Recent Advances on Edible Films Based on Fruits and Vegetables-A Review

Effect of eucalyptus nanofibril as reinforcement in biodegradable thermoplastic films based on rice starch (Oryza sativa): Evaluation as primary packaging for crackers

This study investigated the incorporation of eucalyptus nanocellulose (CNF) into rice starch-based thermoplastic (TPS) films, evaluating the effects of four CNF concentrations (0 %, 2 %, 4 %, and 6 %, w/w) on the physicochemical properties of the films. The analyses included scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), solubility, mechanical properties, optical properties, biodegradability, and application for cookie preservation. Atomic force microscopy (AFM) confirmed good CNF dispersion at 4 %, while higher concentrations caused agglomeration. FTIR analysis revealed effective interactions between CNF and the starch matrix. The TPS + 4 % CNF film showed reductions in water solubility (44 %), solubility in acidic (34 %) and basic (32 %) conditions, water vapor permeability (51 %), and water retention capacity (27 %) compared to pure TPS. Tensile strength increased from 3 MPa (pure TPS) to 6.5 MPa (TPS with 4 % CNF), while elongation at break ranged from 38 % (pure TPS) to 65 % (TPS with 2 % CNF). At 6 % CNF, elongation decreased to 45 %, with increased rigidity. The TPS + 4 % CNF film demonstrated good performance in mechanical strength and water vapor barrier properties, while higher CNF concentrations resulted in stiffer, less flexible films due to restricted polymer chain mobility. Higher CNF concentrations also increased the film's opacity. With 90 % biodegradability after 15 days, the reinforced film showed environmental potential. In cookie preservation, TPS + 4 % CNF demonstrated promising performance, with moisture barrier and texture preservation capabilities comparable to oriented polypropylene (BOPP). The combination of biodegradable primary packaging with non-biodegradable secondary packaging offers an innovative solution for food protection with reduced environmental impact.

Formulation and biological evaluation of sodium alginate-based films blended with watercress oil: A Promising solution for combating foodborne pathogens and potential food packaging applications

The main objective of this study is to prepare sodium alginate (SA)-based biofilms incorporated with watercress oil (WCO) as an antimicrobial material for sustainable food packaging. The physicochemical, antioxidant, and antibacterial properties of the prepared bio-based films were investigated. The antioxidant activity showed a remarkable increase, with DPPH inhibition increasing from 13.6 % in WCO-0/SA (without WCO loading) to 92.6 % in WCO-5/SA (loading of WCO with a high concentration). Results also displayed the superior antimicrobial activities of WCO-5/SA against Salmonella enterica (27 mm), E. coli O157 (25 mm), Listeria monocytogenes (22 mm), and Staphylococcus aureus (20 mm),1 h, log reduction studies demonstrated a whole 6-log decrease in bacterial population counts, proving these films' abilities to combat bacterial contamination efficiently. Additionally, the findings demonstrated the potential of films as long-lasting films through the sustained release of phenolic compounds that resulted in a final content of 782 mg GAE/g DW for WCO-5/SA films. Based on these obtained data, the SA films incorporated with WCO have potential to function as active packaging materials that are environmentally friendly and may improve food safety, extend shelf-life and contribute towards sustainability by reducing reliance on conventional plastics.

Production of polysaccharide and protein edible films: Challenges and strategies to scale-up

Polymeric films are among the main packaging materials used by food industry, and they can be produced using petrochemical-based polymers and biopolymers. Although the use of petrochemical-based polymers for food packaging is associated with a harmful impact on the environment, and human health through direct contact with food, the food industry cannot avoid their use due to the lack of fully viable alternatives. Therefore, there is an imperative need for potential food packaging alternatives made from natural, bio-based polymers that should be safe and biodegradable. In this group, edible polysaccharides and proteins present several advantages, making them green and safe alternatives. Therefore, several pilot and semi-commercial attempts have been made to commercialize the production of edible packaging materials. However, their industrial-scale production still presents big challenges. These challenges are related to the properties of edible biopolymers, such as low elasticity and high hygroscopicity, and, others are associated with the commercial-scale manufacturing technologies, which causes a slower implementation of edible films at the industrial level. This study aims to discuss edible films' main properties and limitations and propose possibilities for their industrial-scale production, focusing on maintaining their natural and ecofriendly food packaging with evolved functionalities.

Eco-sustainable, edible, biodegradable and antioxidant pectin and bacterial cellulose films loaded with coconut oil for strawberry preservation

Strawberry is one of the most problematic fresh fruits susceptible to damage or mold due to their sensitive skin. For this, we developed films made of bacterial cellulose [BC, 25 % (w/w)], pectin [P, 75 % (w/w)] loaded with coconut oil for strawberry preservation. XRD patterns of the BC showed three distinct peaks at Bragg angles (2θ) of 14.6°, 16.9°, and 22.7°, indicating the structural characteristics of cellulose I. CG-MS demonstrated that coconut oil contained triacylglycerols like lauric acid, linoleic acid, and dodecanoic acid. Moreover, coconut oil showed antioxidant activity of about 50 % and antimicrobial activity in yeast extracted from strawberries. FTIR spectroscopy, TGA/DTG, mechanical testing, water vapor permeability, AFM and SEM images showed that the oil was successfully incorporated into the film. Next, mass loss and swelling degree and wettability studies revealed that formed films maintained hydrophobic characteristics. In fact, these films presented a high-water vapor barrier because preserved a major part of the characteristics of the biocellulose, turning the bioplastics inert to water. In addition, coconut oil loaded into BC + P bioplastic presented low release due to its hydrophobicity character. Despite this, our bioplastic worked as a mechanical barrier, protecting the fruits from microorganisms and other forms of damage. Furthermore, antioxidant activity from both film-formed was similar (28 %), and these bioplastics preserved the strawberries for 192 h, whereas uncoated fruits degraded at 72 h. Indeed, our bioplastics were more effective in reducing fruit mass loss, especially BC + P + O film. Our findings showed that the essential oil acted as a reducing agent of strawberry mass loss, decreasing its skin transpiration, being an inexpensive and feasible alternative for fruits preservation.

Influence of Honey Bee Brood Protein on the Hydrophilic, Mechanical, and Thermal Properties of Polysaccharide Gel Films

Growing concerns over the environmental impact of plastic packaging have driven interest in sustainable alternatives, particularly biopolymer-based films. This study developed ternary-blended polysaccharide gel films composed of carboxymethyl starch (CMS), chitosan (CS), and pectin (PT), with dialdehyde carboxymethyl cellulose (DCMC) as a crosslinker, and investigated the effects of honey bee brood protein (BBP) (0-0.4% w/v) on their mechanical, barrier, and thermal properties. A completely randomized design (CRD) was employed to evaluate the impact of BBP concentration on film characteristics. Results demonstrated that adding 0.4% BBP enhanced water vapor barrier properties and thermal stability while reducing hydrophilicity. The optimal formulation was observed at 0.1% BBP, providing the highest tensile strength (7.73 MPa), elongation at break (32.23%), and water-absorption capacity (369.01%). The improvements in thermal stability and hydrophilicity were attributed to BBP's hydrophobic amino acids, which interacted with DCMC to form a denser polymer network, enhancing structural integrity and moisture resistance. Additionally, BBP incorporation contributed to the biodegradability of polysaccharide gel films, improving their environmental sustainability compared to conventional biopolymers. The findings suggest that BBP can serve as a functional additive in polysaccharide-based films, balancing performance and eco-friendliness for applications in biodegradable food and medical packaging.

