Alginate-Based Edible Films and Coatings for Food Packaging Applications

Disposable Food Packaging and Serving Materials-Trends and Biodegradability

Food is an integral part of everyone’s life. Disposable food serving utensils and tableware are a very convenient solution, especially when the possibility of the use of traditional dishes and cutlery is limited (e.g., takeaway meals). As a result, a whole range of products is available on the market: plates, trays, spoons, forks, knives, cups, straws, and more. Both the form of the product (adapted to the distribution and sales system) as well as its ecological aspect (biodegradability and life cycle) should be of interest to producers and consumers, especially considering the clearly growing trend of “eco-awareness”. This is particularly important in the case of single-use products. The aim of the study was to present the current trends regarding disposable utensils intended for contact with food in the context of their biodegradability. This paper has summarized not only conventional polymers but also their modern alternatives gaining the attention of manufacturers and consumers of single-use products (SUPs).

Marine Polysaccharides for Wound Dressings Application: An Overview

Wound dressings have become a crucial treatment for wound healing due to their convenience, low cost, and prolonged wound management. As cutting-edge biomaterials, marine polysaccharides are divided from most marine organisms. It possesses various bioactivities, which allowing them to be processed into various forms of wound dressings. Therefore, a comprehensive understanding of the application of marine polysaccharides in wound dressings is particularly important for the studies of wound therapy. In this review, we first introduce the wound healing process and describe the characteristics of modern commonly used dressings. Then, the properties of various marine polysaccharides and their application in wound dressing development are outlined. Finally, strategies for developing and enhancing marine polysaccharide wound dressings are described, and an outlook of these dressings is given. The diverse bioactivities of marine polysaccharides including antibacterial, anti-inflammatory, haemostatic properties, etc., providing excellent wound management and accelerate wound healing. Meanwhile, these biomaterials have higher biocompatibility and biodegradability compared to synthetic ones. On the other hand, marine polysaccharides can be combined with copolymers and active substances to prepare various forms of dressings. Among them, emerging types of dressings such as nanofibers, smart hydrogels and injectable hydrogels are at the research frontier of their development. Therefore, marine polysaccharides are essential materials in wound dressings fabrication and have a promising future.

Current Advances on the Development and Application of Probiotic-Loaded Edible Films and Coatings for the Bioprotection of Fresh and Minimally Processed Fruit and Vegetables

The application of probiotics has emerged as an innovative bioprotection technology to preserve fresh and minimally processed fruit and vegetables. This review discusses the most recent advances on the development and application of probiotic-loaded edible films/coatings as a strategy to preserve fresh or minimally processed fruit and vegetables. Available studies have shown a variety of materials, including hydrocolloids (polysaccharides and proteins) and lipids, used alone or in combination to formulate edible films/coatings loaded with probiotics. Plasticizers and surfactants are usually required to formulate these edible films/coatings. The reported antimicrobial effects of probiotic-loaded edible films/coating and quality parameters of coated fruit and vegetables could vary according to the characteristics of the materials used in their formulation, loaded probiotic strain and its dose. The antimicrobial effects of these films/coatings could be linked to the action of various metabolites produced by embedded probiotic cells with inhibitory effects on microorganisms contaminating fruit and vegetable surfaces. The implication of the use of probiotic-loaded edible films/coatings should be their antimicrobial effects against pathogenic and spoilage microorganisms and efficacy to control the ripening of fruit and vegetables, helping the coated products to maintain their safety, quality, nutritional and functional characteristics for a more prolonged storage period.

Influence of Two Different Coating Application Methods on the Maintenance of the Nutritional Quality of Fresh-Cut Melon during Storage

This study aimed at evaluating the effects of two coating application methods, spraying and dipping, on the quality of fresh-cut melons. An alginate-based coating containing both ascorbic and citric acid was applied at two concentrations (5% and 10%) with both methods on fresh-cut melon. The nutritional quality of the products was investigated during 11 days of storage at 10 °C. The suitability and adaptability of the applied coatings on the fruit were evaluated based on rheological and microstructural properties. Moisture, carotenoids, total polyphenols and ascorbic acid content were analyzed on melon samples during storage. Results showed that the coating solution applied by the dipping method and at the highest concentration (10%), allowed to better maintain some quality characteristics of fresh-cut melon, thanks also to the better coating homogeneity and higher thickness observed through microstructural analysis.

