Antioxidant and antimicrobial chitosan films enriched with aqueous sage and rosemary extracts as food coating materials: Characterization of the films and detection of rosmarinic acid release

Catharanthus roseus extract-assisted silver nanoparticles chitosan films with high antioxidant and antimicrobial properties for fresh food preservation

Although the potential of chitosan (CS) -based biomass packaging materials for food preservation is encouraging, their use is severely constrained by the poor mechanical, UV, antioxidant, and solubility qualities. This study successfully combined silver nanoparticles made from Catharanthus roseus extracts with chitosan (CS-Ca-Ag) to enrich the functions of CS film. The films' Young's modulus values (45.489 MPa) were considerably raised after adding the extract-biosynthesized silver nanoparticles, in contrast to the chitosan film, and their water vapor permeability (2.386 × 10-12 g·mm-1·Pa-1·h-1) was greatly reduced. Furthermore, the antibacterial, antioxidant, and UV adsorption capabilities of CS-Ca-Ag films were significantly improved. The prepared Cs-Ca-Ag film had high biocompatibility and safety, making it suitable for strawberry coatings and chicken packaging. The CS-Ca-Ag film effectively limited the weight loss of fresh food, reduced nutrient loss, prevented microbial growth, and significantly extended food's shelf life. CS-based reinforced films containing Catharanthus roseus extract and silver nanoparticles showed potential food coating and packaging material applications.

Effects of keto acid crosslinking on the structure and properties of chitosan based casted and hot-pressed films

Crosslinking is one of the most effective ways to enhance the performance of bio-based films, and suitable crosslinking agents are crucial for the enhancement. In this study, four α-ketoacids, namely glyoxylate, pyruvate, oxaloacetate, and α-ketoglutarate were used to crosslink chitosan at room temperature. The effects of crosslinking on the structure and properties of chitosan films were studied, and the reaction mechanism was explored. Fourier Transform Infrared spectroscopy and X-ray Photoelectron Spectroscopy indicated that ion attraction and Schiff base reactions occurred between keto acids and chitosan. Glyoxylate developed the most effective covalent crosslinking with chitosan, whereas α-ketoglutarate had the highest ionic crosslinking ratio. Keto acid crosslinking reduced the orderliness of chitosan, improved the uniformity of the film matrix and increased its UV-blocking capacity. Glyoxylate-crosslinked chitosan film demonstrated excellent tensile strength (160 MPa), water stability (water solubility about 11.71 %), and extremely low oxygen permeability (2.65 × 10-16 cm3·cm/cm-2·s-1· Pa-1). Despite the weakened thermal stability and water barrier property, glyoxylate crosslinking shows great potential for the preparation of high-strength and high‑oxygen-resistance chitosan films. Furthermore, the glyoxylate-crosslinked chitosan film could be produced by hot pressing and performed satisfactorily.

Polymers Derived from Agro-Industrial Waste in the Development of Bioactive Films in Food

This review explores the potential of biopolymers as sustainable alternatives to conventional plastics in food packaging. Biopolymers derived from plant or animal sources are crucial in extending food shelf life, minimizing degradation, and protecting against oxidative and microbial agents. Their physical and chemical properties, influenced by the raw materials used, determine their suitability for specific applications. Biopolymers have been successfully used in fruits, vegetables, meats, and dairy products, offering antimicrobial and antioxidant benefits. Consequently, they represent a functional and eco-friendly solution for the packaging industry, contributing to sustainability while maintaining product quality.

Mentha pulegium L. and Salvia officinalis L. Bioactive Compounds: Focus on Their Application in Agriculture and Food Packaging

Plants are a valuable source of diverse natural active compounds with distinct biological characteristics and mechanisms. Considering plant extracts and phytochemicals have biological action both in vitro and in vivo, plants are being used as alternative sources in agriculture and food industry. Mentha pulegium L. and Salvia officinalis L. from the Lamiaceae family are some of the most popular and widely utilized medicinal plants due to their bioactive compounds such as essential oils (EOs) and phenolics, which have powerful antioxidant and antimicrobial characteristics. It is evident that these plants have also a variety of applications due to their various components and concentrations. This study aimed to provide an overview on the two species' composition and biological activities to review the applications of their crude extracts and EOs in agriculture as natural pesticides to protect different cultures and in food industry to produce biobased food packaging.

