Development of a chicken feather protein film containing clove oil and its application in smoked salmon packaging

UV Radiation and Protein Hydrolysates in Bio-Based Films: Impacts on Properties and Italian Salami Preservation

UV radiation was combined with the incorporation of fish protein hydrolysates to improve the performance of active bio-based films for food packaging. UV radiation was not used previously to enhance the packaging performance of blend films of starch/protein, and fish protein hydrolysates were not incorporated in bio-based polymer surfaces previously. Rice starch and fish proteins (from Whitemouth croaker muscle) were utilized to prepare films by the casting technique, which were UV-radiated under different exposure times (1, 5, and 10 min). The packaging performance of the films was determined according to the mechanical and barrier performance, solubility, and color. Fish protein hydrolysates (from Argentine croaker muscle) were then incorporated into the films (bulk structure or surface). The results showed that UV radiation for 1 min increased the tensile strength and modified the optical properties of films. It also altered the structure of the polymeric matrix, as demonstrated by the microstructure and thermal analysis, in agreement with the data obtained in packaging properties. The evaluation of antioxidant capacity through 2,2-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and reducing power indicated that incorporating fish protein hydrolysates either in the films' bulk structure or film surface promoted antioxidant properties; control films (produced with rice starch/fish proteins without hydrolysates) also presented antioxidant potential. According to the peroxide value and thiobarbituric acid reactive substance (TBARS) assays, control films and the films containing hydrolysates in their bulk structure or on the surface could prevent the lipid oxidation of Italian salami. Thus, combining UV radiation to shape the characteristics of bio-based materials with fish protein hydrolysates to reduce lipid oxidation contributes to the performance of active bio-based films for food packaging.

Chicken Feather Protein Dispersant for Effective Crude Oil Dispersion in the Marine Environment

Various studies report that aside from the adverse impact of the crude oil on the marine environment, there is the likelihood that chemical dispersants used on the surface of water as oil-treating agents themselves possess a degree of toxicity, which have additional effects on the environment. To eliminate the subject of toxicity, there exist several materials in nature that have the ability to form good emulsions, and such products include protein molecules. In this study, chicken feathers which are known to contain ≥90% protein were used to formulate a novel dispersant to disperse crude oil in seawater (35 ppt). Protein from chicken feathers was extracted and synthesized into the chicken feather protein (CFP) dispersant using deionized water as a solvent. Emulsions formed from CFP-synthesized dispersants were stable over a considerably long period of time, whereas the droplet sizes of the emulsion formed were on the average very small in diameter, making droplet coalescence very slow. The CFP dispersants exhibited moderate surface and interfacial activity at normal seawater salinity. Using the US EPA's baffled flask test, at 800 and 1000 mg/ml CFP surfactant-to-oil ratios, dispersion effectiveness values of 56.92 and 68.64 vol % were obtained, respectively, which show that CFP has a great potential in crude oil dispersion. Moreover, the acute toxicity test performed on Nile tilapia showed that CFP was practically nontoxic with an LC50 value of more than 100 mg/L after 96 h of exposure. The results obtained showed that the CFP dispersant is environmentally friendly.

Construction and application of nano ZnO/eugenol@yam starch/microcrystalline cellulose active antibacterial film

The goal of this study was to develop new biocomposite films that can better protect and prolong the shelf life of food. Here, a ZnO: eugenol@yam starch/microcrystalline cellulose (ZnO:Eu@SC) antibacterial active film was constructed. Because of the advantages of metal oxides and plant essential oils, codoping with these can effectively improve the physicochemical and functional properties of composite films. The addition of an appropriate amount of nano-ZnO improved the compactness and thermostability, reduced the moisture sensitivity, and enhanced the mechanical and barrier properties of the film. ZnO:Eu@SC exhibited good controlled release of nano-ZnO and Eu in food simulants. Nano-ZnO and Eu release was controlled by two mechanisms: diffusion (primary) and swelling (secondary). After loading Eu, the antimicrobial activity of ZnO:Eu@SC was significantly enhanced, resulting in a synergistic antibacterial effect. Z₄:Eu@SC film extended the pork shelf life by 100 % (25 °C). In humus, the ZnO:Eu@SC film was effectively degraded into fragments. Therefore, the ZnO:Eu@SC film has excellent potential in food active packaging.

