Trends in Chitosan as a Primary Biopolymer for Functional Films and Coatings Manufacture for Food and Natural Products

Chitosan-based nanocomposite films with carnauba wax, rosin resin, and zinc oxide nanoparticles

This work aimed to develop edible emulsion-based barriers in the form of chitosan composite films, with a focus on assessing the impacts of carnauba wax, rosin resin, and zinc oxide nanoparticles on their properties. Six films were produced by casting using chitosan as polymer base and glycerol as plasticizer. Acetic acid and polysorbate 80 were also used to facilitate the dissolution and mixing of the components. The six filmogenic solutions contained chitosan at 1.2% w/v, wax or resin content with 0 or 0.6% m/v and ZnO with 0 or 0.05% m/v. The dried films were characterized according to their chemical, barrier, mechanical, thermal and optical properties. All treatments resulted in flexible films. Chitosan films appeared smoother and more uniform under SEM imaging, while carnauba wax films displayed roughness due to their hydrophobic nature. Wax and resin films were less transparent and water soluble than the chitosan-only films. On the other hand, the addition of ZnO in the formulations increased the solubility of the films. The sorption degree was in line with the solubility results, i.e., films with ZnO presented higher sorption degree and solubility values. All treatments showed low or non-light UV transmission, indicating that the films provide good barrier to UV light. In the visible light region, films of resin with ZnO showed the lowest transmittance values, hence offering a good barrier to visible light. Among the evaluated films, chitosan, and resin films with ZnO nanoparticles were more rigid and resistant to deformation. Overall, films produced with rosin resin and ZnO nanoparticles showed potential improvements in barrier, mechanical, thermal, and optical properties, mainly due to their low water solubility, good UV protection and low permeability to water vapor and oxygen, which are suitable for using in formulations, intended to produce edible films and coatings.

Developing active and intelligent biodegradable packaging from food waste and byproducts: A review of sources, properties, film production methods, and their application in food preservation

Food waste and byproducts (FWBP) are a global issue impacting economies, resources, and health. Recycling and utilizing these wastes, due to processing and economic constraints, face various challenges. However, valuable components in food waste inspire efficient solutions like active intelligent packaging. Though research on this is booming, its material selectivity, effectiveness, and commercial viability require further analysis. This paper categorizes FWBP and explores their potential for producing packaging from both animal and plant perspectives. In addition, the preparation/fabrication methods of these films/coatings have also been summarized comprehensively, focusing on the advantages and disadvantages of these methods and their commercial adaptability. Finally, the functions of these films/coatings and their ultimate performance in protecting food (meat, dairy products, fruits, and vegetables) are also reviewed systematically. FWBP provide a variety of methods for the application of edible films, including being made into coatings, films, and fibers for food preservation, or extracting active substances directly or indirectly from them (in the form of encapsulation) and adding them to packaging to endow them with functions such as barrier, antibacterial, antioxidant, and pH response. In addition, the casting method is the most commonly used method for producing edible films, but more film production methods (extrusion, electrospinning, 3D printing) need to be tried to make up for the shortcomings of the current methods. Finally, researchers need to conduct more in-depth research on various active compounds from FWBP to achieve better application effects and commercial adaptability.

Edible-algae base composite film containing gelatin for food packaging from macroalgae, Gracilaroid (Gracilaria fisheri)

BACKGROUND

Conventional petroleum-based packaging films cause severe environmental problems. In the present study, bio-edible film was introduced as being safe to replace petroleum-based polymers. A food application for edible sachets and a composite edible film (EF) from marine algae, Gracilaria fisheri (GF) extract, were proposed.

RESULTS

Carbohydrates were the most prevalent component in fresh GF fronds. Under neutral conditions comprising 90 °C for 40 min, the structure of the extract was determined by Fourier transform infrared to be a carrageenan-like polysaccharide. Glycerol was the best plasticizer for EF formation because it had the highest tensile strength (TS). The integration of gelatin into the algal composite film with gelatin (CFG) was validated to be significant. The best casting temperatures for 2 h were 70 and 100 °C among the four tested temperatures (25, 60, 70 and 100 °C). Temperatures did not result in any significant (P ≤ 0.05) differences in any character (color values, TS, water vapor permeability, oxygen transmission, thickness and water activity), except elongation at break. Visually, the CFG had a slightly yellow appearance. The best-to-worst order of film stability in the three tested solvents was oil, distilled water (DW) and ethanol. Its stability in ethanol (0-100%), temperature of DW (30-100 °C) and pH (3-7 in DW) demonstrated inverse relationships with the concentration or different conditions, except for pH 8-10 in DW. All treatments were significantly (P ≤ 0.05) different.

CONCLUSION

The novel material made from polysaccharides from algae, G. fisheri, was used to improve EF. The edible sachet application is plausible from the EF. © 2024 Society of Chemical Industry.

Modified polysaccharides for food packaging applications: A review

Development of new food packaging materials is crucial to reduce the use of single-use plastics and to limit their destructive impact on the environment. Polysaccharides provide an alternative solution to this problem. This paper summarizes and discusses recent research results on the potential of modifying polysaccharides as materials for film and coating applications. Modifications of polysaccharides significantly affect their properties, as well as their application usability. Although modifications of biopolymers for packaging applications have been widely studied, polysaccharides have attracted little attention despite being a prospective, environmentally friendly, and economically viable packaging alternative. Therefore, this paper discusses approaches to the development of biodegradable, polysaccharide-based food packaging materials and focuses on modifications of four polysaccharides, such as starch, chitosan, sodium alginate and cellulose. In addition, these modifications are presented not only in terms of the selected polysaccharide, but also in terms of specific properties, i.e. hydrophilic, barrier and mechanical properties, of polysaccharides. Such a presentation of results makes it much easier to select the modification method to improve the unsatisfactory properties of the material. Moreover, very often it happens that the applied modification improves one and worsens another property, which is also presented in this review.

