Characterization of antimicrobial multilayer film based on ethylcellulose-pectin incorporated with nanoemulsions of trans-cinnamaldehyde essential oil

In this study, polymer solution casting was utilized to fabricate a multilayer film with ethylcellulose (EC) as the outer layers and trans-cinnamaldehyde-loaded pectin as the inner layer. A significant increase in whiteness and UV-visible light blocking capability and a remarkable decrease in total color difference and yellowness of the films were seen via increasing the thickness of EC outer layers. Scanning electronic microscopy observation showed that the inner and outer layers had a smooth and uniform surfaces with clear boundary. The thicker film has better stretchability and strength, but is less flexible than thinner film. Glass transition temperature did not change remarkably with increasing thickness of EC outer layers, but thermal stability was slightly improved. FTIR-ATR spectra revealed the formation of hydrogen bonds between the two adjacent layers. The multilayer films exhibited excellent antimicrobial efficacy against Gram-positive and Gram-negative foodborne pathogens. The results suggested that this multilayer film has potential applications in active food packaging.

Development of novel carboxymethyl cellulose/gelatin-based edible films with pomegranate peel extract as antibacterial/antioxidant agents for beef preservation

Novel antioxidant and antibacterial composite films were fabricated by incorporating pomegranate peel extract (PPE) into gelatin and carboxymethyl cellulose matrices. Increasing PPE concentration significantly (p < 0.05) altered physical properties and improved UV (decrease in light transmission 87.30 % to 9.89 % at 400 nm) and water resistance, while FTIR and molecular docking results revealed hydrogen bonding between PPE and film matrix. PPE incorporation enhanced antioxidant activity up to 84.15 ± 0.12 % and also restricted gram-positive and gram-negative bacterial growth by 72.4 % and 65.9 % respectively after 24 h, measured by antimicrobial absorption assays. For beef packaging applications at refrigeration temperatures, PPE films were most effective at extending shelf-life up to 3 days, as evidenced by reduced total viable counts, total volatile basic nitrogen, weight loss, and pH changes compared to control films. Therefore, these antioxidant and antibacterial films have potential applications in food packaging to protect against mechanical stress, light exposure, microbial spoilage, and oxidative free radicals.

Electrospun Fibers Loaded with Probiotics: Fundamentals, Characterization, and Applications

Increasing demand for safe, efficient, and eco-friendly solutions for pharmaceutical and food industries has led researchers to explore new approaches to bacterial storage. Several advantages make electrospinning (ES) a promising technique for food systems, including simple manufacturing equipment, a relatively low spinning cost, a wide variety of spinnable materials, and a mild process that is easily controlled, which allows continuous fabrication of ultrafine polymeric fibers at submicron or nanoscales without high temperatures or high pressures. This review briefly describes recent advances in the development of electrospun fibers for loading probiotics (PRB) by focusing on ES technology, its efficiency for loading PRB into fibers (viability, digestive stability, growth rate, release, thermal stability, and interactions of fibers with PRB), and the application of PRB-loaded fibers as active packaging (spoilage/microbial control, antioxidant effect, shelf life). Based on the literature reviewed, the incorporation of PRB into electrospun fibers is both feasible and functional. However, several studies have been limited to proof-of-principle experiments and the use of model biological products. It is necessary to conduct further research to establish the industrial applicability of PRB-loaded fibers, particularly in the fields of food and medicine.

Hibiscus Sabdariffa L. Extract as a Natural Additive in Food Packaging Biodegradable Films to Improve Antioxidant, Antimicrobial, and Physicochemical Properties

In this study, biodegradable active films were prepared from potato starch and polyvinyl alcohol at different proportions, mixed with acetone extract of Hibiscus sabdariffa L. (HS) and using glycerol as a plasticizer. Functional properties, antimicrobial, and antioxidant capacity were evaluated. Potato starch films with a proportion of polyvinyl alcohol up to 50% and HS extract had significant antioxidant capacity and antibacterial effect against most of the analyzed strains. Adding polyvinyl alcohol (PVOH) and HS extract improved the mechanical performance and reduced water vapor permeability of the materials. The active biobased films with HS extract presented good physicochemical, antimicrobial, and antioxidant properties. These materials are considered as suitable for food packaging, and the active compounds in the roselle extract are a natural antibacterial option for the food area. The materials based entirely on biodegradable products are an excellent alternative when developing and marketing biobased materials, minimizing the environmental impact of food packaging.

