Effects of palm wax on the physical, mechanical and water barrier properties of fish gelatin films for food packaging application

A novel gelatin composite film with melt extrusion for walnut oil packaging

Gelatin have excellent film-forming and barrier properties, but its lack of biological activity limits its application in packaging. In this study, fish gelatin incorporated with apple polyphenol/cumin essential oil composite films were successfully prepared by melt extrusion. The cross-linking existed in gelatin and apple polyphenol improved the thermal stability and oxidation resistance of the film. The synergistic effect of apple polyphenols and cumin essential oil decreased the sensitivity of the film to water, especially the water solubility decreased from 41.60 % to 26.07 %. The plasticization of essential oil nearly doubled the elongation at break while maintaining the tensile strength of the film (11.45 MPa). Furthermore, the FG-CEO-AP film can inhibit peroxide value to extend the shelf life about 20 days in the walnut oil preservation. In summary, the apple polyphenol/cumin essential oil of FG film exhibits excellent comprehensive properties and high preparation efficiency for utilization as an active packaging material.

Effect of edible coating of gelatin-sodium alginate with the addition of green tea (Camellia sinensis) extract on the characteristics of star fruit (Averrhoa carambola L.) during storage

Star fruit has a good nutritional value but was very easy to damage. Edible coating can be used to extend the shelf life of star fruit. Green tea had been added to improve the mechanical properties and functional value of edible coating. This study aimed to evaluate the application of edible coating gelatin-sodium alginate with the addition of green tea to the physicochemical and microbiological characteristics of star fruit. This research was conducted by making edible coating solutions from gelatin, sodium alginate, glycerol, and green tea of various concentrations (0%, 5%, 10%, and 15%). The coating solution was applied to star fruit and stored for 1, 6, and 13 days to determine the effect of coating on the physicochemical and microbiological properties of star fruit. The results showed that adding green tea was not significantly different from the color change of the coating solution. However, there was a change in viscosity and pH along with the concentration of green tea extract (p < 0.05). FTIR analyses indicated that an interaction existed between gelatin-sodium alginate and green tea extract. The addition of green tea to star fruit with an edible coating of gelatin and sodium alginate could prevent weight loss (25.84%), reduce respiration rate (11.035 mg CO2/kg/h), maintain fruit anatomy, protect against color change, inhibit pH changes (4.22), total titrated acid (0.22%), increase vitamin C (244.55 mg/g), and even reduce damage for up to 13 days of storage. This study indicates that edible coating with the addition of green tea might be effective to retain the quality and extend the storage life star fruit.

Tannic acid crosslinked chitosan/gelatin/SiO2 biopolymer film with superhydrophobic, antioxidant and UV resistance properties for prematuring fruit packaging

The environmental pollution caused by plastic films urgently requires the development of non-toxic, biodegradable, and renewable biopolymer films. However, the poor waterproof and UV resistance properties of biopolymer films have limited their application in fruit packaging. In this work, a novel tannic acid cross-linked chitosan/gelatin film with hydrophobic silica coating (CGTS) was prepared. Relying on the adhesion of tannic acid and gelatin to silica, the coating endows CGTS film with excellent superhydrophobic properties. Especially, the contact angle reaches a maximum value 152.6°. Meanwhile, tannic acid enhanced the mechanical strength (about 36.1 %) through the forming of hydrogen bonding and the network structure. The prepared CGTS films showed almost zero transmittance to ultraviolet light and exhibited excellent radical scavenging ability (∼76.5 %, DPPH). Hence, CGTS film is suitable as a novel multifunctional packaging material for the agriculture to protect premature fruits, or the food industry used in environments exposed to ultraviolet radiation and rainwater.

Gelatin/dextran active films incorporated with cinnamaldehyde and α-tocopherol for scallop (Patinopecten yessoensis) adductor muscle preservation

Scallops are rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid but perishable due to their microbial growth and lipid oxidation. In this study, gelatin/dextran films containing cinnamaldehyde and α-tocopherol (0% + 0%, 0.3% + 0.3%, 0.6% + 0.6%, 0.9% + 0.9%, and 1.2% + 1.2%, w/w) as active fillers were developed by solution casting method, and their preservation effects on scallop adductor muscle refrigerated at 4°C for 0, 3, 6, 9, and 12 days were evaluated. Inclusion of the two active fillers did not influence the thermal stability of the films but created heterogenous and discontinuous film microstructure and increased the film hydrophobicity. Increase in the concentrations of active fillers lowered the mechanical properties and water vapor permeability of the films but increased their crystallinity, thickness, water contact angle, opacity, antibacterial property, and antioxidant property. The longest release times for both cinnamaldehyde and α-tocopherol were found in 95% (v/v) ethanol solution. The gelatin/dextran films containing 1.2% (w/w) of active fillers (Gelatin [Ge]/Dextran [Dx]/1.2 film) improved the chemical stability of refrigerated scallop adductor muscle. The total viable count (TVC) of the unpackaged scallop adductor muscle exceeded the recommended limit of 7 lg CFU/g on day 6 (7.07 ± 0.50 lg CFU/g), whereas the TVC of the Ge/Dx/1.2 film-packaged scallop adductor muscle was still below the limit on day 9 (5.60 ± 0.50 lg CFU/g). Thus, the Ge/Dx/1.2 film can extend the shelf life of refrigerated scallop adductor muscle by at least 3 days. Overall, the developed gelatin/dextran active packaging films are promising for the preservation of aquatic food products.

