Edible Films Research Articles

Advances in biomaterials based food packaging systems: Current status and the way forward

World hunger is getting worse, while one-third of food produced around the globe is wasted and never consumed. It is vital to reduce food waste to promote the sustainability of food systems, and improved food packaging solutions can augment this effort. The utilization of biomaterials in smart food packaging not only enhances food preservation and safety but also aligns with current demands for eco-friendly technologies to mitigate the impacts of climate change. This review provides a comprehensive overview of the developments in the field of food packaging based on the innovative use of biomaterials. It emphasizes the potential use of biomaterials derived from nature including cellulose, chitosan, keratin, etc. for this purpose. Various smart food packaging technologies such as active and intelligent packaging are discussed in detail including scavenging additives, colour-changing environment indicators, sensors, RFID tags, etc. The article also delves into the utilization of edible films and coatings, nanoparticle fillers and 2D materials in food packaging systems. Furthermore, it outlines the challenges and opportunities in this dynamic domain, emphasizing the ongoing need for research and innovation to shape the future of sustainable and smart food packaging solutions to enhance and monitor the shelf-life of food products.

Mechanical Properties Characteristics of Sago Starch and Chitosan-Based Edible Films with Varying Concentrations

Mechanical Properties Characteristics of Sago Starch and Chitosan-Based Edible Films with Varying Concentrations

Development of soybean meal protein isolate-based active edible film incorporating bioactive compounds rich kinnow (Citrus reticulata) peel

Soybean meal, a reservoir of high-quality protein has been produced in large quantities from the soybean oil processing industry and is mostly used as animal feed. The present work was aimed at the development and characterization of soybean meal protein-based antimicrobial edible film incorporating debittered kinnow peel powder (KPP) and valorizing the underutilized soybean meal protein as well as kinnow peel bioactive compounds. The incorporation of kinnow peel powder reduced the solubility, moisture content and swelling ability of the film than the film prepared without KPP. The addition of KPP up to 20 % (w/w) increased the mechanical and barrier properties of the films. The antioxidant and antimicrobial activity of the film increased by 19 to 20 %, and 75 to 79 %, respectively after the incorporation of KPP. The results of structural characteristics (Fourier transform infrared spectroscopy and X-ray diffraction), and morphology (Scanning electron microscopy) showed the good compatibility of KPP and soybean protein isolate. Thermal properties studied through differential scanning colorimetry showed higher melting temperature of KKP added films as compared to control film. The present work indicated that KPP can be successfully used to develop an active edible film and can be used for storing a variety of food products like cheese, paneer, chocolate bars, cut fruits, etc.

Carrageenan-based Film Utilization for Eco-friendly Tea Bag

This study addresses concerns related to potential health risks associated with chlorine residues in traditional tea bags, which exhibit resistance to decomposition in soil. Consequently, the study utilized carrageenan, derived from <i>Eucheuma cottonii</i> seaweed, as a coating material for edible film. This research explores the impact of carrageenan concentration and drying temperature on the performance of tea bags. This study applied the randomized complete block design to analyze the impact of three carrageenan concentrations (1%, 3%, and 5%) at three different drying temperatures (80ºC, 85ºC, and 90ºC) on carrageenan-based film. The investigation comprehensively evaluates the compliance of the carrageenan-based film with commercial-grade quality standards through critical factors such as thickness, solubility, mechanical strength and hedonic analysis. The findings indicate that the most effective carrageenan-based edible film can be produced at a concentration of 3% and a drying temperature of 90°C, highlighting its potential as an eco-friendly alternative in tea bag production.

Thermally Degradable Water Diffusion Barrier Assembled by Gelatin and Beeswax toward Edible Electronics.

Making ingestible devices edible facilitates diagnosis and therapy inside the body without the risk of retention; however, food materials are generally soft, absorb water molecules, and are not suitable for electronic devices. Here, we fabricated an edible water diffusion barrier film made by gelatin-beeswax composites for the encapsulation of transient electronics. Hydrophobic beeswax and hydrophilic gelatin are inherently difficult to mix; therefore, we created an emulsion simply by raising the temperature high enough to melt the materials and vigorous stirring them. As they cool, the beeswax with a relatively high solidification temperature aggregates and forms microspheres, which increases the gelatin gel's viscoelasticity and immobilizes the emulsion structure in the film. The thermoresponsive gelatin imparts degradability to the barrier and its stickiness also enables transfer of metal patterned electronics. Furthermore, we designed an edible resonator on the film and demonstrated its operation in an abdominal phantom environment; the resonator was made to be degradable in a warm aqueous solution by optimizing the composition ratio of the gelatin and beeswax. Our findings provide insight into criteria for making transient electronics on hydrophilic substrates with hydrophobic water diffusion barriers. This proof-of-concept study expands the potential of operating edible electronics in aqueous environments in harmony with the human body and nature.