Carvacrol and thymol effect in vapor phase on Escherichia coli and Salmonella serovar Typhimurium growth inoculated in a fresh salad

This study aimed to evaluate the antimicrobial effect of thymol and carvacrol in inhibiting Escherichia coli and Salmonella serovar Typhimurium inoculated on a fresh green salad through the vapor phase. A film-forming solution was prepared by dissolving starch, sorbitol, and variying concentrations of carvacrol, thymol, and a mixture of both. The film-forming solution containing the respective antimicrobial agent was then added lid, which was sealed rigidly and hermetically to achieve different concentrations (105 mg/L of air of carvacrol, 105 mg/L of air of thymol, and a mixture of 52 mg/L of air of carvacrol and 52 mg/L of air of thymol). Each active package contained fresh green salad inoculated with E. coli or Salmonella serovar Typhimurium. The active packages were then sealed and refrigerated at a temperature of 6 °C for 48 h. Growth/inhibition curves were modelled using the Weibull equation, and consumer acceptance was evaluated. Carvacrol can reduce up to 0.5 log-cycles, while thymol can reach almost 1 log cycle. Blending the components with half the concentration has a synergistic effect, inhibiting up to 2.5 log cycles. Consumer ratings revealed no significant differences between the packages. However, the average score was 5.4 on a 9-point hedonic scale, evaluators' comments did not indicate dislike or a strong taste characteristic of thymol and carvacrol.

Exploring chitosan-plant extract bilayer coatings: Advancements in active food packaging via polypropylene modification

UV-ozone activated polypropylene (PP) food films were subjected to a novel bilayer coating process involving primary or quaternary chitosan (CH/QCH) as the first layer and natural extracts from juniper needles (Juniperus oxycedrus; JUN) or blackberry leaves (Rubus fruticosus; BBL) as the second layer. This innovative approach aims to redefine active packaging (AP) development. Through a detailed analysis by surface characterization and bioactivity assessments (i.e., antioxidant and antimicrobial functionalities), we evaluated different coating combinations. Furthermore, we investigated the stability and barrier characteristics inherent in these coatings. The confirmed deposition, coupled with a comprehensive characterization of their composition and morphology, underscored the efficacy of the coatings. Our investigation included wettability assessment via contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), which revealed substantial enhancements in surface concentrations of elements and functional groups of CH, QCH, JUN, and BBL. Scanning electron microscopy (SEM) unveiled the coatings' heterogeneity, while time-of-flight secondary ion mass spectrometry (ToF-SIMS) and CA profiling showed moderately compact bilayers on PP, providing active species on the hydrophilic surface, respectively. The coatings significantly reduced the oxygen permeability. Additionally, single-layer depositions of CH and QCH remained below the overall migration limit (OML). Remarkably, the coatings exhibited robust antioxidative properties due to plant extracts and exceptional antimicrobial activity against S. aureus, attributed to QCH. These findings underscore the pivotal role of film surface properties in governing bioactive characteristics and offer a promising pathway for enhancing food packaging functionality.

Recent progress on Pickering emulsion stabilized essential oil added biopolymer-based film for food packaging applications: A review

Nowadays food safety and protection are a growing concern for food producers and food industry. The stability of food-grade materials is key in food processing and shelf life. Pickering emulsions (PEs) have gained significant attention in food regimes owing to their stability enhancement of food specimens. PE can be developed by high and low-energy methods. The use of PE in the food sector is completely safe as it uses solid biodegradable particles to stabilize the oil in water and it also acts as an excellent carrier of essential oils (EOs). EOs are useful functional ingredients, the inclusion of EOs in the packaging film or coating formulation significantly helps in the improvement of the shelf life of the packed food item. The highly volatile nature, limited solubility and ease of oxidation in light of EOs restricts their direct use in packaging. In this context, the use of PEs of EOs is suitable to overcome most of the challenges, Therefore, recently there have been many papers published on PEs of EOs including active packaging film and coatings and the obtained results are promising. The current review amalgamates these studies to inform about the chemistry of PEs followed by types of stabilizers, factors affecting the stability and different high and low-energy manufacturing methods. Finally, the review summarizes the recent advancement in PEs-added packaging film and their application in the enhancement of shelf life of food.