Gelatin based preservation technologies on the quality of food: a comprehensive review

Gelatin has played a great potential in food preservation because of its low price and superior film forming characteristics. This review provides a comprehensive overview of the latest research progress and application of gelatin preservation technologies (film, coating, antifreeze peptide, etc.), discussing their preservation mechanisms and efficiency through the viewpoints of quality and shelf life of animal and aquatic products as well as fruits and vegetables. It showed that bioactive and intelligent gelatin-based films exhibit antibacterial, antioxidant, water resistance and pH responsive properties, making them excellent for food preservation. In addition, pH responsive properties of films also intuitively reflect the freshness of food by color. Similarly, gelatin and its hydrolysate can be widely used in antifreeze peptides to reduce the mass loss of food during freezing and extend the shelf life of frozen food. However, extensive works are still required to extend their commercial application values.

Lipid incorporated biopolymer based edible films and coatings in food packaging: A review

In the evolving landscape of food packaging, lipid-based edible films and coatings are emerging as a sustainable and effective solution for enhancing food quality and prolonging shelf life. This critical review aims to offer a comprehensive overview of the functional properties, roles, and fabrication techniques associated with lipid-based materials in food packaging. It explores the unique advantages of lipids, including waxes, resins, and fatty acids, in providing effective water vapor, gas, and microbial barriers. When integrated with other biopolymers, such as proteins and polysaccharides, lipid-based composite films demonstrate superior thermal, mechanical, and barrier properties. The review also covers the application of these innovative coatings in preserving a wide range of fruits and vegetables, highlighting their role in reducing moisture loss, controlling respiration rates, and maintaining firmness. Furthermore, the safety aspects of lipid-based coatings are discussed to address consumer and regulatory concerns.

Characterization of Polyvinyl Alcohol (PVA)/Polyacrylic Acid (PAA) Composite Film-Forming Solutions and Resulting Films as Affected by Beeswax Content

Recently, the food packaging industry has focused on developing an eco-friendly and sustainable food packaging system. This study describes the effect of beeswax on the physical, structural, and barrier properties of a polyvinyl alcohol (PVA)/polyacrylic acid (PAA) composite film. The incorporation of beeswax improved the barrier properties against oxygen, water, and oil. However, the addition of a high content of beeswax caused phase separation in the film-forming solution. The destabilization mechanisms such as clarification and creaming formation in the film-forming solution were revealed by turbidimetric analysis. The results of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) indicates that non-homogeneous structures in the film-forming solution were formed as a function of increased beeswax content due to the agglomeration of beeswax. The mechanical properties of the films were also evaluated to determine the most appropriate content of beeswax. There was a slight decrease in tensile strength and an increase in elongation as beeswax content increased up to 10%. Thus, the PVA/PAA composite film with 10% beeswax was chosen for further applications. In summary, the PVA/PAA composite film developed in this study with 10% beeswax exhibited a significant improvement in barrier properties and has the potential for use in commerce.

Effect of Cymbopogan citratus Fibre on Physical and Impact Properties of Thermoplastic Cassava Starch/Palm Wax Composites

Cymbopogan citratus fibre (CCF) is an agricultural waste plant derived from a natural cellulosic source of fibre that can be used in various bio-material applications. This paper beneficially prepared thermoplastic cassava starch/palm wax blends incorporated with Cymbopogan citratus fibre (TCPS/PW/CCF) bio-composites at different CCF concentrations of 0, 10, 20, 30, 40, 50 and 60 wt%. In contrast, palm wax loading remained constant at 5 wt% concentration using the hot moulding compression method. TCPS/PW/CCF bio-composites were characterised in the present paper via their physical and impact properties. The addition of CCF significantly improved impact strength by 50.65% until 50 wt% CCF loading. Furthermore, it was observed that the inclusion of CCF resulted in a little decrement in biocomposite solubility compared to neat TPCS/PW biocomposite from 28.68% to 16.76%. Water absorption showed higher water resistance in the composites incorporating 60 wt.% fibre loading. The TPCS/PW/CCF biocomposites with different fibre contents had 11.04-5.65% moisture content, which was lower than the control biocomposite. The thickness of all samples decreased gradually with increasing fibre content. Overall, these findings provide evidence that CCF waste can be utilised as a high-quality filler in biocomposites due to its diverse characteristics, including improving the properties of biocomposites and strengthening their structural integrity.

