Improvement of starch films for food packaging through a three-principle approach: Antioxidants, cross-linking and reinforcement

Molecular changes and interactions of wheat flour biopolymers during bread-making: Implications to upcycle bread waste into bioplastics

This study aims to understand the molecular and supramolecular transformations of wheat endosperm biopolymers during bread-making, and their implications to fabricate self-standing films from stale white bread. A reduction in the Mw of amylopectin (51.8 × 106 vs 425.1 × 106 g/mol) and water extractable arabinoxylans WEAX (1.79 × 105 vs 7.63 × 105 g/mol), and a decrease in amylose length (245 vs 748 glucose units) was observed after bread-baking. The chain length distribution of amylopectin and the arabinose-to-xylose (A/X) ratio of WEAX remained unaffected during bread-making, suggesting that heat- or/and shear-induced chain scission is the mechanism responsible for molecular fragmentation. Bread-making also resulted in more insoluble cell wall residue, featured by water unextractable arabinoxylan of lower A/X and Mw, along with the formation of a gluten network. Flexible and transparent films with good light-blocking performance (<30 % transmittance) and DPPH-radical scavenging capacity (~8.5 %) were successfully developed from bread and flour. Bread films exhibited lower hygroscopicity, tensile strength (2.7 vs 8.5 MPa) and elastic modulus (67 vs 501 MPa) than flour films, while having a 6-fold higher elongation at break (10.0 vs 61.2 %). This study provides insights into the changes in wheat biopolymers during bread-making and sets a precedent for using stale bread as composite polymeric materials.

A Cost-Effective and Chemical-Recycling Approach for Facile Preparation of Regenerated Cellulose Materials

Cellulose is difficult to melt or dissolve. The dissolution and regeneration process paves the way to convert cellulose into diverse forms but still suffers from high costs and environmental pollution. Here, we developed a method that uses aqueous alkali to efficiently dissolve cellulose at a temperature above 0 °C in minutes for fabricating regenerated cellulose. Cellulose was modified with minimal carboxymethyl groups to weaken the intermolecular interaction and improve its dissolution. The modified cellulose can be commercially obtained from carboxymethyl cellulose manufacturing with low cost and high quality. The use of only aqueous alkali reduces pollution and facilitates chemical recycling, and the moderate dissolving temperature reduces energy consumption. The regenerated cellulose materials display excellent mechanical properties and can be recycled or biodegraded after use. The method allows the use of diverse raw materials and modifications to broaden its applicability. The study develops a low-cost and eco-friendly method to fabricate regenerated cellulose.

Comprehensive Evaluation of the Physicochemical Attributes, Antioxidant Capacity, and pH-Responsive Behavior of Starch Films Enhanced by Laver Incorporation

Herein, a new starch film incorporating laver was developed to address issues related to inadequate water resistance and suboptimal preservation quality in food packaging. The integration of laver into starch film formulations offers a compelling avenue for creating biodegradable, active, and smart food packaging. Scanning electron microscope (SEM) analysis revealed that the starch film with a laver concentration of 70% exhibited a uniformly flat microstructure, as expected. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of intermolecular interactions and hydrogen bonding between the starch and laver. Viscoelastic tests demonstrated the superior film-forming performance of the starch/laver composite films. Moreover, it was found that the most favorable concentration of incorporated laver was 10%. Specifically, the S7-3 film emerged as a promising candidate for food packaging applications, boasting the highest contact angle (CA) value of 114.98 ± 1.28°, the lowest water solubility (WS) value of 15.38%, and a reduced water vapor transmission rate (WVTR) value of 2.52 g/m2 × h. Additionally, the S3-7 film displayed an extraordinary tensile strength of 32.47 MPa, an elongation at break of 19.04%, and a Young's modulus of 606.83 MPa. Furthermore, the starch/laver composite films exhibited outstanding UV-blocking capabilities, exceptional pH-responsive behavior, and significant antioxidant activity, underscoring their potential for packaging applications with laver integration.

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

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

Citric acid crosslinked soluble soybean polysaccharide films for active food packaging applications

In this work, a nontoxic crosslinking agent, citric acid (CA), was used to crosslink glycerol-plasticized SSPS films via a heat activated reaction. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results confirmed the occurrence of esterification reaction between CA and SSPS. Microstructure of the CA-crosslinked SSPS films were characterized by scanning electron microscopy, atomic force microscopy and X-ray diffraction. The water resistance, mechanical, UV-barrier, water vapor barrier, antioxidant and thermal properties of SSPS films were enhanced by CA crosslinking. The SSPS film crosslinked with 5 % CA exhibited a maximum tensile strength of 6.5 MPa and a minimum water solubility of 34.3 %. The CA-crosslinked SSPS film also presented superior antibacterial properties against Gram-positive and Gram-negative bacteria. Application test results showed that the CA-crosslinked SSPS film can effectively delay the oxidative deterioration of lard during storage, suggesting that the developed CA-crosslinked SSPS film could be a promising candidate for active food packaging.

A review of starch-based biocomposites reinforced with plant fibers

Renewable and biodegradable resources have gained increasing attention as promising alternatives to synthetic plastics. Among the diverse raw materials employed in bioplastics production, starch emerges as an attractive, low-cost, and largely available source. However, the inherent properties of starch-based materials often limit their utility across various applications, necessitating strategic modifications to enhance their performance. A common approach to boost these materials involves incorporating natural fillers into biopolymer matrices. Incorporating natural fibers within starch matrices enables the development of biocomposites with improved properties while retaining their renewable and biodegradable characteristics. This review briefly addresses fundamental aspects of starch structure, obtention, and processing, as well as the main pre-treatments of natural fibers and processing methods currently applied to produce starch-based composites. It also highlights the most recent advances in this field, elucidates the effect of the incorporation of fibers on the biocomposite properties, and discusses the critical parameters affecting the synergic combination between starch and fibers.