Cellulose nanofiber-based multifunctional composite films integrated with zinc doped-grapefruit peel-based carbon quantum dots

This study aimed to develop a multifunctional active composite film to extend the shelf life of minced pork. The composite film was prepared by incorporating zinc-doped grapefruit peel-derived carbon quantum dots (Zn-GFP-CD) into a cellulose nanofiber (CNF) matrix. The resulting film significantly improved UV-blocking properties from 39.0 % to 85.7 % while maintaining the film transparency. Additionally, the CNF/Zn-GFP-CD5% composite film exhibits strong antioxidant activity with ABTS and DPPH radical scavenging activities of 99.8 % and 77.4 %, respectively. The composite film also showed excellent antibacterial activity against both Gram-negative and Gram-positive bacteria. When used in minced pork packaging, the composite films effectively inhibit bacterial growth, maintaining bacterial levels below 7 Log CFU/g after 15 days and sustaining a red color over a 21-day storage period. Additionally, a significant reduction in the lipid oxidation of the minced pork was observed. These CNF/Zn-GFP-CD composite films have a great potential for active food packaging applications to extend shelf life and maintain the visual quality of packaged meat.

Development of chitosan/polycaprolactone-thymol Janus films with directional transport and antibacterial properties for meat preservation

Reducing contamination from percolate is critical to the preservation of foods with high water content, such as pork. This study aims to develop a novel active packaging material for meat preservation by precisely controlled dual-channel one-step electrospinning. Compared to traditional strategies of preparing Janus films, this method allows for greater flexibility and efficiency. The structure and properties of the Janus film are characterized by scanning electron microscopy (SEM), water contact angle (WCA), directional liquid transport investigation, Thymol release and permeation features, and biocompatibility evaluation. Moreover, the Janus film is applied to the packaging of pork with modified atmosphere packaging to demonstrate its practical application prospects in the food active packaging field. The results revealed that the two sides of the film showed completely different wettability, and the change rate of WCA increased with the increase of the scale of hydrophilic fibers. The permeation features of thymol loaded in the film was consistent with the results of antibacterial properties and biocompatibility assessment. Moreover, the Janus film can effectively prolong the shelf life, improve the quality and safety of the pork.

Lactobacillus bulgaricus-loaded and chia mucilage-rich gum arabic/pullulan nanofiber film: An effective antibacterial film for the preservation of fresh beef

In recent years, the development of probiotic film by incorporating probiotics into edible polymers has attracted significant research attention in the field of active packaging. However, the influence of the external environment substantially reduces the vitality of probiotics, limiting their application. Therefore, to improve the probiotic activity, this study devised a novel nanofiber film incorporating chia mucilage protection solution (CPS), gum arabic (GA), pullulan (PUL), and Lactobacillus bulgaricus (LB). SEM images indicated the successful preparation of the nanofiber film incorporating LB. CPS incorporation significantly improved the survival ability of LB, with a live cell count reaching 7.62 log CFU/g after 28 days of storage at 4 °C - an increase of 1 log CFU/g compared to the fiber film without CPS. The results showed that the fiber film containing LB inhibited Escherichia coli and Staphylococcus aureus. Finally, the novel probiotic nanofiber film was applied to beef. The results showed that the shelf life of the beef during the experiments was extended for 2 days at 4 °C. Therefore, the novel probiotic film containing LB was suitable for meat preservation.

Sustainable strategies for using natural extracts in smart food packaging

The growing demand for sustainable and eco-friendly food packaging has prompted research on innovative solutions to environmental and consumer health issues. To enhance the properties of smart packaging, the incorporation of bioactive compounds derived from various natural sources has attracted considerable interest because of their functional properties, including antioxidant and antimicrobial effects. However, extracting these compounds from natural sources poses challenges because of their complex chemical structures and low concentrations. Traditional extraction methods are often environmentally harmful, expensive and time-consuming. Thus, green extraction techniques have emerged as promising alternatives, offering sustainable and eco-friendly approaches that minimise the use of hazardous solvents and reduce environmental impact. This review explores cutting-edge research on the green extraction of bioactive compounds and their incorporation into smart packaging systems in the last 10 years. Then, an overview of bioactive compounds, green extraction techniques, integrated techniques, green extraction solvents and their application in smart packaging was provided, and the impact of bioactive compounds incorporated in smart packaging on the shelf lives of food products was explored. Furthermore, it highlights the challenges and opportunities within this field and presents recommendations for future research, aiming to contribute to the advancement of sustainable and efficient smart packaging solutions.