Improvement of Physicochemical Properties of Cheese Whey Edible Film through Egg White Addition

Improvement of Physicochemical Properties of Cheese Whey Edible Film through Egg White Addition

A novel composite edible film based on quince seed gel and whey protein concentrate as affected by transglutaminase crosslinking

SummaryThe development of edible films, which serve as a safe alternative to synthetic polymers by utilising by‐products from the agricultural industry, has become a focus of research as they contribute to the sustainable use of resources. In the present study, quince seed gel (QSG) and whey protein concentrate (WPC) (1:1 w/w) were used as base components to develop edible films using glycerol as a plasticiser. The proteins were sonicated to denature and then the proteins were modified by cross‐linking with the enzyme transglutaminase (TGase). The thickness, moisture content, solubility, permeability and digestibility of each edible films were investigated. In addition to the morphological, mechanical, optical, thermal and structural properties, the edible films were further characterised. The thickness, moisture, water vapour and oxygen permeability and the water solubility of the films were positively influenced by the cross‐linking and the digestibility of proteins decreased with the cross‐linking. A remarkable change in the secondary structures was observed in the FTIR spectra of the films. The stronger networks and their smooth surface of crosslinked films were confirmed by AFM images. The results of this research shows that QSG/WPC films cross‐linked with TGase have potential for use in food packaging systems due to their advantages and may be an attractive alternative to synthetic materials in further studies.

Development of novel intelligent and edible dual-functional electrospun nanofiber films for shrimp preservation and freshness monitoring in real-time

The developed trend of novel intelligent packaging materials is changing from food traditional appearance detection to actual spoilage monitoring, aiming to supply a strategy to determine the edibility of food. In this work, a dual-functional electrospun nanofiber film (NFM) noted GZAT was prepared by the co-loading of anthocyanin (ANT) and thymol (THY) into polymer fibers of gelatin and zein. The prepared film was extensively characterized. The GZAT film displayed enhanced mechanical properties and decreased water vapor permeability (WVP) compared with gelatin/zein film (the control). The GZAT film also displayed excellent sensitive colorimetric responses to the pH solutions. Moreover, it exhibited excellent antioxidant property and antibacterial behavior against Escherichia coli ATC25922 (E. coli), Listeria monocytogenes ATCC 19115 (L. monocytogenes) and Staphylococcus aureus ATCC 6538 (S. aureus). Not only that, the dual functions of the GZAT film were confirmed that the shelf life of packaged shrimps was successfully extended to 11 days at 4 °C along with the colorimetric response indicating the freshness of the shrimps. Based on the above characteristic, the prepared GZAT film exhibited great potential as an intelligent packaging film with both real-time freshness indicator and freshness preservation.

Development and characterization of innovative bio-based edible films supplemented with cell-free supernatant and whole-cell postbiotic of Lactobacillus gasseri

More recently, the concepts of cell-free supernatants (CFS, so-called postbiotics) and whole-cell postbiotics (WCP) of probiotics have gained increasing attention for the development of bio-based films. However, reports on CFS and WCP of Lactobacillus gasseri remain scarce. In this study, pea protein isolate/psyllium mucilage was incorporated with CFS and WCP of L. gasseri to produce bio-based edible films. pH, total soluble solid content, antioxidant activity, total phenolic content, antimicrobial activity, and structural analyses were conducted to characterize the CFS and WCP of L. gasseri. Furthermore, the effects of CFS (10% and 20%, v/v) and WCP (10% and 20%, v/v) on the physicochemical, mechanical, barrier, optical, microstructural, and antimicrobial properties of the bio-based films were investigated. The results showed that CFS and WCP exhibited antioxidant and antibacterial activities and were significant sources of phenolic compounds. The incorporation of 20% WCP caused a significant increase in the thickness and water vapor permeability of films, while a significant increase in moisture content was observed with 10% WCP. The control and 10% WCP films had the highest tensile strength values. Furthermore, the addition of 10% WCP resulted in a significant increase in elasticity. Films incorporating CFS and WCP exhibited lower opacity values and darker, yellow, and red color intensities. The addition of CFS and WCP caused a rough texture and cracked structure on the surface of the film. In conclusion, pea protein/psyllium mucilage-based films containing CFS and WCP of L. gasseri can be considered as a new alternative for environmentally friendly bio-based films.