Percolation Threshold of Bacterial Nanocrystals in Biopolymeric Matrices to Build Up Strengthened Biobased Food Packaging

Bacterial cellulose nanocrystals (BCNCs) extracted from cellulose residues, resulting from film-cutting operations used for the commercial production of dressings, were studied as reinforcement for films based on gelatin, pectin, and hydroxypropylmethyl cellulose (HPMC). The biopolymer matrices differ in their monomer and functional group (gelatin: -COOH and -NH; pectin: -COOH and HPMC -OH). The addition of BCNCs into a polymer matrix for biopolymeric nanocomposite formulation was based on values around the theoretical percolation threshold. The results of this study showed that the BCNCs had a diameter and mean length range of (27 ± 1) nm and (180 ± 10) nm, respectively, producing films reaching 120.13 MPa of tensile strength, 10.9 GPa of Young's modulus, and a toughness of 335.17 × 106 J/m3. All films showed good transparency and a smooth surface. Surface micrographs (SEM) revealed homogeneous, compact, smooth regions, and no macropores. The crystallinity index of the BCNCs produced was 68.69%. The crystallinity of the gelatin, pectin, and HPMC films improved from 10.25 to 44.61%, from 29.79 to 53.04%, and from 18.81 to 39.88%, respectively. These results show the possibility of using films for freeze-dried food packaging.

Developing and Characterization of a Biopolymeric Membrane Derived from Mature Banana Peel Biomass

Biopolymeric films derived from starch are gaining attention due to their potential applications, which are primarily attributed to their availability and biodegradability. Here, we report developing and characterizing a biopolymeric film utilizing banana peel waste (BM2). Analytical techniques were employed, including water absorption analysis, determination of soluble matter, UV-visible absorption spectrophotometry, tensile strength assessment, morphological examination using scanning electron microscopy (SEM), and thermal analysis through thermogravimetric analysis (TGA). The water absorption analysis revealed a noteworthy absorption percentage of 115.23% and 61.75% of soluble matter. The UV-visible absorption spectrophotometry results demonstrated a light absorbance degree ranging from 0.9 to 720 nm, particularly between 400 and 1000 nm. However, the mechanical strength tests indicated relatively low resistance at 0.8 MPa, attributed to the irregular surface observed in the film's morphology as evidenced by scanning electron microscopy (SEM). Thermal analysis conducted via TGA offered valuable insights into the degradation behavior of the film. The findings reveal a degradation temperature ranging from 160 to 300 °C, thereby elucidating the thermal stability of the film and its potential applications. While mechanical limitations were evident, the biopolymeric film derived from banana peel waste demonstrated noteworthy water absorption properties, presenting potential in specific applications, particularly those that do not necessitate elevated mechanical strength. Continued efforts in optimizing and refining the film's structure promise to bolster its mechanical properties, making it suitable for various applications.

Optimizing Edible Sorghum Bowls: Effects of Roasting and Edible Flower Powder Enhancement on Technological, Nutritional, Antioxidant, and Functional Properties

The widespread reliance on single-use plastics (SUPs) has fostered a global throwaway culture, especially in the food packaging industry, where convenience and low cost have driven their adoption, posing serious environmental threats, particularly to marine ecosystems and biodiversity. Edible and ecofriendly packaging made from millet, specifically sorghum (Sorghum bicolor (L.) Moench), is a promising solution to mitigate SUP consumption and promote sustainability. This study explores the development of edible sorghum bowls, enhanced through roasting and incorporating 3 g of hibiscus and rose flower powders. The standardized sorghum bowl was analyzed for nutritional value; optical, technological, functional, and mechanical properties; and shelf life, and the results were discussed. The bowls, 18.5 g of average weight, dimensions of 10.2 cm, and a thickness of 3 mm, were baked in a unique bowl-shaped mold at 80°C for 7 min. Enhancing the bowls with flower powder improved their optical properties and nutrient content. The addition of flower powder also increased phytochemical levels, according to qualitative analysis, while roasting sorghum reduced tannin and phytic acid content. The IC50 values revealed that hibiscus (47.74 mg/mL) and rose (39.87 mg/mL) enrichment boosted antioxidant activity. Sensory evaluations favored roasted bowls across all attributes, while Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyzer (TGA) analyses confirmed significant structural changes. The enhanced bowls exhibited greater hardness and hold hot or cold snacks for 90 min without compromising structural integrity. Additionally, these bowls demonstrated an extended shelf life, low microbial count (1 × 101CFU/g), reduced toxicity (3%-10% mortality in brine shrimp assays), and complete biodegradation within 15 days in wet soil. These findings indicate that sorghum-based edible bowls present a nutritious, viable, less toxic alternative to SUPs, appealing to a broad demographic, especially in the food and tourism sector, and contributing to environmental conservation by reducing plastic waste and suitable for wide consumption.

Valorization of raw papaya (Carica papaya) and citrus peels for development of antimicrobial and biodegradable edible film

Most of the food packaging materials used in the market are petroleum-based plastics; such materials are neither biodegradable nor environmentally friendly and require years to decompose. To overcome these problems, biodegradable and edible materials are encouraged to be used because such materials degrade quickly due to the actions of bacteria, fungi, and other environmental effects. The present study examined that starch can be effectively used as raw material to develop biodegradable, edible films. In this regard, Raw papaya and Citrus Peel were chosen to make biodegradable plastic film blended with corn starch. Raw papaya powder was combined with citrus peel powder for the development of film in treatments of T1, T2, T3, T4 and T5. RPP and CPP blend with Corn starch (CS) to maximize the film-forming properties and characteristics. The films were subjected to various parameter analysis like thickness, optical properties and barrier properties. As per the results, T3 was an optimized film, as it had minimum thickness (0.26 ± 0.01), high tensile strength (5.79 ± 0.12), elongation at break of 11.92 ± 0.03, High transparency (1.42 ± 0.06), and high degradation temperature. From the results, it is inferred that the prepared films are ideally suitable for food packaging and their production on a larger scale can considerably cut down the plastic wastage.

Carboxymethyl cellulose-chitosan edible films for food packaging: A review of recent advances

Polysaccharide-based edible films have been widely developed as food packaging materials in response to the rising environmental concerns caused by the extensive use of plastic packaging. In recent years, the integration of carboxymethyl cellulose (CMC) and chitosan (CS) for a binary edible film has received considerable interest because this binary edible film can retain the advantages of both constituents (e.g., the great oxygen barrier ability of CMC and moderate antimicrobial activity of CS) while mitigating their respective disadvantages (e.g., the low water resistance of CMC and poor mechanical strength of CS). This review aims to present the latest advancements in CMC-CS edible films. The preparation methods and properties of CMC-CS edible films are comprehensively introduced. Potential additives and technologies utilized to enhance the properties are discussed. The applications of CMC-CS edible films on food products are summarized. Literature shows that the current preparation methods for CMC-CS edible film are solvent-casting (main) and thermo-mechanical methods. The CMC-CS binary films have superior properties compared to films made from a single constituent. Moreover, some properties, such as physical strength, antibacterial ability, and antioxidant activity, can be greatly enhanced via the incorporation of some bioactive substances (e.g. essential oils and nanomaterials). To date, several applications of CMC-CS edible films in vegetables, fruits, dry foods, dairy products, and meats have been studied. Overall, CMC-CS edible films are highly promising as food packaging materials.

