermal properties, while its impact on the improvement of barrier properties is limited. Plasma treatment increases surface roughness that enables surface adhesion, ink printability, and reduces the contact angle. Plasma-treated films loaded with antimicrobial compounds demonstrate strong antimicrobial efficacy, mainly due to the increase in their diffusion rate and the non-thermal nature of cold plasma that protects the functionality of bioactive compounds. This review also elaborates on the existing challenges and future needs. Overall, it can be concluded that the application of cold plasma is an effective strategy to modify the inherent limitations of biopolymer-based packaging materials for food packaging applications.

Fabricating Starch-Based Bioplastic Reinforced with Bagasse for Food Packaging

Nowadays, food packaging plastics is one of the largest markets that consume thermoplastics. Regardless, the packaging industry accounts for the majority of plastic waste that is polluting the environment. Furthermore, because petroleum sources are limited and on the verge of depletion, there is a need to develop alternative materials that can perform the same functions as conventional plastics. Hence, many solutions have emerged in the now time being. Biopolymers have demonstrated great potential as green materials, despite their poor market penetration. They can be a very remarkable alternative and moreover possess an outstanding friendliness characteristic. Bioplastics are a critical key player in turning the plastics sector from a wasteful linear economy to a circular economy. Their expanding use will have better impacts, not just in terms of the environment and economy, but also in terms of functionality. This paper has been attempted to accomplish a biopolymer—made out of starch and sugarcane bagasse pulp in the regard of replacing the current standard plastic as packaging material. The results state the fabricated biopolymer of starch and bagasse composite is very prominent to take the lead as packing material of future possibilities for green material adoption. Moreover, the addition of the bagasse enhanced the mechanical property, and the castor oil boosted the flexibility and hence elongation. Through such work of the article, the conclusion of the bio-based film to compete at a superior level with the current plastic film properties in the market is basically proved.

Photoreactivity and Enhanced Mechanical Properties and Water Stability in Polysaccharide-Based Films Using Vanadium Ion Coordination

Different strategies have been employed to improve the physicochemical and mechanical properties of soft polysaccharide-based materials. Some of these strategies include covalent cross-linking or chemical modification and blending of polymers. In an alternative approach, we used vanadium ion coordination to create dynamic covalent bonds and obtain films with enhanced properties. We prepared bio-based films using pectin and chitosan, two naturally occurring polysaccharides, with glycerol added as a plasticizer to increase the flexibility and elasticity of the material. We incorporated the vanadium ion into the films via soaking in V(V) solutions. Films were characterized through FT-IR to examine the different interactions inside the films. Scanning electron microscopy showed laminated sheets separated by ∼0.16 μm in the V(V)-containing films as compared to ∼0.75 μm in the films without V(V). Rheological studies showed that V(V)-coordinated films possessed better mechanical properties (higher storage modulus) and water stability than films without vanadium. Upon irradiation with blue light, diffuse reflectance spectroscopy and color analysis showed the changes in the color of the film with irradiation from yellow to blue, consistent with the photochemical reduction of V(V) to V(IV). A small change in modulus was observed during light irradiation without significant structural changes observed within the film in scanning electron microscopy. These results show that it is possible to create robust and water-stable polysaccharide-based materials through coordination of the functional groups of polysaccharides with metal ions.

Developing highly transparent yet ultraviolet blocking fully biocomposite films based on chitin and lignin using ethanol/water as processing solvents

Developing fully biobased products with functionality in a green fashion is highly desirable to meet the increasing demand for environmental sustainability and mitigate “white pollution” by petroleum-based counterparts. Here, chitin from shrimp shells was propionylated to obtain chitin propionate (CP) with significantly improved solubility in organic solvents, organosolv lignin (OSL) was extracted from the forest harvest residuals. The fully biobased composite consisting of CP as a matrix and OSL as a UV-blocker were successfully prepared using acidic ethanol/water as a green processing solvent. The results indicated that the 5% OSL addition enabled the CP film to block approximately 98% UV light while allowing 71% visible light transmittance; tensile and thermal properties were also retained. Nearly 100% UV light was blocked with 20% OSL addition, but visible light transmittance was moderately sacrificed. This study provides an alternative solution to produce novel fully biobased films with high transparency yet excellent UV protection for potential packaging applications.