Assessment of properties of gluten-based edible film formulated with beeswax and DATEM for hamburger bread coating

Using edible films and coatings is one of the effective methods of improving the quality of bread. The aim of the present work was the development of gluten-based films containing lipids to be applied as bread coating, intending to improve quality and delay staleness. In this study, two types of lipids including beeswax and DATEM (diacetyl tartaric ester monoglycerides) were incorporated into gluten film at different levels. The findings showed that inserting both lipids together into gluten for film preparation, weakened the developed films in terms of mechanical and moisture barrier properties. Adding DATEM to the gluten film formulae decreased the elongation at the break and the tensile strength of the film. Using gluten-beeswax coatings for hamburger bread, compared to gluten-DATEM coatings, indicated a significant decrease in the hardness and staling feature. Moreover, applying sorbate as a preservative along with the solvents used in the film preparation prevented the growth of mold during the bread shelf life. In conclusion, the findings in this study indicated that the type and levels of lipids added to the edible gluten-based films and coatings affected the film properties and coated hamburger bread quality, significantly.

Design of Biodegradable Films Using Pecan Nut Cake Extracts for Food Packing

The excessive consumption of plastic packaging and its consequent disposal and accumulation in the environment have aroused the interest of researchers in developing packaging that can cause less harm to nature. In this sense, this article presents research on the addition of antioxidant extracts from pecan nut cake in biodegradable packaging made with a polymeric mixture of gelatin and corn starch. The films produced were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thickness, mechanical properties, water vapor permeability (WVP), solubility, water contact angle, optical properties, in vitro bioactive activity, and biodegradability. A higher concentration of total phenolic compounds (101.61 mg GAE/g) was found for the condition where alcohol content and extraction time were 65% and 20 min, respectively. Pecan nut cake (PNC( extracts did not influence the film’s tensile strength, and elongation at break was tightly increased by adding 10–20% extracts. The film’s characterization pointed to more than 67% solubility, and adding PNC extract implied more hydrophilic surfaces (contact angles lower than 65°). Furthermore, the film opacity showed a linear relation with PNC extract concentration, and a higher luminosity (L*) was observed for the film without extract. Furthermore, the antioxidant activity of the films was enhanced with the addition of PNC extracts, and complete biodegradation was observed until the ninth day. Therefore, biodegradable films prepared from a mixture of gelatin starch and enriched with PNC extracts showed excellent mechanical properties and potential as carriers of antioxidant compounds, allowing us to propose their use as active packing.

Study of Candelilla Wax Concentrations on the Physical Properties of Edible Nanocoatings as a Function of Support Polysaccharides

Solid lipid nanoparticles (SLN) based on candelilla wax were prepared using the hot homogenization technique. The resulting suspension had monomodal behavior with a particle size of 809-885 nm; polydispersity index < 0.31, and zeta potential of -3.5 mV 5 weeks after monitoring. The films were prepared with SLN concentrations of 20 and 60 g/L, each with a plasticizer concentration of 10 and 30 g/L; the polysaccharide stabilizers used were either xanthan gum (XG) or carboxymethyl cellulose (CMC) at 3 g/L. The effects of temperature, film composition, and relative humidity on the microstructural, thermal, mechanical, and optical properties, as well as the water vapor barrier, were evaluated. Higher amounts of SLN and plasticizer gave the films greater strength and flexibility due to the influence of temperature and relative humidity. The water vapor permeability (WVP) was lower when 60 g/L of SLN was added to the films. The arrangement of the SLN in the polymeric networks showed changes in the distribution as a function of the concentrations of the SLN and plasticizer. The total color difference (ΔE) was greater when the content of the SLN was increased, with values of 3.34-7.93. Thermal analysis showed an increase in the melting temperature when a higher SLN content was used, whereas a higher plasticizer content reduced it. Edible films with the most appropriate physical properties for the packaging, shelf-life extension, and improved quality conservation of fresh foods were those made with 20 g/L of SLN, 30 g/L of glycerol, and 3 g/L of XG.