Physicochemical characteristics of Pangasius sp. skin-gelatin-based-edible film enriched with silver nanoparticles

Background: Edible films intended for food packaging have been produced from hydrocolloids, lipids, resins, and composites, including gelatin. Gelatin is known to have a good filming ability and has been suggested as an alternative to non-biodegradable plastics. Naturally active compounds incorporated into film packaging may not only protect the food product from oxidation and microbial contamination, but they may also alter the physicochemical properties of the film. Silver nanoparticles have been used in food packaging as active agents due to their antibacterial and antifungal properties. The addition may affect the characteristics of the packaging. Therefore, this study aims to determine the effect of the addition of silver nanoparticles on the physicochemical characteristics of edible film from Pangasius sp. skin gelatin. Methods: Mangrove extract of Bruguiera gymnorrhiza was used to synthesize silver into nanoparticle size. In this study, silver nanoparticles (AgNPs) with different concentrations (0, 2, 4 and 8%) were added into gelatin-based edible film. The edible films produced were observed for their physicochemical characteristics, including thickness, tensile strength, elongation, water vapour transmission, moisture content, pH, and colour. Results: AgNPs affected the colour of the fish-gelatin-based edible film, as an increased concentration of AgNPs resulted in a darker film. Nevertheless, the addition of AgNPs showed no significant effect on the thickness (145–216 µm), tensile strength (14.58–19.72 MPa), elongation (21.86–54.19%), water vapour transmission (30.91–42.55 g/m2/day), moisture content (9.57–11.16%) or pH (5.92–6.01) of the fish-gelatin-based edible film. Conclusions: The addition of AgNPs has no significant effect on gelatin-based edible film physicochemical properties except colour. Therefore, the incorporated edible film has the potential to be developed further.

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.

The application of film based on gelatin/hydroxymethyl cellulose and red beetroot betalain in smart food packaging.

Edible films containing anthocyanin and betacyanin as indicators of freshness are promising systems for food smart packaging. This research aimed to develop a smart color film for food packaging using gelatin/hydroxypropylmethyl cellulose (HPMC) and red beet betalain. In this study, edible films with different ratios of gelatin to HPMC were prepared successfully, and the ratio of 3:1 was determined as optimal samples based on water vapor permeability (WVP) and mechanical properties. Betalain with different concentrations was then added to the optimal film, and the physical and mechanical properties of the resulting films were evaluated. Also, TVB-N test to assess their ability to detect beef meat and shrimp spoilage was studied. The addition of betalain improved the solubility, WVP, mechanical properties, and 2,2-diphenyl-l-picrylhydrazyl free radical scavenging activity of the film. As a final point, the incorporation of betalain into the gelatin/HPMC films can be used to indicate the freshness of food.

Soy protein-polyphenols conjugates interaction mechanism, characterization, techno-functional and biological properties: An updated review

Soy protein is a promising nutritional source with improved functionality and bioactivities due to conjugation with polyphenols (PP)—the conjugates between soy protein and PP held by covalent and noncovalent bonds. Different approaches, including thermodynamics, spectroscopy, and molecular docking simulations, can demonstrate the outcomes and mechanism of these conjugates. The soy protein, PP structure, matrix properties (temperature, pH), and interaction mechanism alter the ζ-potential, secondary structure, thermal stability, and surface hydrophobicity of proteins and also improve the techno-functional properties such as gelling ability, solubility, emulsifying, and foaming properties. Soy protein-PP conjugates also reveal enhanced in vitro digestibility, anti-allergic, antioxidant, anticancer, anti-inflammatory, and antimicrobial activities. Thus, these conjugates may be employed as edible film additives, antioxidant emulsifiers, hydrogels, and nanoparticles in the food industry. Future research is needed to specify the structure-function associations of soy protein-PP conjugates that may affect their functionality and application in the food industry.

Starch‐based and green tea extract films: characterisation and evaluation of the shelf life of interleaved sliced calabrese sausage

SummaryThis study aimed to develop and characterise cassava starch‐based films incorporating green tea extract and to assess the antioxidant effectiveness of these edible films against oxidative degradation in sliced calabrese sausage. The films were formulated with 3.5% starch (w/v) and 35% glycerol (w/w), with the addition of commercial green tea extract at concentrations of 1.0%, 2.5%, and 5.0% (w/v of film‐forming solution). The formulations with extract showed significantly higher per cent elongation at break compared to the control (without extract) (P < 0.05), with higher tensile strength observed in the film with 1.0% extract. The best results in antioxidant activity kinetics with IC50 values between 0.012 and 0.14 mg mL−1 over 60 days were obtained with 1% of the extract. The cassava starch film with 1.0% extract inhibited the lipid oxidation of calabrese sausage for 18 days. The presence of 1.0% extract in the film reduces lipid oxidation in calabrese sausage without sensorial alteration, extending shelf life and suggesting it as an alternative to conventional plastics.