Effect of natural deep eutectic solvent and chitosan nanoparticles on physicochemical properties of locust bean gum films

Novel bio-based films containing Locust Bean Gum (LBG) and Chitosan (CH) or Chitosan nanoparticles (CH-NPs)/natural deep eutectic solvents (NADES) were investigated. The films with different LBG and CH-NPs w/w ratios in the absence or in the presence of NADES plasticizer were prepared by a semi-continuous knife-coating process. The detailed characterization of the films confirmed their transparency, uniformity, and homogeneity, without cracks or pores. FTIR spectra confirmed physical entanglements and miscibility between film components and suggested the occurrence of interaction between CH and LBG components. The mechanical, optical, rheological, thermal and water barrier properties of the new films were also evaluated. It was found that addition of CH-NPs reduced the apparent viscosity of LBG solution, and that the presence of NADES provided more flexible films with less mechanical and barrier resistance. In contrast, the addition of CH-NPs to the LBG solution provided films with enhancement of tensile strength and Young's modulus and a slight increase in water vapour permeability.

A Soy Protein-Based Composite Film with a Hierarchical Structure Inspired by Nacre

Soy protein-based composite film is a potential replacement for petroleum-based film with multipurpose applications and cleaner production. It is difficult to improve both the tensile strength and toughness of a protein-based film without sacrificing its elongation. In this study, inspired by the hierarchical structure of nacre, a facile yet delicate strategy was developed to fabricate a novel bio-based film with excellent toughness and high strength. Triglycidylamine (TGA) crosslinked soy protein (SPI) as hard phase and thermoplastic polyurethane elastomer (TPU) as soft phase comprise an alternative lay-up hierarchical structure. The interface of these two phases is enhanced using triglycidylamine (TGA) surface-modified TPU (MTPU). The tensile strength of SPI/MTPU/TGA films increases by 392% to 7.78 MPa and their toughness increases by 391% to 8.50 MJ/m3 compared to soy protein/glycerol film. The proposed hierarchical structure can also be extended to other high-performance materials and polymers.

BIO-BASED ELECTROACTIVE COMPOSITE BIOPOLYMER FILMS FROM CASSAVA STARCH / ANACARDIC ACID

The United Nations have established Responsible Consumption and Production as one Sustainable Development Goal. This goal demands strategies for the efficient utilization of natural resources, agro-industrial waste, and the development of eco-friendly materials. Thus, the objective of this work was to develop bio-based films synthesized with anacardic acid (AA) extracted from the Cashew Nut Shell Liquid (CNSL) and starch extracted from cassava. Biopolymer films were synthesized at different pH values with various concentrations of AA. The biopolymer films prepared at basic pH presented higher tensile strength and the addition of AA also contributed to increasing the tensile strength. Infrared spectroscopy allowed the establishment of possible hydrogen bond interaction between AA and the polymeric chain of cassava starch, which could contribute to its higher tensile strength. The degradation rate was not affected by the synthesis pH, but by the presence of AA. Cyclic voltammetry allowed evidence of the electroactivity of glucose and AA in the composite biopolymer films. The results allowed it to conclude that it was possible to obtain a composite biopolymer from thermochemical synthesis with AA and cassava starch. The presence of AA can improve tensile strength, decrease the rate of biodegradability, and improve the electroactivity of the films.

Degradation of Bio-Based Film Plastics in Soil Under Natural Conditions

Degradation of Bio-Based Film Plastics in Soil Under Natural Conditions

Starch/pectin‐biobased films: How initial dispersions could affect their performances

AbstractBioplastics receive constantly increasing attention as interesting alternatives to fossil‐derived plastics, due to their renewability and degradability. Among them, edible coatings and films have been focused by a growing amount of research. Starch‐based films are promising candidates for future plastics because of starch convenient price and large availability, combined with suitable properties. Chemical, physical, and mechanical properties of such films could be enhanced by mixing starch with other additives and copolymers, which affect the characteristics of the film‐forming dispersions. This work investigates how the behavior of different starch/pectin‐based dispersions—in terms of stability and gelification—influences the quality of the resulting films. Characterization of dispersions by Turbiscan analysis, based on multiple light scattering—detects any destabilization phenomenon and its extent. The produced films are investigated from morphological and mechanical point of view by standard tests. Film quality improves as phase separation decreases and degree of gelification increases in film‐forming dispersions.