An overview of the potential application of chitosan in meat and meat products

Chitosan is considered the second most ubiquitous polysaccharide next to cellulose. It has gained prominence in various industries including biomedicine, textile, pharmaceutical, cosmetic, and notably, the food industry over the last few decades. The polymer's continual attention within the food industry can be attributed to the increasing popularity of greener means of packaging and demand for foods incorporated with natural alternatives instead of synthetic additives. Its antioxidant, antimicrobial, and film-forming abilities reinforced by the polymer's biocompatible, biodegradable, and nontoxic nature have fostered its usage in food packaging and preservation. Microbial activity and lipid oxidation significantly influence the shelf-life of meat, resulting in unfavorable changes in nutritional and sensory properties during storage. In this review, the scientific studies published in recent years regarding potential applications of chitosan in meat products; and their effects on shelf-life extension and sensory properties are discussed. The utilization of chitosan in the form of films, coatings, and additives in meat products has supported the extension of shelf-life while inducing a positive impact on their organoleptic properties. The nature of chitosan and its compatibility with various materials make it an ideal biopolymer to be used in novel arenas of food technology.

Sustainable polylactic acid spunlace nonwoven fabrics with lignin/zinc oxide/water-based polyurethane composite coatings

In this paper, polylactic acid spunlace nonwoven fabrics were coated with lignin/zinc oxide/water-based polyurethane composite formulations, including five different ratios of lignin and zinc oxide, via a film applicator and thermally cured. The coated and thermally cured nonwoven fabrics were tested in terms of color values, tensile strength, abrasion resistance, ultraviolet protection, hydrophobicity, antibacterial activity, air, and vapor permeability properties. Characterization studies were conducted by FTIR, DSC, TGA, XRD, and SEM. The ultraviolet protection factor of 215.47 and a water contact angle of 90.27° were obtained with the fabric coated with WPU-1:5 formulation. Nonwoven fabric coated with the WPU-1:5 formulation showed evident antibacterial activity against S. aureus and E. coli bacteria as 89 % and 100 %, respectively. With the addition of lignin/ZnO into water-based polyurethane coating paste, PLA nonwoven fabric exhibited improved antibacterial activity, tensile strength, abrasion resistance, and ultraviolet light protection performance. However, composite coatings decreased air and vapor permeability and hydrophobicity of fabrics, but acceptable results were obtained. The results indicate that polylactic acid nonwoven fabrics, when treated with lignin/ZnO/WPU composite coatings, exhibit enhanced mechanical and functional properties, rendering them promising for applications in protective medical textiles.

Application of antimicrobial chitosan-Furcellaran-hydrolysate gelatin edible coatings enriched with bioactive peptides in shelf-life extension of pork loin stored at 4 and -20 °C

In this study, the authors investigate the preservative capabilities of edible coatings comprising a blend of chitosan, furcellaran and gelatin hydrolysate enhanced with the bioactive peptides RW4 and LL37. The preservative effects on pork samples stored for 21 days at 4 °C and 6 months at -20 °C were studied, while examining changes in microbiological contamination, pH levels, water activity and sensory attributes. Microbiological analyses reveal the coatings' antimicrobial efficacy against aerobic bacteria, microscopic fungi and yeasts, particularly during the initial storage period, when coated samples exhibit microbial reductions of 0.5-2 log CFU/g compared to the controls. The coatings have no discernible impact on water activity during storage in refrigerated or freezer conditions. Notably, differences in pH development can be observed between the coated and control samples, potentially attributable to the antimicrobial action of the coatings. Sensory analysis allows to highlight the inhibition of deterioration related to sensory attributes through the use of edible coatings. In conclusion, employing bioactive peptide-enriched edible coatings holds promise for extending the shelf-life of perishable foods.

Fabrication and characterization of transparent nanocomposite films based on poly (lactic acid)/polyethylene glycol reinforced with nano glass flake

Developing new biodegradable packaging with superior properties and advanced functionalities is one of the most emerging research areas of interest in food packaging. In this study, PLA/PEG-based nanocomposite films incorporated with different amounts of nano glass flake (NGF) (0, 0.5, 1, and 2 phr) were fabricated via casting solution for applications in food packaging. The ATR-FTIR displayed no chemical interaction between the PLA/PEG-based matrix and NGF particles. The scanning electron microscopy (SEM) observations exhibited a relatively smooth and homogeneous surface without defects. Incorporation of the NGF into the PLA/PEG-based matrix did not affect the color and opacity of the fabricated films. The prepared nanocomposite films were highly transparent and exhibited superior properties such as increased hydrophobicity, appreciable oxygen barrier properties, and enhanced thermal stability. Dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) analysis confirmed the existence of a single glass-transition temperature (Tg) as evidence of miscibility. According to the research results, the PLA/PEG/NGF1 nanocomposite film significantly offered the best overall performance. This work has developed new insight into the potential application of nano glass flakes in food packaging.

Enhanced mechanical and functional properties of chitosan/polyvinyl alcohol/hydroxypropyl methylcellulose/alizarin composite film by incorporating cinnamon essential oil and tea polyphenols

In this study, cinnamon essential oil and tea polyphenols were added to chitosan/ polyvinyl alcohol/ hydroxypropyl methylcellulose/ alizarin composite films to enhance their mechanical and functional properties. Their addition to the composite films enhanced their antibacterial and antioxidant properties and significantly improved its elongation at break (p < 0.05). Cinnamon essential oil reduced the water vapor permeability, water content, and water solubility of composite films and improved their transparency. The composite films with additive exhibited excellent UV-barrier ability and pH responsivity. Fourier Transform infrared spectroscopy and X-Ray Diffraction analyses confirmed hydrogen bond formation between the polymer molecules and additives. The results of Scanning Electron Microscope-Focused Ion Beam revealed improved surface and cross-section morphology of the films, leading to the generation of a cross-linked structure. Thermogravimetric and differential scanning calorimetry analysis indicated enhanced thermal stability of the composite films upon cinnamon essential oil addition. Analysis of storage quality indicators (TBARS value, TVC, and TVB-N) revealed that the composite films could prolong the freshness of surimi. The incorporation of cinnamon essential oil and tea polyphenols into the composite films has demonstrated significant potential as an effective and natural alternative for active food packaging.