Interaction mechanisms of edible film ingredients and their effects on food quality

Traditional food packaging has problems such as nondegradable and poor food safety. Edible films play an important role in food packaging, transportation and storage, having become a focus of research due to their low cost, renewable, degradable, safe and non-toxic characteristics. According to the different materials of edible films substrate, edible films are usually categorized into proteins, polysaccharides and composite edible films. Functional properties of edible films prepared from different substrate materials also vary, single substrate edible films are defective in some aspects. Functional ingredients such as proteins, polysaccharides, essential oils, natural products, nanomaterials, emulsifiers, and so on are commonly added to edible films to improve their functional properties, extend the shelf life of foods, improve the preservation of sensory properties of foods, and make them widely used in the field of food preservation. This paper introduced the classification, characteristics, and modification methods of common edible films, discussed the interactions among the substrate ingredients of composite edible films, the influence of functional ingredients on the properties of edible films, and the effects of modified edible films on the quality of food, aiming to provide new research ideas for the wide application and further study of edible films.

Carboxymethyl cellulose/poly (vinyl alcohol) based active film incorporated with tamarind seed coat waste extract for food packaging application

Incorporating a bioactive food waste extract into biodegradable polymers is a promising green approach to producing active films with antioxidant and antibacterial activity for food packaging. Active packaging films from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) incorporated with tamarind seed coat waste extract (TS) were prepared by solvent casting method using citric acid as a crosslinking agent. The effect of TS content on the film properties was determined by measuring the optical, morphology, mechanical, water vapor transmission rate (WVTR), antioxidant, and antimicrobial attributes. The CMC/PVA-TS films were also tested on fresh pork. The addition of TS did not significantly affect the film structure and WVTR but it improved the mechanical and UV barrier properties. The films possessed antioxidant and antimicrobial ability against bacteria (S. aureus and E. coli). Thus, CMC/PVA packaging was successfully prepared, and the incorporation of TS enhanced the antioxidant and antimicrobial properties of the film, which extended the shelf-life of fresh pork.

Starch films loaded with tannin: the study of rheological and physical properties

Recently, the research on innovative food packaging has been oriented toward biodegradable materials to lower the environmental impact generated by conventional plastics. The films often carry functional additives interacting with the matrix and modifying its physical properties. In this work tannin, a scarcely exploited active additive, was used to obtain potato starch-based films, and its content was optimized on the basis of mechanical and microscopic tests. Rheological measurements were adopted to evaluate the tannin-starch interaction and the microstructure of the film forming solutions (FFSs). Their thickness, color, thermal conductivity, elastic modulus (Eel), elongation at break (EAB), surface wettability and water solubility were evaluated. Furthermore, microstructure was investigated through Fourier-transform infrared spectroscopy (FTIR), polarized light (POM) and scanning electron microscopy (SEM). It was observed that all FFSs behave as weak gels and tannin addition weakens the gel structure and decreases the gelatinization temperature from about 60 °C to 57 °C. Plastic and deformable films (Eel = 1.96 MPa and EAB = 189 %) were obtained at low tannin fractions, whereas, at a higher concentration, stiffer films (Eel = 12 MPa and EAB = 10 %), with hydrophobic behavior were produced. Among the tested tannin fractions, an intermediate value of 1.7 % (w/w) was found to be promising for industrial purposes.

Flame-retardant phytic acid-decorated thermoplastic starch/halloysite nanotube composite films with enhanced mechanical strength and excellent barrier properties

Thermoplastic starch (TPS), a green and fully biodegradable composite, is considered the most viable option for replacing petroleum-based polymers. However, the poor mechanical properties, high flammability and moisture absorption susceptibility of TPS severely restrict its large-scale applications. Through PA phosphorylation and blending with halloysite nanotubes (HNTs), phytic acid (PA)-phosphorylated HNT/TPS composite films (HNTPSFs) were fabricated with enhanced mechanical strength, excellent flame retardancy, and improved barrier properties. The introduction of HNTs substantially increased the mechanical properties (tensile strength increased 54.3 % and elongation at break decreased 37.0 %) of TPS films and reduced the diffusion of water vapor (decreased 34.1 %). Thermogravimetric analysis studies demonstrated that the HNTPSFs had exceptional thermal stability at their anticipated working temperatures. Furthermore, when the PA content in the composite films increased, the peak heat release rate, total heat release and fire growth index of the HNTPSFs all decreased substantially, demonstrating the improved flame retardancy of HNTPSFs. Hence, the synthesized fully biodegradable TPS composites show enormous potential in the field of renewable biopolymers.