Fruit Vinegars as Natural and Bioactive Chitosan Solvents in the Production of Chitosan-Based Films

Natural fruit vinegars, derived from various fruits, enhance culinary experience and offer potential health benefits due to their bioactive compounds. In this study, fruit vinegars (apple, blackcurrant, and cherry) were used as natural solvents for producing chitosan films, introducing an environmentally friendly approach. Fruit vinegars and chitosan-based solutions were examined for their antioxidant and antimicrobial properties. In turn, the obtained chitosan films were characterized by their antimicrobial, mechanical, and structural properties. Both fruit vinegars and film-forming chitosan solutions showed antioxidant activity, and chitosan-cherry vinegar solutions exhibited the highest antiradical and ferrous ion-chelating effect. All solvents and chitosan-based solutions were characterized by antimicrobial properties, especially against Pseudomonas aeruginosa (inhibition zone > 28 mm). Antimicrobial activity was also preserved in the case of chitosan-based film, especially when produced with cherry vinegar, which showed activity against the broadest spectrum of bacteria. The largest zone of inhibition for all samples was observed for P. aeruginosa in the range of 19 mm from the inhibition zone to >28 mm, depending on the type of vinegar used as a solvent. The conducted tests showed that the type of vinegar used also affects the mechanical parameters of the films obtained, such as elongation at break, for which values were recorded from 3.97 to 4.93 MPa, or tensile strength, for which the values were recorded from 48.48 to 70.58 MPa. The results obtained demonstrate that natural fruit vinegars, serving as chitosan solvents, can be an alternative to traditionally used acidic solvents, yielding films with favorable properties.

Improving properties of chitosan/polyvinyl alcohol films using cashew nut testa extract: potential applications in food packaging

Cashew nut testa, a by-product of cashew nut processing, is abundant in phenolic compounds and exhibits strong antioxidant properties, making it a potential additive for enhancing the antioxidant properties of biodegradable films used in food packaging. This study explores the fabrication of biodegradable chitosan/polyvinyl alcohol films incorporating varying concentrations of cashew nut testa extract (CNTE; 0, 1, 2 and 3% v/v) and evaluates their physical, structural, mechanical, optical and antioxidant properties. The results demonstrate that increasing extract concentration generally increased the thickness, tensile strength, Young's modulus, thermal stability and antioxidant capacity of the films, while reducing the moisture content, swelling degree, elongation at break, and light transmittance. Specifically, the film with 3% extract showed approximately 11% lower moisture content and 31% lower swelling degree compared with the plain film. It also displayed the highest tensile strength and Young's modulus at 28.63 and 147.35 MPa, respectively. Microstructural analysis revealed that the incorporation of CNTE resulted in a smoother and slightly denser film structure. Antioxidant activity, determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay, was not detected in the plain film but increased with increasing extract concentration. The film with 3% CNTE exhibited the highest antioxidant activity of 58.93 µmol Trolox equivalents (TE) g-1 film. This study highlights the potential of CNTE as an effective edible additive for developing antioxidant and ultraviolet barrier films with improved mechanical strength and water resistance for food packaging applications.

Antioxidant packaging films based upon starch-montmorillonite with forsythia flower extract: characterization and application

Plastic pollution is one of the most acute environmental problems in the world, so active packaging materials made from biodegradable natural polymers have received widespread attention in recent years. In this paper, forsythia flower extract, serving as an active ingredient, was integrated into the starch-sodium alginate-montmorillonite composite film. The physicochemical properties and functional packaging applications of the composite films were investigated. The results demonstrate the formation of a tightly-knit network structure through molecular interactions among forsythia flowers, starch, sodium alginate, and montmorillonite. Notably, the addition of forsythia flower extracts conferred better UV resistance (from 200 nm to 400 nm) and outstanding antioxidant properties to the composite films. After 18 days of storage, in comparison with the control group, the decay rate of fresh cherry tomatoes packaged with the composite film containing forsythia flower extract showed a significant reduction of 40%, the hardness increased by 25%, and the content of vitamin C was enhanced by 33%. Hence, the forsythia flower extract composite film offers a novel perspective for the design and development of bio-based packaging films for preserving fresh fruits. The results serve as a foundation for the subsequent advancement and application of forsythia flower in the field of packaging.