Characterization of Moringa oleifera Seed Oil for the Development of a Biopackage Applied to Maintain the Quality of Turkey Ham

Moringa oleifera has a high level of active chemicals that are useful in the food industry, and they have antibacterial and food preservation properties. The characterization of M. oleifera seed oil (MOS) may vary due to agronomic and environmental factors. Therefore, it was necessary to know the composition of lipids present in our oil extracted under pressing at 180 °C and thus determine if it is suitable to produce a biopackaging. Within the characterization of the oil, it was obtained that MOS presented high-quality fatty acids (71% oleic acid) with low values of acidity (0.71 mg KOH/g) and peroxide (1.74 meq O2/kg). Furthermore, MOS was not very sensitive to lipoperoxidation by tert-butyl hydroperoxide (tBuOOH) and its phenolic components, oleic acid and tocopherols, allowed MOS to present a recovery of 70% after 30 min of treatment. Subsequently, a biopackaging was developed using a multiple emulsion containing corn starch/carboxymethylcellulose/glycerol/MOS, which presented good mechanical properties (strength and flexibility), transparency, and a barrier that prevents the transfer of UV light by 30% and UV-C by 98%, as well as a flux with the atmosphere of 5.12 × 10-8 g/ m.s. Pa that prevents moisture loss and protects the turkey ham from O2. Hence, the turkey ham suffered less weight loss and less hardness due to its preservation in the biopackaging.

Edible coatings and films for shelf-life extension of fruit and vegetables

The execution of the edible coatings and films for food preservation; vegetables, fruits, meat, and dry fruits has been ladened in history. The study of literature portrays enough pieces of evidence dating back from centuries of coatings or films being utilized for the conservation of numerous fruits and vegetables to stretch their average shelf-life. The mechanism that remains operative in extending the shelf-life of fruits and vegetables beyond the normal shelf-life is the controlled entry and exit of moisture and gases. The non- biodegradable packaging which is also non-sustainable can be substituted with compostable and edible coatings and films made up of natural biopolymers. Therefore, keeping in mind the environment and consumer safety, a score of research has been going on from former decades for the development of edible coatings and films with efficient shelf life-extending qualities. The films composed of proteins exhibit a good mechanical strength while the polysaccharide composed films and coatings show efficient gas blocking qualities, however, both lack moisture shielding attributes. These shortcomings can be fixed by combining them with lipids and or some appropriate hydrocolloids. The edible coatings and films have been integrated with various food products; however, they haven't been completely successful in substitution of the total fraction of their non-edible counterparts. The implementation of edible coatings and films have shown to serve an immense value in extending the shelf-life of fruits and vegetables along with being a sustainable and eco-friendly approach for food packaging.

Effect of a Chitosan Coating Enriched with an Olive Leaf Extract on the Characteristics of Pork Burgers

Chitosan coatings have been investigated for improving food shelf-life. The addition of an olive leaf extract could enhance its beneficial effect. The aim of this study was to evaluate the effectiveness of an olive leaf extract added to a chitosan coating in delaying deterioration in refrigerated pork burgers without additives packaged under a 40% oxygen and 60% carbon dioxide modified atmosphere. Some general parameters (microbial counts, instrumental color and texture, and lipid and protein oxidation) were measured over the storage of pork burgers without coating (Control), with a chitosan-based coating (Chitosan) and with a chitosan-based coating enriched with an olive leaf extract (Chitoex). The coating impacted the effect of the storage time on most parameters. Both coatings were especially effective at limiting the changes that occur over time in the headspace gases, some texture parameters (hardness, gumminess, and chewiness) and lipid oxidation, although the effect on the microbial counts was weak. Chitoex was more effective than Chitosan at preventing changes in the headspace gases on day 11 and in lipid oxidation on all the sampling days. In conclusion, the Chitoex coating could be useful for prolonging the storage of pork burgers by preventing changes in texture and reducing lipid oxidation.

A critical review on biodegradable food packaging for meat: Materials, sustainability, regulations, and perspectives in the EU

The development of biodegradable packaging is a challenge, as conventional plastics have many advantages in terms of high flexibility, transparency, low cost, strong mechanical characteristics, and high resistance to heat compared with most biodegradable plastics. The quality of biodegradable materials and the research needed for their improvement for meat packaging were critically evaluated in this study. In terms of sustainability, biodegradable packagings are more sustainable than conventional plastics; however, most of them contain unsustainable chemical additives. Cellulose showed a high potential for meat preservation due to high moisture control. Polyhydroxyalkanoates and polylactic acid (PLA) are renewable materials that have been recently introduced to the market, but their application in meat products is still limited. To be classified as an edible film, the mechanical properties and acceptable control over gas and moisture exchange need to be improved. PLA and cellulose-based films possess the advantage of protection against oxygen and water permeation; however, the addition of functional substances plays an important role in their effects on the foods. Furthermore, the use of packaging materials is increasing due to consumer demand for natural high-quality food packaging that serves functions such as extended shelf-life and contamination protection. To support the importance moving toward biodegradable packaging for meat, this review presented novel perspectives regarding ecological impacts, commercial status, and consumer perspectives. Those aspects are then evaluated with the specific consideration of regulations and perspective in the European Union (EU) for employing renewable and ecological meat packaging materials. This review also helps to highlight the situation regarding biodegradable food packaging for meat in the EU specifically.