Fish oil-containing edible films with active film incorporated with extract of Psidium guajava leaves: preparation and characterization of double-layered edible film

Background The utilization of zein and gum arabic has grown in an attempt to formulate wall materials based on protein–polysaccharide complexes. This mixture provides a versatile shelter for hydrophilic (guava leaf extract, GLE) or lipophilic (fish oil, FO) bioactive compounds from unwanted environmental factors, and it can be used as an edible film-forming polymer. This study was undertaken to characterize FO-containing edible films that were double-layered with a film containing GLE. Methods Modified zein and gum arabic solutions (MG complex) were mixed at a ratio of 1:1.5 (v/v), adjusted to pH 5, added with glycerol (20% of the complex) and FO (5% of the complex), and finally adjusted to pH 5. This was prepared as the bottom/lower layer. The upper/active layer was prepared by mixing MG complex, glycerol, and GLE (1, 3, and 5% w/v of the complex). Physical, mechanical, microstructural, thermal, microbiological, and oxidative measurements were also performed. Results The total phenolic and flavonoid contents in GLE were 15.81 mg GAE/g extract and 6.99 mg QE/g extract, respectively. The IC50 of the DPPH radical scavenging activity of GLE was 26.86 ppm with antibacterial activity against Bacillus subtilis and Escherichia coli of 9.83 and 12.55 mm. The total plate counts of films double-layered with a film containing GLE were retained below 3 log CFU/g during 28-day storage. The peroxide values of these films were dimmed for no more than 9.08 meq/kg sample on day 28 of storage. Thickness (872.00-971.67 μm), water vapor transmission rate (12.99-17.04 g/m2/day), tensile strength (1.56-2.02 kPa), elongation at break (61.53-75.41%), glass transition (52.74-57.50°C), melting peak (131.59-142.35°C), inhibition against B. subtilis (33.67-40.58 mm), and inhibition against E. coli (2.05-9.04 mm) were obtained by double-layer films. Conclusions GLE can be successfully incorporated into the active layer of a double-layer film to improve its characteristics while significantly slowing down the microbial contamination and oxidation rate.

Gamma irradiation-induced crosslinking and enhanced functionality of fish gelatin-agar edible films

Fish gelatin-agar edible films have potential for sustainable food packaging, but their limitations particularly water sensitivity require improvement. In this research, the effects of radiation from gamma rays at rates ranging from 0 to 40 kGy on the films' mechanical characteristics, microstructure, color, opacity, and water resistance were examined. Overall, gamma irradiation at doses of up to 30 kGy substantially improved the water resistance of the gelatin-agar film, as demonstrated by decreased water solubility, water absorption, and film vapor permeability. This could be due to crosslinking within the biopolymer network. However, at doses of 40 kGy, potential chain scission in the film's polymeric structure might occur, which counteracts further improvement and consequently starts degrading its water resistance. Similarly, the improvement of film's tensile strength and modulus of elasticity peaked at an optimal dose of 30 kGy, and then decreased at higher doses, while the film's elongation at break remained unaffected. FTIR and SEM analysis supported changes in functional group and structural morphology in these observations. Although irradiation caused some yellowing, an optimal dose range (at around 20–30 kGy) was identified to achieve improved functionality without degrading film integrity. These findings highlight the potential of gamma irradiation as a viable technique for modifying fish gelatin-agar films for enhanced performance in food packaging applications.

Physicochemical and Mechanical Properties of Thyme Essential Oil Containing Sodium Alginate Films

In this study, it was aimed to develop edible film from sodium alginate (%2 w/v) (SA) without additives and with three different concentrations of thyme essential oil (TEO) (0.5%, 1%, 1.5% v/v) additives with glycerol as a plasticizer using the casting technique. The physicochemical, mechanical, structural, and antioxidant properties of enriched SA films were also characterized. The highest film solubility (FS) was found as 91.78% in SA films. Mechanical properties of films were found between 50.06 MPa and 27.14 MPa for tensile strength (TS) and between 13.88% and 32.02% for elongation at break (EAB). The highest total phenolic content (TPC) and antioxidant activity was found as 382.19 mg GAE/kg and 16.20% in SA film incorporated with TEO 1.5% respectively. With the TEO added to the films, the L* value in the films increased and the film colors approached white and it is seen that the film colors approach yellow with an increase in b*.When the results of SEM analysis are evaluated it was found that SA films were more homogeneous compared to other films. In general, when the results of film analysis were evaluated, it was concluded that the addition of TEO, improves the physical and chemical properties of sodium alginate film well.