Application of Poultry Gelatin to Enhance the Physicochemical, Mechanical, and Rheological Properties of Fish Gelatin as Alternative Mammalian Gelatin Films for Food Packaging

This study aimed to describe the properties of cold water fish gelatin (FG) blended with poultry gelatin (PG) for a production of a sachet containing olive oil. To find a desirable film, the different ratio of FG-PG-based films were characterized in terms of mechanical properties. As the proportion of PG in PG-FG-based increased, the tensile strength and Young's modulus were increased, and the elongation at break and heat seal strength of the films were decreased. The 50-50 film had favorable characteristics to use as a sachet. The amount of acid index and peroxide of the oil stored in the sachets after 14 days showed that there is a significant difference (p < 0.05) between the films. The barrier properties of the films including the water vapor permeability and oxygen permeability of films were increased from 1.21 to 4.95 × 10^-11 g m^-1 Pa^-1 s^-1 and 48 to 97 cm³ mµ/m² d kPa, respectively. Dark, red, yellow, and opaque films were realized with increasing PG. Fourier transform infrared (FTIR) spectra approved a wide peak of approximately 2500 cm^-1. The rheological analysis indicated that, by adding PG, viscosity, elastic modulus (G') and loss modulus (G'') were increased significantly (p < 0.05) about 9.5, 9.32 and 18 times, respectively. Therefore, an easy modification of FG with PG will make it suitable for oil sachet packaging applications for the food industry.

Fabrication and Characterization of Intelligent Multi-Layered Biopolymer Film Incorporated with pH-Sensitive Red Cabbage Extract to Indicate Fish Freshness

This study aimed to fabricate an intelligent monolayer and multi-layered biodegradable films incorporated with red cabbage extract (RCE) to act as a safe and reliable freshness indicator. A film-forming solution (FFS) of gelatin, carboxymethyl cellulose (CMC) and chitosan was prepared and fortified with 0.5% (w/v) of RCE for developing intelligent monolayer films. The intelligent multi-layer film was prepared via layer by layer casting of gelatin, chitosan (added with 0.5% of RCE) and CMC biopolymers. The thickness of the multi-layered film was the highest (0.123 ± 0.001 mm) compared to gelatin-, CMC- and chitosan-based monolayer films (p < 0.05). Chitosan film has the highest tensile strength (p < 0.05), followed by multi-layer, CMC and gelatin films. Elongation at break was slightly higher in CMC (35.67 ± 7.62%) compared to the multi-layer film (33.12 ± 9.88%) and gelatin film (p > 0.05). Water vapor permeability was higher in the multi-layer film (1.244 ± 0.05 × 10−5 g mm h−1cm−2 P−1) than the other monolayer films. Moisture content was highest in chitosan film followed by the multi-layered film (p < 0.05) and then the CMC and gelatin films. CMC film showed the highest solubility compared to multi-layered and chitosan film (p < 0.05). Additionally, transmittance and transparency values in the multi-layered film were the lowest compared to the chitosan-, CMC- and gelatin-based films. L* and a* values were the lowest, while b* values increased in the multi-layered film compared to the other film samples (p < 0.05). pH sensitivity and ammonia gas tests revealed similar color changes in chitosan and multi-layer films. However, FTIR spectra confirmed that dye leaching was not detected for the multi-layered film soaked in ethanol. The biodegradability test showed rapid degradation of multi-layered and chitosan films within 1 month. Based on the optimum results of the multi-layered film, it was applied to monitor the fresh quality of tilapia fish fillets at 4 °C for 10 days. The results of freshness acceptability were noted on day 6 due to the change in color of the multi-layer film with an estimated total volatile basic nitrogen content of 21.23 mg/100 g. Thus, the multi-layered film can be used as an indicator to monitor the quality of the fish freshness without leaching dye onto the food surface.

Antimicrobial and Antioxidant Activity of Apricot (Mimusopsis comersonii) Phenolic-Rich Extract and Its Application as an Edible Coating for Fresh-Cut Vegetable Preservation

Edible coatings have several advantages in preserving foods, such as avoiding water loss, controlling microbial growth, and reducing the need for preservatives added directly to the product. Antimicrobial action can be obtained by adding antimicrobial substances including phenolic compounds commonly found in plant extracts. This study evaluated the phenolic compounds content, antioxidant and antimicrobial activity of pulp, and seed extracts of Mimusopsis comersonii (popularly known in Brazil as abrico), besides the phenolic compounds were identified and quantified in the pulp extract. Edible coatings were incorporated with pulp extract in order to evaluate the preservation of minimally processed apples and baroa potatoes against foodborne bacteria, and enzymatic browning was also determined. Myricetin-3-glucoside, quercetin-3-glucoside, and kaempferol-3-glucoside were identified as major flavonoids in the apricot pulp extract. The seed and pulp extracts inhibited all tested microorganisms, especially Staphylococcus aureus and Salmonella Typhimurium. Edible coatings added with 9% of phenolic extract showed in vitro antimicrobial activity, in addition to being effective in preventing enzymatic browning in minimally processed apples and baroa potatoes for up to 15 days of storage. They were also effective in reducing up to 2 log CFU/g of aerobic mesophiles after 15 days of storage for apples, even though no microbial inhibition in baroa potatoes was observed under the same conditions. The addition of pulp phenolic extract in edible coatings proved to be an alternative in the preservation of apples and in the antibrowning activity of minimally processed baroa potatoes.