Renovation of Agro-Waste for Sustainable Food Packaging: A Review

Waste management in the agricultural sector has become a major concern. Increased food production to satisfy the surge in population has resulted in the generation of large volumes of solid waste. Agro-waste is a rich source of biocompounds with high potential as a raw material for food packaging. Utilization of agro-waste supports the goal of sustainable development in a circular economy. This paper reviews recent trends and the development of agro-wastes from plant and animal sources into eco-friendly food packaging systems. Different plant and animal sources and their potential development into packaging are discussed, including crop residues, process residues, vegetable and fruit wastes, and animal-derived wastes. A comprehensive analysis of the properties and production methods of these packages is presented. Future aspects of agro-waste packaging systems and the inherent production problems are addressed.

Evaluation of Active LDPE Films for Packaging of Fresh Orange Juice

Microbial development, enzymatic action, and chemical reactions influence the quality of untreated natural orange juice, compromising its organoleptic characteristics and causing nutritional value loss. Active low-density polyethylene (LDPE) films containing green tea extract (GTE) were previously prepared by a blown film extrusion process. Small bags were prepared from the produced films, which were then filled with fresh orange juice and stored at 4 °C. Ascorbic acid (AA) content, sugar content, browning index, color parameters, pH, total acidity (TA) and microbial stability were evaluated after 3, 7, and 14 days of storage. The packaging containing GTE maintained the microbial load of fresh juice beneath the limit of microbial shelf-life (6 log CFU/mL) for the bacterial growth, with a more prominent effect for LDPE with 3%GTE. Regarding yeasts and molds, only the CO_LDPE_3GTE package maintained the microbial load of fresh juice below the limit for up to 14 days. At 14 days, the lowest levels of AA degradation (32.60 mg/100 mL of juice) and development of brown pigments (browning index = 0.139) were observed for the packages containing 3% of GTE, which had a pH of 3.87 and sugar content of 11.4 g/100 mL of juice at this time. Therefore, active LDPE films containing 3% of GTE increase the shelf-life of fresh juice and can be a promising option for storage of this food product while increasing sustainability.

Preparation Methods and Functional Characteristics of Regenerated Keratin-Based Biofilms

The recycling, development, and application of keratin-containing waste (e.g., hair, wool, feather, and so on) provide an important means to address related environmental pollution and energy shortage issues. The extraction of keratin and the development of keratin-based functional materials are key to solving keratin-containing waste pollution. Keratin-based biofilms are gaining substantial interest due to their excellent characteristics, such as good biocompatibility, high biodegradability, appropriate adsorption, and rich renewable sources, among others. At present, keratin-based biofilms are a good option for various applications, and the development of keratin-based biofilms from keratin-containing waste is considered crucial for sustainable development. In this paper, in order to achieve clean production while maintaining the functional characteristics of natural keratin as much as possible, four important keratin extraction methods—thermal hydrolysis, ultrasonic technology, eco-friendly solvent system, and microbial decomposition—are described, and the characteristics of these four extraction methods are analysed. Next, methods for the preparation of keratin-based biofilms are introduced, including solvent casting, electrospinning, template self-assembly, freeze-drying, and soft lithography methods. Then, the functional properties and application prospects of keratin-based biofilms are discussed. Finally, future research directions related to keratin-based biofilms are proposed. Overall, it can be concluded that the high-value conversion of keratin-containing waste into regenerated keratin-based biofilms has great importance for sustainable development and is highly suggested due to their great potential for use in biomedical materials, optoelectronic devices, and metal ion detection applications. It is hoped that this paper can provide some basic information for the development and application of keratin-based biofilms.

Recent Advances in PLA-Based Antibacterial Food Packaging and Its Applications

In order to reduce environmental pollution and resource waste, food packaging materials should not only have good biodegradable ability but also effective antibacterial properties. Poly(lactic acid) (PLA) is the most commonly used biopolymer for food packaging applications. PLA has good physical properties, mechanical properties, biodegradability, and cell compatibility but does not have inherent antibacterial properties. Therefore, antibacterial packaging materials based on PLA need to add antibacterial agents to the polymer matrix. Natural antibacterial agents are widely used in food packaging materials due to their low toxicity. The high volatility of natural antibacterial agents restricts their application in food packaging materials. Therefore, appropriate processing methods are particularly important. This review introduces PLA-based natural antibacterial food packaging, and the composition and application of natural antibacterial agents are discussed. The properties of natural antibacterial agents, the technology of binding with the matrix, and the effect of inhibiting various bacteria are summarized.