Electrostatic Interaction-Based Fabrication of Calcium Alginate-Zein Core-Shell Microcapsules of Regulable Shapes and Sizes

Core-shell microcapsules with combined features of hydrophilicity and hydrophobicity have become much popular. However, the assembly of biocompatible and edible materials in hydrophilic-hydrophobic core-shell microcapsules is not easy. In this work, based on electrostatic interactions, we prepared controllable calcium alginate (ALG)-zein core-shell particles of different shapes and sizes using hydrophilic ALG and hydrophobic zein by a two-step extrusion method. Negatively charged hydrogel beads of spherical, ellipsoidal, or fibrous shape were added into a positively charged zein solution (dissolved in 70% (v/v) aqueous ethanol solution) to achieve different-shaped core-shell particles. Interestingly, the size, shape, and shell thickness of the particles can be regulated by the needle diameter, stirring speed, and zein concentration. Moreover, for simplification, the core-shell particles were also synthesized by a one-step extrusion method, in which an ALG solution was added dropwise into a 70% (v/v) aqueous ethanol solution containing zein and CaCl₂. The particles synthesized in this work showed controlled digestion of encapsulated medium-chain triglyceride (MCT) and sustained release of encapsulated thiamine and ethyl maltol. Our preparation method is simplistic and can be extended to fabricate a variety of hydrophilic and hydrophobic core-shell structures to encapsulate a broad spectrum of materials.

Humulus lupulus Cone Extract Efficacy in Alginate-Based Edible Coatings on the Quality and Nutraceutical Traits of Fresh-Cut Kiwifruit

In this work, an innovative coating strategy that is able to prolong the shelf-life of fresh-cut kiwifruit was proposed, and the effectiveness of the procedure was evaluated for a period of ten days under cold storage (4 °C). Alginate (2% m/v) functionalized with green extracts from hop (Humulus lupulus L.) cones (HE; 0.5 and 1%, v/v) was used as a coating material in order to assess the best performing strategy, leading to the most stable product. At the concentrations used to formulate the edible coatings, no contribution related to hop bitterness on the final product was recorded. The results were compared to control samples (without edible coating and coated only with alginate at 2% m/v). The plant extract was characterized by its main chemical traits and by 1H NMR profiling, revealing the presence of antioxidant and antimicrobial bioactive compounds (i.e., alpha and beta hop acids, xanthohumol). Furthermore, the characteristics of the samples during cold storage were evaluated by physico-chemical (i.e., weight loss, soluble solid content, titratable acidity, pH, color attributes) and nutraceutical (i.e., total polyphenol, ascorbic acid content, total carotenoids, chlorophylls) traits. The results showed that the incorporation of hop extracts into the edible coatings tested was able to preserve the quality and nutraceutical traits of fresh-cut kiwifruit during cold storage, thus prolonging their shelf life and marketability.

Comprehensive Review of Polysaccharide-Based Materials in Edible Packaging: A Sustainable Approach

Edible packaging is a sustainable product and technology that uses one kind of "food" (an edible material) to package another kind of food (a packaged product), and organically integrates food with packaging through ingenious material design. Polysaccharides are a reliable source of edible packaging materials with excellent renewable, biodegradable, and biocompatible properties, as well as antioxidant and antimicrobial activities. Using polysaccharide-based materials effectively reduces the dependence on petroleum resources, decreases the carbon footprint of the "product-packaging" system, and provides a "zero-emission" scheme. To date, they have been commercialized and developed rapidly in the food (e.g., fruits and vegetables, meat, nuts, confectioneries, and delicatessens, etc.) packaging industry. However, compared with petroleum-based polymers and plastics, polysaccharides still have limitations in film-forming, mechanical, barrier, and protective properties. Therefore, they need to be improved by reasonable material modifications (chemical or physical modification). This article comprehensively reviews recent research advances, hot issues, and trends of polysaccharide-based materials in edible packaging. Emphasis is given to fundamental compositions and properties, functional modifications, food-packaging applications, and safety risk assessment of polysaccharides (including cellulose, hemicellulose, starch, chitosan, and polysaccharide gums). Therefore, to provide a reference for the development of modern edible packaging.