Bio-Nanocomposite Based on Edible Gelatin Film as Active Packaging from Clarias gariepinus Fish Skin with the Addition of Cellulose Nanocrystalline and Nanopropolis

This study develops bio-nano composite gelatin-based edible film (NEF) by combining nanogelatin, cellulose nanocrystal (CNC), and nanopropolis (NP) fillers to improve the resulting film characteristics. The NEF was characterized in terms of thickness, swelling, pH, water content, solubility, vapor and oxygen permeability, mechanical properties, heat resistance, morphology, transparency, and color. The results showed that the thickness and swelling increased significantly, whilst the pH did not significantly differ in each treatment. The water content and the water solubility also showed no significant changes with loadings of both fillers. At the same time, vapor and oxygen permeability decreased with addition of the fillers but were not significantly affected by the loading amounts. The heat resistance properties increased with the filler addition. Tensile strength and Young’s modulus increased for the films loaded with >3% CNC. The elongation at break showed a significant difference together with transparency and color change. The greater the CNC concentration and NP loading were, the darker the resulting transparency and the color of the NEF. Overall results show a considerable improvement in the properties of the resulting NEFs with the incorporation of CNC and NP fillers.

Biopolymer-based functional films for packaging applications: A review

Food packaging is a coordinated system comprising food processing, protection from contamination and adulteration, transportation and storage, and distribution and consumption at optimal cost with a minimum environmental impact to the packed food commodity. Active packaging involves deliberate addition of the functional ingredients either in the film or the package headspace to preserve the food quality, improve safety and nutrition aspects, and enhance the shelf-life. In this review, recent advances in the fabrication of biopolymer-based films, their classification (biodegradable-, active-, and intelligent packaging films), advanced fabrication strategies (composite-, multilayer-, and emulsified films), and special functions induced by the biopolymers to the film matrix (mechanical-, water resistance and gas barrier-, and optical properties, and bioactive compounds reservoir) were briefly discussed. A summary of conclusions and future perspectives of biopolymer-based packaging films as advanced biomaterial in preserving the food quality, improving safety and nutrition aspects, and enhancing shelf-life of the products was proposed.

Molecular Modeling Approaches Can Reveal the Molecular Interactions Established between a Biofilm and the Bioactive Compounds of the Essential Oil of Piper divaricatum

Molecular modeling approaches are used in a versatile way to investigate the properties of diverse organic and inorganic structures such as proteins, biomolecules, nanomaterials, functionalized nanoparticles, and membranes. However, more detailed studies are needed to understand the molecular nature of interactions established in gelatin biofilms impregnated with bioactive compounds. Because of this, we used computational methods to evaluate how the major compounds of Piper divaricatum essential oil can interact with the gelatin biofilm structure. For this, we used as inspiration the paper published, where various properties of the essential oil impregnated gelatin biofilm P. divaricatum are reported. After our computer simulations, we related our molecular observations to biofilm’s structural and mechanical properties. Our results suggest that the major compounds of the essential oil were able to interrupt intermolecular interactions between the chains of the biofilm matrix. However, the compounds also established interactions with the amino acid residues of these chains. Our molecular analyses also explain changes in the structural and mechanical properties of the essential oil-impregnated biofilm. These results can support the planning of functional packaging impregnated with bioactive compounds that can protect food against microorganisms harmful to human health.

Intelligent colorimetric pH sensoring packaging films based on sugarcane wax/agar integrated with butterfly pea flower extract for optical tracking of shrimp freshness

A novel pH colorimetric film was prepared from various sugarcane wax (SW) concentrations (1, 1.5 and 2% w/v) on agar matrix (Agr) combined with butterfly pea flower (BF) extract for monitoring the shrimp freshness. A combination of BF anthocyanins with SW as lipid (hydrophobic) showed different changes in color under acidic conditions (pH 2-6) with slight changes under alkalinity (pH 7-12), which matched the visual color changes of two different ammonia vapors (50 and 100 mmol/l). FTIR, XRD spectra, and SEM micrographs revealed that SW was effectively fixed into the Agr-BF network during the film-forming process. The different homogenized SW films enhanced the physical and mechanical properties without significant differences in elongation and water vapor permeability. Remarkably, SW films displayed complete protection against UV-vis light (0%) and valuable reduction in visible light. This study presents SW colorimetric films as promising natural derivatives for smart packaging in tracking food freshness.