A Review on Edible Coatings and Films: Advances, Composition, Production Methods, and Safety Concerns

Food is a crucial source for the endurance of individuals, and quality concerns of consumers are being raised with the progression of time. Edible coatings and films (ECFs) are increasingly important in biobased packaging because they have a prime role in enhancing the organoleptic characteristics of the food products and minimizing the spread of microorganisms. These sustainable ingredients are crucial for a safer and healthier environment. These are created from proteins, polysaccharides, lipids, plasticizers, emulsifiers, and active substances. These are eco-friendly since made from innocuous material. Nanocomposite films are also beginning to be developed and support networks of biological polymers. Antioxidant, flavoring, and coloring compounds can be employed to improve the quality, wellbeing, and stability of packaged foods. Gelatin-enhanced fruit and vegetable-based ECFs compositions have the potential to produce biodegradable films. Root plants like cassava, potato, and sweet potato have been employed to create edible films and coatings. Achira flour, amylum, yam, ulluco, and water chestnut have all been considered as novel film-forming ingredients. The physical properties of biopolymers are influenced by the characteristics, biochemical confirmation, compatibility, relative humidity, temperature, water resistance, and application procedures of the components. ECFs must adhere to all regulations governing food safety and be generally recognized as safe (GRAS). This review covers the new advancements in ECFs regarding the commitment of novel components to the improvement of their properties. It is expected that ECFs can be further investigated to provide innovative components and strategies that are helpful for global financial issues and the environment.

Preparation of chitosan/Enoki mushroom foot polysaccharide composite cling film and its application in blueberry preservation

In this study, the composite cling film was prepared by solution casting method using chitosan and golden mushroom foot polysaccharide as substrates, and the structure and physicochemical indexes of the composite cling film were characterized by Fourier infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The results showed that compared with single chitosan film, the composite cling film has better mechanical properties and antioxidant properties, and the barrier of UV light and water vapor is also stronger. Due to its high nutritional value, blueberry has a short shelf life due to its thin skin and poor storage resistance. Therefore, in this study, blueberry was used as the object of freshness preservation, and the single chitosan film group and the uncovered group were used as controls, and the weight loss, total bacterial colony, decay rate, respiration intensity, malondialdehyde content, hardness, soluble solids, titratable acid, anthocyanin content, and VC content of blueberry were used as freshness preservation indexes for experiments. The comprehensive results showed that the freshness preservation effect of the composite film group was significantly higher than that of the control group, with better antibacterial properties, antioxidant properties, etc., which could effectively delay fruit decay and deterioration, thus prolonging the shelf life, and thus the chitosan/Enoki mushroom foot polysaccharide composite preservation film has a high potential as a new freshness preservation material for blueberry.

Chitosan-Based Hydrogel in the Management of Dermal Infections: A Review

The main objective of this review is to provide a comprehensive overview of the current evidence regarding the use of chitosan-based hydrogels to manage skin infections. Chitosan, a naturally occurring polysaccharide derived from chitin, possesses inherent antimicrobial properties, making it a promising candidate for treating various dermal infections. This review follows a systematic approach to analyze relevant studies that have investigated the effectiveness of chitosan-based hydrogels in the context of dermal infections. By examining the available evidence, this review aims to evaluate these hydrogels' overall efficacy, safety, and potential applications for managing dermal infections. This review's primary focus is to gather and analyze data from different recent studies about chitosan-based hydrogels combating dermal infections; this includes assessing their ability to inhibit the growth of microorganisms and reduce infection-related symptoms. Furthermore, this review also considers the safety profile of chitosan-based hydrogels, examining any potential adverse effects associated with their use. This evaluation is crucial to ensure that these hydrogels can be safely utilized in the management of dermal infections without causing harm to patients. The review aims to provide healthcare professionals and researchers with a comprehensive understanding of the current evidence regarding the use of chitosan-based hydrogels for dermal infection management. The findings from this review can contribute to informed decision-making and the development of potential treatment strategies in this field.

Chitosan-based electrospun nanofibers for encapsulating food bioactive ingredients: A review

Today, society has been more aware of healthy food products and related items containing bioactive compounds, which potentially contribute to human health. Unfortunately, the long-term stability and bioactivity of biologically active compounds against environmental factors compromise their target and effective action. In this way, lab-designed vehicles, such as nanoparticles and nanofibers, provide enough properties for their preservation and suitable delivery. Here, the electrospinning technique acts as an effective pathway for fabricating and designing nanofibers for the entrapments of biomolecules, in which several biopolymers such as proteins, polysaccharides (e.g., maltodextrin, agarose, chitosan), silk, among others, can be used as a wall material. It is likely that chitosan is one of the most employed biomaterials in this field. Therefore, in this review, we reveal the latest advances (over the last 2-3 years) in designing chitosan-based electrospun nanofibers and nanocarriers for encapsulation of bioactive compounds, along with the key applications in smart food packaging as well. Key findings and relevant breakthroughs are a priority in this review to provide a cutting-edge analysis of the literature. Finally, particular attention has been paid to the most promising developments.

Wall Materials for Encapsulating Bioactive Compounds via Spray-Drying: A Review

Spray-drying is a continuous encapsulation method that effectively preserves, stabilizes, and retards the degradation of bioactive compounds by encapsulating them within a wall material. The resulting capsules exhibit diverse characteristics influenced by factors such as operating conditions (e.g., air temperature and feed rate) and the interactions between the bioactive compounds and the wall material. This review aims to compile recent research (within the past 5 years) on spray-drying for bioactive compound encapsulation, emphasizing the significance of wall materials in spray-drying and their impact on encapsulation yield, efficiency, and capsule morphology.