Tuning the mechanical properties of pectin films with polyphenol-rich plant extracts

The mechanical properties of pectin films enhanced with polyphenol-rich fruit extracts were investigated. The scavenging and reducing activity of plant extracts incorporated into the pectin films were determined using bench assays, and their antioxidant activity was correlated with a high presence of polyphenols, which were predominantly comprised of flavonoids and anthocyanins. The pectin films generated from the extracts exhibited a range of mechanical properties; tensile strength (4.99 MPa - 6.91 MPa), elongation at break (45.8 % - 52.3 %), and stiffness (1835 g mm-1 - 2765 g mm-1). To investigate the underlying relationships between plant extract composition and mechanical properties, Projection to Latent Structures (PLS) models were developed. The PLS models revealed that extracts containing high sugar and polyphenol content increase the tensile strength and moisture content of films. The elongation at break of the films was improved or diminished depending on the profile of sugar, acids, and polyphenols in the fruit extracts. Furthermore, the structures and concentration of anthocyanins and flavonoids were identified to strongly influenced the elongation at break differences. By modifying the concentration of sugars, organic acids, and polyphenols, the mechanical properties of pectin-based films can be tuned for tailored applications as food packaging materials.

Formulation Study on Edible Film from Waste Grape and Red Cabbage

(1) Background: Recent research on the valorization of agro-industrial waste has attempted to obtain new products. Grape residue is a waste product used in the grape wine industry that is rich in anthocyanins, as well as leaves and waste parts from red cabbage processing. Anthocyanins, thanks to their various functionalities, can be recovered and used as active and intelligent agents in food packaging. Anthocyanins have antioxidant properties that help to prevent cardiovascular disease. (2) Methods: In this study, the process of extracting waste was studied using solvent and supercritical CO₂ extraction. The obtained anthocyanins were used in starch-based food film formulations. Several formulations were studied using rheometric techniques and the effect of adding anthocyanins on optimal film formulation was investigated. (3) Results: Solvent extractions resulted in a maximum extraction yield. The extracts obtained were used for the preparation of coating and edible films, optimized in the formulation. (4) Conclusions: The addition of anthocyanins to films resulted in increased sample structuring and mechanical properties that are valid for applications, like dipping using coverage methods. The packaging is also attractive and pH-sensitive.

Combined Effect of Citric Acid and Polyphenol-Rich Grape Seed Extract towards Bioactive Smart Food Packaging Systems

Alginate films (2% w·v^-1) were prepared with varying concentrations (5-20% w/w) of citric acid and aqueous grape seed extract (GSE) filtrate (11.66 ± 1.32 g GAE/L) using the solvent-evaporation method. Crosslinking alginate via ester bonds (FTIR analysis) with citric acid up to 10% (w/w) led to a 33% increase in tensile strength, a 34% reduction in water vapor transmission rate (WVTR), and had no impact on elongation at break. Crosslinking alginate with citric acid in the presence of GSE increased the tensile strength by 17%, decreased WVTR by 21%, and significantly improved DPPH scavenging activity. Moreover, after incubation for 24 h at 37 °C, the film-forming solutions exhibited increased antimicrobial activity, resulting in 0.5- and 2.5-log reductions for Escherichia coli and Staphylococcus aureus, respectively, compared to the values obtained without the addition of GSE. The stronger inhibitory effect observed against Gram-positive bacteria can be attributed to the unique composition and structure of their cell walls, which creates a barrier that restricts the penetration of polyphenols into the cells. The pH adjustment of the GSE film-forming solution from 2.0 to 10.0 shifted the UV/VIS absorption spectra, resulting in a colour change from yellow to red. The findings of this study have showcased the potential of combining GSE and citric acid to enhance the functionality and bioactivity of alginate films for applications in smart food packaging.

A mechanically robust biodegradable bioplastic of citric acid modified plasticized yam starch with anthocyanin as a fish spoilage auto-detecting smart film

The current scenario of environmental pollution caused by non-biodegradable plastic and depleting non-renewable resources has called upon the need for biodegradable bioplastic production from renewable resources. Starch bioplastics production from underutilized sources is a viable option for packaging materials that are non-toxic, environmentally benign, and easily biodegradable under disposed conditions. Pristine bioplastic production results in some undesirable qualities and hence requires further modification in order to elevate its potential applicability in real-world scenarios. In this work, yam starch was extracted from a local variety of yams through an eco-friendly and energy-efficient process which was further utilized for bioplastic production. The produced virgin bioplastic was subjected to physical modification through the introduction of plasticizers such as glycerol, while citric acid (CA) was employed as modifier in order to produce the desired starch bioplastic film. The different compositions of starch bioplastics were analyzed for their mechanical properties and maximum tensile strength of 24.60 MPa was observed as the best possible experimental result. The biodegradability feature was further highlighted through soil burial test. Apart from their general function of preservation and protection, the produced bioplastic can be employed for pH-sensitive food spoilage detection through the minute introduction of plant-derived anthocyanin extract into it. The produced pH-sensitive bioplastic film showed distinct changes in color upon an extreme change in the pH value and hence has potential to be used as a smart food packaging material.

Facile fabrication of robust bilayer film loaded with chitosan active microspheres for potential multifunctional food packing

The utilization of microcarriers is an effective technique to protect and slow down the release of active ingredients, while the combination of microcarriers and film materials is an important way to expand the application scenario of active ingredients. The aim of this study was to develop a simple and facile strategy for designing a multifunctional bilayer bioactive film that combines stable mechanical properties, sustained-release characteristics for active ingredients with good antioxidant and antibacterial properties. The EGCG-loaded chitosan active microspheres were prepared by sol-gel method, and then the carboxymethyl cellulose solution containing the active microspheres was assembled onto the carboxymethyl chitosan gel substrate based on intermolecular hydrogen bonding to construct a film with a stable bilayer structure. The results indicated that the bilayer film had dense microstructure and excellent mechanical strength (37.05 MPa), and exhibited UV-blocking properties and excellent gas barrier performance. Meanwhile, the loading of active ingredients (EGCG) in the microspheres enabled the bilayer film to exhibit excellent antioxidant and antibacterial properties, and the controlled release of EGCG by the film was sustainable and showed pH responsiveness. The results of this work provide a new perspective for the design and development of bio-based active packaging film with tunable functional characteristics.