Biodegradable gelatin-based films with nisin and EDTA that inhibit Escherichia coli

In this study, we developed gelatin-based films for active packaging with the ability to inhibit E. coli. We created these novel biodegradable gelatin-based films with a nisin-EDTA mix. FT-IR, TGA, and SEM analysis showed that nisin interacted with the gelatin by modifying its thermal stability and morphology. The use of nisin (2,500 IU/mL) with concentrations of Na-EDTA (1.052 M stock solution) distributed in the polymer matrix generated a significant decrease in the growth of E. coli when compared to the control. In freshly made films (t0), the growth of E. coli ATCC 25922 was reduced by approximately 3 logarithmic cycles. Two weeks after the films were made, a reduction in antimicrobial activity was observed in approximately 1, 1 and 3 logarithmic cycles of the films with 5%, 10% and 20% of the compound (nisin/Na-EDTA) distributed in the polymer matrix, respectively. This evidences an antimicrobial effect over time. Also, biodegradation tests showed that the films were completely degraded after 10 days. With all these results, an active and biodegradable packaging was successfully obtained to be potentially applied in perishable foods. These biodegradable, gelatin-based films are a versatile active packaging option. Further research on the barrier properties of these films is needed.

Advancements in Biodegradable Active Films for Food Packaging: Effects of Nano/Microcapsule Incorporation

Food packaging plays a fundamental role in the modern food industry as a main process to preserve the quality of food products from manufacture to consumption. New food packaging technologies are being developed that are formulated with natural compounds by substituting synthetic/chemical antimicrobial and antioxidant agents to fulfill consumers' expectations for healthy food. The strategy of incorporating natural antimicrobial compounds into food packaging structures is a recent and promising technology to reach this goal. Concepts such as "biodegradable packaging", "active packaging", and "bioactive packaging" currently guide the research and development of food packaging. However, the use of natural compounds faces some challenges, including weak stability and sensitivity to processing and storage conditions. The nano/microencapsulation of these bioactive compounds enhances their stability and controls their release. In addition, biodegradable packaging materials are gaining great attention in the face of ever-growing environmental concerns about plastic pollution. They are a sustainable, environmentally friendly, and cost-effective alternative to conventional plastic packaging materials. Ultimately, a combined formulation of nano/microencapsulated antimicrobial and antioxidant natural molecules, incorporated into a biodegradable food packaging system, offers many benefits by preventing food spoilage, extending the shelf life of food, reducing plastic and food waste, and preserving the freshness and quality of food. The main objective of this review is to illustrate the latest advances in the principal biodegradable materials used in the development of active antimicrobial and antioxidant packaging systems, as well as the most common nano/microencapsulated active natural agents incorporated into these food-packaging materials.

A Review of Nonbiodegradable and Biodegradable Composites for Food Packaging Application

The dependency on nonbiodegradable-based food packaging, increase in population growth, and persistent environmental problems are some of the driving forces in considering the development of biodegradable food packaging. This effort of green packaging has the potential to solve issues on plastic wastes through the combination of biodegradable composite-based food packaging with plant extracts, nanomaterials, or other types of polymer. Modified biodegradable materials have provided numerous alternatives for producing green packaging with mechanical strength, thermal stability, and barrier performance that are comparable to the conventional food packaging. To the best of our knowledge, the performance of nonbiodegradable and biodegradable composites as food packaging in terms of the above properties has not yet been reviewed. In this context, the capability of biodegradable polymers to substitute the nonbiodegradable polymers was emphasized to enhance the packaging biodegradation while retaining the mechanical strength, thermal stability, barrier properties, and antioxidant and antimicrobial or antibacterial activity. These are the ultimate goal in the food industry. This review will impart useful information on the properties of food packaging developed from different polymers and future outlook toward the development of green food packaging.

Antimicrobial Food Packaging Based on Prodigiosin-Incorporated Double-Layered Bacterial Cellulose and Chitosan Composites

Nowadays, food packaging systems have shifted from a passive to an active role in which the incorporation of antimicrobial compounds into biopolymers can promote a sustainable way to reduce food spoilage and its environmental impact. Accordingly, composite materials based on oxidized-bacterial cellulose (BC) and poly(vinyl alcohol)-chitosan (PVA-CH) nanofibers were produced by needleless electrospinning and functionalized with the bacterial pigment prodigiosin (PG). Two strategies were explored, in the first approach PG was incorporated in the electrospun PVA-CH layer, and TEMPO-oxidized BC was the substrate for nanofibers deposition (BC/PVA-CH_PG composite). In the second approach, TEMPO-oxidized BC was functionalized with PG, and afterward, the PVA-CH layer was electrospun (BC_PG/PVA-CH composite). The double-layer composites obtained were characterized and the nanofibrous layers displayed smooth fibers with average diameters of 139.63 ± 65.52 nm and 140.17 ± 57.04 nm, with and without pigment incorporation, respectively. FTIR-ATR analysis confirmed BC oxidation and revealed increased intensity at specific wavelengths, after pigment incorporation. Moreover, the moderate hydrophilic behavior, as well as the high porosity exhibited by each layer, remained mostly unaffected after PG incorporation. The composites’ mechanical performance and the water vapor transmission rate (WVTR) evaluation indicated the suitability of the materials for certain food packaging solutions, especially for fresh products. Additionally, the red color provided by the bacterial pigment PG on the external surface of a food packaging material is also a desirable effect, to attract the consumers’ attention, creating a multifunctional material. Furthermore, the antimicrobial activity was evaluated and, PVA-CH_PG, and BC_PG layers exhibited the highest antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Thus, the fabricated composites can be considered for application in active food packaging, owing to PG antimicrobial potential, to prevent foodborne pathogens (with PG incorporated into the inner layer of the food packaging material, BC/PVA-CH_PG composite), but also to prevent external contamination, by tackling the exterior of food packaging materials (with PG added to the outer layer, BC_PG/PVA-CH composite).