Biomass-derived nanoparticles reinforced chitosan films: as high barrier active packaging for extending the shelf life of highly perishable food

This study emphasizes the potential of biomass-derived nanoparticles such as nanocellulose (NC), nanohemicellulose (NHC), and nanolignin (NL) as reinforcements in chitosan (C) films to produce a higher barrier active packaging film. The incorporation of NC, NHC, and NL (1.5%) significantly improves the mechanical, water, and UV barrier properties of the chitosan film (P < 0.0001). Additionally, NHC and NL reinforcement significantly enhance antioxidant and antimicrobial activity. The physicochemical, sensory, and microbiological properties of fresh meat packed in chitosan films with 1.5% nanoparticles, as well as a commercial LDPE film, were assessed when stored at 4 °C for up to 18 days. C-NHC and C-NL packaging films preserved the quality of meat until the 18th day, whereas the meat packed in the LDPE film spoiled entirely on the sixth day. In conclusion, chitosan films with biomass-derived nanoparticles could be an excellent packaging material for highly perishable food, such as fresh meat, with an extended shelf life.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05896-9.

Sustained release, antimicrobial, and antioxidant properties of modified porous starch-based biodegradable polylactic acid/polybutylene adipate-co-terephthalate/thermoplastic starch active packaging film

Porous starch (PS) is a modified starch with commendable biodegradable and adsorption properties. PS exhibits poor thermal stability, and the aqueous solution casting method is conventionally used for PS-activated packaging films. This approach limits the large-scale production of films and makes it difficult to play the functions of porous pores. In this study, PS was prepared by enzymatic digestion combined with freeze-drying and adsorbed with clove essential oil (CEO) after cross-linking with sodium trimetaphosphate. Subsequently, a novel PLA/PBAT/TPS/ScPS-CEO sustained release active packaging film was prepared by blending PLA, PBAT, TPS, and ScPS-CEO using industrial melt extrusion. Compared with PS, ScPS effectively slowed down the release of CEO from the film, with the maximum release of active substances at equilibrium increasing by approximately 100 %, which significantly enhanced the persistence of the antimicrobial and antioxidant properties. The polylactic acid/poly (butylene adipate-co-terephthalate)/thermoplastic starch/trimetaphosphate-crosslinked porous starch incorporated with clove essential oil (PLA/PBAT/TPS/ScPS-CEO) film could reduce the proteolysis, lipid oxidation and microbial growth of salmon, extending its shelf life by approximately 100 % at 4 °C. These results indicate that the ScPS can be used in fresh packaging material in practical applications.

Development of innovative active packaging films using gelatin/pullulan-based composites incorporated with cinnamon essential oil-loaded metal-organic frameworks for meat preservation

This study aimed to investigate the effect of cinnamon essential oil (CEO)-loaded metal-organic frameworks (CEO@MOF) on the properties of gelatin/pullulan (Gel/Pull)-based composite films (Gel/Pull-based films). The incorporation of CEO@MOF into Gel/Pull-based films demonstrated significant antimicrobial activity against S. aureus, S. enterica, E. coli, and L. monocytogenes. Additionally, CEO@MOF integrated film exhibited a 98.16 % ABTS radical scavenging, with no significant change in the mechanical properties of the neat Gel/Pull film. The UV blocking efficiency of the composite films increased significantly from 81.38 to 99.56 % at 280 nm with the addition of 3 wt% CEO@MOF. Additionally, Gel/Pull/CEO@MOF films effectively extended the shelf life of meat preserved at 4 °C by reducing moisture loss by 3.35 %, maintaining the pH within the threshold limit (6.2), and inhibiting bacterial growth by 99.9 %. These results propose that CEO@MOF has significant potential as an effective additive in active packaging to improve shelf life and food safety.

