Advances in the application of chitosan as a sustainable bioactive material in food preservation

Development of multifunctional chitosan-based composite film loaded with tea polyphenol nanoparticles for strawberry preservation

Incorporating polysaccharide-based composite films with nanobiotechnology offers a new strategy for food preservation. This study initially focuses on the preparation of tea polyphenol nanoparticles (TPNP), novel and derived from natural antibacterial agents, which serve to improve stability. Afterwards chitosan-based composite films loaded with TPNP (CTN film) were developed using solution casting method. The incorporation of TPNP significantly improved the UV/water/oxygen barrier properties, mechanical properties and thermal stability, alongside notable physical properties including water contact angle (93.65 ± 0.04°), low water vapor permeability (33.72 ± 3.32 g/m2h) and oxygen permeability (0.11 ± 0.02 g/m2h), tensile strength (61.83 ± 0.70 %), and elongation at break (31.60 ± 6.12 %). The CTN film not only exhibited exceptional biodegradability and nontoxicity, but also demonstrated remarkable antimicrobial efficacy against Escherichia coli and Bacillus subtilis. Additionally, it showcased potent antioxidant activity, boasting DPPH and ABTS radical scavenging rates up to 89.25 ± 0.18 % and 93.84 ± 0.42 %. The CTN film was successfully formed on the surface of strawberries through dip-coating process and their shelf life was extended from 4 to 6 days at 20 °C without side-effect on the weight loss, harness, pH and total soluble solids, illustrating its potential for enhancing food preservation.

Preparation of modified chitosan-based nano-TiO2-nisin composite packaging film and preservation mechanism applied to chilled pork

Here, we developed a nano-TiO2-nisin-modified chitosan composite packaging film and investigated its properties and antibacterial activity, as well as its effect on chilled pork preservation time. The results indicated that the preservation time of chilled pork coated with a nano-TiO2-nisin-modified chitosan film (including 0.7 g/L nano-TiO2, irradiated with ultraviolet light for 40 min, and dried for 6 h) followed by modified atmosphere packaging (50% CO2 + 50% N2) increased from 7 to 20 days at 4 °C. Both nano-TiO2 and nisin enhanced the mechanical strength of the chitosan film, and nisin promoted nano-TiO2 dispersion and compatibility in chitosan. Treatment with 0.4 g/L nano-TiO2 for 60 min considerably inhibited spoilage bacteria, particularly Acinetobacter johnnii XBB1 (A. johnnii XBB1). As nano-TiO2 concentration and photocatalytic time increased, K+, Ca2+, and Mg2+ leakage in A. johnnii XBB1 increased but Na+/K+-ATPase and Ca2+/Mg2+-ATPase activities decreased. In A. johnnii XBB1, TiO2 significantly downregulated the expression of putrefaction-related genes such as cysM and inhibited cell self-regulation and membrane wall system repair. Therefore, our nano-TiO2-nisin-modified chitosan film could extend the shelf life without the addition of any chemical preservatives, demonstrating great potential for application in food preservation.

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.

Layer-by-layer assembly of chitosan/alginate thin films containing Salmonella enterica bacteriophages for antibacterial applications

The emergence of antibiotic resistant bacteria and the ineffectiveness of routine treatments inspired development of alternatives to biocides for antibacterial applications. Bacteriophages are natural predators of bacteria and are promising alternatives to antibiotics. This study presents fabrication of a Salmonella enterica bacteriophage containing ultra-thin multilayer film composed of chitosan and alginate and demonstrates its potential as an antibacterial coating for food packaging applications. Chitosan/alginate film was prepared through layer-by-layer (LbL) self-assembly technique. A bacteriophage, which belongs to Siphoviridae morphotype (MET P1-001_43) and infects Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis), was post-loaded into chitosan/alginate film. The LbL growth, stability, and surface morphology of chitosan/alginate film as well as phage deposition into multilayers were analysed through ellipsometry, QCM-D and AFM techniques. The bacteriophage containing multilayers showed antibacterial activity at pH 7.0. In contrast, anti-bacterial activity was not observed at acidic conditions. We showed that wrapping a Salmonella Enteritidis contaminated chicken piece with aluminium foil whose surface was modified with phage loaded chitosan/alginate multilayers decreased the number of colonies on the chicken meat, and it was as effective as treating the meat directly with phage solution.