Cross-linked biopolymeric films by citric acid for food packaging and preservation

There is a growing interest in the development of degradable and biopolymeric food packaging films (BFPFs) based on green ingredients and strategies due to their biocompatibility, sustainability, and renewable nature of bio-materials. The performance of BFPFs can be improved either by modifying the biopolymer molecules or by combining them with various additives, including nanomaterials, cross-linkers, bioactive compounds and other polymers. Among them, green cross-linking technology is considered as an effective method to improve the performance of BFPFs; citric acid (CA) is widely used as a natural green cross-linker in different BFPFs. In this study, after an overview on CA chemistry, different types of BFPFs cross-linked by CA have been discussed. In addition, this work summarizes the application of CA cross-linked BFPFs/coatings for food preservation in recent years. The role of CA as a cross-linking agent differs in various types of biopolymers, i.e. polysaccharide-based, protein-based and biopolyester-based biopolymers. Moreover, the cross-linking of CA with different biopolymer molecules is mainly related to the CA content and reaction state; the cross-linking process is significantly influenced by conditions such as temperature and pH. In conclusion, this work shows that CA as a natural green cross-linking agent could improve the performance of different BFPFs and enhance their food preservation capacity.

Development of a Halochromic, Antimicrobial, and Antioxidant Starch-Based Film Containing Phenolic Extract from Jaboticaba Peel

In this study, the antioxidant, antimicrobial, mechanical, optical, and barrier attributes of Solanum lycocarpum starch bio-based edible films incorporated with a phenolic extract from jaboticaba peel were investigated. Aiming to determine the effect of the polymers and the phenolic extract on the properties of the films, a three-factor simplex-lattice design was employed, and the formulation optimization was based on the produced films' antioxidant potential. The optimized formulation of the starch-PEJP film showed a reddish-pink color with no cracks or bubbles and 91% antioxidant activity against DPPH radical. The optimized starch-PEJP film showed good transparency properties and a potent UV-blocking action, presenting color variation as a function of the pH values. The optimized film was also considerably resistant and highly flexible, showing a water vapor permeability of 3.28 × 10-6 g m-1 h-1 Pa-1. The microbial permeation test and antimicrobial evaluation demonstrated that the optimized starch-PEJP film avoided microbial contamination and was potent in reducing the growth of Escherichia coli, Staphylococcus aureus, and Salmonella spp. In summary, the active starch-PEJP film showed great potential as an environmentally friendly and halochromic material, presenting antioxidant and antimicrobial properties and high UV-protecting activity.

Potato Starch-Based Film Incorporated with Tea Polyphenols and Its Application in Fruit Packaging

Effects of tea polyphenols (TP) on the physical properties, barrier properties and functionality of potato starch-based film were determined, while the interaction mechanism between TP and starch in film and the application of this film in fruit packaging were further evaluated. TP exhibited different effects on the physical properties of potato starch-based film, including thickness (0.083 to 0.087 mm), moisture content (9.27% to 9.68%), color (ΔE value: 5.41 to 10.55), light transmittance (51% to 62%), tensile properties and thermal properties, and improved its barrier properties, including water vapor permeability (9.68 to 11.84 × 10^-11 g m^-1 s^-1 Pa^-1),oxygen permeability (1.25 to 2.78 × 10^-16 g m^-1 s^-1 Pa^-1) and antioxidant activity. According to the determination of wide-angle X-ray diffraction, Fourier transform infrared and scanning electron microscope, TP could interact with starch chains via hydrogen bonds to form non-crystal complexes, thus affecting the cross-linking among starch chains and further changing the microstructure of film. Furthermore, film incorporated with TP could improve the storage quality (including weight and texture) of blueberries, and inhibit the enzymatic browning of fresh-cut bananas during storage. All present results suggested that tea polyphenols had potential to enhance the properties and function of potato starch-based film, and the film exhibited the application prospect in fruit packaging and preservation.

Physicochemical and Antibacterial Properties of Alginate Films Containing Tansy (Tanacetum vulgare L.) Essential Oil

Tansy (Tanacetum vulgare) is a common plant used in folk medicine for digestive problems, fevers, and migraines; against parasites; and as an insect repellent. The active substances in essential oil are responsible for its antimicrobial and antioxidant activity. Thus, tansy essential oil (TO) was added to alginate films to fabricate materials with antioxidant and antibacterial properties for food packaging. Sodium alginate films with glycerol and TO were tested in terms of structure, mechanical, thermal, antioxidant, and antibacterial properties. The structure of the films was examined using SEM and an ATR-FTIR spectrophotometer. The addition of TO to the alginate film significantly changed the films' microstructure, making them rougher and porous. A low-intensity band at 1739 cm^-1, indicative of the presence of TO, appeared in all spectra of alginate films with TO. Moreover, the studies revealed that essential oil acted as a plasticizer, slightly reducing tensile strength from about 7 MPa to 5 MPa and increasing elongation at break from 52% to 56% for the sample with 2% TO. The alginate films enriched in TO exhibited antioxidant properties (280 μmol Trolox/100 g of the sample with 2% TO) and antibacterial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.