Endoglucanase pretreatment aids in isolating tailored-cellulose nanofibrils combining energy saving and high-performance packaging

Cellulose nanofibrils (CNFs) have emerged as a potential alternative to synthetic polymers in packaging applications owing to their oxygen and grease barrier performance and mechanical properties. However, the performance of CNF films is dependent on the intrinsic characteristics of fibers, which are changed during CNF isolation. Understanding the variations in these characteristics during CNF isolation is crucial for tailoring CNF film properties to achieve optimum performance in packaging applications. In this study, CNFs were isolated by endoglucanase-assisted mechanical ultra-refining. The changes in the intrinsic characteristics of CNFs and their impact on CNF films were systematically investigated as functions of the degree of defibrillation, enzyme loading, and reaction time using the design of experiments. Enzyme loading had a significant effect on the crystallinity index, crystallite size, surface area, and viscosity. Meanwhile, the degree of defibrillation greatly influenced the aspect ratio, degree of polymerization, and particle size. CNF films prepared from CNFs isolated under two optimized scenarios (casting and coating applications) exhibited high thermal stability (approximately 300 °C), high tensile strength (104-113 MPa), high oil resistance (kit n°12), and low oxygen transmission rate (1.00-3.17 cc·m^-2.day^-1). Therefore, endoglucanase pretreatment can obtain CNFs at lower energy consumption, resulting in films with higher transmittance, higher barrier performance, and lower surface wettability than the control samples without enzymatic pretreatment and other unmodified net CNF films reported in the literature without intensive loss of mechanical and thermal performance.

Investigation of Cross-Linked Chitosan-Based Membranes as Potential Adsorbents for the Removal of Cu2+ Ions from Aqueous Solutions

Rapid industrialization has led to huge amounts of organic pollutants and toxic heavy metals into aquatic environment. Among the different strategies explored, adsorption remains until the most convenient process for water remediation. In the present work, novel cross-linked chitosan-based membranes were elaborated as potential adsorbents of Cu²⁺ ions, using as cross-linking agent a random water-soluble copolymer P(DMAM-co-GMA) of glycidyl methacrylate (GMA) and N,N-dimethylacrylamide (DMAM). Cross-linked polymeric membranes were prepared through casting aqueous solutions of mixtures of P(DMAM-co-GMA) and chitosan hydrochloride, followed by thermal treatment at 120 °C. After deprotonation, the membranes were further explored as potential adsorbents of Cu²⁺ ions from aqueous CuSO₄ solution. The successful complexation of copper ions with unprotonated chitosan was verified visually through the color change of the membranes and quantified through UV-vis spectroscopy. Cross-linked membranes based on unprotonated chitosan adsorb Cu²⁺ ions efficiently and decrease the concentration of Cu²⁺ ions in water to a few ppm. In addition, they can act as simple visual sensors for the detection of Cu²⁺ ions at low concentrations (~0.2 mM). The adsorption kinetics were well-described by a pseudo-second order and intraparticle diffusion model, while the adsorption isotherms followed the Langmuir model, revealing maximum adsorption capacities in the range of 66-130 mg/g. Finally, it was shown that the membranes can be effectively regenerated using aqueous H₂SO₄ solution and reused.

A Review of Regulatory Standards and Advances in Essential Oils as Antimicrobials in Foods

As essential oils (EOs) possess GRAS status, there is a strong interest in their application to food preservation. Trends in the food industry suggest consumers are drawn to environmentally friendly alternatives and less synthetic chemical preservatives. Although the use of EOs has increased over the years, adverse effects have limited their use. This review aims to address the regulatory standards for EO usage in food, techniques for delivery of EOs, essential oils commonly used to control pathogens and molds, and advances with new active compounds that overcome sensory effects for meat products, fresh fruits and vegetables, fruit and vegetable juices, seafood, dairy products, and other products. This review will show adverse sensory effects can be overcome in various products by the use of edible coatings containing encapsulated EOs to facilitate the controlled release of EOs. Depending on the method of cooking, the food product has been shown to mask flavors associated with EOs. In addition, using active packaging materials can decrease the diffusion rate of the EOs, thus controlling undesirable flavor characteristics while still preserving or prolonging the shelf life of food. The use of encapsulation in packaging film can control the release of volatile or active ingredients. Further, use of EOs in the vapor phase allows for contact indirectly, and use of nanoemulsion, coating, and film wrap allows for the controlled release of the EOs. Research has also shown that combining EOs can prevent adverse sensory effects. Essential oils continue to serve as a very beneficial way of controlling undesirable microorganisms in food systems.

Chitosan as an Outstanding Polysaccharide Improving Health-Commodities of Humans and Environmental Protection

Public health, production and preservation of food, development of environmentally friendly (cosmeto-)textiles and plastics, synthesis processes using green technology, and improvement of water quality, among other domains, can be controlled with the help of chitosan. It has been demonstrated that this biopolymer exhibits advantageous properties, such as biocompatibility, biodegradability, antimicrobial effect, mucoadhesive properties, film-forming capacity, elicitor of plant defenses, coagulant-flocculant ability, synergistic effect and adjuvant along with other substances and materials. In part, its versatility is attributed to the presence of ionizable and reactive primary amino groups that provide strong chemical interactions with small inorganic and organic substances, macromolecules, ions, and cell membranes/walls. Hence, chitosan has been used either to create new materials or to modify the properties of conventional materials applied on an industrial scale. Considering the relevance of strategic topics around the world, this review integrates recent studies and key background information constructed by different researchers designing chitosan-based materials with potential applications in the aforementioned concerns.

The effect of essential oils mixture on chitosan-based film surface energy and antiadhesion activity against foodborne bacteria

In the food sector, the formation of biofilms as a result of microbial adherence on food-grade surfaces causes a major problem resulting in significant economic losses. Thereby, this work aimed to elaborate a biodegradable film using chitosan (CS-film) and reinforce its antiadhesion activity by incorporating pelargonium, clove, thyme, and cinnamon essential oils (EOs). Firstly, the antibacterial activity of these EOs alone and combined against four foodborne bacteria were analyzed by the microdilution method. Synergism was observed in the case of EOs combination. Secondly, the physicochemical characteristics and antiadhesion behavior of the CS-films were assessed by the contact angle method and ESEM, respectively. Results revealed that the EOs mixture treatment impacted considerably the physicochemical characteristics of the CS-film and reduced its qualitative and quantitative hydrophobicity. Moreover, the treated CS-film showed a strong antiadhesion behavior against Enterococcus hirae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with percentages of non-covered surface equal to 97.65 ± 1.43%, 98.76 ± 0.32%, 99.68 ± 0.28%, and 95.63 ± 1.32% respectively. From all these results, the CS-film treated with the mixture of EOs presents a great potential for application as surface coating and food packaging preventing microbial adhesion and thus, avoiding food contamination and spoilage.