Recent advances in starch-based coatings for the postharvest preservation of fruits and vegetables

Efficient and low-cost postharvest preservation of fruits and vegetables has always been one of the urgent problems to be solved in the food field. Due to the wide sources, good environmental and human safety, and high biodegradability, starch-based coating preservation method has great application prospects in the postharvest preservation of fruits and vegetables. However, starch materials also have the disadvantages of poor mechanical properties and easy water absorption performance, which makes it difficult to fully meet the requirements in practical production. Therefore, starch is often used in combination with other components to form composite materials. This paper began with an introduction to the preservation principles of edible starch-based coatings, including inherent properties and extra functional properties. Besides, the preservation principles of edible coatings and the recent advances in the field of fruit and vegetable preservation were also comprehensively reviewed, focusing on the preparation and application of starch-based coatings. The information will contribute to the further development of starch-based coatings to improve the postharvest preservation effect of fruits and vegetables.

Multicomponent chitosan complex/polyvinyl alcohol blended film with full-band UV-shielding performance and excellent antioxidant property for active food packaging

Utilizing renewable natural resources to construct multifunctional packaging materials is critical to achieving sustainable development in the food packaging industry. In this study, we crafted transparent films with comprehensive UV-shielding and antioxidant properties by blending a multicomponent chitosan complex with polyvinyl alcohol (PVA), subsequently applied to preserve peanut butter. The multicomponent chitosan complex, synthesized from chitosan, ferulic acid (FA), and 5-oxo-3,5-dihydro-2H-thiazolo [3,2-a] pyridine-7-carboxylic acid (TPCA) through direct heating in water, served as the foundation. This chitosan complex was seamlessly blended with PVA, resulting in the creation of a transparent film through the solvent casting method. A meticulous investigation into the chemical structure and physicochemical properties of the blended films was conducted. The FA and TPCA components exhibited robust ultraviolet absorption properties, conferring virtually complete full-band ultraviolet shielding ability to the blend film. Additionally, FA endowed the blended film with significant antioxidant activity. The effectiveness of the chitosan complex/PVA blended film in preserving peanut butter from oxidative spoilage was demonstrated, showcasing its robustness in food preservation. Our research underscores the significance of creating advanced packaging materials from sustainable sources.

High transparency, water vapor barrier and antibacterial properties of chitosan/carboxymethyl glucan/poly(vinyl alcohol)/nanoparticles encapsulating citral composite film for fruit packaging

Utilizing antibacterial packaging material is an effective approach to delay fruit rotting and spoilage thereby minimizing financial losses and reducing health harm. However, the barrier and mechanical properties of biodegradable antibacterial packaging materials are barely compatible with transparency. Herein, antimicrobial nanoparticles encapsulating citral (ANPs) were first prepared by emulsification under the stabilization of oxidized dextran (ODE) and ethylene diamine. Then, composite films with high transparency, good water vapor barrier, and mechanical and antibacterial properties for fruits packaging were prepared from chitosan (CS), carboxymethyl-glucan (CMG), poly(vinyl alcohol) (PVA), and ANPs by solvent casting strategy. The synergistic effects of electrostatic interaction and hydrogen bonding could regulate crystalline architecture, generating high transparency of the composite films (90 %). The mechanical properties of the composite film are improved with elongation at break up to 167 % and stress up to 32 MPa. The water vapor barrier property of the film is appropriate to the packed fruit for less weight loss and firmness remaining. Simultaneously, the addition of ANPs endowed the film with excellent antimicrobial and UV-barrier capabilities to reduce fruit mildew, thereby extending the shelf life of fruits. More importantly, the composite polymer solution could be sprayed or dipped directly on fruits as a coating for food storage to improve food shelf life, substantially expanding its ease of use and scope of use.