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

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

Monitoring fish freshness with pH-sensitive hydrogel films containing quercetin or eucalyptol

This research developed pH-sensitive smart films using carboxymethyl cellulose (CMC) and collagen (COL), combined with either quercetin (QCT) or eucalyptol (EUC), to prevent fish meat spoilage. COL, extracted from isinglass, was confirmed as type I through SDS-PAGE. The films were characterized using FESEM, FTIR, and TGA. The addition of QCT or EUC enhanced antioxidant levels to 60.16% and 70.83%, respectively, up from a baseline of 10.4%. It also increased tensile strength from 3.32 ± 0.22 to 11.8 ± 0.25 and 13.2 ± 0.27 MPa, and enhanced elongation at break from 5 ± 3.1% to 27.7 ± 1.1% and 30.15 ± 2.1%. Fish meat packaged with QCT showed a lower spoilage rate due to the antibacterial and antioxidant effects of EUC and QCT (TVBN = 7.37 ± 0.01), compared to CMC/COL film (TVBN = 10.11 ± 0.02) and non-packaged fish (TVBN = 11.23 ± 0.01). The films exhibit >80% transparency, highlighting their suitability for food packaging. CMC/COL/QCT is preferred for fish packaging because it offers better mechanical properties and lower TVB-N levels.

Development and characterization of curcumin-loaded chitosan/egg yolk freshness-keeping edible films for chilled fresh pork packaging application

In this study, a novel fresh-keeping edible film was prepared using egg yolk (EY) and chitosan (CS) with varying concentrations of curcumin (Cur) for food packaging. The addition of Cur notably enhanced tensile strength, elongation at break, and water resistance from 15.70 MPa to 24.24 MPa, 43.79 % to 63.69 %, and 1.599 g·mm·(m2·h·kPa)-1 to 1.541 g·mm·(m2·h·kPa)-1, respectively. Cur also impacted moisture content, swelling degree, and film color. SEM revealed a uniform distribution of Cur, creating a smooth and dense film surface. FT-IR analysis suggested that hydrogen bonding facilitated Cur integration into the film network. The films demonstrated excellent UV-blocking and antioxidant properties attributed to Cur's chromogenic and phenolic hydroxyl groups. Consequently, they effectively inhibited lipid oxidation and weight loss in meat, thereby prolonging the shelf-life of chilled pork by at least 2 d. In conclusion, this study provided a simple and cost-effective idea to incorporate actives with EY as a natural emulsifier, presenting an effective solution for developing active packaging materials to enhance the safety and quality of meat products.

Chitosan Coating with Rosemary Extract Increases Shelf Life and Reduces Water Losses from Beef

This study aimed to evaluate the influence of films based on chitosan and rosemary extract on the physicochemical, microbiological, and oxidative characteristics of beef. Refrigerated steaks of Longissimus dorsi were distributed in a factorial arrangement (4 × 4) into four treatments consisting of four edible films (control; chitosan; chitosan + 4% rosemary extract; and chitosan + 8% rosemary extract) and four days of aging (0, 2, 4, and 8 days). Incorporating 4% or 8% rosemary extract into the chitosan film improved the characteristics of the films in terms of moisture absorption and elasticity. The edible coatings with chitosan and rosemary extract and the different days of aging increased the tenderness and decreased the lipid oxidation of beef. In addition, the chitosan films containing rosemary extract increased the water-holding capacity and decreased the cooking losses of beef. The films containing 4% and 8% rosemary extract decreased the development of mesophilic and psychrotrophic bacteria and Staphylococcus ssp. in beef. We recommend incorporating 4% rosemary extract into chitosan-based coatings to preserve the quality of refrigerated beef.

Preparation and characterization of biodegradable food packaging films using lemon peel pectin and chitosan incorporated with neem leaf extract and its application on apricot fruit

The present study aims to develop and characterize biodegradable packaging films from lemon peel-derived pectin and chitosan incorporated with a bioactive extract from neem leaves. The films (PCNE) contained varying concentrations of neem leaf extract and were comprehensively assessed for their physical, optical, mechanical, and antimicrobial attributes. The thickness, moisture content, water solubility, and water vapor permeability of the biodegradable packaging films increased with the increasing concentration of neem leaf extract. Comparatively, the tensile strength of the films decreased by 42.05 % compared to the control film. The Scanning Electron Microscopy (SEM) confirmed that the resultant blended pectin-chitosan films showed a uniform structure without cracks. Furthermore, the analysis targeting Staphylococcus aureus and Aspergillus niger indicated that the films had potent antimicrobial activity. Based on these results, the optimum films were selected and subsequently applied on apricot fruits to increase their shelf life at ambient temperature. The findings, after examining factors such as colour, firmness, total soluble solids, shrinkage, weight loss, and appearance, concluded that the apricots coated by PCNE-5 had the most delayed signs of spoilage and increased their shelf life by 50 %. The results showed the potential applicability of lemon peel pectin-chitosan-neem leaf extract blend films in biodegradable food packaging.