Incorporation of Lipids into Wheat Bran Cellulose/Wheat Gluten Composite Film Improves Its Water Resistance Properties

This work evaluated the improvement effects of lipids incorporation on water resistance of composite biodegradable film prepared with wheat bran cellulose/wheat gluten (WBC/WG) using an alkaline–ethanol film forming system. Four types of lipids, paraffin wax (PW), beeswax (BW), paraffin oil (PO), and oleic acid (OA), were tested. We found that PW, BW, and PO incorporation at 5–20% improved water vapor permeability (WVP) and surface hydrophobicity of prepared films. Particularly, incorporation of 15% BW could best improve the water resistance properties of the film, with the lowest WVP of 0.76 × 10⁻¹² g/cm·s·Pa and largest water contact angle (WCA) of 86.18°. Incorporation of OA led to the decline in moisture barrier properties. SEM images revealed that different lipids incorporation changed the morphology and of the composite film, and cross-sectional morphology indicated BW-incorporated film obtained more uniform and compact structures compared to other films. Moreover, Fourier transform infrared spectra indicated that the incorporation of PW or BW enhanced the molecular interactions between the film components, confirmed by the chemical shift of characteristic peaks at 3277 and 1026 cm⁻¹. Differential scanning calorimetry results revealed that incorporation of PW, BW, and PO increased films’ melting point, decomposition temperatures, and enthalpy values. Furthermore, the presence of most lipids decreased tensile strength and elongation at the break of the film. Overall, the composite film containing 15% BW obtained the most promising water resistance performance and acceptable mechanical properties, and it thus most suitable as a hydrophobic biodegradable material for food packaging.

Active and Robust Composite Films Based on Gelatin and Gallic Acid Integrated with Microfibrillated Cellulose

BACKGROUND

Gelatin is a renewable, biodegradable, and inexpensive food polymer. The insufficient mechanical and functional properties of gelatin-based films (GBF) restrict their commercial application in food packaging. This work proposed a facile strategy to prepare an active and robust GBF that has the potential to be used in food packaging.

METHODS

A strong and active GBF was prepared based on the principle of supramolecular chemistry via the incorporation of gallic acid (GA) as an active crosslinking agent and of microfibrillated cellulose (MFC) as a reinforcing agent.

RESULTS

Under the appropriate concentration (1.0 wt%), MFC was evenly dispersed in a gelatin matrix to endow the film with low surface roughness and compact structure. Compared with the GF, the tensile strength and elongation at break of the resultant film reached 6.09 MPa and 213.4%, respectively, representing the corresponding improvement of 12.8% and 27.6%. Besides, a significantly improved water vapor barrier (from 3.985 × 10^-8 to 3.894 × 10^-8 g·m^-1·Pa^-1·s^-1) and antioxidant activity (from 54.6% to 86.4% for ABTS radical scavenging activity; from 6.0% to 89.1% for DPPH radical scavenging activity) of GBFs were also observed after introducing the aromatic structure of GA and nano-/microfibrils in MFC. Moreover, the UV blocking performance and thermal stability of GGF and GGCFs were also enhanced.

CONCLUSIONS

this work paves a promising way toward facile preparation of multifunctional GBFs that have great potential to be used in fabricating active and safe food packaging materials for food preservation.

Gelatin Reinforced with CNCs as Nanocomposite Matrix for Trichoderma harzianum KUEN 1585 Spores in Seed Coatings

Increasing interest on sustainable agriculture has led to the development of new materials which can be used as seed coating agents. In this study, a new material was developed based on gelatin film reinforced with cellulose nanocrystals (CNC) which was further used as nanocomposite matrix for Trichoderma harzianum KUEN 1585 spores. The nanocomposite films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), showing the formation of new hydrogen bonds between the components with a good compatibility between them. Measurements of water contact angles and tests of water vapor sorption and swelling degree revealed an improvement in the water vapor absorption properties of the films as a result of their reinforcement with CNC. Furthermore, by adding the Trichoderma harzianum KUEN 1585 spp. in the seed coating material, the germination percentage, speed of germination and roots length of the corn seeds improved. The polymeric coating did not inhibit the growth of T. harzianum KUEN 1585, with this material being a good candidate in modern agriculture.