A review on versatile applications of biomaterial/polycationic chitosan: An insight into the structure-property relationship

Chitosan is a versatile and generous biopolymer obtained by alkaline deacetylation of naturally occurring chitin, the second most abundant biopolymer after cellulose. The excellent physicochemical properties of polycationic chitosan are attributed to the presence of varied functional groups such as amino, hydroxyl, and acetamido groups enabling researchers to tailor the structure and properties of chitosan by different methods such as crosslinking, grafting, copolymerization, composites, and molecular imprinting techniques. The prepared derivatives have diverse applications in the food industry, water treatment, cosmetics, pharmaceuticals, agriculture, textiles, and biomedical applications. In this review, numerous applications of chitosan and its derivatives in various fields have been discussed in detail with an insight into their structure-property relationship. This review article concludes and explains the chitosan's biocompatibility and efficiency that has been done so far with future usage and applications as well. Moreover, the possible mechanism of chitosan's activity towards several emerging fields such as energy storage, biodegradable packaging, photocatalysis, biorefinery, and environmental bioremediation are also discussed. Overall, this comprehensive review discusses the science and complete information behind chitosan's wonder function to improve our understanding which is much needful as well as will pave the way towards a sustainable future.

Influence of cellulose viscosity on the physical, mechanical, and barrier properties of the chitosan-based films

This research paper presents a comprehensive investigation into developing biodegradable films for food packaging applications using chitosan (CN) in conjunction with three distinct types of cellulose (CE), each characterized by varying viscosities. The primary objective was to assess the influence of cellulose viscosity on the physical, mechanical, and barrier properties of the resulting films. The medium-viscosity cellulose imparted numerous advantageous qualities to the biodegradable films. These films exhibited optimal thickness (31 μm), ensuring versatility in food packaging while maintaining favorable mechanical properties, blending strength, and flexibility. Also, medium-viscosity cellulose significantly improved the films' barrier performance, particularly regarding oxygen permeability [1.80 × 10-6 (g.mm.m-2. s-1)]. Furthermore, the medium-viscosity cellulose contributed to superior moisture-related properties, including reduced water vapor permeability [14.80 × 10-9 (g.mm.m-2. s-1. Pa-1)], moisture content (13.22 %), and water solubility (22.87 %), while maintaining an appropriate degree of swelling (41.88 %). Moreover, the study employed advanced analytical techniques, including FTIR, XRD, and TGA, to provide critical insights into the films' chemical, structural, and thermal aspects. This research underscored the importance of the viscosity of film formulation materials as a crucial element in designing and efficiently producing films for food packaging.

Effect of tea polyphenols on chitosan packaging for food preservation: Physicochemical properties, bioactivity, and nutrition

Chitosan packaging has been widely studied for food preservation, the application of which is expanded by the incorporation of tea polyphenols. This paper reviews the influence of tea polyphenols incorporation on chitosan-based packaging from the perspectives of physicochemical properties, bioactivity used for food preservation, and nutritional value. The physicochemical properties included optical properties, mechanical properties, water solubility, moisture content, and water vapor barrier property, concluding that the addition of tea polyphenols improved the opacity, water solubility, and water vapor barrier property of chitosan packaging, and the mechanical properties and water content were decreased. The bioactivity used for food preservation, that is antioxidant and antimicrobial properties, is enhanced by tea polyphenols, improving the preservation of food like meat, fruits, and vegetables. In the future, efforts will be needed to improve the mechanical properties of composite film and adjust the formula of tea polyphenols/chitosan composite film to apply to different foods. Besides, the identification and development of high nutritional value tea polyphenol/chitosan composite film is a valuable but challenging task. This review is expected to scientifically guide the application of tea polyphenols in chitosan packaging.

Preparation of bioactive film based on chitosan and essential oils mixture for enhanced preservation of food products

Recently, the concept of biodegradable and bioactive packaging and surface coating has become a trend. In this work, the bioactive films of chitosan were elaborated following the casting method. Contrary to the films containing the Cinnamomum zeylanicum Blume, Thymus satureioides Cosson, and Syzygium aromaticum essential oils (EOs) mixtures, the control film was thin, colorless, and showed high moisture content, swelling degree, and elongation at break. Concerning the physicochemical parameters, the incorporation of the EOs mixtures minimized the hydrophobicity of the material (θw < 65°) and modified randomly its surface free energy components (γ-; γ+; γLW). The theoretical prediction of Aspergillus sp. and Rhizopus sp. adherence to the chitosan-based films was relatively correlated to the experimental results (r = -0.601). The latter showed that 6.80 % and 19.02 % of the control film surface was covered by Aspergillus sp. and Rhizopus sp. spores, respectively. In contrast, no fungal adherence was noticed in the case of the film incorporating the triple EOs mixture. These promising results revealed that chitosan film containing C. zeylanicum, T. satureioides, and S. aromaticum EOs mixtures could be utilized as a surface coating or bioactive packaging in the food industry.