Pearlescent Mica-Doped Alginate as a Stable, Vibrant Medium for Two-Dimensional and Three-Dimensional Art

Emergent technologies are driving forces in the development of innovative art media that progress the field of modern art. Recently, artists have capitalized on the versatility of a new technology to create, restore, and modify art: additive manufacturing or three-dimensional (3D) printing. Additively manufactured art relies heavily on plastic-based materials, which typically require high heat to induce melting for workability. The necessity for heat limits plastic media to dedicated 3D printers. In contrast, biologically derived polymers such as polysaccharides used to create "bioinks" often do not require heating the material for workability, broadening the types of techniques available for printing. Here, we detail the formulation of a bioink consisting of mica pigments suspended in alginate as a new, vibrant art medium for 2D and 3D compositions. The properties that make alginate an ideal colorant binder are detailed: low cost with wide availability, nontoxicity and biocompatibility, minimal color, and an array of attractive physicochemical properties that offer workability and processing into 2D and 3D structures. Further, the chemical composition, morphology, and dispersibility of an array of mica pigment additives are characterized in detail as they pertain to the quality of an art medium. Alginate-based media with eight mica colors were formulated, where mica addition resulted in vibrantly colored inks with moderate hiding power and coverage of substrates necessary for 2D printing with thin horizontal and vertical lines. The utility of the media is demonstrated via the generation of 2D and 3D vibrant structures.

Study of biological activities and physicochemical properties of Yamú (Brycon siebenthalae) viscera hydrolysates in sodium alginate-based edible coating solutions

The fishing industry produces waste such as viscera, which is an environmental problem for many countries. Obtaining protein from these wastes are useful for the food industry. In this study, the chemical composition, amino acid profile, solubility, digestibility and thermal properties of Yamú protein isolate (PI) and its hydrolysates obtained by enzymatic hydrolysis were characterized. The hydrolysates (0.05, 0.1, 0.5, 1 and 2% w/v) were mixed with a sodium alginate-based solution to form an edible coating solution (ECS). Antioxidant capacity antimicrobial activity, Zeta potential (ζ) and adsorption kinetics properties were determined. PI contains 88% (w/w) protein showing better solubility, digestibility and thermal stability properties. The hydrolysate concentrations with DPPH inhibitory ECS were 0.1 and 0.5% (w/v). The kinetic properties of ECS showed good stability and excellent adsorption. These results suggest that this Yamú protein has high nutritional potential as an ingredient for the production of functional foods.

Biodegradable Alginate Films with ZnO Nanoparticles and Citronella Essential Oil-A Novel Antimicrobial Structure

The petroleum-based materials could be replaced, at least partially, by biodegradable packaging. Adding antimicrobial activity to the new packaging materials can also help improve the shelf life of food and diminish the spoilage. The objective of this research was to obtain a novel antibacterial packaging, based on alginate as biodegradable polymer. The antibacterial activity was induced to the alginate films by adding various amounts of ZnO nanoparticles loaded with citronella (lemongrass) essential oil (CEO). The obtained films were characterized, and antibacterial activity was tested against two Gram-negative (Escherichia coli and Salmonella Typhi) and two Gram-positive (Bacillus cereus and Staphylococcus aureus) bacterial strains. The results suggest the existence of synergy between antibacterial activities of ZnO and CEO against all tested bacterial strains. The obtained films have a good antibacterial coverage, being efficient against several pathogens, the best results being obtained against Bacillus cereus. In addition, the films presented better UV light barrier properties and lower water vapor permeability (WVP) when compared with a simple alginate film. The preliminary tests indicate that the alginate films with ZnO nanoparticles and CEO can be used to successfully preserve the cheese. Therefore, our research evidences the feasibility of using alginate/ZnO/CEO films as antibacterial packaging for cheese in order to extend its shelf life.

Synergistic Antimicrobial Activities of Combinations of Vanillin and Essential Oils of Cinnamon Bark, Cinnamon Leaves, and Cloves

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.

House fly (Musca domestica) larvae meal as an ingredient with high nutritional value: Microencapsulation and improvement of organoleptic characteristics