Citric Acid-Crosslinked Highly Porous Cellulose Nanofiber Foam Prepared by an Environment-Friendly and Simple Process

In this study, cellulose nanofiber (CNF) foams are prepared by an environment-friendly, time-saving, and simple process using bio-based citric acid (CA) as a green crosslinking agent. Scanning electron microscope and Fourier transform infrared spectroscopy examine the foam morphology and confirm the crosslinking. The prepared foam shows a very high porosity (>98%) with a low density (24.02 mg cm-3) with more than 200% improvement in mechanical strength and modulus compared to the neat CNF foam. In addition, the inclusion of CA into CNF improves thermal stability, antioxidant activity, and hydrophobicity. Furthermore, the prepared foam demonstrates a good sound absorption behavior, suitable for environment-friendly and lightweight sound-absorbing foam.

Reinforcement of starch film with Castanea sativa shells polysaccharides: Optimized formulation and characterization

Chestnut (Castanea sativa) shells, generated from the peeling process of the fruit, contains appreciable amounts of lignin and cellulose. In this work, a starch-based film reinforced with these polysaccharides was developed. Response Surface Methodology was employed to optimize the composition of the film with improved elongation, tensile strength, and elasticity modulus properties. The optimal film was characterized regarding structural, optical barrier and thermal properties. The optimum composition was obtained with 10% (w/w) fibers and 50% (w/w) glycerol; the elongation responses, tensile strength and modulus of elasticity reached values of 34.19%, 7.31 N and 4.15 N, respectively. The values of tension strength and modulus of elasticity were approximately 3.5 times higher than those obtained for the control film. The reinforced film was opaque and exhibited improved water solubility, UV-barrier capacity, and thermal stability compared to control. The optimized starch film based on chestnut shells fibers' has the potential to produce biodegradable food packaging with improved properties.

Effect on the Properties of Edible Starch-Based Films by the Incorporation of Additives: A Review

At present, people more actively pursuing biodegradable-based food packaging to lower the environmental problems of plastic-based packaging. Starch could become a promising alternative to plastic because of its properties (easily available, nontoxic, tasteless, biodegradable, ecofriendly, and edible). This review article is focused mainly on the impact of the properties of starch-based biodegradable films, such as their thickness, morphology, and optical, water-barrier, mechanical, oxygen-barrier, antioxidant, and antimicrobial properties, after the incorporation of additives, and how such films fulfill the demands of the manufacturing of biodegradable and edible food-based film with preferable performance. The incorporation of additives in starch-based films is largely explained by its functioning as a filler, as shown via a reduction in water and oxygen permeability, increased thickness, and better mechanical properties. Additives also showed antimicrobial and antioxidant properties in the films/coatings, which would positively impact the shelf life of coated or wrapped food material.

Current Trends in the Utilization of Essential Oils for Polysaccharide- and Protein-Derived Food Packaging Materials

Essential oils (EOs) have received attention in the food industry for developing biopolymer-derived food packaging materials. EOs are an excellent choice to replace petroleum-derived additives in food packaging materials due to their abundance in nature, eco-friendliness, and superior antimicrobial and antioxidant attributes. Thus far, EOs have been used in cellulose-, starch-, chitosan-, and protein-based food packaging materials. Biopolymer-based materials have lower antioxidant and antibacterial properties in comparison with their counterparts, and are not suitable for food packaging applications. Various synthetic-based compounds are being used to improve the antimicrobial and antioxidant properties of biopolymers. However, natural essential oils are sustainable and non-harmful alternatives to synthetic antimicrobial and antioxidant agents for use in biopolymer-derived food packaging materials. The incorporation of EOs into the polymeric matrix affects their physicochemical properties, particularly improving their antimicrobial and antioxidant properties. EOs in the food packaging materials increase the shelf life of the packaged food, inhibit the growth of microorganisms, and provide protection against oxidation. Essential oils also influence other properties, such as tensile, barrier, and optical properties of the biopolymers. This review article gives a detailed overview of the use of EOs in biopolymer-derived food packaging materials. The innovative ways of incorporating of EOs into food packaging materials are also highlighted, and future perspectives are discussed.

Highly effective and sustainable antibacterial membranes synthesized using biodegradable polymers

In order to reduce foodborne diseases caused by bacterial infections, antibacterial membranes have received increasing research interests in recent years. In this study, highly effective antibacterial membranes were prepared using biodegradable polymers, including polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and carboxymethyl cellulose (CMC). The cation exchange property of CMC was utilized to introduce silver to prepare antibacterial materials. The presence of silver in the membranes was confirmed by EDS mapping, and the reduction of silver ions to metallic silver was confirmed by the Ag3d XPS spectrum which displayed peaks at 374.46 eV and 368.45 eV, revealing that the oxidation state of silver changed to zero. Two common pathogenic bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), were used to investigate the antibacterial performance of the prepared membranes. Zone of inhibition and bacteria-killing tests revealed that the antibacterial membranes were efficient in inhibiting the growth of bacteria (diameters of inhibition zone ranged from 16 mm to 19 mm for fresh membranes) and capable of killing 100% of bacteria under suitable conditions. Furthermore, after 6 cycles of continuous zone of inhibition tests, the membranes still showed noticeable antibacterial activities, which disclosed the sustainable antibacterial properties of the membranes.