N-lauric-O-carboxymethyl chitosan: Synthesis, characterization and application as a pH-responsive carrier for curcumin particles

A pH-responsive amphiphilic chitosan derivative, N-lauric-O-carboxymethyl chitosan (LA-CMCh), is synthesized. Its molecular structures are characterized by FTIR, 1H NMR, and XRD methods. The influencing factors are investigated, including the amount of lauric acid (LA), carboxymethyl chitosan (CMCh), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysuccinimide (NHS), and their molar ratio, reaction time, and reaction temperature on the substitution. The degrees of substitution (DS) of the lauric groups on the -NH2 groups are calculated based on the integrated data of 1H NMR spectra. The optimum reaction condition is obtained as a reaction time of 6 h, a reaction temperature of 80 °C, and a molar ratio of lauric acid to O-carboxymethyl chitosan to N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to N-hydroxysuccinimide of 1:3:4.5:4.5, respectively. The crystallinity and initial decomposition temperature of LA-CMCh decrease, but the maximum decomposition temperature increases. The crystallinity is reduced due to the introduction of LA and the degree of hydrogen bonding among LA-CMCh molecules. LA-CMCh could self-aggregate into particles, which size and critical aggregation concentration depend on the degree of substitution and medium pH. LA-CMCh aggregates could load curcumin up to 21.70 %, and continuously release curcumin for >200 min. LA-CMCh shows nontoxicity to fibroblast HFF-1 cells and good antibacterial activity against S. aureus and E. coli, indicating that it could be used as an oil-soluble-drug carrier.

A water-soluble and biocompatible chitosan-based fluorescent probe for real-time monitoring formaldehyde in living cells and zebrafish

Formaldehyde (HCHO) is a common environmental toxicant that can harm the human respiratory tract and nervous system when exposed for long period of time. As a carcinogen, HCHO also increases the risk of cancer in humans. HCHO can be produced endogenously in living systems and plays an essential role in physiological and biochemical reactions and pathogenesis. Therefore, monitoring the level of HCHO in vivo and in vitro has become the focus of attention. The designed naphthalene fluorophore was introduced onto modified chitosan to prepare a chitosan-based fluorescent probe (CS-FA) for HCHO detection. Compared to other small-molecule probe analogs for the detection of HCHO, the randomly coiled polymer chain of chitosan enabled CS-FA to "enrich" HCHO using the synergistic binding of hydrazino-naphthalimide recognition sites. Thus, the reaction of the analyte with the recognition site was accelerated, resulting in a faster equilibrium fluorescence response (2-3 min) and high sensitivity. In addition, the introduction of biomass material chitosan also improved the biocompatibility of the probe. Then a series of composite materials (test strips and hydrogel) were prepared based on the probe to expand the application form of the probe.

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.

A comprehensive review of chitosan applications in paper science and technologies

Using environmentally friendly biomaterials in different aspects of human life has been considered extensively. In this respect, different biomaterials have been identified and different applications have been found for them. Currently, chitosan, the well-known derivative of the second most abundant polysaccharide in the nature (i.e., chitin), has been receiving a lot of attention. This unique biomaterial can be defined as a renewable, high cationic charge density, antibacterial, biodegradable, biocompatible, non-toxic biomaterial with high compatibility with cellulose structure, where it can be used in different applications. This review takes a deep and comprehensive look at chitosan and its derivative applications in different aspects of papermaking.

Emerging technologies for preservation and quality evaluation of postharvest edible mushrooms: A review

Edible mushrooms are the highly demanded foods of which production and consumption have been steadily increasing globally. Owing to the quality loss and short shelf-life in harvested mushrooms, it is necessary for the implementation of effective preservation and intelligent evaluation technologies to alleviate this issue. The aim of this review was to analyze the development and innovation thematic lines, topics, and trends by bibliometric analysis and review of the literature methods. The challenges faced in researching these topics were proposed and the mechanisms of quality loss in mushrooms during storage were updated. This review summarized the effects of chemical processing (antioxidants, ozone, and coatings), physical treatments (non-thermal plasma, packaging and latent thermal storage) and other emerging application on the quality of fresh mushrooms while discussing the efficiency in extending the shelf-life. It also discussed the emerging evaluation techniques based on the various chemometric methods and computer vision system in monitoring the freshness and predicting the shelf-life of mushrooms which have been developed. Preservation technology optimization and dynamic quality evaluation are vital for achieving mushroom quality control. This review can provide a comprehensive research reference for reducing mushroom quality loss and extending shelf-life, along with optimizing efficiency of storage and transportation operations.