Starch-pectin smart tag containing purple carrot peel anthocyanins as a potential indicator of analogous meat freshness

Smart films of starch/pectin and purple carrot peel (PCP) containing anthocyanins were developed, characterized, and used as pH-responsive tags to monitor plant-based chicken analogous. This study innovates by incorporating PCP in the film solution both as an extract and as a powder, and the resulting tags were applied to a plant-based food. PCP powder <100-mesh was directly incorporated into the film-forming suspension. For powder >100-mesh, two extracts were tested: an aqueous solution and a 1 % NADES solution added to the film-forming suspension. Quantification of PCP anthocyanins by HPLC showed a higher extraction under acidic conditions (1664 mg C3G equivalents 100 g-1). Films with PCP presented greater light protection. Films with 15 % and 25 % PCP and those with added extract showed better tensile strength (3.0-3.6 MPa), elongation at break (16-20 %) and a water contact angle of 52°. All films responded to pH variations (1 to 14) and ammonia vapor and showed ΔE* values >5. After 3 days, films used as smart tags monitoring chicken analogous presented noticeable color differences for PCPNADES (55 ± 8) and 15%PCP (40 ± 1). PCP showed strong potential as a pigmenting agent in films, especially as an aqueous extract with NADES for use as pH-responsive tags in chicken analogous.

Cellulose-Based Transparent Edible Antibacterial Oxygen-Barrier Coating for Long-Term Fruit Preservation

Long-term preservation of fresh fruit and vegetables without a cold chain is a great challenge to food security because fruits and vegetables are highly vulnerable to poor storage conditions. Fruit spoilage is a complex biochemical process that involves many factors, including microbial reproduction, oxidation, metabolism, and H2O evaporation. Only the synergy of the multiple spoilage inhibition methods can achieve long-term freshness preservation. Herein, a multifunctional cellulose-based preservation coating with antibacterial, oxygen/water vapor barrier, and antioxidant properties is proposed, which is based on cellulose microgel (CMG) and prepared using multi-component composites with montmorillonite (MMT), cationic cellulose derivative (Cell-P+), and L-ascorbic acid (Vc). It has good wetting properties on fruits with different surfaces. This method can successfully preserve the long-term freshness of various fruits. This highly transparent, edible, and washable multifunctional cellulose-based fruit preservation coating can improve the quality of agricultural products, extend the shelf life of food, and reduce the cost of cold-chain transportation.

Effects of chestnut shell extract and citric acid on the properties of navel orange pomace/chitosan composite films

The improper use of citrus peel and nondegradable plastic film can cause substantial issues, such as environmental pollution and resource waste. Herein, navel orange pomace powder (NOPP) and chitosan (CS) were used as the raw material and film-forming additive, respectively, to prepare biobased composite films. Chestnut shell extract (CHE) and citric acid (CA) were added to the prepared NOPP/CS biobased multifunctional films. Based on ensuring the tensile strength of the film above 10 MPa, the elongation at break of the film can be increased from 19.11 % to 34.93 %, the water contact angle can reach 60°, and the water vapor transmittance can be significantly reduced to approximately 1.1 × 10-10 gs-1m-1Pa-1. Additionally, the antibacterial ability and antioxidant capacity of the composite film were improved. We observed that the multifunctional film could significantly inhibit the browning of fresh-cut apples, where the browning index was maintained between 60 and 65, which was 25 % lower than that of the control. The newly developed film therefore possesses the potential to replace the traditional plastic cling film. This research contributes to the literature regarding the source of raw materials for biobased materials and highlights the value of navel orange processing by-products.

An in-depth review: Unraveling the extraction, structure, bio-functionalities, target molecules, and applications of pectic polysaccharides

Pectic polysaccharides have long been a challenging subject of research in the field of macromolecular science, given their complex structures and wide range of biological effects. However, the extensive exploration of pectic polysaccharides has been limited due to the intricacy of their structures. In this comprehensive review, we aim to provide a thorough summary of the existing knowledge on pectic polysaccharides, with a particular focus on aspects such as classification, extraction methodologies, structural analysis, elucidation of biological activities, and exploration of target molecules and signaling pathways. By conducting a comprehensive analysis of existing literature and research achievements, we strive to establish a comprehensive and systematic framework that can serve as a reference and guide for further investigations into pectic polysaccharides. Furthermore, this review delves into the applications of pectic polysaccharides beyond their fundamental attributes and characteristics, exploring their potential in fields such as materials, food, and pharmaceuticals. We pay special attention to the promising opportunities for pectic polysaccharides in the pharmaceutical domain and provide an overview of related drug development research. The aim of this review is to facilitate a holistic understanding of pectic polysaccharides by incorporating multifaceted research, providing valuable insights for further in-depth investigations into this significant polymer.

Gelatin-chitosan interactions in edible films and coatings doped with plant extracts for biopreservation of fresh tuna fish products: A review

The preservation of tuna fish products, which are extremely perishable seafood items, is a substantial challenge due to their instantaneous spoilage caused by microbial development and oxidative degradation. The current review explores the potential of employing chitosan-gelatin-based edible films and coatings, which are enriched with plant extracts, as a sustainable method to prolong the shelf life of tuna fish products. The article provides a comprehensive overview of the physicochemical properties of chitosan and gelatin, emphasizing the molecular interactions that underpin the formation and functionality of these biopolymer-based films and coatings. The synergistic effects of combining chitosan and gelatin are explored, particularly in terms of improving the mechanical strength, barrier properties, and bioactivity of the films. Furthermore, the application of botanical extracts, which include high levels of antioxidants and antibacterial compounds, is being investigated in terms of their capacity to augment the protective characteristics of the films. The study also emphasizes current advancements in utilizing these composite films and coatings for tuna fish products, with a specific focus on their effectiveness in preventing microbiological spoilage, decreasing lipid oxidation, and maintaining sensory qualities throughout storage. Moreover, the current investigation explores the molecular interactions associated with chitosan-gelatin packaging systems enriched with plant extracts, offering valuable insights for improving the design of edible films and coatings and suggesting future research directions to enhance their effectiveness in seafood preservation. Ultimately, the review underscores the potential of chitosan-gelatin-based films and coatings as a promising, eco-friendly alternative to conventional packaging methods, contributing to the sustainability of the seafood industry.

Effects of amylose and amylopectin fine structure on the thermal, mechanical and hydrophobic properties of starch films

The fine structures of pumpkin, potato, wheat, cassava, and pea starches were determined, followed by an evaluation of how these structures affected the properties of starch films. The structures significantly influenced film properties. Starches with larger molecular weights exhibited greater thermal stability. The tensile strength of starch film was negatively associated with the amylose chain length (r = -0.88, p < 0.05). The chain length distributions of amylose and amylopectin affected the mechanical properties of starch films by influencing structure ordering, supported by the positive correlation between the double helix content and the tensile strength (r = 0.95, p < 0.05). The amylopectin B1, B2, and B3 chains increased film mechanical strength. Conversely, amylopectin A-chains reduced the mechanical strength. The water contact angle was negatively correlated with the B3 chain proportion (r = -0.93, p < 0.05). The pumpkin starch exhibited the highest tensile strength (14.29 MPa), while the wheat starch film showed the highest water contact angle (112°). This study offers valuable insights into the structure-function relationships of starch films, thereby facilitating the acquisition of starch films with enhanced strength and stability through screening or designing starch structures. Consequently, this will expand the application of starch films as packaging materials in various food products.