Characterization of multilayer bacterial cellulose-chitosan films loaded with grape bagasse antioxidant extract: Insights into spectral and water properties, microstructure, and antioxidant activity

This work explores the development and characterization of composite multilayer films comprising bacterial cellulose (BC) and chitosan enriched with antioxidant compounds from grape bagasse extract (GE) and glycerol. SEM images revealed a compact structure with successful interactions between BC and chitosan, confirmed by FT-IR analysis. Equilibrium moisture content, water vapor permeability (WVP), swollen capacity, and solubility were systematically investigated, unveiling the influence of glycerol and GE concentrations. Moisture content increased with elevated glycerol and GE levels, attributed to their hydrophilic nature. WVP rose with higher concentrations of hydrophilic compounds, affecting the films' permeability. Swollen capacity decreased, and solubility increased with the addition of GE and glycerol, indicating a more compact film structure. The incorporation of GE conferred antioxidant properties to the films, as evidenced by DPPH and ABTS+ assays, and Total Phenolic Content (TPC) determination. TPC values varied from 0 to 1.75 mg GAE/g dried film, depending on GE. Fourier Transform Infrared Spectroscopy (FT-IR) highlighted polymeric associations, and UV-Vis spectra demonstrated enhanced UV-blocking properties. Overall, these multilayer films offer promising applications in food packaging, leveraging natural antioxidant sources for an enhanced functionality.

Storage stability of Asian seabass oil-in-water Pickering emulsion packed in pouches made from electrospun and solvent casted bilayer films from poly lactic acid/chitosan-gelatin blend containing epigallocatechin gallate

Bilayer pouches were fabricated with chitosan (CS)-fish gelatin (FG) mixture containing epigallocatechin gallate (EGCG) deposited over the poly lactic acid (PLA) film through solvent casting and electrospinning techniques. Pickering emulsions (PE) of Asian seabass depot fat oil stabilized by zein colloidal particles were packed in bilayer pouches and stored at 28 ± 2 °C. The PE packed in pouch containing EGCG had higher emulsion and oxidative stability after 30 days of storage as witnessed by the smaller droplet size and lower values of thiobarbituric acid reactive substances, peroxide, conjugated diene and volatile compounds in comparison with control (PE packed in monolayer PLA pouch) (P < 0.05). EGCG incorporated pouch retained more linoleic acid (C18:2 n-6) and linolenic acid (C18:3 n-9) in emulsion than PLA pouch. Therefore, pouch from bilayer PLA/CS-FG films comprising EGCG could serve as active packaging and extended the shelf life of Pickering emulsion.

Enhanced carbohydrate-based plastic performance by incorporating cerium-based metal-organic framework for food packaging application

The development of biodegradable active packaging films with hydrophobic characteristics is vital for extending the shelf life of food and reducing the reliance on petroleum-based plastics. In this study, novel hydrophobic cerium-based metal-organic framework (Ce-MOF) nanoparticles were successfully synthesized. The Ce-MOF nanoparticles were then incorporated into the cassava starch matrix at varying concentrations (0.5 %, 1.5 %, 3 %, and 4 % w/w of total solid) to fabricate cassava-based active packaging films via the solution casting technique. The influence of Ce-MOF on the morphology, thermal attributes, and physicochemical properties of the cassava film was subsequently determined through further analyses. Biomedical analysis including antioxidant activity and the cellular morphology evaluation in the presence of the films was also conducted. The results demonstrated that the consistent dispersion of Ce-MOF nanofillers within the cassava matrix led to a significant enhancement in the film's crystallinity, thermal stability, antioxidant activity, biocompatibility, and hydrophobicity. The introduction of Ce-MOF also contributed to the film's reduced water solubility. Considering these outcomes, the developed cassava/Ce-MOF films undoubtedly have significant potential for active food packaging applications.

Multipurpose arrowroot starch films with anthocyanin-rich grape pomace extract: Color migration for food simulants and monitoring the freshness of fish meat

Extraction of anthocyanins from grape pomace, is a way of valuing these abundant by-products with low added value. Its integration into films may allow it to be used in bioactive packaging, which creates new color and solubility properties for food and smart food packaging which tracks the freshness of fish. Films of arrowroot starch added with different concentrations of grape pomace extract (GPE) were flexible to handle, reddish and presented a high content of anthocyanins. The water vapor permeability increased by 17 %, while the tensile strength of arrowroot starch film decreased by 79 % with the addition of 40 % GPE. The addition of GPE increased the solubility of the starch film in aqueous and lipid food simulants by 121 and 119 %. The GPE pigment preferentially migrated to the aqueous simulant due to the hydrophilic nature of anthocyanins and starch. The GPE film showed distinguishable color changes in different pH buffer solutions from pink at pH 2 to light blue at pH 7 and slightly yellowish green at pH 10. When the composite films were monitored for fish meat freshness, the change in color of the film from reddish pink to slightly green after 96 h of storage at 25 °C was evident.