Insects have potential to become food ingredients, but it is necessary to improve the sensory properties of insects to help them to be better accepted by the population. The purpose of this study was to produce and characterize house fly larval meal (FLM) converted to a micro-encapsulated powder to improve appearance and other organoleptic characteristics. FLM showed high protein (54%) and lipid (22%) content, with a microbiological activity compatible for food purposes. Moreover, the high content of essentials amino acids (lysine, cysteine and leucine) and unsaturated fatty acids (oleic, linoleic and palmitoleic) make FLM a valuable nutritional source. Spray drying was selected to encapsulate FLM (0.5-2% w/v) using maltodextrin (20% w/v) and alginate (0.5% w/v). Encapsulation improved the appearance of FLM, creating a white-beige, monodispersed micro-powder (9 µm in size). Micro-powder with 2% FLM is considered a good source of protein (5.1%). Microencapsulation also dramatically reduced the volatile emissions of FLM. In conclusion, novel FLM micro-powders were developed using a simple and scalable encapsulation technique. The micro-powder with 2% FLM is a good source of protein, has a pleasant appearance similar to vegetable meals and has improved odor compared to typical insect meals. Thus, insect-based food ingredients in micro-powders could become more accepted by the general population.

Effect of low concentrations of SiO2 nanoparticles on the physical and chemical properties of sodium alginate-based films

This work investigated the effect of adding low concentrations of nano-SiO₂ (0.5, 1.0 and 1.5%) in the properties of films based on sodium alginate, to identify lower thresholds in the proportion of the reinforcing agent. It was found that, even in the smallest proportion, thermal stability of the nanocomposites improved significantly (with degradation onset increased by almost 15% compared with the control film). The surface morphology showed pronounced roughness at nano-SiO₂ concentrations greater than 1.0%, indicating agglomeration of part of the nanomaterial. Mechanical properties were reduced for the samples with concentrations equal to 1.0 and 1.5%, however, without significant differences between them. Conversely, water vapor and light barrier properties have not undergone significant changes in any formulation. Therefore, the use of 0.5% nano-SiO₂ in alginate films would be an easy and economically interesting way to improve thermal stability, without significantly reducing mechanical properties of the pure material.

Application of plant natural products for the management of postharvest diseases in fruits

Prevention of postharvest losses has been a very important concern in the scientific world for many centuries, since adoption of an effective means to curtail such losses is believed to help in reaching sustainability in horticultural production and prevention of hunger around the world. The main means of deterioration in fruits, which may occur after harvest, include physiological changes/losses, physical losses, biochemical changes, changes in enzymatic activities and pathological deterioration. Among these, diseases cover the most important part; the losses due to diseases range from 5% to 20%, and this figure may extend up to >50% in the cases of certain susceptible cultivars. Fungicides have been the most important tool for the management of postharvest diseases for many years, together with hygiene, cold storage and packaging. However, due to the scientifically confirmed hazards of agro-chemicals on environment and human health, the acceptability of agro-chemicals decreased and scientists turned their attention towards natural alternatives. Most tropical and subtropical fruits contain a superficial cuticle, which helps them to regulate respiration and transpiration and protects against microbial decay. However, the waxy cuticle is generally being removed or damaged during washing or other handling practices. Therefore, the application of protective coatings (including wax) has been used in the fruit industry since the twelfth century, against microbial decay and for maintaining an acceptable standard of postharvest quality. This review aims to summarise and discuss the main natural products used for this purpose, to provide a broad-in-scope guide to farmers and the fruit storage sector.

Recent Advances in the Development of Smart and Active Biodegradable Packaging Materials

Interest in the development of smart and active biodegradable packaging materials is increasing as food manufacturers try to improve the sustainability and environmental impact of their products, while still maintaining their quality and safety. Active packaging materials contain components that enhance their functionality, such as antimicrobials, antioxidants, light blockers, or oxygen barriers. Smart packaging materials contain sensing components that provide an indication of changes in food attributes, such as alterations in their quality, maturity, or safety. For instance, a smart sensor may give a measurable color change in response to a deterioration in food quality. This article reviews recent advances in the development of active and smart biodegradable packaging materials in the food industry. Moreover, studies on the application of these packaging materials to monitor the freshness and safety of food products are reviewed, including dairy, meat, fish, fruit and vegetable products. Finally, the potential challenges associated with the application of these eco-friendly packaging materials in the food industry are discussed, as well as potential future directions.

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.