Starch-based bio-nanocomposites films reinforced with cellulosic nanocrystals extracted from Kudzu (Pueraria montana) vine

In the current study, starch-based active nanocomposite films reinforced with cellulosic nanocrystals (CNCs) of Kudzu were developed as an alternative option to existing biodegradable plastic packaging. Firstly, Kudzu CNCs were prepared by subjecting Kudzu fibers to the processes such as depolymerization followed by bleaching, acid hydrolysis, and mechanical dispersion. Further, nanocomposite films were formulated by blending pearl millet starch (PMS) and glycerol (30%) with different Kudzu CNCs compositions (0-7 wt%) using the solution casting process. The prepared PMS/Kudzu CNCs nanocomposite films were analyzed for their morphological (SEM and TEM), thermal (TGA and DSC), structural (FTIR), mechanical (tensile strength (TS), elongation at break and young modulus), and water barrier properties. The PMS/Kudzu CNCs films possessed improved crystallinity, heat and moisture-barrier properties, TS, and young-modulus after reinforcement. The optimum reinforcer concentration of CNCs was 5%. The Kudzu CNCs reinforced starch film offers a promising candidate for developing biodegradable films.

Progress in Starch-Based Materials for Food Packaging Applications

The food packaging sector generates large volumes of plastic waste due to the high demand for packaged products with a short shelf-life. Biopolymers such as starch-based materials are a promising alternative to non-renewable resins, offering a sustainable and environmentally friendly food packaging alternative for single-use products. This article provides a chronology of the development of starch-based materials for food packaging. Particular emphasis is placed on the challenges faced in processing these materials using conventional processing techniques for thermoplastics and other emerging techniques such as electrospinning and 3D printing. The improvement of the performance of starch-based materials by blending with other biopolymers, use of micro- and nano-sized reinforcements, and chemical modification of starch is discussed. Finally, an overview of recent developments of these materials in smart food packaging is given.

Nutritional Characteristics Assessment of Sunflower Seeds, Oil and Cake. Perspective of Using Sunflower Oilcakes as a Functional Ingredient

Ample amounts of by-products are generated from the oil industry. Among them, sunflower oilcakes have the potential to be used for human consumption, thus achieving the concept of sustainability and circular economy. The study assessed the nutritional composition of sunflower seeds, cold-pressed oil and the remaining press-cakes with the aim of its valorization as a food ingredient. Sunflower oil contains principally oleic (19.81%) and linoleic (64.35%) acids, which cannot be synthetized by humans and need to be assimilated through a diet. Sunflower seeds are very nutritive (33.85% proteins and 65.42% lipids and 18 mineral elements). Due to the rich content of lipids, they are principally used as a source of vegetable oil. Compared to seeds, sunflower oilcakes are richer in fibers (31.88% and 12.64% for samples in form of pellets and cake, respectively) and proteins (20.15% and 21.60%), with a balanced amino acids profile. The remaining oil (15.77% and 14.16%) is abundant in unsaturated fatty acids (95.59% and 92.12%). The comparison between the three products showed the presence of valuable components that makes them suitable for healthy diets with an adequate intake of nutrients and other bioactive compounds with benefic effects.

Anchor and bridge functions of APTES layer on interface between hydrophilic starch films and hydrophobic soyabean oil coating

One of the well-recognized weaknesses of starch-based materials is their sensitivity to moisture, which limits their expanding applications. Natural materials, soyabean oils have been used as a coating for starch film, but the poor interface between hydrophilic starch and hydrophobic soyabean oil needs to be improved. In this work, (3-Aminopropyl) triethoxysilane (APTES) was used to reinforce the bonding between starch matrix and the coating of bio-based acrylated epoxidized soyabean oil (AESO). Study results show that APTES interacted effectively with both starch films via hydrogen bonding, and chemical bonds with AESO through the Michael addition reaction. Pull adhesion and cross-cutting tests demonstrated that the interfacial adhesion was significantly improved after treating their surface with APTES. The interfacial adhesion strength increased over 4 times after treating with 1.6 wt% APTES. The starch films treated with APTES and AESO coating were intact after soaking in water for more than 2 h.

Stabilization Techniques of Essential Oils by Incorporation into Biodegradable Polymeric Materials for Food Packaging

Human health, food spoilage, and plastic waste, which are three great topical concerns, intersect in the field of food packaging. This has created a trend to replace synthetic food preservatives with natural ones, to produce bio-functional food packaging, and to shift towards biodegradable polymeric materials. Among the natural bioactive agents, essential oils are gaining more and more attention in food packaging applications due to their various benefits and fewer side-effects. However, their volatility, hydrophobicity, and strong odor and taste limit the direct use in food-related applications. Fixation into polymeric matrices represents a suitable strategy to promote the benefits and reduce the drawbacks. Emulsification and electrospinning are largely used techniques for protection and stabilization of essential oils. These methods offer various advantages in active food packaging, such as controlled release, ensuring long-term performance, decreased amounts of active agents that gain enhanced functionality through increased available surface area in contact with food, and versatility in packaging design. This review focuses on creating correlations between the use of essential oils as natural additives, stabilization methods, and biodegradable polymeric matrices or substrates in developing bioactive food packaging materials. Documentation was performed via the Scopus, ScienceDirect, and PubMed databases, selecting the publications after the year 2018. Particular attention was given to the publications that tested materials on food/food pathogens to evaluate their performances in retarding spoilage. Research gaps were also identified on the topic, materials being tested mainly at short time after preparation without considering the long-term storage that usually occurs in actual practice between production and use, and insufficient research related to upscaling.