Polysaccharide film containing cinnamaldehyde-chitosan nanoparticles, a new eco-packaging material effective in meat preservation

The development of novel eco-friendly materials like chitosan for food storage and preservation has become crucial in eliminating plastic packaging and minimizing waste. In this work, cinnamaldehyde has been encapsulated in chitosan nanoparticles and subsequently incorporated into a 2 % chitosan film. The obtained nanoparticles achieved an average radius size of 89.80 nm, PDI of 0.40, and spherical morphology determined by SEM. Cinnamaldehyde was encapsulated in chitosan nanoparticles achieving values of encapsulation close to 7 %, showing a biphasic release profile with sustained release during 5 days. Films with an average thickness of 0.124 mm and elongation at break of 63.66 % to 76.50 % were obtained. Finally, the antimicrobial properties of the films was tested showing reduction values in total aerobic value of 4.85 log cfu/g, total coliform of 1.26 log cfu/g and grow potential value of < 0.5 log10 for Listeria monocitogenes over 20 days.

Multifunctional alginate films blended with polyphenol-rich extract from unconventional edible sources: Bioactive properties, UV-light protection, and food freshness monitoring

The development of active and smart packaging from non-conventional food sources is an ecological trend to ensure safe food supply in the food chain. The study aimed to develop multifunctional films based on alginate blended with different concentrations of purple onion peel (POPE) and butterfly-pea flower extract (BFE). The addition of the extracts increased the opacity of the films by 80 %, indicating greater UV-light barrier ability. The tensile strength and elongation at break of the films increased by 70 % and 30 %, while water vapor permeability decreased by 15 %. The interaction between the extract and the alginate positively modified the structure of the films, increasing the melting temperature of the films (112-131 °C). Mixing both extracts in the matrix generated materials with antioxidant activity, antimicrobial capabilities, and sensitivity to freshness factors (gases, pH, and temperature) superior to films added with a single extract, suggesting better active and intelligent performances. The films protected the color of food products against the effects of UV-light, being strongly capable of colorimetrically checking the deterioration of protein-rich products. Therefore, alginate films blended with POPE and BFE have a promising potential for developing smart materials, preserving, and monitoring the food quality.

Exploring the potential of jujube seed powder in polysaccharide based functional film: Characterization, properties and application in fruit preservation

In this study, we fabricated a novel biodegradable functional film using natural polysaccharides by adding jujube seed powder as an active ingredient. Scanning electron microscopy analysis showed agglomerate formation in the film with increasing concentration of seed powder. Fourier transform-infrared spectroscopy study demonstrated an electrostatic interaction between pectin and chitosan. The water solubility and swelling degree significantly decreased from 55.5 to 47.7 % and 66.0 to 41.9 %, respectively, depicting the film's water resistance properties. Higher opacity and lower transmittance value of the film indicated its protective effect towards light-induced oxidation of food. It was observed that the fabricated active film biodegraded to 82.33 % in 6 days. The DPPH radical scavenging activity of 98.02 % was observed for the functional film. The film showed antifungal activity against B. cinerea and P. chrysogenum. The highest zone of inhibition was obtained against food spoiling bacteria B. subtilis followed by S. aureus, P. aeruginosa and E. coli. Genotoxicity studies with the fabricated film showed a mitotic index of 8 % compared to 3 % in the control film. We used the fabricated film to preserve grapefruits, and the result showed that it could preserve grapes for ten days with an increase in antioxidant activity and polyphenolic content.