Recent advances in the production of biomedical systems based on polyhydroxyalkanoates and exopolysaccharides

In recent years, growing attention has been devoted to naturally occurring biological macromolecules and their ensuing application in agriculture, cosmetics, food and pharmaceutical industries. They inherently have antigenicity, low immunogenicity, excellent biocompatibility and cytocompatibility, which are ideal properties for the design of biomedical devices, especially for the controlled delivery of active ingredients in the most diverse contexts. Furthermore, these properties can be modulated by chemical modification via the incorporation of other (macro)molecules in a random or controlled way, aiming at improving their functionality for each specific application. Among the wide variety of natural polymers, microbial polyhydroxyalkanoates (PHAs) and exopolysaccharides (EPS) are often considered for the development of original biomaterials due to their unique physicochemical and biological features. Here, we aim to fullfil a gap on the present associated literature, bringing an up-to-date overview of ongoing research strategies that make use of PHAs (poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-co-3-hydroxyvalerate), poly (3-hydroxyoctanoate), poly(3-hydroxypropionate), poly (3-hydroxyhexanoate-co-3-hydroxyoctanoate), and poly (3-hydroxybutyrate-co-3-hydroxyhexanoate)) and EPS (bacterial cellulose, alginates, curdlan, pullulan, xanthan gum, dextran, hyaluronan, and schizophyllan) as sources of interesting and versatile biomaterials. For the first time, a monograph addressing the properties, pros and cons, status, challenges, and recent progresses regarding the application of these two important classes of biopolymers in biomedicine is presented.

Synthesis of Silver and Gold Nanoparticles in Sodium Alginate Matrix Enriched with Graphene Oxide and Investigation of Properties of the Obtained Thin Films

Polymer nanocomposites containing nanometals became a subject of interest due to their bactericidal properties. Different polysaccharides have been used as matrices for nanosilver and nanogold synthesis. In this study, we present a novel, environmentally friendly method for the preparation of sodium alginate/nanosilver/graphene oxide (GOX) and sodium alginate/nanogold/graphene oxide GOX nanocomposites and their characteristics. The formation of approximately 10–20 nm ball-shaped Ag and Au nanoparticles was confirmed by UV–vis spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra. The incorporation of GOX sheets within the ALG matrix improved the thermal stability of the nanocomposites film, which was measured using the differential scanning calorimetry (DSC). We also estimated the molecular weights of polysaccharide chains of the matrix with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). The composites were more prone to enzymatic hydrolysis. The strongest bacteriostatic activity was observed for the sample containing nanosilver.

Fabrication of packaging paper sheets decorated with alginate/oxidized nanocellulose‑silver nanoparticles bio-nanocomposite

Packaging is as important as the product itself because it is a crucial marketing and communication tool for business. Oxidized nanocellulose (ONC), extracted from agriculture residues of bagasse raw material using ecofriendly ammonium persulfate hydrolysis method, is used as support/reducing agent for the generation of silver nanoparticles (AgNPs) via photochemical procedure and reinforcing element in paper functionalization. The natural polymer, sodium alginate (SA) is exploited to enhance the binding of the ONC-AgNPs over cellulose fibers. The SA/ONC-AgNPs bio-nanocomposite is incorporated on paper matrix, which represents a more suitable choice respect to other substrates for its renewable, biocompatible, biodegradable, and cost-effective properties. Structural and antimicrobial evaluations show that the papers embedded with the SA/ONC-AgNPs possess good mechanical, thermal, barrier and antibacterial properties.

Composite Coatings of Chitosan and Alginate Emulsions with Olive Oil to Enhance Postharvest Quality and Shelf Life of Fresh Figs (Ficus carica L. cv. 'Pingo De Mel')

Fresh figs are very appreciated and have been associated with health benefits. However, these fruits are highly perishable. In this study, edible coatings were studied envisaging their positive effect in enhancing figs' shelf-life. Fig fruits cv. 'Pingo de mel' were harvested at commercial ripening stage and single emulsion-based coatings, composed of chitosan + olive oil and alginate + olive oil, were applied. After coatings application by dipping each fruit in the emulsion-based solutions at 4 °C and drying, the coated fruits were sprayed with crosslinking solutions (6% tripolyphosphate and 1% calcium chloride for chitosan and alginate-based coatings, respectively). Then, were maintained at 4 °C and analyzed after 1, 7, 14 and 19 days of storage. After each time interval, fruits were further maintained at 25 °C for 2 days. The results have shown that coatings were effective on delaying fungal decay and postharvest ripening indicators (respiration rate, mass loss, softening and total soluble solids/titratable acidity ratio). The results foresee a fruits' shelf life between 14 and 19 days under refrigeration at 4 °C that may be followed up to 2 days at ambient temperature, higher than that estimated for uncoated fruits (less than 14 days at 4 °C plus to 2 days at ambient temperature).