A novel anthocyanin indicator film with rosmarinic acid copigmentation having enhanced stability and pH indicator ability for monitoring pork freshness

BACKGROUND

Anthocyanin-based pH-sensing films have been widely fabricated for potential application in monitoring food freshness. However, the color fading of anthocyanins limits their application for the food industry due to their low stability. In addition, the color sensitivity and pH indicator ability of anthocyanin-based films currently available are not satisfied and need to be improved.

RESULTS

Chitosan/xanthan gum (CX)-based colorimetric films with addition of purple cabbage anthocyanin (PAN) and different amounts of rosmarinic acid (RA) were fabricated. RA copigmentation in chitosan/xanthan gum-purple cabbage anthocyanin-rosmarinic acid (CX-P-RA) films significantly improved the stability and pH response sensitivity of PAN, and the combined copigmentation of RA and xanthan gum exhibited an additive effect. The addition of RA significantly improved the tensile strength and elongation at break, thermal stability, antioxidant and antibacterial activities of CX-P-RA films. Moreover, addition of RA enhanced the pH sensitivity and colorimetry of CX-P-RA films, which exhibited a good response to different pH values. CX-P-RA2 film was tested to monitor the freshness of pork. It showed visible color changes during the storage of pork. In addition, the ∆E of CX-P-RA2 film was highly correlated with changes in total volatile basic nitrogen in pork (R2  = 0.951).

CONCLUSION

These results indicated that CX-P-RA2 film can be used as a pH-sensing indicator with good stability and high sensitivity for real-time monitoring of pork freshness. © 2023 Society of Chemical Industry.

Determination of Biogenic Amine Level Variations upon Storage, in Chicken Breast Coated with Edible Protective Film

A new chitosan-based protective film containing rosemarinic acid (0.282% w/w) has been elaborated. The film was formed from a water-oil emulsion system and applied to poultry meat samples using a dip-coating technique. Various physicochemical parameters of the coatings, such as thickness, Young's modulus, elongation at break, water vapor transmission rates, and antioxidant activity, were tested with free-standing film samples peeled from a Petri dish. Compared to neat chitosan films obtained similarly, new films cast from the emulsion showed significantly better elasticity (Young's modulus was diminished from 1458 MPa to about 29 MPa). Additionally, barrier properties for moisture transition decreased from 7.3 to 5.8 g mm m-2 day-1 kPa-1. The coated poultry samples were subsequently evaluated in juxtaposition with uncoated ones in a storage test. Levels of selected biogenic amines (histamine, tyramine, tryptamine, phenylethylamine, putrescine, cadaverine, spermine, and spermidine), total bacterial count, and lipid oxidation levels in the meat samples were analyzed during storage at 4 °C (up to 96 h). The results obtained for the biogenic amines, total bacterial content, calculated biogenic amine index, and the ratio of spermidine to spermine in meat samples suggest the advantage of the proposed coatings with rosmarinic acid in protecting poultry meat against environmental factors and rapid spoilage.

Effect of active antimicrobial films on quality parameters and shelf-life of fresh yufka dough

This research aimed to develop polypropylene (PP) antimicrobial films loaded with different concentrations of sorbic acid (SA) for packaging of fresh yufka dough. PP-SA at 6% showed improved mechanical, UV absorption, and moisture barrier properties. Also, the obtained films exhibited in vitro antibacterial and anti-mold properties. Moisture content and aw of packaged dough with different types of active films were not significantly changed upon storage period. Extended storage of dough layered with PP-SA films at concentrations 0-4% for 45 days led to significant decrease of pH from 5.75 in fresh dough to 5.05 in control (p < 0.05). Color attributes including yellowness and whiteness indices of dough were declined and increased, respectively as function of prolonged storage and increase in the concentration of SA. The growth of aerobic psychrotrophic bacteria and filamentous fungi were significantly retarded in yufka dough packaged with PP-SA6% film compared to that packaged with control as well as PP-SA2-4% films. Direct addition of SA into the bulk of dough was not effective in preservation of dough against the growth of bacteria and fungi. Application of antimicrobial preservatives in the composition of PP films could be beneficial in preserving fresh foods such as bakery products against spoilage microorganisms.