Performance and Structure Evaluation of Gln-Lys Isopeptide Bond Crosslinked USYK-SPI Bioplastic Film Derived from Discarded Yak Hair

To reduce the waste from yak hair and introduce resource recycling into the yak-related industry, an eco-friendly yak keratin-based bioplastic film was developed. We employed yak keratin (USYK) from yak hair, soy protein isolate (SPI) from soybean meal as a film-forming agent, transglutaminase (EC 2.3.2.13, TGase) as a catalytic crosslinker, and glycerol as a plasticizer for USYK-SPI bioplastic film production. The structures of the USYK-SPI bioplastic film were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-Ray diffraction (XRD). The mechanical properties, the thermal behavior, light transmittance performance, and water vapor permeability (WVP) were measured. The results revealed that the added SPI possibly acted as a reinforcement. The formation of Gln-Lys isopeptide bonds and hydrophobic interactions led to a stable crosslinking structure of USYK-SPI bioplastic film. The thermal and the mechanical behaviors of the USYK-SPI bioplastic film were improved. The enhanced dispersion and formation of co-continuous protein matrices possibly produced denser networks that limited the diffusion of water vapor and volatile compounds in the USYK-SPI bioplastic films. Moreover, the introduction of SPI prompted the relocation of hydrophobic groups on USYK molecules, which gave the USYK-SPI bioplastic film stronger surface hydrophobicity. The SPI and USYK molecules possess aromatic amino residuals (tyrosine, phenylalanine, tryptophan), which can absorb ultraviolet radiation. Thus, the USYK-SPI bioplastic films were shown to have an excellent UV barrier. The synergy effect between USYK and SPI is not only able to improve rigidity and the application performance of keratin-based composite film but can also reduce the cost of the keratin-based composite film through the low-cost of the SPI alternative which partially replaces the high-cost of keratin. The data obtained from this research can provide basic information for further research and practical applications of USYK-SPI bioplastic films. There is an increasing demand for the novel USYK-SPI bioplastic film in exploit packaging material, biomedical materials, eco-friendly wearable electronics, and humidity sensors.

Quality and Shelf-Life Stability of Pork Meat Fillets Packaged in Multilayer Polylactide Films

In the present study, the effectiveness of a multilayer film of polylactide (PLA), fully bio-based and compostable, was ascertained to develop a novel sustainable packaging solution for the preservation of fresh pork meat. To this end, the multilayer PLA films were first characterized in terms of their thermal characteristics, structure, mechanical performance, permeance to water and aroma vapors and oxygen, and optical properties and, for the first time, compared with two commercial high-barrier multilayer packaging films. Thereafter, the multilayers were thermosealed to package fillets of fresh pork meat and the physicochemical changes, lipid oxidation levels, and microbiological counts were monitored in the food samples during storage under refrigeration conditions. Results showed that the meat fillets packaged in PLA developed a redder color and showed certain indications of dehydration and oxidation, being more noticeably after 11 days of storage, due to the higher water vapor and oxygen permeance values of the biopolymer multilayer. However, the pH changes and bacterial growth in the cold-stored fresh pork meat samples were minimal and very similar in the three tested multilayer films, successfully accomplishing the requirements of the food quality and safety standards at the end of storage.

Aquaculture and agriculture-by products as sustainable sources of omega-3 fatty acids in the food industry

The valorization of by-products is currently a matter of great concern to improve the sustainability of the food industry. High quality by-products derived from the food chain are omega-3 fatty acids, being fish the main source of docosahexaenoic acid and eicosapentaenoic acid. The search for economic and sustainable sources following the standards of circular economy had led to search for strategies that put in value new resources to obtain different omega-3 fatty acids, which could be further employed in the development of new industrial products without producing more wastes and economic losses. In this sense, seeds and vegetables, fruits and crustaceans by products can be an alternative. This review encompasses all these aspects on omega-3 fatty acids profile from marine and agri-food by-products together with their extraction and purification technologies are reported. These comprise conventional techniques like extraction with solvents, cold press, and wet pressing and, more recently proposed ones like, supercritical fluids fractionation and purification by chromatographic methods. The information collected indicates a trend to combine different conventional and emerging technologies to improve product yields and purity. This paper also addresses encapsulation strategies for their integration in novel foods to achieve maximum consumer acceptance and to ensure their effectiveness.