Simple and green synthesis of calcium alginate/AgCl nanocomposites with low-smoke flame-retardant and antimicrobial properties

Fire hazards and infectious diseases result in great threats to public safety and human health, thus developing multi-functional materials to deal with these issues is critical and yet has remained challenging to date. In this work, we report a facile and eco-friendly synthetic approach for the preparation of calcium alginate/silver chloride (CA/AgCl) nanocomposites with dual functions of excellent flame-retardant and antibacterial activity. Multi characterization techniques and antibacterial assays were performed to investigate the flame-retardant and antibacterial properties of the CA/AgCl nanocomposites. The obtained results show that the CA/AgCl nanocomposites exhibited much higher limiting oxygen index value (> 60%) than that of CA (48%) with a UL-94 rating of V-0. Moreover, CA/AgCl particularly displayed an efficiently smoke-suppressive feature by achieving a total smoke release value of 2.7 m²/m², which was reduced by 91%, compared to CA. The antibacterial rates of the CA/AgCl nanocomposites against E. coli and S. aureus were measured to be 99.67% and 99.77%, respectively, while CA showed quite weak antibacterial rates. In addition, the flame-retardant and antibacterial mechanisms were analyzed and proposed based on the experimental data. This study provides a novel nanocomposite material with both flame-retardant and antibacterial properties which show promising application prospects in the fields of decorative materials and textile industry.

Emulsions Incorporated in Polysaccharide-Based Active Coatings for Fresh and Minimally Processed Vegetables

The consumption of minimally processed fresh vegetables has increased by the consumer's demand of natural products without synthetic preservatives and colorants. These new consumption behaviors have prompted research on the combination of emulsion techniques and coatings that have traditionally been used by the food industries. This combination brings great potential for improving the quality of fresh-cut fruits and vegetables by allowing the incorporation of natural and multifunctional additives directly into food formulations. These antioxidant, antibacterial, and/or antifungal additives are usually encapsulated at the nano- or micro-scale for their stabilization and protection to make them available by food through the coating. These nano- or micro-emulsions are responsible for the release of the active agents to bring them into direct contact with food to protect it from possible organoleptic degradation. Keeping in mind the widespread applications of micro and nanoemulsions for preserving the quality and safety of fresh vegetables, this review reports the latest works based on emulsion techniques and polysaccharide-based coatings as carriers of active compounds. The technical challenges of micro and nanoemulsion techniques, the potential benefits and drawbacks of their use, the development of polysaccharide-based coatings with natural active additives are considered, since these systems can be used as alternatives to conventional coatings in food formulations.

Per- and polyfluoroalkyl substances and their alternatives in paper food packaging

Per- and polyfluoroalkyl substances (PFAS) have been used in food contact paper and paperboard for decades due to their unique ability to provide both moisture and oil/grease resistance. Once thought to be innocuous, it is now clear that long chain PFAS bioaccumulate and are linked to reproductive and developmental abnormalities, suppressed immune response, and tumor formation. Second-generation PFAS have shorter biological half-lives but concerns about health risks from chronic exposure underscore the need for safe substitutes. Waxes and polymer film laminates of polyethylene, poly(ethylene-co-vinyl alcohol), and polyethylene terephthalate are commonly used alternatives. However, such laminates are neither compostable nor recyclable. Lamination with biodegradable polymers, including polyesters, such as polylactic acid (PLA), polybutylene adipate terephthalate, polybutylene succinate, and polyhydroxyalkanoates, are of growing research and commercial interest. PLA films are perhaps the most viable alternative, but performance and compostability are suboptimal. Surface sizings and coatings of starches, chitosan, alginates, micro- and nanofibrilated cellulose, and gelatins provide adequate oil barrier properties but have poor moisture resistance without chemical modification. Plant proteins, including soy, wheat gluten, and corn zein, have been tested as paper coatings with soy being the most commercially important. Internal sizing agents, such as alkyl ketene dimers, alkenyl succinic anhydride, and rosin, improve moisture resistance but are poor oil/grease barriers. The difficulty in finding a viable replacement for PFAS chemicals that is cost-effective, fully biodegradable, and environmentally sound underscores the need for more research to improve barrier properties and process economics in food packaging products.