Polysaccharide-Based Biodegradable Films: An Alternative in Food Packaging

Packaging can mitigate the physical, chemical, and microbiological phenomena that affects food products’ quality and acceptability. However, the use of conventional packaging from non-renewable fossil sources generates environmental damage caused by the accumulation of non-biodegradable waste. Biodegradable films emerge as alternative biomaterials which are ecologically sustainable and offer protection and increase food product shelf life. This review describes the role of biodegradable films as packaging material and their importance regarding food quality. The study emphasizes polysaccharide-based biodegradable films and their use in foods with different requirements and the advances and future challenges for developing intelligent biodegradable films. In addition, the study explores the importance of the selection of the type of polysaccharide and its combination with other polymers for the generation of biodegradable films with functional characteristics. It also discusses additives that cause interactions between components and improve the mechanical and barrier properties of biodegradable films. Finally, this compilation of scientific works shows that biodegradable films are an alternative to protecting perishable foods, and studying and understanding them helps bring them closer to replacing commercial synthetic packaging.

Green and multifunctional chitosan-based conformal coating as a controlled release platform for fruit preservation

Food waste caused by the decay of perishable foods is a serious global issue. However, traditional preservative materials don't perform well in preventing food decay. Here, a green and multifunctional conformal coating is prepared by the hydrogen-bonding interactions among chitosan, nano-humic acid and curcumin, which is different from traditional preservative films obtained by solution blending. Thanks to the formation of hydrogen-bonding network, the surface roughness of the coating increased from 9.43 nm to 33.3 nm, which makes it more matches with the micro/nano structure of the fruit surface and obtains a good coating effect for various fruits. Furthermore, this coating shows distinctive mechanical properties (the tensile strength of 31.4 MPa), antioxidant and antibacterial activities (the inhibition zone ≥5 mm), and can be used to control the long-term release (up to 38 days) of natural preservative onto fruit surfaces. Through the demonstration of four perishable fruits, the coating can keep freshness and appearance at least 9 days longer than the uncoated samples, confirming the universal effectiveness of the coating in preventing fruit decay. This coating is easy to produce and use, washable, degradable, and makes from cheap or waste renewable biomaterials, which does not cause additional health and environmental concerns.

Economical Chemical Recycling of Complex PET Waste in the Form of Active Packaging Material

Since millions of tons of packaging material cannot be recycled in conventional ways, most of it ends up in landfills or even dumped into the natural environment. The researched methods of chemical depolymerization therefore open a new perspective for the recycling of various PET materials, which are especially important for packaging. Food preservative packaging materials made from PET plastics are complex, and their wastes are often contaminated, so there are no sophisticated solutions for them in the recycling industry. After integrating the biopolymer chitosan, which is derived from natural chitin, as an active surface additive in PET materials, we discovered that it not only enriches the packaging material as a microbial inhibitor to reduce the bacteria Staphylococcus aureus and Escherichia coli, thus extending the shelf life of the contained food, but also enables economical chemical recycling by alkaline or neutral hydrolysis, which is an environmentally friendly process. Alkaline hydrolysis at a high temperature and pressure completely depolymerizes chitosan-coated PET packaging materials into pure terephthalic acid and charcoal. The products were characterized by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The resulting reusable material represents raw materials in chemical, plastic, textile, and other industries, in addition to the antimicrobial function and recyclability itself.

Development of self-assembled zein-fucoidan complex nanoparticles as a delivery system for resveratrol

Resveratrol is a well-studied dietary polyphenol with diverse health-promoting bioactivities. However, the aqueous insolubility and chemical instability of resveratrol hamper its practical application. This study set out to address these limitations by constructing zein-fucoidan composite nanoparticles as a delivery system of resveratrol. The optimized resveratrol-loaded zein-fucoidan particles (RE-ZFP) were obtained at zein-to-fucoidan ratio of 2:1 (w/w) and zein-to-resveratrol ratio of 10:1 (w/w), and RE-ZFP showed evenly distributed and smoothly spherical microstructures, mean particle size of 121 nm, ζ-potential of - 41 mV, encapsulation efficiency for resveratrol of 95.4%. Electrostatic, steric, hydrophobic, and hydrogen-bonding interactions were major forces required to form RE-ZFP. In addition, RE-ZFP exhibited greater photostability and colloidal stability (including pH, ionic, and storage stabilities) than resveratrol-loaded zein particles (RE-ZP). Particularly, RE-ZFP showed fairly good pH stability. Moreover, zein-fucoidan-based delivery system exhibited a controlled release of resveratrol under in vitro digestion. Finally, zein-fucoidan nanocarriers presented extremely low cytotoxicity to HIEC-6 cells. All the findings demonstrate that the zein-fucoidan nanoparticles developed in the current work will be a prospective strategy for loading resveratrol and other hydrophobic bioactive ingredients and thus extending their application in nutraceuticals or pharmaceuticals.

Polysaccharides: Sources, Characteristics, Properties, and Their Application in Biodegradable Films

Biodegradable films emerge as alternative biomaterials to conventional packaging from fossil sources, which, in addition to offering protection and increasing the shelf life of food products, are ecologically sustainable. The materials mostly used in their formulation are based on natural polysaccharides, plasticizing agents, and bioactive components (e.g., antimicrobial agents or antioxidants). The formulation of biodegradable films from polysaccharides and various plasticizers represents an alternative for primary packaging that can be assigned to specific food products, which opens the possibility of having multiple options of biodegradable films for the same product. This review describes the main characteristics of the most abundant polysaccharides in nature and highlights their role in the formulation of biodegradable films. The compilation and discussion emphasize studies that report on the mechanical and barrier properties of biodegradable films when made from pure polysaccharides and when mixed with other polysaccharides and plasticizing agents.