Modified polysaccharides for food packaging applications: A review

Development of new food packaging materials is crucial to reduce the use of single-use plastics and to limit their destructive impact on the environment. Polysaccharides provide an alternative solution to this problem. This paper summarizes and discusses recent research results on the potential of modifying polysaccharides as materials for film and coating applications. Modifications of polysaccharides significantly affect their properties, as well as their application usability. Although modifications of biopolymers for packaging applications have been widely studied, polysaccharides have attracted little attention despite being a prospective, environmentally friendly, and economically viable packaging alternative. Therefore, this paper discusses approaches to the development of biodegradable, polysaccharide-based food packaging materials and focuses on modifications of four polysaccharides, such as starch, chitosan, sodium alginate and cellulose. In addition, these modifications are presented not only in terms of the selected polysaccharide, but also in terms of specific properties, i.e. hydrophilic, barrier and mechanical properties, of polysaccharides. Such a presentation of results makes it much easier to select the modification method to improve the unsatisfactory properties of the material. Moreover, very often it happens that the applied modification improves one and worsens another property, which is also presented in this review.

Capillary electromigration methods for food analysis and Foodomics: Advances and applications in the period March 2021 to March 2023

This work presents a revision of the main applications of capillary electromigration (CE) methods in food analysis and Foodomics. Papers that were published during the period March 2021 to March 2023 are included. The work shows the multiple CE methods that have been developed and applied to analyze different types of molecules in foods and beverages. Namely, CE methods have been applied to analyze amino acids, biogenic amines, heterocyclic amines, peptides, proteins, phenols, polyphenols, pigments, lipids, carbohydrates, vitamins, DNAs, contaminants, toxins, pesticides, additives, residues, small organic and inorganic compounds, and other minor compounds. In addition, new CE procedures to perform chiral separation and for evaluating the effects of food processing as well as the last developments of microchip CE and new applications in Foodomics will be also discussed. The new procedures of CE to investigate food quality and safety, nutritional value, storage, and bioactivity are also included in the present review work.

Intelligent packaging based on chitosan/fucoidan incorporated with coleus grass (Plectranthus scutellarioides) leaves anthocyanins and its application in monitoring the spoilage of salmon (Salmo salar L.)

The innovation of this study was to develop a novel biodegradable intelligent packaging based on chitosan/fucoidan combined with different amounts (1, 3 and 5 wt% on chitosan basis) of coleus grass (Plectranthus scutellarioides) leaves anthocyanins (CGL) to monitor the spoilage of salmon (Salmo salar L.). The addition of fucoidan improved the barrier and mechanical properties of the chitosan films (CS) due to hydrogen bonds and intermolecular electrostatic interactions. Moreover, the addition of CGL not only improved the physical properties but also improved the biological activity of chitosan/fucoidan film (CF). The DPPH and ABTS radical scavenging activity of CF contained 5 wt% CGL was 1.83 and 1.75 times than CF, respectively. The inhibition zone size of CF films containing 5 wt% CGL (CF-5%CGL) was approximately 2.04 (Escherichia coli) and 2.16 (Staphylococcus aureus) times higher than that of CF. Moreover, CF-CGL displayed obvious color changes in different pH environments and is highly sensitive to ammonia gas. The CF-CGL has visible color changes during the monitoring of salmon spoilage and extended the shelf life of salmon. According to our findings, CF-CGL film might be employed as a possible intelligent packaging material for monitoring and preserving salmon in the future.

New Functional Bionanocomposites by Combining Hybrid Host-Guest Systems with a Fully Biobased Poly(lactic acid)/Poly(butylene succinate-co-adipate) (PLA/PBSA) Binary Blend

In this study, we have developed innovative polymer nanocomposites by integrating magnesium-aluminum layered double hydroxide (LDH)-based nanocarriers modified with functional molecules into a fully biobased poly(lactic acid)/poly(butylene succinate-co-adipate) (PLA/PBSA) matrix. These LDH-based hybrid host-guest systems contain bioactive compounds like rosmarinic acid, ferulic acid, and glycyrrhetinic acid, known for their antioxidant, antimicrobial, and anti-inflammatory properties. The bioactive molecules can be gradually released from the nanocarriers over time, allowing for sustained and controlled delivery in various applications, such as active packaging or cosmetics. The morphological analysis of the polymer composites, prepared using a discontinuous mechanical mixer, revealed the presence of macroaggregates and nano-lamellae at the polymer interface. This resulted in an enhanced water vapor permeability compared to the original blend. Furthermore, the migration kinetics of active molecules from the thin films confirmed a controlled release mechanism based on their immobilization within the lamellar system. Scaling-up experiments evaluated the materials' morphology and mechanical and thermal properties. Remarkably, stretching deformation and a higher shear rate during the mixing process enhanced the dispersion and distribution of the nanocarriers, as confirmed by the favorable mechanical properties of the materials.