Pectin extracted from red dragon fruit (Hylocereus polyrhizus) peel and its usage in edible film

Pectin was extracted from red dragon fruit (Hylocereus polyrhizus) peel using two different extraction methods: subcritical water extraction (SCWE) and conventional acid extraction (AE), from two different types of peels, fresh peel puree and dried peel powder. SCWE method on fresh peel puree showed an ∼18.88 % increase in pectin yield compared to AE. Extracted pectin is classified as low methoxyl pectin (DE: 8.51–50.64 %), with an average molecular weight ranging from 115.23 kDa to 577.84 kDa and a Gal-A content of 44.09 % - 53.90 %. The potential of pectin from fresh peel puree to be applied as a biodegradable film was further explored. Different pectin concentrations (3–5 % w/v) were used to prepare the films. Regarding the film performance, PF-S5, which was produced from SCWE with 5 % of pectin concentration, exhibits better thermal stability (Tdmax 250 °C, residue of 28.69 %) and higher moisture barrier (WVP 5.59 × 10−11 g.cm−1.s−1.Pa−1). In comparison, PF-A showed lower water solubility (45.14–69.15 %), higher water contact angle (33.01° - 44.35°), and better mechanical properties (TS: 2.12–4.11 MPa, EB: 48.72–61.39 %). Higher molecular weight accompanied by higher DE and Gal-A content contributes to better pectin film properties.

Enhancement of Chicken Breast Shelf-Life Using Gondhoraj (Citrus hystrix) Zest Edible Wrap: Physicochemical, Antioxidant, and Antibacterial Properties

Aims: The study aims to evaluate the physicochemical, antioxidant, and antibacterial properties of Gondhoraj (Citrus hystrix) essential oil (GPO) incorporated into a starch-based edible film (GF) for packaging chicken breast meat to enhance safety and shelf life. Study Design: Active packaging films were formulated with GPO concentrations of 0.2%, 0.4%, and 0.8% (v/v) in pre-film forming starch solution. Place of Study: Department of Food Technology, Guru Nanak Institute of Technology, Kolkata. Methodology: Films were created using the casting technique. Opacity and light barrier properties were measured via light absorption between 200 and 800 nm. Moisture content, antibacterial, and antioxidant properties were assessed. The coliform count in chicken meat packed with GF was evaluated. Results: GF demonstrated lower water solubility (0.068 ± 0.09% - 0.090 ± 0.00%) compared to the control starch film and greater opacity (3.150 ± 0.03 - 8.924 ± 0.09) with light absorption between 200 and 800 nm. Antioxidant activity, measured by DPPH and ABTS+ assays, was 70.36 ± 2.48% and 83.78 ± 0.54%, respectively. After refrigeration at 4°C ± 1 hour, the chicken sample with GF had the lowest coliform count (4.88 ± 0.06 CFU/g) compared to the uncoated sample. After 7 days of refrigerated storage, the moisture content noted was (91.18 ± 0.17). Conclusion: The shelf life study revealed no significant difference (p<0.05) in organoleptic qualities between coated and uncoated chicken samples. Thus, GF exhibits strong antibacterial and antioxidant properties, enhancing the nutritional quality and prolonging the shelf life of chicken meat during refrigeration.

Novel nanoemulsion-loaded hydroxyl propyl methyl cellulose films as bioactive food packaging materials containing Satureja khuzestanica essential oil

This study was conducted in response to a gap in the production of hydroxyl propyl methyl cellulose (HPMC) edible films from Satureja khuzestanica essential oil (SKEO) and to survey the preservation effect of natural edible films on the vapor phase. For these purpose varying concentrations of SKEO ranging from 1.25 % (EF1) to 7.5 % (EF5) led to producing different edible films for potential food packaging applications and the physicochemical, mechanical, and antimicrobial properties of edible films were evaluated across solid, liquid, and vapor phases. The incorporation of nanoemulsions into the polymer films led to an increase in thickness and opacity, while the addition of SKEO resulted in reduced water solubility without impacting film density. Notably, the antibacterial efficacy of the films was most pronounced against S. aureus, with a zone of inhibition measuring 41 ± 1 mm for EF5 on solid media. Time killing assays further demonstrated that specific formulations (EF3, EF4, and EF5) were capable of eradicating all microorganisms within 60 min. Moreover, SKEO edible films exhibited significant inhibitory effects against E. coli under refrigeration conditions (4 °C). These results highlighted the effect of herbal edible films in enhancing the functionality of bioactive food packaging technologies.