Bibliometric study and potential applications in the development of starch films with nanocellulose: A perspective from 2019 to 2023

This study aimed to perform a bibliometric analysis of starch films with nanocellulose, using the Scopus database and VOSviewer and Bibliometrix software. A total of 258 documents were identified between 2019 and 2023, reflecting a growing interest in research, particularly in journals such as the International Journal of Biological Macromolecules, Polymers, and Carbohydrate Polymers. The most common terms were "starch" (349 occurrences), "cellulose" (207), and "tensile strength" (175). China (58 articles), Brazil (38), and India (33) led scientific production, with authors like Ilyas (13 articles) and Sapuan (10) at the forefront. Approximately 41.7 % of the studies used corn starch. The analysis revealed that 66 % of the studies investigated films with cellulose nanofibrils (CNF), 32 % with cellulose nanocrystals (CNC), and 2 % with bacterial nanocellulose (CB). The majority of studies (94.1 %) used the casting method for film production. Additionally, 35.44 % focused on reinforcing films with nanocellulose, while 7 % developed blends with other biopolymers. About 59.44 % examined the performance of starch films for food packaging, 11.25 % explored practical applications in various foods. Furthermore, 7.94 % incorporated active agents to improve antioxidant and antimicrobial properties, 1.30 % investigated active packaging. Moreover, 2.36 % explored the use of films in materials engineering, and 2.36 % explored biomedical potential. Only 0.40 % evaluated the impact of films on wastewater treatment. The analysis highlights the potential of starch films with nanocellulose, demonstrating their diverse applications and the growing interest in the field.

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.

An insect lac blanket-mimetic and degradable shellac hydrogel/chitosan packaging film with controllable gas permeation for fresh-cut vegetables preservation

Fresh-cut products are extremely perishable due to the processing operations, and the atmosphere environment, especially CO2, O2 and H2O, could profoundly affect their shelf life. Herein, an insect "lac blanket"-mimetic and facile strategy was proposed for fresh-cut vegetables preservation, employing porous shellac hydrogel microparticles as gas "switches" in chitosan film to regulate CO2, O2 and H2O vapor permeability. Thus, the shellac hydrogel/chitosan hybrid film presented the controllable and wide range of gas permeability, compared with the chitosan film. The shellac-COOH nanoscale vesicles aggregated to form shellac hydrogel network via hydrophobic binding. The shellac hydrogel microparticles played a certain lubricating effect on the hybrid film casting solution. The hydrogen bond network between shellac hydrogel and chitosan contributed to the excellent mechanical properties of the hybrid film. The hybrid film also exhibited remarkable water-resistant, antifogging properties, optical transparency and degradability. The hybrid packaging films prepared through this strategy could adjust the internal gas (CO2, O2, H2O and ethylene) contents within the packages, and further exhibited admirable preservation performance on three fresh-cut vegetables with different respiratory metabolisms. This gas permeation-controlled strategy has great potential in fresh food preservation and various other applications that need a modified atmosphere.

Global Research Network Analysis of Edible Coatings and Films for Preserving Perishable Fruit Crops: Current Status and Future Directions

Edible coatings and films have gained substantial attention as a promising and sustainable technology for fruit preservation. This study employed a bibliometric analysis to identify core research areas, research gaps, and emerging trends, thus providing a comprehensive roadmap for future research on the use of edible coatings and films for fruit quality preservation. The study involved 428 research articles related to edible coatings and films for fruit preservation published in the Scopus database before 06 October 2023. Utilizing Vosviewer and R for network analysis, we generated network visualization maps, research performance statistics, and identified key contributors and their collaborations. The results show the evolution of this field into three distinct phases: Initial Exploration (1998-2007), Growing Interest (2008-2015), and Rapid Expansion (2016-2023). The study revealed contributions from 1713 authors, with the first article appearing in 1998. Brazil and China emerged as the most productive countries in this domain. The core research areas focus on biomaterials, functional properties, and natural substances. Identified research gaps include pilot and industrial-scale applications, the lack of a regulatory framework and safety guidelines, and the application of artificial intelligence (AI), particularly deep learning and machine learning, in this field of edible coatings and films for fruit preservation. Overall, this study offers a scientific understanding of past achievements and ongoing research needs, thus aiming to boost a broader adoption of edible coatings and films by consumers and the food industry to preserve fruit quality, thereby enhancing their societal and environmental impact.

Insights into recent innovations in barrier resistance of edible films for food packaging applications

The utilization of biopolymer-based food packaging holds significant promise in aligning with sustainability goals and enhancing food safety by offering a renewable, biodegradable, and safer alternative to traditional synthetic polymers. However, these biopolymer-derived films often exhibit poor barrier and mechanical properties, potentially limiting their commercial viability. Desirable barrier properties, such as moisture and oxygen resistance, are critical for preserving and maintaining the quality of packaged food products. This review comprehensively explores different traditional and advance methodologies employed to access the barrier properties of edible films. Additionally, this review thoroughly examines various approaches aimed at enhancing the barrier properties of edible films, such as the fabrication of multilayer films, the selection of biopolymers for composite films, as well as the integration of plasticizers, crosslinkers, hydrophobic agents, and nanocomposites. Moreover, the influence of process conditions, such as preparation techniques, homogenization, drying conditions, and rheological behavior, on the barrier properties of edible films has been discussed. The review provides valuable insights and knowledge for researchers and industry professionals to advance the use of biopolymer-based packaging materials and contribute to a more sustainable and food-safe future.

The application of starch-based edible film in food preservation: a comprehensive review

Using renewable resources for food packaging not only helps reduce our dependence on fossil fuels but also minimizes the environmental impact associated with traditional plastics. Starch has been a hot topic in the field of current research because of its low cost, wide source and good film forming property. However, a comprehensive review in this field is still lacking. Starch-based films offer a promising alternative for sustainable packaging in the food industry. The present paper covers various aspects such as raw material sources, modification methods, and film formation mechanisms. Understanding the physicochemical properties and potential commercial applications is crucial for bridging the gap between research and practical implementation. Finally, the application of starch-based films in the food industry is discussed in detail. Different modifications of starch can improve the mechanical and barrier properties of the films. The addition of active substances to starch-based films can endow them with more functions. Therefore, these factors should be better investigated and optimized in future studies to improve the physicochemical properties and functionality of starch-based films. In summary, this review provides comprehensive information and the latest research progress of starch-based films in the food industry.

Development of acid-free chitosan films in food coating applications: Provolone cheese as a case study

Chitosan has been extensively explored in food coatings. Still, its practical application is largely hampered by its conventional wet processing in acetic acid, whose residuals negatively impact food quality and safety. Here, we propose a new method to formulate chitosan coatings for food applications by avoiding organic acid processing and validate them on a cheese model. The procedure entails modifying a previously reported process based on HCl chitosan treatment and neutralising the resulting gel. The obtained chitosan is solubilised in water using carbonic acid that forms in situ by dissolving carbon dioxide gas. The reversibility of water carbonation allows for easy removal of carbonic acid residues, resulting in acid-free chitosan films and coatings. The performance of the coating was tested against state-of-the-art chitosan-based and polymeric coatings. We preliminarily characterised the films' properties (water stability, barrier, and optical properties). Then, we assessed the performance of the coating on Provolone cheese as a food model (mass transfer and texture profiles over 14 days). The work demonstrated the advantage of the proposed approach in solving some main issues of food quality and safety, paving the way for an effective application of chitosan in future food contact applications.