Chitosan-Based Antibacterial Films for Biomedical and Food Applications

Antibacterial chitosan films, versatile and eco-friendly materials, have garnered significant attention in both the food industry and medicine due to their unique properties, including biodegradability, biocompatibility, and antimicrobial activity. This review delves into the various types of chitosan films and their distinct applications. The categories of films discussed span from pure chitosan films to those enhanced with additives such as metal nanoparticles, metal oxide nanoparticles, graphene, fullerene and its derivatives, and plant extracts. Each type of film is examined in terms of its synthesis methods and unique properties, establishing a clear understanding of its potential utility. In the food industry, these films have shown promise in extending shelf life and maintaining food quality. In the medical field, they have been utilized for wound dressings, drug delivery systems, and as antibacterial coatings for medical devices. The review further suggests that the incorporation of different additives can significantly enhance the antibacterial properties of chitosan films. While the potential of antibacterial chitosan films is vast, the review underscores the need for future research focused on optimizing synthesis methods, understanding structure-property relationships, and rigorous evaluation of safety, biocompatibility, and long-term stability in real-world applications.

Composite films based on carboxy methyl cellulose and sodium alginate incorporated Thymus vulgaris purified leaves extract for food application: Assessment, antimicrobial and antioxidant properties

The current study was conducted to develop biodegradable films with matrix composed from carboxymethyl cellulose (CMC), sodium alginate (SA) and different concentrations from Thymus vulgaris purified leaves extract (TVE). The color properties, physical properties, shape of surface, manners of crystallinity, mechanical properties and thermal properties of produced films were investigated. The continuous addition of TVE up to 1.6 % inside films matrix imparted the yellow color of extract that increased opacity to 2.98 and reduced moisture, swelling, solubility and water vapor permeability (WVP) of films up to 10.31 %, 30.17 %, 20.18 % and (1.12× 10^-10 g.m^-1 s^-1 pa^-1), respectively. Furthermore, the surface micrographs showed smoother surface after using small concentrations of TVE and turned to irregular with rough surface at higher concentrations. The FT-IR analysis indicated typically bands that demonstrated physical interaction between TVE extract and CMC/SA matrix. The fabricated films showed suitable thermal stability with decreasing trend by incorporation of TVE inside CMC/SA films. Furthermore, the developed CMC/SA/TVE2 showed significant effects on preserving the levels of moisture content, titrable acidity, force to puncture and sensory properties of cheddar cheese during cold storage days compared with commercial packaging materials.

Chitosan-based packaging films with an integrated antimicrobial peptide: Characterization, in vitro release and application to fresh pork preservation

Chitosan (CS) films were developed incorporating peptide HX-12C. The films were studied to determine their microstructures, physical properties, release properties of peptide HX-12C and functional properties. The results indicated that there may be hydrogen bonding interactions between CS and peptide HX-12C, thereby creating a homogeneous internal microstructure and lower crystallinity (10.8-12.8 %). Compared with CS film, CS-HX-12C films displayed lower light transmission, MC (20.8-19.9 %), WVP (8.82-8.59 × 10^-11·g·m^-1·s^-1·Pa^-1), OTR (0.015-0.037 cc/(m².day)) and higher WS (15.7-32.4 %) values. Moreover, controlled-release experiments showed that pH, ionic strength and temperature could all significantly affect the release of peptide HX-12C from the films. Finally, the increase of pH value and TVC and lipid oxidation of fresh pork were delayed due to the treatment with CS-2%HX-12C film. However, incorporating peptide HX-12C into CS films did not improve the mechanical properties of the films and their effects against protein oxidation. Our results suggest that the CS-based antimicrobial packaging films integrated with peptide HX-12C exhibit the potential for fresh pork preservation.