Biobased materials for active food packaging: A review

A large portion of food is lost due to the damage caused by different environmental factors such as moisture, oxidation, irradiation, microbial contamination, and others. Thus, food should be protected from such damages by developing strategies, such as packaging, to enhance its quality, stability, and shelf-life. The usage of conventional petroleum-based packaging materials is a great risk to health and environmental safety. In contrast, the utilization of biobased films and coatings for food packaging applications could be a safe approach, both from human health and environmental perspective. This review briefly overviews the desired properties of biobased packaging materials. It mainly discusses the potential of different natural (polysaccharides, lipids, and proteins) and synthetic polymers for their film and coating-forming abilities considering their abundance, biological properties (biocompatible, biodegradable, non-toxic), and morphological and physiological features. It also discusses the role of different additives and nanomaterials for their potential to impart additional structural and functional properties to packaging materials.

O-ATRP synthesized poly(β-pinene) blended with chitosan for antimicrobial and antioxidant bio-based films production

Antioxidant and antimicrobial activities are important characteristics of active film packaging designed to extend food preservation. In this study, functional bio-based films were produced using different concentrations of antioxidant poly(β-pinene) bio-oligomer synthesized via organocatalyzed atom transfer radical polymerization (O-ATRP) and blended with chitosan of different molecular weights. The structural, mechanical, thermal, solubility, antioxidant, and antimicrobial properties of the films were investigated. The poly(β-pinene)-chitosan blends presented significant pores and irregularities with the increase of poly(β-pinene) concentration over 30%. Chitosan molecular weight did not show any important influence in the physical properties of the blends. Poly(β-pinene) load decreased the materials' tensile strength and melting temperature, exhibiting a plasticizing effect on chitosan chains. The antioxidant and antimicrobial activities of the films were improved by poly(β-pinene) incorporation and mainly depended on its concentration. Therefore, the incorporation of poly(β-pinene) in chitosan films can be an alternative for active packaging production.

A facile approach for tuning optical and surface properties of novel biobased Alginate/POTE handleable films via solvent vapor exposure

Novel biobased films consisting of alginate blends with poly (octanoic acid 2-thiophen-3-yl-ethyl ester) (POTE), a conducting polymer, were prepared by solution casting, and their optical, morphological, thermal, and surface properties were studied. Using UV–visible spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM), the effects of tetrahydrofuran solvent vapors on the optical properties and surface morphology of biobased films with different POTE contents were studied. Results indicate that morphological rearrangements of POTE take place during the process of solvent exposure. Specifically, the solvent vapor induced the formation of POTE small crystalline domains, which allows envisioning the potential of tuning UV–visible absorbance and wettability behavior of biobased films. Finally, theoretical electronic calculations (specifically frontier molecular orbitals analysis) provided consistent evidence on POTE's preferential orientation and selectivity toward the THF-vapor medium.

Research Progress of Edible Film in Meat and Meat Products

Meat and its products are highly perishable food, and its quality has been the focus of academic attention. Edible film, which is composed of protein, lipid and polysaccharide, can be used as carrier of natural active substance to increase the color, flavor and function of meat products. It can effectively prolong the shelf life of meat products without burdening the environment. Different Meat and meat products need specific packaging conditions, composite bio-based film in the field of meat preservation has broad potential. In this paper, the preparation methods of edible film and its application in meat and meat products at home and abroad are reviewed to provide reference for the application of functional edible film in meat and meat products.

High strength biobased films prepared from xylan/chitosan polyelectrolyte complexes in the presence of ethanol

The effect of different ethanol concentrations (0; 3; 9; 12 and 16 wt%) on the degree of ionization of xylan and chitosan, the characteristics of polyelectrolyte complex (PEC) suspensions, and the derived films, were exhaustively analyzed through several analytical techniques. Results indicate that the degree of ionization of both polyelectrolytes was reduced, whereas particle sizes and z-potential values of PEC suspensions were remarkably modified. As ethanol concentration was increased up to 12 wt%, the crystallinity of films decreased. Furthermore, the stress at break increased from 45 to 75 MPa. Wet stress-strain results were promising (up to 5.0 MPa, 55%) for all films. Although water vapor permeability was not modified, the swelling capacity was favorably reduced (12%). Results reveal that, for preparing films, it might not be necessary to remove all the ethanol used for xylan precipitation and purification.