One-pot co-crystallized hexanal-loaded ZIF-8/quaternized chitosan film for temperature-responsive ethylene inhibition and climacteric fruit preservation

Controlling ethylene production and microbial infection are key factors to prolong the shelf life of climacteric fruit. Herein, a nanocomposite film, hexanal-loaded ZIF-8/CS (HZCF) with "nano-barrier" structure, was developed by a one-pot co-crystallized of ZIF-8 in situ growth on quaternized chitosan (CS) and encapsulation of hexanal into ZIF-8 via microporous adsorption. The resultant film realized the temperature responsive release of hexanal via the steric hindrance and hierarchical pore structure as "nano-barrier", which can inhibit ethylene production in climacteric fruit on demand. Based on this, the maximum ethylene inhibition rate of HZCF was up to 52.6 %. Meanwhile, the film exhibits excellent antibacterial, mechanical, UV resistance and water retention properties, by virtue of the functional synergy between ZIF-8 and CS. Contributed to the multifunctional features, HZCF prolonged the shelf life of banana and mango for at least 16 days, which is 8 days longer than that of control fruit. More strikingly, HZCF is washable and biodegradable, which is expected to replace non-degradable plastic film. Thus, this study provides a convenient novel approach to simplify the encapsulation of active molecule on metal-organic frameworks (MOFs), develops a packaging material for high-efficient freshness preservation, and helps to alleviate the survival crisis caused by food waste.

Revolutionizing tropical fruits preservation: Emerging edible coating technologies

Tropical fruits, predominantly cultivated in Southeast Asia, are esteemed for their nutritional richness, distinctive taste, aroma, and visual appeal when consumed fresh. However, postharvest challenges have led to substantial global wastage, nearly 50 %. The advent of edible biopolymeric nanoparticles presents a novel solution to preserve the fruits' overall freshness. These nanoparticles, being edible, readily available, biodegradable, antimicrobial, antioxidant, Generally Recognized As Safe (GRAS), and non-toxic, are commonly prepared via ionic gelation owing to the method's physical crosslinking, simplicity, and affordability. The resulting biopolymeric nanoparticles, with or without additives, can be employed in basic formulations or as composite blends with other materials. This study aims to review the capabilities of biopolymeric nanoparticles in enhancing the physical and sensory aspects of tropical fruits, inhibiting microbial growth, and prolonging shelf life. Material selection for formulation is crucial, considering coating materials, the fruit's epidermal properties, internal and external factors. A variety of application techniques are covered such as spraying, and layer-by-layer among others, including their advantages, and disadvantages. Finally, the study addresses safety measures, legislation, current challenges, and industrial perspectives concerning fruit edible coating films.

Physical properties of cellulose nanocrystal/magnesium oxide/chitosan transparent composite films for packaging applications

Hitherto unreported hybrid nanofillers (CNC:MgO) reinforced chitosan (CTS) based composite (CNC:MgO)/CTS films were synthesized using a solution-casting blend technique and synergistic effect of hybrid nanofiller in terms of properties enhancement were investigated. Optical microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) technique, fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM) were used to characterize the films. The hybrid nanofiller considerably changed the transparency and color of the CTS films. The tensile strengths of (3 wt%) CNC/CTS, (3 wt%) MgO/CTS, (1:1)(CNC:MgO)/CTS, (1:2)(CNC:MgO)/CTS and (2:1)(CNC:MgO)/CTS films were 27.49 %, 35.60 %, 91.62 %, 38.22 %, and 29.32 % higher than pristine CTS films respectively, while the water vapor permeation were 28.21 %, 30.77 %, 34.62 %, 38.46 %, and 37.44 % lower than pristine CTS film, respectively. Moreover, the CTS composite films exhibited an improvement in overall water barrier properties after incorporating hybrid nanofillers. Our observations suggest that chitosan-based hybrid nanofiller composite films are a good replacement for plastic-based packaging materials within the food industry.

Multi-functional polyvinyl alcohol/tannin acid composite films incorporated with lignin nanoparticles loaded by potassium sorbate

The biocompatible, biodegradable and strong polyvinyl alcohol-based films have been widely investigated and used in the field of active packaging. To endow with diverse function, this paper firstly prepared lignin nanoparticles loaded with potassium sorbate (LNP@PS) as additives to exploit additional antibacterial, UV blocking, oxygen barrier, and water barrier properties. Besides, tannin acid (TA) was incorporated for compensating and further enhancing mechanical properties. Results showed that the PVA-based composite films containing 3 % LNP@PS and 5 % TA could achieve the optimal tensile strength at 74.51 MPa, water vapor permeability at 7.015·10-13·g·cm/cm2·s·Pa and oxygen permeability at 1.93 cm3/m2·24 h MPa, which was an 165 % of increase, 47 % and 112 % of reduction respectively compared to pure PVA films. Additionally, the composite films exhibited apparently superior bacteria and oxygen resistance properties evidenced by microbial infection and free radical scavenging performance. In addition, the slow-release effect of PS assisted the strawberry preservation with an extension of 3 days, which provided a promising novel route to prepare active food packaging material.

Moisture loss inhibition with biopolymer films for preservation of fruits and vegetables: A review

In cold storage, fruits and vegetables still keep a low respiratory rate. Although cold storage is beneficial to maintain the quality of some fruits and vegetables, several factors (temperature and humidity fluctuations, heat inflow, air velocity, light, etc.) will accelerate moisture loss. Biopolymer films have attracted great attention for fruits and vegetables preservation because of their biodegradable and barrier properties. However, there is still a certain amount of water transfer occurring between storage environment/biopolymer films/fruits and vegetables (EFF). The effect of biopolymer films to inhibit moisture loss of fruits and vegetables and the water transfer mechanism in EFF system need to be studied systematically. Therefore, the moisture loss of fruits and vegetables, crucial properties, major components, fabrication methods, and formation mechanisms of biopolymer films were reviewed. Further, this study highlights the EFF system, responses of fruits and vegetables, and water transfer in EFF. This work aims to clarify the characteristics of EFF members, their influence on each other, and water transfer, which is conducive to improving the preservation efficiency of fruits and vegetables purposefully in future studies. In addition, the prospects of studies in EFF systems are shown.

Fundamental investigation of micro-nano cellulose and lignin interaction for transparent paper: Experiment and electrostatic potential calculation

Plastic has significant negative consequences for the environment and human health, demanding greener alternatives. Lignocellulose is a sustainable biomass material, and its paper has been considered as a potential material to replace plastics. Micro-nano lignocellulose, derived from natural plants, possesses a small size and abundant hydrogen bonding capacity. However, there is no clear explanation for the interactions between lignin and micro-nano cellulose, and little understanding of how the interaction can affect the papers' structure and optical properties. Electrostatic potential calculation is a reliable tool to explain non-covalent interactions, and can explore the binding between lignin and micro-nano cellulose. In this paper, kenaf - a non-wood fiber raw material - was employed to prepare micro-nano lignocellulose. The resulting slurry facilitated the production of transparent paper via a simple casting method. The prepared transparent micro-nano paper exhibited high transparency (~90 %), UVA resistance (~80 %), and hydrophobicity (~114°). More importantly, the electrostatic potential calculation demonstrates the inherent relationship between structure and performance, providing practical knowledge for constructing film materials.