New Zinc-Based Active Chitosan Films: Physicochemical Characterization, Antioxidant, and Antimicrobial Properties

The improvement of the antioxidant and antimicrobial activities of chitosan (CS) films can be realized by incorporating transition metal complexes as active components. In this context, bioactive films were prepared by embedding a newly synthesized acylpyrazolonate Zn(II) complex, [Zn(Q^PhtBu)₂(MeOH)₂], into the eco-friendly biopolymer CS matrix. Homogeneous, amorphous, flexible, and transparent CS@Zn_n films were obtained through the solvent casting method in dilute acidic solution, using different weight ratios of the Zn(II) complex to CS and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Raman, and scanning electron microscopy (SEM) techniques. The X-ray single-crystal analysis of [Zn(Q^PhtBu)₂(MeOH)₂] and the evaluation of its intermolecular interactions with a protonated glucosamine fragment through hydrogen bond propensity (HBP) calculations are reported. The effects of the different contents of the [Zn(Q^PhtBu)₂(MeOH)₂] complex on the CS biological proprieties have been evaluated, proving that the new CS@Zn_n films show an improved antioxidant activity, tested according to the DPPH method, with respect to pure CS, related to the concentration of the incorporated Zn(II) complex. Finally, the CS@Zn_n films were tried out as antimicrobial agents, showing an increase in antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus) with respect to pure CS, when detected by the agar disk-diffusion method.

Genipin-Crosslinked Gelatin/Chitosan-Based Functional Films Incorporated with Rosemary Essential Oil and Quercetin

Functional food packaging films were prepared using a binary mixture of chitosan and gelatin through crosslinking with genipin and hybridization with rosemary essential oil and quercetin. The mixture of chitosan and gelatin produced the compatible film, and the added fillers also showed good compatibility. The physical properties of the chitosan/gelatin film were not greatly affected by crosslinking with genipin, and the functionality of the composite film was increased by the addition of rosemary essential oil and quercetin. The bioactive additives did not significantly affect the hydrophobicity and water vapor barrier properties of the chitosan/gelatin film but significantly changed the color, while the mechanical and thermal properties were slightly affected. The addition of these functional fillers significantly improved the UV protection, antioxidant, and antibacterial properties of the chitosan/gelatin film. Therefore, the novel chitosan/gelatin film with genipin crosslinking and the integration of rosemary essential oil and quercetin is considered to have high potential for applications in active food packaging.

A shelf-life study for the evaluation of a new biopackaging to preserve the quality of organic chicken meat

Widespread use of traditional packaging constitutes a serious ecological problem leading to a shift to biodegradable and compostable materials. The aim of this work is to study the ability of a new biopackaging (BP), based on biodegradable and compostable material, to preserve the quality of organic chicken meat for 14 days in comparison with a polyethylene terephthalate (PET) material. Results showed that the indices of Biogenic Amines (BAs) and the 18 monitored Volatile Organic Compounds (VOCs) have a similar trend in both packaged meats. For example, the total BAs concentration in meat increased from 390 to 961 mg Kg^-1 in BP and from 393 to 800 mg Kg^-1 in PET, as well as the microbiological counts. The new biopackaging (BP) showed similar properties of non-biodegradable material (PET) to preserve the shelf life of organic chicken meat and it could be used instead of plastic materials to promote a circular economy.

Characterisation and Antibacterial Properties of Novel Biodegradable Films Based on Alginate and Roselle (Hibiscus sabdariffa L.) Extract

Composite films were prepared with alginate and roselle extract (HE) at different concentrations (1%, 3%, and 5% w/v) via solvent casting technique and analyzed in terms of physical, mechanical, and antibacterial properties. The incorporation of HE into alginate films resulted in rough and heterogeneous surface characteristics with increasing concentrations of HE. The thickness and water vapor permeability of alginate-HE composite films were significantly higher (p < 0.05) compared to pure alginate films. Moreover, water content, solubility, swelling, tensile strength, and elongation at break value of the composite films decreased (p < 0.05) with increasing concentrations of the extract. FTIR spectra revealed shifts and intensity variations in the composite films and the formation of new peaks suggesting a possible interaction between alginate and HE. Alginate-HE films exhibited good antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Klebsiella pneumoniae) bacteria. The antibacterial effect of the films, more pronounced against Gram-positive bacteria, increased with higher amounts of HE. The resulting films may be utilised as new biodegradable, antibacterial films in the food packaging industry to prolong shelf life and preserve food safety.

Graphical Abstract

Supplementary Information

The online version of this article (10.1007/s12649-022-01710-3) contains supplementary material, which is available to authorized users.

Chitin and derivative chitosan-based structures - Preparation strategies aided by deep eutectic solvents: A review

The high molecular weight of chitin, as a biopolymer, challenges its extraction due to its insolubility in the solvents. Also, chitosan, as the N-deacetylated form of chitin, can be employed as a primary material for different industries. The low mechanical stability and poor plasticity of chitosan films, as a result of incompatible interaction between chitosan and the used solvent, have limited its industrialization. Deep eutectic solvents (DESs), as novel solvents, can solve the extraction difficulties of chitin, and the low mechanical stability and weak plasticity of chitosan films. Also, DESs can be considered for the different chitosan and chitin productions, including chitin nanocrystal and nanofiber, N,N,N-trimethyl-chitosan, chitosan-based imprinted structures, and DES-chitosan-based beads and monoliths. This review aims to focus on the preparation and characterization (chemistry and morphology) of DES-chitin-based and DES-chitosan-based structures to understand the influence of the incorporation of DESs into the chitin and chitosan structure.