Binderless films from lignin-rich residues of enzymatic saccharification

The goal of this study was to examine the conversion of lignin-rich residues from (hard)wood cellulosic sugar production into films without adding binders. Enzymatic hydrolysis was conducted on alkaline pretreated aspen wood to attain saccharification (liberation of monomeric sugars). Non-converted lignin-rich residues in the solid waste stream were fibrillated and formed into films with the aid of micro/nanofibrillated wood (non-saccharified). The films were hotpressed to activate the adhesive characteristic of the lignin in situ. Results showed that hotpressing drastically improved water resistance and wet strength. These effects, not attributable to densification alone, are judged to have arisen from heat-induced hydrolytically stable bonding and hydrophobization. The fully biobased films, even at highly moist (98% RH) conditions, are comparable in strength and stiffness, and tested significantly more biodegradable compared to polystyrene polymer. Overall, this study offers a simple route for converting wood saccharification residues without pre-refining for lignin, thereby favoring cost efficiency of a coproduction strategy in the cellulosic sugar production.

Structure and Applications of Pectin in Food, Biomedical, and Pharmaceutical Industry: A Review

Pectin is a biocompatible polysaccharide with intrinsic biological activity, which may exhibit different structures depending on its source or extraction method. The extraction of pectin from various industrial by-products presents itself as a green option for the valorization of agro-industrial residues by producing a high commercial value product. Pectin is susceptible to physical, chemical, and/or enzymatic changes. The numerous functional groups present in its structure can stimulate different functionalities, and certain modifications can enable pectin for countless applications in food, agriculture, drugs, and biomedicine. It is currently a trend to use pectin to produce edible coating to protect foodstuff, antimicrobial bio-based films, nanoparticles, healing agents, and cancer treatment. Advances in methodology, use of different sources of extraction, and knowledge about structural modification have significantly expanded the properties, yields, and applications of this polysaccharide. Recently, structurally modified pectin has shown better functional properties and bioactivities than the native one. In addition, pectin can be used in conjunction with a wide variety of biopolymers with differentiated properties and specific functionalities. In this context, this review presents the structural characteristics and properties of pectin and information on the modification of this polysaccharide, its respective applications, perspectives, and future challenges.

Physically cross-linked chitosan/dextrin cryogels entrapping Thymus vulgaris essential oil with enhanced mechanical, antioxidant and antifungal properties

Herein, we entrapped Thymus vulgaris essential oil (EO) within the physically cross-linked sponge-like architecture of cryogels by ice template-assisted freeze-drying. Their 3D cryogenically-structured network was built through hydrogen bonding formed by blending two naturally-derived polysaccharides, chitosan and dextrin. The embedment of EOs within the cryogel matrix generates porous films with an increased elasticity that allows their fast shape recovery after full compression. Thus, the swollen EOs-loaded cryogel films exhibited an elastic modulus of 3.00 MPa, which is more than 40 times higher than that of polysaccharide films without EOs (an elastic modulus of only 0.07 MPa). In addition, the encapsulation of bioactive compounds endows the bio-based films with both antioxidant and antifungal properties, showing a radical scavenging activity of 65% and a zone inhibition diameter of 40 mm for Candida parapsilosis fungi. Our results recommend the entrapment of EOs into bio-based cryogel carriers as a straightforward approach to provide ‘green’ polysaccharide-based films having both improved physicochemical properties and remarkable antifungal activity.

Ginkgo signs R&D pact with Sumitomo

Ginkgo Bioworks has agreed to use its synthetic biology capabilities to improve the production of an unidentified biobased chemical from Sumitomo Chemical and make other Sumitomo products. An earlier agreement between Sumitomo and Zymergen, a Ginkgo competitor, yielded a biobased film for use in displays and touch screens. Both Sumitomo partners are riding high with investors at the moment. Zymergen made a successful initial public offering in May, while Ginkgo is in the process of going public by merging with a special purpose acquisition company, or SPAC.

Characterization and storage study of chickpea flour films with UV-barrier and Cu-remove properties

An important challenge to food industries is the stability of oxidation-sensitive compounds in packaged foods. In this study, we developed an eco-friendly chickpea flour film (CFF) as an innovative active food packaging material. We investigated the functional properties of films, its copper removal activity and UV-barrier properties during 90 days of storage. The water vapor permeability (1.35 × 10−11 gm−1s−1Pa−1), water content (17.50%) and solubility (35.15%), optical and mechanical properties of chickpea flour films were comparable to that of other bio-based films. The properties of CFF did not change during storage. CFF had UV-light shielding behavior and copper-removal capacity. CFF blocked more than the 95% of the UV spectrum. Maximum Cu-removal capacity (∼ 99.5%) was no affected by the concentrations of copper ions studied. The adsorption data fitted the Langmuir adsorption model, suggesting monolayer coverage. These found properties and eco-friendliness endow the chickpea flour films with great application potential as active packaging film to protect foods against UV radiation and copper promoted oxidative degradation.