Unveiling the potential of linseed mucilage, its health benefits, and applications in food packaging

Industrial waste products derived from the oil industry often contain valuable substances and elements with great potential. These by-products can be used for various purposes, including as nutrients, bioactive compounds, fuels, and polymers. Linseed mucilage (LM) is one such example of a beneficial by-product obtained from linseed. It possesses favorable chemical and functional properties, depending on its method of extraction. Different pretreatments, such as enzymatic extraction, microwave-assisted extraction, pulse electric field, and ultrasound-assisted extraction, have been explored by various researchers to enhance both the yield and quality of mucilage. Furthermore, LM has exhibited therapeutic effects in the treatment of obesity, diabetes, constipation, hyperlipidemia, cancer, and other lifestyle diseases. Additionally, it demonstrates favorable functional characteristics that make it suitable to be used in bioplastic production. These properties preserve food quality, prolong shelf life, and confer antimicrobial activity. It also has the potential to be used as a packaging material, especially considering the increasing demand for sustainable and biodegradable alternatives to plastics because of their detrimental impact on environmental health. This review primarily focuses on different extraction techniques used for linseed mucilage, its mechanism of action in terms of health benefits, and potential applications in food packaging.

Advances of blend films based on natural food soft matter: Multi-scale structural analysis

The blend films made of food soft matter are of growing interest to the food packaging industries as a pro-environment packaging option. The blend films have become a novel pattern to replace traditional plastics gradually due to their characteristics of biodegradability, sustainability, and environmental friendliness. This review discussed the whole process of the manufacturing of food soft matter blend films from the raw material to the application due to multi-scale structural analysis. There are 3 stages and 12 critical analysis points of the entire process. The raw material, molecular self-assembly, film-forming mechanism and performance test of blend films are investigated. In addition, 11 kinds of blend films with different functional properties by casting are also preliminarily described. The industrialization progress of blend films can be extended or facilitated by analysis of the 12 critical analysis points and classification of the food soft matter blend films which has a great potential in protecting environment by developing sustainable packaging solutions.

Impact of soybean protein isolate concentration on chitosan-cellulose nanofiber edible films: Focus on structure and properties

Chitosan and cellulose nanofiber films are frequently employed as biodegradable materials for food packaging. However, many exhibit suboptimal hydrophobicity and antioxidant properties. To address these shortcomings, we enhanced the performance by adding different concentrations of soybean protein isolate (SPI) to chitosan-cellulose nanofiber (CS-CNF) films. As SPI concentration varied, the turbidity, particle size, and ζ-potential of the film-forming solutions initially decreased and subsequently increased. This suggests that 1 % SPI augments the electrostatic attraction and compatibility. Rheological analysis confirmed a pronounced apparent viscosity at this concentration. Analyses using Fourier transform infrared spectra, Raman spectra, X-ray diffraction, and Scanning electron microscope revealed the presence of hydrogen bonds and electrostatic interactions between SPI and CS-CNF, indicative of superior compatibility. When SPI concentration was set at 1 %, notable enhancements in film attributes were observed: improvements in tensile strength and elongation at break, a reduction in water vapor permeability by 8.23 %, and an elevation in the contact angle by 18.85 %. Furthermore, at this concentration, the ABTS+ and DPPH scavenging capacities of the film surged by 61.53 % and 46.18 %, respectively. Meanwhile, the films we prepare are not toxic. This research offers valuable insights for the advancement and application of protein-polysaccharide-based films.

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

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

Films properties of QPM corn starch with Delonix regia seed galactomannan as an edible coating material

Plant-based polysaccharides are considered a good alternative for obtaining edible films and coatings. In this research the objective was to determine the physicochemical characteristics of corn starch obtained from QPM Sac-Beh (SBCS) and Delonix regia galactomannan (DRG) and use them to produce films. Films were elaborated from 1 %(w/v) film-forming solutions (FFS) with SBCS:DRG 1:0, 1:1, and 0:1 ratio. Some films were prepared with glycerol 0.4 %(w/v) and vanillin 0.1 %(w/v). SBCS and DRG were characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and differential scanning calorimetry. SBCS presented low crystallinity which agrees with a low gelatinization ΔH observed. The SBCS:DRG 1:0 FFS without glycerol did not form films; however, DRG addition allows film formation. It was also found that glycerol addition reduced tensile strength to 10.3 MPa, from 41.3 MPa. The lowest water vapor permeability was found in films with 1:1 SBCS:DRG and 0.1 %(w/v) vanillin. This formulation was used to coat D'Anjou pears. This coating conserved the pears' color for 24 days while the control ones started to get a brown color on day 6. Based on the results obtained, FFS elaborated with 1:1 SBCS:DRG and 0.1 %(w/v) vanillin had potential use as edible film material for coating on climacteric fruits preservation.

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

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

Application of chitosan and other biopolymers based edible coatings containing essential oils as green and innovative strategy for preservation of perishable food products: A review

Deterioration of perishable foods due to fungal contamination and lipid peroxidation are the most threatened concern to food industry. Different chemical preservatives have been used to overcome these constrains; however their repetitive use has been cautioned owing to their negative impact after consumption. Therefore, attention has been paid to essential oils (EOs) because of their natural origin and proven antifungal and antioxidant activities. Many EO-based formulations have been in use but their industrial-scale application is still limited, possibly due to its poor solubility, vulnerability towards oxidation, and aroma effect on treated foods. In this sense, active food packaging using biopolymers could be considered as promising approach. The biopolymers can enhance the stability and effectiveness of EOs through controlled release, thus minimizes the deterioration of foods caused by fungal pathogens and oxidation without compromising their sensory properties. This review gives a concise appraisal on latest advances in active food packaging, particularly developed from natural polymers (chitosan, cellulose, cyclodextrins etc.), characteristics of biopolymers, and current status of EOs. Then, different packaging and their effectiveness against fungal pathogens, lipid-oxidation, and sensory properties with recent previous works has been discussed. Finally, effort was made to highlights their safety and commercialization aspects towards market solutions.

Carboxymethyl cellulose based films enriched with polysaccharides from mulberry leaves (Morus alba L.) as new biodegradable packaging material

The objective of this study was to determine the properties of a new active packaging film developed by the addition of mulberry leaves polysaccharides (MLP) into carboxymethyl cellulose (CMC). Biodegradable CMC-MLP films were fabricated by casting method with various concentrations of MLP (1, 5 and 10 % w/w). The addition of MLP into the CMC matrix resulted increased thickness (0.126 to 0.163 mm) and roughness of the films. Also, the decline in moisture content from 27.91 to 14.12 %, water vapor permeability from 8.95 to 5.21 × 10-10 g-1 s-1 Pa-1, and a swelling degree from 59.11 to 37.45 % were observed. With the increasing concentration of MLP, the mechanical properties of the films were improved and higher dispersion of UV light were noted. Fourier transform - infrared spectroscopy (FT-IR) and X-ray diffraction revealed good inter-molecular interaction between CMC matrix and MLP. The prepared films showed excellent thermal stability, antioxidant and antibacterial properties as well as susceptibility to biodegradation in the soil environment. Moreover, it was proved that the films have ability to retard oil oxidation. Overall, it was concluded that CMC-MLP films constitute a promising biomaterial that may be applied as active food packaging.