Emerging chitosan-essential oil films and coatings for food preservation - A review of advances and applications

With the rising demand for fresh and ready-to-eat foods, antimicrobial packaging has been developed to control or prevent microbial growth as well as maintain food quality and safety. Chitosan is an advanced biomaterial for antimicrobial packaging to meet the growing needs of safe and biodegradable packaging. The application of natural essential oils as antimicrobial agents effectively controls the growth of spoilage and pathogenic microbes. Thus, chitosan edible coatings and films incorporated with essential oils have expanded the general applications of antimicrobial packaging in food products. This review summarized the effect of essential oils on modifying the physicochemical characteristics of chitosan-based films. Notably, the antimicrobial efficacy of the developed composite films or coatings was highlighted. The advances in the preparation methods and application of chitosan films were also discussed. Broadly, this review will promote the potential applications of chitosan-essential oils composite films or coatings in antimicrobial packaging for food preservation.

The Effect of Chitosan Type on Biological and Physicochemical Properties of Films with Propolis Extract

The aim of the research was to determine the influence of chitosan type and propolis extract concentration on biological and physicochemical properties of chitosan-propolis films in terms of their applicability in food packaging. The films were prepared using three types of chitosan: from crab shells, medium and high molecular weight and propolis concentration in the range of 0.75-5.0%. The prepared polysaccharide films were tested for antimicrobial properties, oxygen transmission rate (OTR) and water vapor transmission rate (WVTR). Moreover, sorption tests and structural analysis were carried out. Microbiological tests indicated the best antimicrobial activity for the film consisting of high molecular weight chitosan and 5.0% propolis extract. Both the type of chitosan and propolis concentration affected transmission parameters-OTR and WVTR. The best barrier properties were recorded for the film composed of high molecular weight chitosan and 5.0% propolis extract. The results of sorption experiments showed a slight influence of chitosan type and a significant effect of propolis extract concentration on equilibrium moisture content of tested films. Moreover, propolis extract concentration affected monolayer water capacity (Mm) estimated using the Guggenheim, Anderson and de Boer (GAB) sorption model. The obtained results indicate that chitosan films with an addition of propolis extract are promising materials for food packaging applications, including food containing probiotic microorganisms.

An Extensive Review of Natural Polymers Used as Coatings for Postharvest Shelf-Life Extension: Trends and Challenges

Global demand for minimally processed fruits and vegetables is increasing due to the tendency to acquire a healthy lifestyle. Losses of these foods during the chain supply reach as much as 30%; reducing them represents a challenge for the industry and scientific sectors. The use of edible packaging based on biopolymers is an alternative to mitigate the negative impact of conventional films and coatings on environmental and human health. Moreover, it has been demonstrated that natural coatings added with functional compounds reduce the post-harvest losses of fruits and vegetables without altering their sensorial and nutritive properties. Furthermore, the enhancement of their mechanical, structural, and barrier properties can be achieved through mixing two or more biopolymers to form composite coatings and adding plasticizers and/or cross-linking agents. This review shows the latest updates, tendencies, and challenges in the food industry to develop eco-friendly food packaging from diverse natural sources, added with bioactive compounds, and their effect on perishable foods. Moreover, the methods used in the food industry and the new techniques used to coat foods such as electrospinning and electrospraying are also discussed. Finally, the tendency and challenges in the development of edible films and coatings for fresh foods are reviewed.

Lipid-Polymeric Films: Composition, Production and Applications in Wound Healing and Skin Repair

The use of lipids in the composition of polymeric-based films for topical administration of bioactive ingredients is a recent research topic; while few products are commercially available, films containing lipids represent a strategic area for the development of new products. Some lipids are usually used in polymeric-based film formulations due to their plasticizing action, with a view to improving the mechanical properties of these films. On the other hand, many lipids have healing, antimicrobial, anti-inflammatory, anti-aging properties, among others, that make them even more interesting for application in the medical-pharmaceutical field. This manuscript discusses the production methods of these films both on a laboratory and at industrial scales, the properties of the developed biopolymers, and their advantages for the development of dermatologic and cosmetic products.

Antimicrobial Food Packaging with Biodegradable Polymers and Bacteriocins

Innovations in food and drink packaging result mainly from the needs and requirements of consumers, which are influenced by changing global trends. Antimicrobial and active packaging are at the forefront of current research and development for food packaging. One of the few natural polymers on the market with antimicrobial properties is biodegradable and biocompatible chitosan. It is formed as a result of chitin deacetylation. Due to these properties, the production of chitosan alone or a composite film based on chitosan is of great interest to scientists and industrialists from various fields. Chitosan films have the potential to be used as a packaging material to maintain the quality and microbiological safety of food. In addition, chitosan is widely used in antimicrobial films against a wide range of pathogenic and food spoilage microbes. Polylactic acid (PLA) is considered one of the most promising and environmentally friendly polymers due to its physical and chemical properties, including renewable, biodegradability, biocompatibility, and is considered safe (GRAS). There is great interest among scientists in the study of PLA as an alternative food packaging film with improved properties to increase its usability for food packaging applications. The aim of this review article is to draw attention to the existing possibilities of using various components in combination with chitosan, PLA, or bacteriocins to improve the properties of packaging in new food packaging technologies. Consequently, they can be a promising solution to improve the quality, delay the spoilage of packaged food, as well as increase the safety and shelf life of food.

A Hybrid Methodology to Minimize Freshwater Consumption during Shrimp Shell Waste Valorization Combining Multi-Contaminant Pinch Analysis and Superstructure Optimization

The conservation and proper management of natural resources constitute one of the main objectives of the 2030 Agenda for Sustainable Development designed by the Member States of the United Nations. In this work, a hybrid strategy based on process integration is proposed to minimize freshwater consumption while reusing wastewater. As a novelty, the strategy included a heuristic approach for identifying the minimum consumption of freshwater with a preliminary design of the water network, considering the concept of reuse and multiple pollutants. Then, mathematical programming techniques were applied to evaluate the possibilities of regeneration of the source streams through the inclusion of intercept units and establish the optimal design of the network. This strategy was used in the shrimp shell waste process to obtain chitosan, where a minimum freshwater consumption of 277 t/h was identified, with a reuse strategy and an optimal value of US $5.5 million for the design of the water network.