Effect of Cross-Linked Alginate/Oil Nanoemulsion Coating on Cracking and Quality Parameters of Sweet Cherries

The cracking of sweet cherries causes significant crop losses. Sweet cherries (cv. Bing) were coated by electro-spraying with an edible nanoemulsion (NE) of alginate and soybean oil with or without a CaCl2 cross-linker to reduce cracking. Coated sweet cherries were stored at 4 °C for 28 d. The barrier and fruit quality properties and nutritional values of the coated cherries were evaluated and compared with those of uncoated sweet cherries. Sweet cherries coated with NE + CaCl2 increased cracking tolerance by 53% and increased firmness. However, coated sweet cherries exhibited a 10% increase in water loss after 28 d due to decreased resistance to water vapor transfer. Coated sweet cherries showed a higher soluble solid content, titratable acidity, antioxidant capacity, and total soluble phenolic content compared with uncoated sweet cherries. Therefore, the use of the NE + CaCl2 coating on sweet cherries can help reduce cracking and maintain their postharvest quality.

Properties and potential applications of mannuronan C5-epimerase: A biotechnological tool for modifying alginate

Given the excellent characteristics of alginate, it is an industrially important polysaccharide. Mannuronan C5-epimerase (MC5E) is an alginate-modifying enzyme that catalyzes the conversion of β-D-mannuronate (M) to its C5 epimer α-L-guluronate (G) in alginate. Both the biological activities and physical properties of alginate are determined by M/G ratios and distribution patterns. Therefore, MC5E is regarded as a biotechnological tool for modifying and processing alginate. Various MC5Es derived from brown algae, Pseudomonas and Azotobacter have been isolated and characterized. With the rapid development of structural biology, the crystal structures and catalytic mechanisms of several MC5Es have been elucidated. It is necessary to comprehensively understand the research status of this alginate-modifying enzyme. In this review, the properties and potential applications of MC5Es isolated from different kinds of organisms are summarized and reviewed. Moreover, future research directions of MC5Es as well as strategies to enhance their properties are elucidated, highlighted, and prospected.

Bactericidal Pectin/Chitosan/Glycerol Films for Food Pack Coatings: A Critical Viewpoint

Pectin and chitosan films containing glycerol (Gly) at 5, 10, 15, 20, 30, and 40 wt % were prepared in an aqueous HCl solution (0.10 M) by the solvent evaporation method. The unwashed film (UF) containing 40 wt % Gly (UF40) had elongation at break (ε, %) of 19%. Washed films (WFs) had high tensile strength (σ > 46 MPa) and low elongation at break (ε, <5.0%), enabling their use in food packaging applications. The polymers’ self-assembling occurred during the washing, increasing the stiffness. The XPS analysis suggests that some HCl is lost during the drying process, resulting in a low acid content on the UF surfaces. The UF40 (at 5.0 mg/mL) exhibits cytocompatibility toward mammalian cells and antimicrobial and anti-adhesive properties against Escherichia coli. The remaining HCl in the UF40 can be a disadvantage for food packaging applications; the UF40 (∅ = 8.5 mm; 55 μm thickness) releases H₃O⁺/HCl, reducing the pH to approximately 3.0 when kept in 200 mL distilled water for approximately 30 min. Therefore, we propose the use of UF40 to coat commercial food packaging. The UF40 has low permeability to water vapor and oxygen and works as a barrier against ultraviolet light. The UF40 is also colorless and completely transparent. The UF40 maintained tomatoes’ structural integrity for 18 days at room temperature with no oxidation or microorganism contamination. This paper presents a critical viewpoint concerning chitosan-based films with antimicrobial activities.

Alginate- and Gelatin-Coated Apple Pieces as Carriers for Bifidobacterium animalis subsp. lactis DSM 10140

Fruit and vegetables are considered good natural supports for microorganisms; however, probiotics could cause negative changes on some organoleptic and sensory traits. Thus, the main topic of this paper was the design of coated apple chips as carriers for probiotics with a high level of sensory traits. The research was divided into two steps. First, four functional strains (Limosilactobacillus reuteri DSM 20016, Bifidobacterium animalis subsp. lactis DSM 10140, and Lactiplantibacillus plantarum c16 and c19) were immobilized on apple pieces through dipping of fruit chips in probiotic suspensions for different contact times (from 15 to 30 min) and stored at 4°C for 12 days. Periodically, the viable count was assessed. As a result of this step, a contact time of 15 min was chosen because it assured an optimal deposition of microorganisms. In the second step, apple pieces inoculated with B. animalis subsp. lactis DSM 10140 were coated with alginate and gelatin and stored at 4 and 8°C for 10 days; pH, microbiological counts, color (browning index), and sensory scores were evaluated. Bifidobacterium animalis DSM 10140 exerted a negative effect on apple chips and cause a significant browning; however, the use of coating counteracted this phenomenon. In fact, coated chips showed higher sensory scores and lower browning index. In addition, gelatin showed better performances in terms of probiotic viability, because at 8°C, a significant viability loss of B. animalis DSM 10140 (1.2 log cfu/g) was found on alginate-coated chips. Gelatin-coated apple pieces with B. animalis subsp. lactis DSM 10140 could be an attractive functional food for a wide audience, although further investigations are required on in vivo effects of this product after consumption.