Cassava-Starch-Based Films Incorporated with Buriti (Mauritia flexuosa L.) Oil: A New Active and Bioactive Material for Food Packaging Applications

The objective of this study was to develop and characterize cassava-starch-based films incorporated with buriti (Mauritia flexuosa L.) oil and emulsifier (Tween 20). An experimental factorial design 22 with three central points was used to develop the films, by varying the concentrations of buriti oil (0.15 to 0.45% w/v) and emulsifier (0.02 to 0.04% w/v). Film thickness and weight increased with increasing buriti oil concentration. The water vapor permeability of the films ranged from 0.22 to 0.366 g mm h−1 m−2 kPa−1. The tensile strength values varied from 4.21 to 6.95 MPa, the elasticity modulus varied from 538.53 to 722.78 MPa, and elongation to rupture varied from 1.13 to 1.66%. The film color was characterized as yellowish, dark, and intense (higher oil content); and clear and a low-intensity color (lower oil content). The films presented a total carotenoid content ranging from 3.63 to 29.73 μg β-carotene/g, which may have resulted in their antioxidant potential against DPPH• (1,1-diphenyl-2-picryl-hydrazyl) radical (from 74.28 to 87.74%). The central formulation of the experimental design (buriti oil 0.30% and emulsifier 0.03%) presented a good performance and can be applied as packaging for foods with a lower water content and that demand protection against oxidation.

Activity of Clove Oil and Chitosan Nanoparticles Incorporated PVA Nanocomposite Against Pythium aphanidermatum

The loss of fresh produces owing to the microbial infestation is a major challenge to the global food industry. The drastic food loss caused mainly by the fungal attack demands the need for development of active packaging materials with antimicrobial properties. Many studies have already been reported on the applications of polymers like polyvinyl alcohol (PVA) engineered with antimicrobial components as active antifungal packaging materials. In the current study, material properties of PVA alone, PVA incorporated with chitosan nanoparticles (PCS), clove oil (PCO), and their combination (PCSCO) have been studied for its microbial barrier and antifungal properties. All the developed films were characterised by the XRD and FTIR analysis, which confirmed the molecular interactions among the individual components of the nanocomposite. At the same time, the bionanocomposite PCSCO was found to have low moisture content and film solubility indicating its suitability for the modified atmosphere packaging applications. In addition, the presence of chitosan nanoparticles and clove oil was found to provide the microbial barrier properties to the PCS, PCO, and PCSCO films. The PCSCO film was further demonstrated to have superior antifungal activity against the selected Pythium aphanidermatum. The results of the study indicate the potential application of developed nanocomposite film as a promising antifungal packaging material.

Biodegradable Packaging Materials from Animal Processing Co-Products and Wastes: An Overview

Biodegradable polymers are non-toxic, environmentally friendly biopolymers with considerable mechanical and barrier properties that can be degraded in industrial or home composting conditions. These biopolymers can be generated from sustainable natural sources or from the agricultural and animal processing co-products and wastes. Animals processing co-products are low value, underutilized, non-meat components that are generally generated from meat processing or slaughterhouse such as hide, blood, some offal etc. These are often converted into low-value products such as animal feed or in some cases disposed of as waste. Collagen, gelatin, keratin, myofibrillar proteins, and chitosan are the major value-added biopolymers obtained from the processing of animal's products. While these have many applications in food and pharmaceutical industries, a significant amount is underutilized and therefore hold potential for use in the generation of bioplastics. This review summarizes the research progress on the utilization of meat processing co-products to fabricate biodegradable polymers with the main focus on food industry applications. In addition, the factors affecting the application of biodegradable polymers in the packaging sector, their current industrial status, and regulations are also discussed.