Lignin-induced sacrificial conjoined-network enabled strong and tough chitosan membrane for food preservation

As a natural green polymer, chitosan is a promising material for plastic replacement. However, the mutually exclusive strength and toughness severely limit its commercial application, and the improved strength of chitosan-based materials is typically achieved at the expense of elongation or toughness. Herein, inspired by the existed multiple non-covalent interactions in biosynthesized fibers, we successfully fabricated a high-performance lignin/chitosan composite film by constructing sacrificial conjoined-network (hydrogen bonds, electrostatic interaction, etc.), which results in an impressive enhancement in tensile strength (50.2 MPa), elongation (73.6 %), and toughness (2.7 MJ/m³) simultaneously, much superior to the pure chitosan film. In addition, the composite film also demonstrates excellent UV resistance, thermal stability, low oxygen permeability (3.9 cm³/(m²·24h‧0.1 MPa)) and food preservation (with no negligible change for grape, apple, and cherry tomato after 5-10 days). Such developed lignin/chitosan with both components from biomass represents a promising alternative for plastic replacement.

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.

Recent advancements in encapsulation of chitosan-based enzymes and their applications in food industry

Enzymes are readily inactivated in harsh micro-environment due to changes in pH, temperature, and ionic strength. Developing suitable and feasible techniques for stabilizing enzymes in food sector is critical for preventing them from degradation. This review provides an overview on chitosan (CS)-based enzymes encapsulation techniques, enzyme release mechanisms, and their applications in food industry. The challenges and future prospects of CS-based enzymes encapsulation were also discussed. CS-based encapsulation techniques including ionotropic gelation, emulsification, spray drying, layer-by-layer self-assembly, hydrogels, and films have been studied to improve the encapsulation efficacy (EE), heat, acid and base stability of enzymes for their applications in food, agricultural, and medical industries. The smart delivery design, new delivery system development, and in vivo releasing mechanisms of enzymes using CS-based encapsulation techniques have also been evaluated in laboratory level studies. The CS-based encapsulation techniques in commercial products should be further improved for broadening their application fields. In conclusion, CS-based encapsulation techniques may provide a promising approach to improve EE and bioavailability of enzymes applied in food industry.HighlightsEnzymes play a critical role in food industries but susceptible to inactivation.Chitosan-based materials could be used to maintain the enzyme activity.Releasing mechanisms of enzymes from encapsulators were outlined.Applications of encapsulated enzymes in food fields was discussed.

Road to The Red Carpet of Edible Crickets through Integration into the Human Food Chain with Biofunctions and Sustainability: A Review

The Food and Agriculture Organization of the United Nations (FAO) estimates that more than 500 million people, especially in Asia and Africa, are suffering from malnutrition. Recently, livestock farming has increased to supply high-quality protein, with consequent impact on the global environment. Alternative food sources with high nutritive values that can substitute livestock demands are urgently required. Recently, edible crickets have been promoted by the FAO to ameliorate the food crisis. In this review, the distribution, nutritive values, health-promoting properties (antioxidant, anti-inflammatory, anti-diabetic and anti-obesity), safety, allergenicity as well as the potential hazards and risks for human consumption are summarized. Cricket farming may help to realize the United Nations sustainable development goal No. 2 Zero Hunger. The sustainability of cricket farming is also discussed in comparison with other livestock. The findings imply that edible crickets are safe for daily intake as a healthy alternative diet due to their high protein content and health-promoting properties. Appropriate use of edible crickets in the food and nutraceutical industries represents a global business potential. However, people who are allergic to shellfish should pay attention on cricket allergy. Thus, the objective of this review was to present in-depth and up-to-date information on edible crickets to advocate and enhance public perception of cricket-based food.