Chitosan with Natural Additives as a Potential Food Packaging

Recently, the development of materials based on natural polymers have been observed. This is the result of increasing environmental degradation, as well as increased awareness and consumer expectations. Many industries, especially the packaging industry, face challenges resulting from legal regulations. Chitin is the most common biopolymer right after cellulose and is used to produce chitosan. Due to the properties of chitosan, such as non-toxicity, biocompatibility, as well as antimicrobial properties, chitosan-based materials are used in many industries. Many studies have been conducted to determine the suitability of chitosan materials as food packaging, and their advantages and limitations have been identified. Thanks to the possibility of modifying the chitosan matrix by using natural additives, it is possible to strengthen the antioxidant and antimicrobial activity of chitosan films, which means that, in the near future, chitosan-based materials will be a more environmentally friendly alternative to the plastic packaging used so far. The article presents literature data on the most commonly used natural additives, such as essential oils, plant extracts, or polysaccharides, and their effects on antimicrobial, antioxidant, mechanical, barrier, and optical properties. The application of chitosan as a natural biopolymer in food packaging extends the shelf-life of various food products while simultaneously reducing the use of synthetic plastics, which in turn will have a positive impact on the natural environment. However, further research on chitosan and its combinations with various materials is still needed to extent the application of chitosan in food packaging and bring its application to industrial levels.

Preparation, characterization, and antibacterial effect of bio-based modified starch films

There are several problems with common starch films, including strong water absorption and poor mechanical properties. To create a better starch film, octenyl succinate cassava starch ester (OSCS) was first blended with chitosan and nano ZnO to prepare an OSCS/CS/ZnO film. Then, the film was supplemented with different concentrations of ε-PL as a bacteriostatic agent to prepare a film that would resist bacterial invasion. The mechanical properties, barrier properties, optical properties, and color of the modified starch antibacterial films were investigated, and finally the antibacterial properties and cytotoxicity were tested. The results demonstrated that the modified starch antibacterial film had good mechanical properties, improved surface hydrophobicity, and had a UV-blocking effect. The modified starch antibacterial film with ε-PL of 8% had stable and long-lasting antibacterial properties, stable release, and good cytocompatibility. An active packaging material was successfully prepared using ε-PL and had a strong preservative effect on food.

Structural Insights into LDPE/UHMWPE Blends Processed by γ-Irradiation

Ultra-high-molecular-weight polyethylene (UHMWPE) matrices containing low-density polyethylene (LDPE), hydroxyapatite (HAp) as filler, and rosemary extract (RM) as stabilizer were investigated for their qualification for long-term applications. The significant contributions of the blend components were analyzed, and variations in mechanical properties, oxidation strength, thermal behavior, crystallinity, and wettability were discussed. SEM images of microstructural peculiarities completed the introspective survey. The stability improvement due to the presence of both additives was an increase in the total degradation period of 67% in comparison with an unmodified HDPE/UHMWPE blend when the materials were subjected to a 50 kGy γ-dose. There was growth in activation energies from 121 kJ mol^-1 to 139 kJ mol^-1 when HAp and rosemary extract delayed oxidation. The exposure of samples to the action of γ-rays was found to be a proper procedure for accomplishing accelerated oxidative degradation. The presence of rosemary extract and HAp powder significantly increased the thermal and oxidation resistances. The calculation of material lifetimes at various temperatures provided meaningful information on the wearability and integrity of the inspected composites.

Chitosan Edible Films and Coatings with Added Bioactive Compounds: Antibacterial and Antioxidant Properties and Their Application to Food Products: A Review

Chitosan is the deacetylated form of chitin regarded as one of the most abundant polymers and due to its properties, both chitosan alone or in combination with bioactive substances for the production of biodegradable films and coatings is gaining attention in terms of applications in the food industry. To enhance the antimicrobial and antioxidant properties of chitosan, a vast variety of plant extracts have been incorporated to meet consumer demands for more environmentally friendly and synthetic preservative-free foods. This review provides knowledge about the antioxidant and antibacterial properties of chitosan films and coatings enriched with natural extracts as well as their applications in various food products and the effects they had on them. In a nutshell, it has been demonstrated that chitosan can act as a coating or packaging material with excellent antimicrobial and antioxidant properties in addition to its biodegradability, biocompatibility, and non-toxicity. However, further research should be carried out to widen the applications of bioactive chitosan coatings to more foods and industries as well was their industrial scale-up, thus helping to minimize the use of plastic materials.