Characterization and Antimicrobial Activity of Biodegradable Active Packaging Enriched with Clove and Thyme Essential Oil for Food Packaging Application

Bioactive packaging contains natural antimicrobial agents, which inhibit the growth of microorganisms and increase the food shelf life. Solvent casting method was used to prepare the Poly (lactide)-Poly (butylene adipate-co-terephthalate) (PLA-PBAT) film incorporated with the thyme oil and clove oil in various concentrations (1 wt%, 5 wt% and 10 wt%). The clove oil composite films depicted less green and more yellow as compared to thyme oil composite films. Clove oil composite film has shown an 80% increase in the UV blocking efficiency. The tensile strength (TS) of thyme oil and clove oil composite film decreases from 1.35 MPs (control film) to 0.96 MPa and 0.79, respectively. A complete killing of S. aureus that is a reduction from 6.5 log CFU/mL to 0 log CFU/mL was observed on the 10 wt% clove oil incorporated composite film. Clove oil and thyme oil composite film had inhibited E. coli biofilm by 93.43% and 82.30%, respectively. Clove oil composite film had exhibited UV blocking properties, strong antimicrobial activity and has high potential to be used as an active food packaging.

Ohmic heating as an innovative approach for the production of keratin films

Ohmic heating is a thermal processing method based on the application of electric fields directly into a semi-conductive medium. In this study, we explored for the first time the use of ohmic heating to obtain keratin films. The properties of the films prepared by ohmic heating and conventional heating were evaluated and compared under similar thermal profiles. A lower increase in free thiols' concentration was obtained for the keratin solutions and keratin films submitted to ohmic heating (16% increase for the keratin solution extracted from virgin hair, pH 9, submitted to ohmic heating and 23% when submitted to conventional heating). Significant differences in the swelling results were observed for the films prepared with keratin extracted from virgin hair, with a swelling decrease in about 55% for the films prepared by ohmic heating. Generally, the keratin films obtained by ohmic heating showed distinct properties comparatively to the films produced by conventional methods. The application of a fusion protein on the keratin films demonstrated their capacity to be used as substitutes to hair fibers when evaluating the potential of new cosmetic products. This work suggests that ohmic heating show potential to tailor keratin films properties depending on an intended application or functionality.

Formation and characterization of protein-based films from yellow pea (Pisum sativum) protein isolate and concentrate for edible applications

This study investigated the properties of films or bioplastics fabricated using a wet processing method from yellow pea protein isolate (YPI) and protein concentrate (YPC) for potential application in food packaging. The wet processing method included mixing the protein with water and glycerol followed by casting and drying the films in a humidity- and temperature-controlled chamber. Whey protein isolate (WPI) and a film from a blend of equal amounts of YPI and WPI, labelled as YPI + WPI, were also studied. Fourier transform-infra red analysis revealed that films from YPI, YPC, WPI and YPI + WPI were formed by protein polymerisation with the plasticiser, glycerol, via hydrophobic and hydrophilic interactions. The protein films had contact angles of <90° demonstrating that they had a hydrophilic surface, with YPC < YPI < YPI + WPI < WPI. The pattern of ultraviolent light transmission of the films was WPI > YPC > YPI + WPI > YPI, whereas the mechanical and thermal resilience of films formulated from YPI, YPC and the protein blend were comparable to the properties of WPI-based films. The findings demonstrate that yellow pea proteins can be used as biomaterials to develop protein and protein-blend films or bioplastics for food packaging and edible applications.

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Bioplastics were fabricated from yellow pea protein isolate and concentrate, with glycerol.

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Contact angles of pea protein films indicate more hydrophobic surface than whey protein films.

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Pea protein films had more surface structure homogeneity and limited light transmission.

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Pea + whey protein blend did not produce synergistic effects in film property.

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Film physico-mechanical properties are promising for food packaging application.