Revolutionizing single-use food packaging: a comprehensive review of heat-sealable, water-soluble, and edible pouches, sachets, bags, or packets

Edible food packaging has emerged as a critical focal point in the discourse on sustainability, prompting the development of innovative solutions, notably in the realm of edible pouches. Often denoted as sachets, bags, or packets, these distinct designs have garnered attention owing to their water-soluble and heat-sealable attributes, tailored explicitly for single-use applications encompassing oils, instant or dry foods, and analogous products. While extant literature extensively addresses diverse facets of edible films, this review addresses a conspicuous void by presenting a consolidated and specialized overview dedicated to the intricate domain of edible pouches. Through a meticulous synthesis of current research, we aim to illuminate the trajectory of advancements made thus far, delving into critical aspects, including materials, production techniques, functional attributes, consumer perceptions, and regulatory considerations. By furnishing a comprehensive perspective on the potential, challenges, and opportunities inherent in edible pouches, our overarching aim is to stimulate collaborative endeavors in research, innovation, and exploration. In doing so, we aspire to catalyze the broader adoption of sustainable packaging solutions tailored to the exigencies of single-use applications.

Effects of High-Pressure Homogenization Treatment on the Development of Antioxidant Zanthoxylum bungeanum Leaf Powder Films for Preservation of Fresh-Cut Apple

This study determined that Zanthoxylum bungeanum leaves (ZBLs) are rich in functional components such as cellulose, protein, flavone, and polyphenols. Therefore, they were used as the main raw material, with sodium alginate as a thickener and glycerol as a plasticizer, to investigate the preparation of active films from ZBL powder through high-pressure homogenization (HPH). The physical, optical, mechanical, and antioxidant properties of the films were evaluated, and their application in preserving fresh-cut apples was examined. The results showed that the optimal concentration of ZBL powder was 1.5% under a 30 MPa HPH treatment. The resulting HPH-treated films exhibited a denser microstructure and improved water vapor barrier properties and mechanical strength. Compared to the films without HPH treatment, the tensile strength increased from 4.61 MPa to 12.13 MPa, the elongation at break increased from 21.25% to 42.86%, the water vapor permeability decreased from 9.9 × 10-9 g/m·s·Pa to 8.0 × 10-9 g/m·s·Pa, and the transparency increased from 25.36% to 38.5%. Compared to the control group, the fresh-cut apples packaged with the HPH-treated ZBL active films exhibited effective preservation of apple quality during a five-day period at 4 °C and 70% humidity, showing better preservation effects than the other groups. In conclusion, the use of HPH treatment in developing novel biopolymer active films from ZBL powders with enhanced properties holds potential for various applications.

Effect of pH on the Mechanical Properties of Single-Biopolymer Mucilage (Opuntia ficus-indica), Pectin and Alginate Films: Development and Mechanical Characterisation

Pectin and alginate are well-established biopolymers used in natural film development. Single-polymer mucilage films were developed from freeze-dried native mucilage powder of two cultivars, 'Algerian' and 'Morado', and the films' mechanical properties were compared to single-polymer pectin and alginate films developed from commercially available pectin and alginate powders. The casting method prepared films forming solutions at 2.5%, 5%, and 7.5% (w/w) for each polymer. Considerable variations were observed in the films' strength and elasticity between the various films at different polymer concentrations. Although mucilage films could be produced at 5% (w/w), both cultivars could not produce films with a tensile strength (TS) greater than 1 MPa. Mucilage films, however, displayed > 20% elongation at break (%E) values, being noticeably more elastic than the pectin and alginate films. The mechanical properties of the various films were further modified by varying the pH of the film-forming solution. The various films showed increased TS and puncture force (PF) values, although these increases were more noticeable for pectin and alginate than mucilage films. Although single-polymer mucilage films exhibit the potential to be used in developing natural packaging, pectin and alginate films possess more suitable mechanical attributes.

Development of smart packaging halochromic films embedded with anthocyanin pigments; recent advances

Nowadays, innovative biodegradable packaging based on pH-sensitive natural dyes is being developed. These smart systems quickly inform the food quality to the consumer and monitor fresh foods in real-time. Smart packaging protects food against ambiance risks and simultaneously sends information to users for variations and alterations in the packaging settings. Anthocyanin (ACY), among the natural dyes used as indicators serves as water-soluble flavonoid pigments which made reflection in light in the red-blue range and can detect chemical and microbial alterations in foods based on their pH-susceptible conditions; on the other hand, they have considerable antimicrobial and antioxidant functions that result in the longer shelf life of food products. They also have beneficial properties including anti-cancer and anti-inflammatory functions, avoidance of heart diseases, overweight, and diabetes. Hence, this paper deals with the characteristics of smart packaging films based on anthocyanins, as well as their application in various food industries.

Microstructural and Mechanical Properties of Calcium-Treated Cactus Pear Mucilage (Opuntia spp.), Pectin and Alginate Single-Biopolymer Films

Pectin and alginate satisfy multiple functional requirements in the food industry, especially relating to natural packaging formulation. The continuous need for economic and environmental benefits has promoted sourcing and investigating alternative biomaterials, such as cactus pear mucilage from the cladodes of Opuntia spp., as natural packaging alternatives. The structural and mechanical properties of mucilage, pectin and alginate films developed at a 5% (w/w) concentration were modified by treating the films with calcium (Ca) in the calcium chloride (CaCl2) form. Scanning electron microscopy (SEM) showed the 5% (w/w) 'Algerian' and 'Morado' films to display considerable microstructure variation compared to the 5% (w/w) pectin and alginate films, with calcium treatment of the films influencing homogeneity and film orientation. Treating the alginate films with a 10% (w/w) stock CaCl2 solution significantly increased (p < 0.05) the alginate films' tensile strength (TS) and puncture force (PF) values. Consequently, the alginate films reported significantly higher (p < 0.05) film strength (TS and PF) than the pectin + Ca and mucilage + Ca films. The mucilage film's elasticity was negatively influenced by CaCl2, while the pectin and alginate films' elasticity was positively influenced by calcium treatment. These results suggest that the overall decreased calcium sensitivity and poor mechanical strength displayed by 'the Algerian' and 'Morado' films would not make them viable replacements for the commercial pectin and alginate films unless alternative applications were found.

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.

Antioxidant Edible Films Based on Pear Juice and Pregelatinized Cassava Starch: Effect of the Carbohydrate Profile at Different Degrees of Pear Ripeness

Edible films based on fruit and vegetable purees combined with different food-grade biopolymeric binding agents (e.g., pectin, gelatin, starch, sodium alginate) are recognized as interesting packaging materials that benefit from the physical, mechanical, and barrier properties of biopolymers as well as the sensory and nutritional properties of purees. In the current contribution, edible antioxidant films based on pear juice and pregelatinized cassava starch were developed. In particular, the suitability of using pregelatinized cassava starch for the non-thermal production of these novel edible films was evaluated. In addition, the effects on the films' properties derived from the use of pear juice instead of the complete puree, from the content of juice used, and from the carbohydrate composition associated with the ripening of pears were all studied. The produced films were characterized in terms of their total polyphenol content, water sensitivity, and water barrier, optical, mechanical and antioxidant properties. Results showed that the use of pear juice leads to films with enhanced transparency compared with puree-based films, and that juice concentration and carbohydrate composition associated with the degree of fruit ripeness strongly govern the films' properties. Furthermore, the addition of pregelatinized cassava starch at room temperature discloses a significant and favorable impact on the cohesiveness, lightness, water resistance, and adhesiveness of the pear-juice-based films, which is mainly attributed to the effective interactions established between the starch macromolecules and the juice components.