Environment and food safety: a novel integrative review

Environment protection and food safety are two critical issues in the world. In this review, a novel approach which integrates statistical study and subjective discussion was adopted to review recent advances on environment and food safety. Firstly, a scientometric-based statistical study was conducted based on 4904 publications collected from the Web of Science Core Collection database. It was found that the research on environment and food safety was growing steadily from 2001 to 2020. Interestingly, the statistical analysis of most-cited papers, titles, abstracts, keywords, and research areas revealed that the research on environment and food safety was diverse and multidisciplinary. In addition to the scientometric study, strategies to protect environment and ensure food safety were critically discussed, followed by a discussion on the emerging research topics, including emerging contaminates (e.g., microplastics), rapid detection of contaminants (e.g., biosensors), and environment friendly food packaging materials (e.g., biodegradable polymers). Finally, current challenges and future research directions were proposed.

Functionality and Applicability of Starch-Based Films: An Eco-Friendly Approach

The accumulation of high amounts of petro-based plastics is a growing environmental devastation issue, leading to the urgent need to innovate eco-safe packaging materials at an equivalent cost to save the environment. Among different substitutes, starch-based types and their blends with biopolymers are considered an innovative and smart material alternative for petrol-based polymers because of their abundance, low cost, biodegradability, high biocompatibility, and better-quality film-forming and improved mechanical characteristics. Furthermore, starch is a valuable, sustainable food packaging material. The rising and growing importance of designing starch-based films from various sources for sustainable food packaging purposes is ongoing research. Research on "starch food packaging" is still at the beginning, based on the few studies published in the last decade in Web of Science. Additionally, the functionality of starch-based biodegradable substances is technically a challenge. It can be improved by starch modification, blending starch with other biopolymers or additives, and using novel preparation techniques. Starch-based films have been applied to packaging various foods, such as fruits and vegetables, bakery goods, and meat, indicating good prospects for commercial utilization. The current review will give a critical snapshot of starch-based films' properties and potential applicability in the sustainable smart (active and intelligent) new packaging concepts and discuss new challenges and opportunities for starch bio composites.

Bio-based multilayer films: A review of the principal methods of production and challenges

The development of biodegradable packaging materials has been drawing attention worldwide to minimize the environmental impact of traditional petroleum-based plastics. Nevertheless, it is challenging to obtain bio-based materials with suitable properties for packaging applications. Films produced from a single biopolymer often lack some important properties. An alternative to overcome this limitation is the multilayer assembly. Under this technology, two or more materials with specific and complementary properties are combined into a single-layered structure, thus improving the performance of bio-polymer plastics. This review presents the main aspects of bio-based multilayer film production technologies, discussing their advantages and disadvantages, which have to be considered to produce the most suitable film for each specific application. Most of the studies reported that such films resulted in increased mechanical performance and decreased water, oxygen, and dioxide carbon permeability. This approach allows the addition of compounds leading to antioxidant or antibacterial activity. Finally, a discussion about the future challenges is also presented.

Effects of cinnamon essential oil on the physical, mechanical, structural and thermal properties of cassava starch-based edible films

The edible films were mainly made from oxidized hydroxypropyl cassava starch incorporated with cinnamon essential oil (CEO). The effects of CEO amount on the physical and mechanical properties of films were studied, and the structures of films with and without CEO were characterized. The results showed that the elongation at break, water resistance, water vapor transmission coefficient, as well as oxygen and ultraviolet barrier properties of the films (p < 0.05) significantly increased with addition of CEO, while the tensile strength of the films decreased. The field emission scanning electron microscopic (FE-SEM) images and infrared (IR) spectra showed that the CEO had good compatibility with other components and could be evenly dispersed in the film, which was conducive to the stable release of the active components. X-ray diffraction (XRD) patterns showed that the addition of CEO increased the crystallinity of the film, indicating that the compatibility and structural stability of the crystal structure of the film were improved. The thermogravimetric analysis results showed that CEO was beneficial to improve the thermal stability of the films. This study provided a potential to develop edible films from modified cassava starch with CEO.

Corn starch based films treated by dielectric barrier discharge plasma

Cold plasma is an innovative strategy to strengthen the polysaccharide-based films characteristics. This study evaluated the effects of dielectric barrier discharge (DBD) plasma on the hydrophilic character, water vapor permeability (WVP), and tensile properties of corn starch-based films. Starch films were exposed to plasma processing operating at an excitation frequency of 200 Hz for 10, 15, and 20 min. DBD plasma resulted in further enhanced tensile strength and stiffness, and lower hydrophilicity and water solubility; however, it did not present significant effects on the WVP of the resulting films within the ranges studied. Higher hydrophobicity, strength, and stiffness were verified after 20 min. The results presented in this work suggest that the DBD plasma has the potential to make starch-based films a more suitable packaging material.

Two Fascinating Polysaccharides: Chitosan and Starch. Some Prominent Characterizations for Applying as Eco-Friendly Food Packaging and Pollutant Remover in Aqueous Medium. Progress in Recent Years: A Review

The call to use biodegradable, eco-friendly materials is urgent. The use of biopolymers as a replacement for the classic petroleum-based materials is increasing. Chitosan and starch have been widely studied with this purpose: to be part of this replacement. The importance of proper physical characterization of these biopolymers is essential for the intended application. This review focuses on characterizations of chitosan and starch, approximately from 2017 to date, in one of their most-used applications: food packaging for chitosan and as an adsorbent agent of pollutants in aqueous medium for starch.