Application of Protein-Based Films and Coatings for Food Packaging: A Review

As the IV generation of packaging, biopolymers, with the advantages of biodegradability, process ability, combination possibilities and no pollution to food, have become the leading food packaging materials. Biopolymers can be directly extracted from biomass, synthesized from bioderived monomers and produced directly by microorganisms which are all abundant and renewable. The raw materials used to produce biopolymers are low-cost, some even coming from agrion dustrial waste. This review summarized the advances in protein-based films and coatings for food packaging. The materials studied to develop protein-based packaging films and coatings can be divided into two classes: plant proteins and animal proteins. Parts of proteins are referred in this review, including plant proteins i.e., gluten, soy proteins and zein, and animal proteins i.e., casein, whey and gelatin. Films and coatings based on these proteins have excellent gas barrier properties and satisfactory mechanical properties. However, the hydrophilicity of proteins makes the protein-based films present poor water barrier characteristics. The application of plasticizers and the corresponding post-treatments can make the properties of the protein-based films and coatings improved. The addition of active compounds into protein-based films can effectively inhibit or delay the growth of microorganisms and the oxidation of lipids. The review also summarized the research about the storage requirements of various foods that can provide corresponding guidance for the preparation of food packaging materials. Numerous application examples of protein-based films and coatings in food packaging also confirm their important role in food packaging materials.

A comprehensive and comparative study of the internal structure and dynamics of natural β-keratin and regeneratedβ-keratin by solid state NMR spectroscopy

Structure and dynamics of natural and regenerated chicken feather β-keratin were investigated by ¹³C cross-polarization (CP) magic angle spinning (MAS) solid state nuclear magnetic resonance (SSNMR) spectral analysis, ¹³C and ¹H spin-lattice relaxation time measurements, and ¹³C two dimensional phase adjusted spinning sidebands (2DPASS) MAS SSNMR measurements. Chemical shift anisotropy (CSA) parameters of both natural and regenerated chicken feather β-keratin were extracted by using 2DPASS MAS SSNMR experiment. The beauty of 2DPASS MAS SSNMR experiment is it can correlate the isotropic and anisotropic dimension with the help of shearing transformation and two dimensional Fourier Transformation. Molecular correlation time at each and every magnetically inequivalent carbon site of both natural and regenerated chicken feather β-keratin were also determined. The change in molecular dynamics of structural protein after pretreatment was monitored by 2DPASS MAS SSNMR and ¹³C relaxation measurement. This type of comprehensive study will provide the information about the interrelation between the structure and dynamics of structural protein and will also shed light in the way of developing methods for conversion of animal by-products to novel product.

Development of Antibacterial Nanocomposite: Whey Protein-Gelatin-Nanoclay Films with Orange Peel Extract and Tripolyphosphate as Potential Food Packaging

Antibacterial and biodegradable whey protein isolate (WPI-) gelatin nanocomposites were prepared using natural orange peel extract (OPE) in percentage of 7, 14, and 21% (v/v solution) and Cloisite 30B (5% w/w dry whey protein) made by a casting method. Mechanical, physical, and antibacterial properties of prepared films were measured as a function of OPE concentration. Higher concentrations of OPE led to higher antibacterial activity, tensile strength, and water solubility, but lower moisture content and transparency. The films microstructures were studied by field emission scanning electron microscopy (FESEM) and ATR-FTIR. Overall, the film containing 21%(v/v) OPE resulted in the best antibacterial, mechanical, and physical performance. Addition of tripolyphosphate (TPP) as a crosslinker to this sample led to the significant increase in transparency. Cloisite 30B, OPE, and TPP can therefore be used to improve the properties of WPI films as a promising natural food packaging.

Preparation and Characterization of Soy Protein Isolate Films Incorporating Modified Nano-TiO2

Antimicrobial films were prepared by incorporating nano-titanium dioxide (TiO2) modified by silane into soy protein isolate (SPI) films. The effects of different concentrations of modified nano-TiO2 (TiO2-NM) on the physical properties, antimicrobial properties, and microstructure of the SPI-based films were investigated. Attenuated total reflectance Fourier-transform infrared spectroscopy indicated that the interaction between the SPI and TiO2-NM was via hydrogen bonds. Scanning electron microscopy and atomic force microscopy both showed that the microstructure of SPI-based films with TiO2-NM was compact. Moreover, as the content of TiO2-NM increased from 0 to 1.5 g/100 mL, the water vapor permeability and oxygen permeability were decreased from 5.43 to 4.62 g· mm/m2d· kPa and 0.470 to 0.110 g· cm−2· d−1, respectively. An increase from 6.67 MPa to 14.56 MPa in tensile strength and a decrease from 36.53% to 27.62% in elongation at break indicate the optimal mechanical properties of all groups. TiO2-NM films had excellent UV barrier properties, with a whiter surface with increasing TiO2-NM content. In addition, the SPI-based films with TiO2-NM showed antimicrobial activity, as evidenced by an inhibitory zone increasing from 0 to 27.34 mm. Therefore, TiO2-NM can be used as an antimicrobial agent in packaging films.