The Potential of Edible Films, Sheets, and Coatings Based on Fruits and Vegetables in the Context of Sustainable Food Packaging Development

Several consumable substances, including fruit and vegetable purees, extracts, juices, and plant residue, were analyzed for their matrix-forming potential. These matrices serve as the basis for the production of edible films, sheets, and coatings that can be eaten as nutritional treats or applied to food products, thereby contributing to their overall good quality. Furthermore, this innovative approach also contributes to optimizing the performance of synthetic packaging, ultimately reducing reliance on synthetic polymers in various applications. This article explores the viability of incorporating fruits and vegetables as basic ingredients within edible films, sheets, and coatings. The utilization of fruits and vegetables in this manner becomes achievable due to the existence of polysaccharides and proteins that facilitate the formation of matrices in their makeup. Moreover, including bioactive substances like vitamins and polyphenols can impart attributes akin to active materials, such as antioxidants or antimicrobial agents. Advancing the creation of edible films, sheets, and coatings derived from fruits and vegetables holds great potential for merging the barrier and mechanical attributes of biopolymers with the nutritional and sensory qualities inherent in these natural components. These edible films made from fruits and vegetables could potentially serve as alternatives to seaweed in sushi production or even replace conventional bread, pancakes, tortillas, and lavash in the diet of people suffering from celiac disease or gluten allergy, while fruit and vegetable coatings may be used in fresh and processed food products, especially fruits and vegetables but also sweets.

Development and application of fruit and vegetable based green films with natural bio-actives in meat and dairy products: a review

In recent years, foodborne outbreaks and food plastic waste accumulation in the environment have impelled a hunt for new, sustainable, novel and innovatory food packaging interventions to face microbial contamination, food quality and safety. Pollution caused from wastes generated by agricultural activities is one of chief rising concerns of the environmentalists across the globe. A solution to this problem is effective and economic valorization of residues from agriculture sector. It would ensure that the by-products/residues from one activity act as ingredients/raw materials for another industry. An example is fruit and vegetable waste based green films for food packaging. Edible packaging is a well-researched area of science where numerous biomaterials have been already explored. Along with dynamic barrier properties, these biofilms often exhibit antioxidant and antimicrobial properties as function of the bioactive additives (e.g. essential oils) often incorporated in them. Additionally, these films are made competent by use of recent technologies (e.g. encapsulation, nano-emulsions, radio-sensors) to ensure high end performance and meet the principles of sustainability. Livestock products such as meat, poultry and dairy products are highly perishable and depend largely upon the mercy of packaging materials to enhance their shelf life. In this review, all the above-mentioned aspects are thoroughly covered with a view to project fruit and vegetable based green films (FVBGFs) as a potential and viable packaging material for livestock products, along with a discussion on role of bio-additives, technological interventions, properties and potential applications of FVBGFs in livestock products. © 2023 Society of Chemical Industry.

Eco-sustainable coatings based on chitosan, pectin, and lemon essential oil nanoemulsion and their effect on strawberry preservation

Films and coatings manufactured with bio-based renewable materials, such as biopolymers and essential oils, could be a sustainable and eco-friendly alternative for protecting and preserving agricultural products. In this work, we developed films and coatings from pectin and chitosan to protect strawberries (Fragaria x ananassa Duch.) from spoilage and microbial contamination. We developed three coatings containing equal amounts of glycerol and Sicilian lemon essential oil (LEO) nanoemulsion. We identified seventeen chemicals from LEO by GC-MS chromatogram, including d-limonene, α-Pinene, β-Pinene, and γ-Terpinene. The pectin and chitosan coatings were further characterized using different physicochemical, mechanical, and biological methods. The films demonstrated satisfactory results in strength and elongation at the perforation as fruit packaging. In addition, the coatings did not influence the weight and firmness of the strawberry pulps. We observed that 100 % essential oil was released in 1440 min resulting from the erosion process. Also, the oil preserved the chemical stability of the films. Antioxidant activity (AA), measured by Electron Paramagnetic Resonance (EPR), showed that the coatings loaded with 2 % LEO nanoemulsion (PC + oil) showed that almost 50 % of AA from LEO nanoemulsion was preserved. The chitosan and the pectin-chitosan coatings (PC + oil) inhibited filamentous fungi and yeast contaminations in strawberries for at least 14 days, showing a relationship between the AA and antimicrobial results.

A Review of the Effect of Plasticizers on the Physical and Mechanical Properties of Alginate-Based Films

In recent years, there has been a growing attempt to manipulate various properties of biodegradable materials to use them as alternatives to their synthetic plastic counterparts. Alginate is a polysaccharide extracted from seaweed or soil bacteria that is considered one of the most promising materials for numerous applications. However, alginate potential for various applications is relatively limited due to brittleness, poor mechanical properties, scaling-up difficulties, and high water vapor permeability (WVP). Choosing an appropriate plasticizer can alleviate the situation by providing higher flexibility, workability, processability, and in some cases, higher hydrophobicity. This review paper discusses the main results and developments regarding the effects of various plasticizers on the properties of alginate-based films during the last decades. The plasticizers used for plasticizing alginate were classified into different categories, and their behavior under different concentrations and conditions was studied. Moreover, the drawback effects of plasticizers on the mechanical properties and WVP of the films are discussed. Finally, the role of plasticizers in the improved processing of alginate and the lack of knowledge on some aspects of plasticized alginate films is clarified, and accordingly, some recommendations for more classical studies of the plasticized alginate films in the future are offered.

Use of fenugreek seed gum in edible film formation: major drawbacks and applicable methods to overcome

Researching on potential biopolymer sources with the aim of developing edible films with better mechanical and barrier properties has become innovative as it would be a key factor to minimize the use of synthetic polymers in food packaging. Therefore, different biopolymers such as galactomannan have been gaining attention recently. Fenugreek seed gum is a rich source of galactomannan which is minimally researched on its applicability in edible film making. The degree of galactose substitution and polymerization are the main factors that determine the functional properties of galactomannan. A strong and cohesive film matrix cannot be produced from fenugreek seed gum as its molecular interaction is weakened due to the high galactose substitution with a high galactose/mannose ratio, 1:1. Structural modifications of galactomannan in fenugreek seed gum will lead to films with the required mechanical properties. Hence, this review summarizes recent scientific studies on the limitations of fenugreek seed gum as a film forming agent and the specific modification techniques that can be applied in order to increase its film forming capability and performance.

Antimicrobial and Antioxidant Edible Films and Coatings in the Shelf-Life Improvement of Chicken Meat

Meat deterioration during processing, distribution, and display can compromise the quality and safety of products, causing several undesirable changes and decreasing products' shelf-life, which has a negative impact on the industry and consumers. In recent years, studies have been carried out using decontamination techniques and new packaging methodologies to overcome deterioration problems, increase sustainability, and reduce waste. Edible films and coatings obtained from biopolymers such as polysaccharides, proteins, and lipids, combined with active compounds, can be an alternative approach. This article focused on recent studies that used alternative biodegradable polymeric matrices in conjunction with natural compounds with antioxidant/antimicrobial activity on chicken meat. Its impact on physicochemical, microbiological, and sensory characteristics was evident, as well as the effect on its shelf-life. In general, different combinations of active edible films or coatings had a positive effect on the chicken meat. Different studies reported that the main results were a decrease in microbial growth and pathogen survival, a slowdown in lipid oxidation evolution, and an improvement in sensory quality and shelf-life (an increase from 4 to 12 days).