Approaches in Animal Proteins and Natural Polysaccharides Application for Food Packaging: Edible Film Production and Quality Estimation

Natural biopolymers are an interesting resource for edible films production, as they are environmentally friendly packaging materials. The possibilities of the application of main animal proteins and natural polysaccharides are considered in the review, including the sources, structure, and limitations of usage. The main ways for overcoming the limitations caused by the physico-chemical properties of biopolymers are also discussed, including composites approaches, plasticizers, and the addition of crosslinking agents. Approaches for the production of biopolymer-based films and coatings are classified according to wet and dried processes and considered depending on biopolymer types. The methods for mechanical, physico-chemical, hydration, and uniformity estimation of edible films are reviewed.

Starch/tea polyphenols nanofibrous films for food packaging application: From facile construction to enhance mechanical, antioxidant and hydrophobic properties

Starch based food packaging has been receiving increasing attention. However, the inherent poor properties of starch restrict its practical applications in the versatile material science field. In this study, a fast, simple, and environmentally friendly route to construct polyfunctional starch/tea polyphenols nanofibrous films (STNFs) by one-step temperature-assisted electrospinning was developed. The effects of introduction of tea polyphenols (TP) on the mechanical and antioxidant activity of STNFs were comprehensively investigated. Results of ABTS·+ free radical scavenging assay showed that the antioxidant activity of STNFs was endowed by addition of TP with optimum mechanical properties confirmed by tensile test. More interestingly, the hydrophobicity of STNFs was improved dramatically with increasing cross-linking time as indicated by water contact angle (WCA) measurement showing no effect on the antioxidant activity of the films. The results of this work offer a major step forward to promote functional starch-based materials for sustainable application in food packaging.

Polysaccharide based films and coatings for food packaging: Effect of added polyphenols

There has been keen interest in developing biodegradable food packaging materials using polysaccharides. Plant polyphenols are natural antioxidants with many health effects. Different types of plant extracts rich in polyphenols have been formulated into polysaccharide based films and coatings for food packaging. The packaging increases the shelf life of food products by decreasing the quality loss due to oxidation and microbiological growth. The release of polyphenols from the films is modulated. Polysaccharide films incorporated with certain types of polyphenols can be used to indicate the freshness of animal based products. To formulate films with desirable mechanical and barrier properties, addition levels and types of plant extracts, plasticisers and composite polysaccharide materials used should be optimized. The potential of polysaccharide based films with added polyphenols to stop the SARS-CoV-2 transmission through food supply chain is discussed. Polysaccharide based films fortified with polyphenol extracts are multifunctional with potential for active and intelligent packaging.

Using Carboxymethyl Cellulose as the Additive With Enzyme-Catalyzed Carboxylated Starch to Prepare the Film With Enhanced Mechanical and Hydrophobic Properties

Carboxymethyl cellulose, a hydrophobic derivative from cellulose that can be prepared from different biomass, has been widely applied in food, medicine, chemical, and other industries. In this work, carboxymethyl cellulose was used as the additive to improve the hydrophobicity and strength of carboxylated starch film, which is prepared from starch catalyzed by bio-α-amylase. This study investigated the effects of different bio-α-amylase dosages (starch 0.5%, starch 1%) and different activation times (10, 30 min) on starch to prepare the carboxylated starch. The effects of different carboxymethyl cellulose content on the carboxylated starch film were investigated by analysis viscosity, fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, x-ray powder diffraction, scanning electron microscope, and contact angle. The results showed that preparing carboxylated starch using activated starch increased the carboxyl content, which could improve the effectiveness of the activated enzyme compared to prolonging the activation time. The carboxyl starch prepared by enzyme catalysis had a lower gelatinization temperature, and enzyme activation destroyed the crystallization area of the starch, thus facilitating the carboxylation reaction. The addition of 15% carboxymethyl cellulose improved the mechanical properties of the prepared film with maximum tensile strength of 44.8 MPa. Carboxymethyl cellulose effectively improved the hydrophobicity of the starch film with the addition amount of 10–30%, while hydrophobic property was stable at 66.8° when the addition amount was exceeded to 35%. In this work, it can be found that carboxymethyl cellulose improve the mechanical and hydrophobic properties of starch film, laying the foundation for the application of carboxylated starch materials.

Yerba Mate Extract in Microfibrillated Cellulose and Corn Starch Films as a Potential Wound Healing Bandage

Microfibrillated cellulose films have been gathering considerable attention due to their high mechanical properties and cheap cost. Additionally, it is possible to include compounds within the fibrillated structure in order to confer desirable properties. Ilex paraguariensis A. St.-Hil, yerba mate leaf extract has been reported to possess a high quantity of caffeoylquinic acids that may be beneficial for other applications instead of its conventional use as a hot beverage. Therefore, we investigate the effect of blending yerba mate extract during and after defibrillation of Eucalyptus sp. bleached kraft paper by ultrafine grinding. Blending the extract during defibrillation increased the mechanical and thermal properties, besides being able to use the whole extract. Afterwards, this material was also investigated with high content loadings of starch and glycerine. The results present that yerba mate extract increases film resistance, and the defibrillated cellulose is able to protect the bioactive compounds from the extract. Additionally, the films present antibacterial activity against two known pathogens S. aureus and E. coli, with high antioxidant activity and increased cell proliferation. This was attributed to the bioactive compounds that presented faster in vitro wound healing, suggesting that microfibrillated cellulose (MFC) films containing extract of yerba mate can be a potential alternative as wound healing bandages.