Limonene and its derived oligomer as bioactive additives in starch/coffee husks biocomposites for food packaging applications

In this study, antioxidant, and antimicrobial starch-based biocomposite films reinforced with coffee husks (S/CH) were developed by incorporating either limonene (LM) (S/CH/LM) or its oligomer derivative, poly(limonene) (PLM) (S/CH/PLM), at different concentrations (5-10 % w/w of starch). Through a comprehensive assessment of film properties, morphology, and structure, a comparative analysis between the two additives was proposed. Scanning electron microscopy (SEM) revealed some defects throughout the polymer matrix after additive incorporation. The tensile strength (TS) and modulus of elasticity (ME) showed a decrease upon the inclusion of both LM and PLM, while the elongation at break (E) increased. Notably, PLM exhibited outstanding antioxidant capacity, enhancing the films by 108 % over control samples. Additionally, at just 5 % concentration, PLM effectively inhibited the growth of Escherichia coli ATCC 11775 (35.33 ± 2.52 mm) and demonstrated an impressive UV-Vis barrier, comparable to the highest amount of LM incorporated. Therefore, this research highlights the potential of coffee husk-reinforced starch biocomposites with limonene-derived additives as a promising solution for food packaging applications. The comparative analysis sheds light on the advantages of using the PLM in terms of antioxidant and antimicrobial properties, contributing to the advancement of active packaging technologies.

Revolution of nanotechnology in food packaging: Harnessing electrospun zein nanofibers for improved preservation - A review

Zein, a protein-based biopolymer derived from corn, has garnered attention as a promising and eco-friendly choice for packaging food due to its favorable physical attributes. The introduction of electrospinning technology has significantly advanced the production of zein-based nanomaterials. This cutting-edge technique enables the creation of nanofibers with customizable structures, offering high surface area and adjustable mechanical and thermal attributes. Moreover, the electrospinning process allows for integrating various additives, such as antioxidants, antimicrobial agents, and flavoring compounds, into the zein nanofibers, enhancing their functionalities for food preservation. In this comprehensive review, the various electrospinning techniques employed for crafting zein-based nanofibers, and we delve into their enhanced properties. Furthermore, the review illuminates the potential applications of zein nanofibers in active and intelligent packaging materials by incorporating diverse constituents. Altogether, this review highlights the considerable prospects of zein-based nanocomposites in the realm of food packaging, offering sustainable and innovative solutions for food industry.

Biopolymer films incorporated with chlorogenic acid nanoparticles for active food packaging application

Food packaging is innovating towards more environmental-friendly polymers and broader applications of bioactive compounds. In this study, active packaging materials were successfully prepared by incorporating chlorogenic acid (CGA) nanoparticles into pullulan/gelatin polymer matrixes. The rhamnolipid (RL) and/or CGA were combined with chitosan (CS) to synthesize active nanoparticles by the ionic crosslinking method. The film containing CS/RL/CGA nanoparticles (F/CRC) exhibited both ultrahigh visible light (400-760 nm) transmittance (approximately 90%) and UVA (320-400 nm)-blocking efficiency (89.06%). Its fluorescent properties can be used for anti-counterfeiting. Significantly, the bacterial inhibition rates of F/CRC against E. coli and S. aureus were 92.14% and 98.72%. F/CRC also showed good antioxidant capability and biosafety. Finally, the packaging test further indicated that F/CRC could delay the browning of bananas and the bacteria growth of chicken samples. This work presents a green and feasible route to produce functional materials with UV-shielding properties for packaging applications.

Exploring the potential of pullulan-based films and coatings for effective food preservation: A comprehensive analysis of properties, activation strategies and applications

Pullulan is naturally occurring polysaccharide exhibited potential applications for food preservation has gained increasing attention over the last half-century. Recent studies focused on efficient preservation and targeted inhibition using active composite ingredients and advanced technologies. This has led to the emergence of pullulan-based biofilm preservation. This review extensively studied the characteristics of pullulan-based films and coatings, including their mechanical strength, water vapor permeability, thermal stability, and potential as a microbial agent. Furthermore, the distinct characteristics of pullulan, production methods, and activation strategies, such as pullulan derivatization, various compounded ingredients (plant extracts, microorganisms, and animal additives), and other technologies (e.g., ultrasound), are thoroughly studied for the functional property enhancement of pullulan-based films and coatings, ensuring optimal preservation conditions for diverse food products. Additionally, we explore hypotheses that further illuminate pullulan's potential as an eco-friendly bioactive material for food packaging applications. In addition, this review evaluates various methods to improve the efficiency of the film-forming mechanism, such as improving the direct coating process, bioactive packaging films, and implementing layer-by-layer coatings. Finally, current analyses put forward suggestions for future advancement in pullulan-based bioactive films, with the aim of expanding their range of potential applications.