Graphene Derivatives in Biopolymer-Based Composites for Food Packaging Applications

This review aims to showcase the current use of graphene derivatives, graphene-based nanomaterials in particular, in biopolymer-based composites for food packaging applications. A brief introduction regarding the valuable attributes of available and emergent bioplastic materials is made so that their contributions to the packaging field can be understood. Furthermore, their drawbacks are also disclosed to highlight the benefits that graphene derivatives can bring to bio-based formulations, from physicochemical to mechanical, barrier, and functional properties as antioxidant activity or electrical conductivity. The reported improvements in biopolymer-based composites carried out by graphene derivatives in the last three years are discussed, pointing to their potential for innovative food packaging applications such as electrically conductive food packaging.

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.

A Review of Polysaccharide-Zinc Oxide Nanocomposites as Safe Coating for Fruits Preservation

Safe coating formulated from biopolymer can be an alternative for better packaging for fruits. Among biopolymers used for safe coating, polysaccharides attracted more attention due to its biocompatibility and edibility. However, polysaccharide-based materials have weaknesses such as low water barrier and mechanical properties which result in lower capability on preserving the coated fruits. Hence, the incorporation of nanoparticles (NPs) such as zinc oxide (ZnO) is expected to increase the ability of polysaccharide-based coating for the enhancement of fruit shelf life. In this review paper, the basic information and the latest updates on the incorporation of ZnO NPs into the polysaccharide-based safe coating for fruit are presented. Various research has investigated polysaccharide-ZnO nanocomposite safe coating to prolong the shelf life of fruits. The polysaccharides used include chitosan, alginate, carrageenan, cellulose, and pectin. Overall, polysaccharide-ZnO nanocomposites can improve the shelf life of fruits by reducing weight loss, maintaining firmness, reducing the ripening process, reducing respiration, reducing the oxidation process, and inhibiting microbial growth. Finally, the challenges and potential of ZnO NPs as an active agent in the safe coating application are also discussed.

Sulfated polysaccharides and its commercial applications in food industries-A review

Polysaccharides a large chain of simple sugars covalently linked by glycosidic bonds which are obtained from living organisms and microbes commercially used in food and pharmaceutical industries. Marine macroalgae or seaweed is an unexploited natural source of polysaccharides, which contains many variant phytonutrients whose cells are enriched with sulfated polysaccharides which have been progressively read these days for their potential value in food and pharmaceutical applications. This review aims the exploration of these polysaccharides in food applications, with a focus on its types and biological properties in the view of food application.

Preparation of Beebread Caviar from Buckwheat Honey through Immobilization with Sodium Alginate

Honeys have a pleasant taste and a wide range of use. They are characterized by a relatively high consumption compared to bee pollen or beebread. Honeys are the most popular bee products. Considering health reasons, beebread exhibits the strongest properties as it has the highest nutritional value as well as strong detoxifying, antioxidant, and antiradical properties. Despite having such valuable properties, consumption of beebread is negligible; sometimes, it is limited only to supplementation in case of diseases. This paper proposes a new food product, that is, beebread caviar made from buckwheat honey. The expiry date and sensory and physicochemical quality of beebread caviar have been determined in this study. Beebread caviar, obtained by immobilization on alginate carrier, contained 0.34 mg GAE/mL extract. It remained stable until five days after preparation. Its total acidity was 33.7 mval/kg. Its extract content was 22.53%. Caviar had a high overall sensory score of 4.8 points on a 5-point scale. Beebread caviar can be successfully classified as probiotic food because beebread contains a large amount of lactic acid. In the form of caviar, a new, attractive, and convenient form of beebread consumption could become one of the products of comfortable and functional food.