Advantages and challenges of Pickering emulsions applied to bio-based films: a mini-review

The strategy of adding hydrophobic compounds to bio-based films (usually based on hydrophilic matrices), forming films containing emulsions, is a technique that has been used to improve some physical properties (such as reducing water solubility and water vapor permeability) and / or to impart properties, such as antioxidant and antimicrobial effects by carrying hydrophobic active components that would otherwise be insoluble in hydrophilic matrices. Although Pickering emulsions have been reported as presenting greater stability when compared with surfactant-stabilized emulsions, little is known about the drying stability of Pickering emulsions (which is important for film applications). Anyway, several studies have indicated that Pickering emulsions are interesting systems to improve the water vapor barrier properties of bio-based films and coatings, and to act as carriers of active hydrophobic components. On the other hand, the tensile properties of those films are usually impaired by the presence of Pickering emulsions. The objective of this review is to present recent developments and future perspectives in bio-based films loaded with Pickering emulsions. © 2020 Society of Chemical Industry.

Can Sustainable Packaging Help to Reduce Food Waste? A Status Quo Focusing Plant-Derived Polymers and Additives

The promotion of sustainable packaging is part of the European Green Deal and plays a key role in the EU’s social and political strategy. One option is the use of renewable resources and biomass waste as raw materials for polymer production. Lignocellulose biomass from annual and perennial industrial crops and agricultural residues are a major source of polysaccharides, proteins, and lignin and can also be used to obtain plant-based extracts and essential oils. Therefore, these biomasses are considered as potential substitute for fossil-based resources. Here, the status quo of bio-based polymers is discussed and evaluated in terms of properties related to packaging applications such as gas and water vapor permeability as well as mechanical properties. So far, their practical use is still restricted due to lower performance in fundamental packaging functions that directly influence food quality and safety, the length of shelf life, and thus the amount of food waste. Besides bio-based polymers, this review focuses on plant extracts as active packaging agents. Incorporating extracts of herbs, flowers, trees, and their fruits is inevitable to achieve desired material properties that are capable to prolong the food shelf life. Finally, the adoption potential of packaging based on polymers from renewable resources is discussed from a bioeconomy perspective.

Effects of Candelilla and Carnauba Wax Incorporation on the Functional Properties of Edible Sodium Caseinate Films

The aim of this study was to evaluate the effects of candelilla (CAN) or carnauba wax (CAR) incorporation on functional properties of edible sodium caseinate (CAS) films. Glycerol and Tween-80 were used as the plasticizer and the emulsifier, respectively. The results showed that the incorporation of waxes increased film opacity, total color differences (∆E), and mechanical resistance and reduced film lightness, water vapor permeability (WVP), and elongation at break. Scanning electron microscopy showed heterogeneous structure of emulsion films with regular distribution of lipid particles. A different internal arrangement was observed as a function of the film composition with both layered and incorporated film structure. Films containing candelilla wax exhibited more regular lipid reorganization, which resulted in better water vapor barrier efficacy and mechanical resistance in comparison to control films. The presence of Tween-80 resulted in better dispersion of lipid particles in film-forming solutions and lower water solubility, lightness, film opacity, and water vapor permeability, whereas the total color differences (∆E) were significantly larger and the improvement in mechanical properties was also achieved.

Development and evaluation of edible films based on cassava starch, whey protein, and bees wax

Films and edible coatings based on biopolymers have been developed as a packaging, which can be obtained from biodegradable materials and have properties similar to common plastics. These edible materials have many applications in the food industry, preventing mass transfer between the product and the surrounding environment. The objective of this study was to develop and evaluate the physicochemical and mechanical properties of edible films based on cassava starch (CS), whey protein (WP), and beeswax (BW). Response surface methodology has been used and the experiments were carried out based on face-centred composite design. On the other hand, three CS-based controls were formulated to evaluate the effect of the inclusion of WP and BW. The optimization of multiple responses established the optimal formulation: CS (3.17 %), WP (1.30 %), BW (0.50 %), presenting the following response variables: tensile stress (1.92 MPa), elongation (40.4 %), Young's modulus (42.1 MPa), water vapor permeability 1.79 × 10^-11 (g mm/s cm² Pa), swelling capacity (300.3 %), thickness (0.128 mm), moisture content (6.74 %), and colour: lightness (89.9), chromaticity a∗ (-1.8), chromaticity b∗ (7.7), saturation (9.9), tone (101.1°), and yellowness index (17.7). The selection and evaluation of this optimal formulation are essential because it is the material that shows the best possible mechanical and physicochemical properties using the studied components. The results, especially its good mechanical properties and low permeability to water vapour, would allow its application as a coating for fruits, vegetables, among others, effectively delaying its weight loss due to dehydration.