Development of an antioxidative packaging film based on khorasan wheat starch containing moringa leaf extract

The aim of this study was to develop and characterize the properties of khorasan wheat starch (KWS) films containing moringa leaf extract (MLE) as an antioxidative packaging material. KWS was isolated from khorasan wheat and used as a film base material. Different amounts (0, 0.4, 0.7, and 1.0%, w/v) of MLE were added to the KWS film-forming solution and the film properties were examined. Tensile strength of the KWS films decreased and elongation at break increased with increasing MLE content. In addition, the KWS films containing MLE possessed good antioxidative activities and ultraviolet light blocking ability. In particular, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging abilities of the KWS films with 1.0% MLE were 59.45% and 37.89%, respectively. Moreover, KWS films containing 1.0% MLE were biodegradable within 30 days. These findings indicate that the developed KWS films containing MLE can be applied as a biodegradable packaging material with antioxidative activity.

Improving the Water Resistance and Mechanical Properties of Feather Keratin/Polyvinyl Alcohol/Tris(Hydroxymethyl)Aminomethane Blend Films by Cross-Linking with Transglutaminase, CaCl₂, and Genipin

The high moisture sensitivity of feather keratin/polyvinyl alcohol/tris(hydroxymethyl)aminomethane (FK/PVA/Tris) blend films hinders their application in the packaging field. Thus, in order to improve the water resistance and mechanical properties of such blend films, we attempted cross-linking the blend film with cross-linking agents such as transglutaminase (TG), CaCl₂, and genipin. Obvious differences in the morphology of the blended films were observed by scanning electron microscopy before and after cross-linking, indicating that cross-linking can inhibit the phase separation of the blend film. Conformational changes in the blend films after cross-linking were detected by Fourier transform infrared spectroscopy. Importantly, from examination of the total soluble mass, contact angle measurements, and water vapor permeability tests, it was apparent that cross-linking greatly improved the water resistance of the blend films, in addition to enhancing the mechanical properties (i.e., tensile strength and elongation at break). However, cross-linking was also found to reduce the oxygen barrier properties of the blend films. Therefore, cross-linking appears to be an effective method for promoting the application of FK/PVA/Tris blend films in the packaging field.

Sea Squirt Shell Protein and Polylactic Acid Laminated Films Containing Cinnamon Bark Essential Oil

Sea squirt (Halocynthia roretzi) shell protein (SSP) was used as a biodegradable film material and laminated with polylactic acid (PLA) to improve its physical and water barrier properties. Cinnamon bark oil (CBO) was incorporated into the SSP film as a bioactive material. After laminating with PLA, the tensile strength and elongation at break of the SSP film increased from 4.07 to 9.09 MPa and from 8.68 to 138.84%, respectively. In addition, water vapor permeability and water solubility decreased from 5.62 to 0.91 × 10^-9 g m/m² s Pa and from 42.17% to 23.93%, respectively. DSC results of the SSP films indicate that melting point temperature increased 140.05 to 163.52 °C by laminating PLA. The addition of 0.5%, 0.7%, and 1.0% CBO conferred the antimicrobial activity against four pathogenic bacteria to the SSP/PLA-laminated films. The SSP/PLA-laminated films containing CBO also had antioxidant activities. Therefore, the SSP/PLA-laminated films containing CBO are applicable as biodegradable packaging films.

PRACTICAL APPLICATION

Sea squirt shell has been discarded after the consumption of sea squirt, and sea squirt shell protein can be a base material for biodegradable films. In this study, sea squirt shell protein and polylactic acid laminated films containing cinnamon bark essential oil were developed. The developed films are promising environmentally-friendly alternatives for active packaging material.