Pressurized liquid extraction of bioactive compounds from grape peel and application in pH-sensing carboxymethyl cellulose films: A promising material to monitor the freshness of pork and milk

This study produced pH-sensing carboxymethyl cellulose (CMC) films functionalized with bioactive compounds obtained by pressurized liquid extraction (PLE) of grape peel to monitor the freshness of pork and milk. A semi-continuous PLE was conducted using hydroethanolic solution (70:30, v/v) at a flow rate of 5 mL/min, 15 MPa, and 60 °C. The films were produced by the casting technique using CMC (2.5 %, w/v), glycerol (1 %, v/v), and functionalized with 10, 30, and 50 % (v/v) grape peel extract. From the results obtained, LC-MS/MS revealed that PLE extracted twenty-seven phenolic compounds. The main phenolic compounds were kaempferol-3-glucoside (367.23 ± 25.88 µg/mL), prunin (270.23 ± 3.62 µg/mL), p-coumaric acid (236.43 ± 26.02 µg/mL), and procyanidin B1 (117.17 ± 7.29 µg/mL). The CMC films presented suitable color and mechanical properties for food packaging applications. The addition of grape peel extract promoted the pH-sensing property, showing the sensitivity of anthocyanins to pH changes. The films functionalized with grape peel extract presented good release control of bioactive compounds, making them suitable for food packaging applications. When applied to monitor the freshness of pork and milk, the films exhibited remarkable color changes associated with the pH of the food during storage. In conclusion, PLE is a sustainable approach to obtaining bioactive compounds from the grape peel, which can be applied in the formulation of pH-sensing films as a promising sustainable material to monitor food freshness during storage.

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.

Sustainable packaging film based on cellulose nanofibres/pullulan impregnated with zinc-doped carbon dots derived from avocado peel to extend the shelf life of chicken and tofu

A cellulose nanofiber (CNF)/pullulan (PUL) based multifunctional composite film was developed for active packaging applications by incorporating Zn-doped avocado-derived carbon dots (Zn-ACDs). The incorporation of Zn-ACDs improved the interfacial compatibility and produced a dense cross-sectional structure of the composite films. The Zn-ACDs added film showed no significant difference in water vapor permeability and surface hydrophilicity compared to the neat CNF/PUL film, but the tensile strength and elongation at break increased by ~45.4 % and ~64.1 %, respectively. The addition of 5 wt% Zn-ACDs to the CNF/PUL matrix resulted in 100.0 % UV blocking properties, excellent antioxidant activity (100.0 % for ABTS and 68.0 % for DPPH), and complete eradication of foodborne pathogens such as Listeria monocytogenes ATCC 15313 and Escherichia coli O157:H7 after 3 h of exposure. The CNF/PUL composite film with Zn-ACDs applied to the active packaging of chicken and tofu significantly reduced the total growth of aerobic microorganisms without significantly changing the actual color of the packaged chicken and tofu for 9 days at 10°C. This study demonstrates that CNF/PUL composite films with Zn-ACDs are a sustainable and environmentally friendly option for protecting food from microbial contamination.

Enhanced mechanical properties and antibacterial activities of chitosan films through incorporating zein-gallic acid conjugate stabilized cinnamon essential oil Pickering emulsion

In this study, zein-gallic acid covalent complex prepared by alkali treatment was utilized as an emulsifier to stabilize cinnamon essential oil (CEO) Pickering emulsion, and the chitosan-based (CZGE) films loaded with CEO Pickering emulsion were prepared by blending. The influences of different contents of CEO Pickering emulsion on the physical properties and biological activities of CZGE films were investigated. The results showed that Pickering emulsion had good compatibility with chitosan matrix and enhanced the interaction between film-forming matrix polymer. In addition, incorporating with CEO Pickering emulsion (15 %, v/v) significantly improved the mechanical and barrier properties of the films, and also enhanced the light transmittance and thermal stability of the films. Furthermore, the loading of emulsion also improved the antioxidant activities of the films and led to the formation of high antimicrobial property against food pathogens, and the slow-release behavior of CEO could effectively extend the biological activity of the films. These results suggested that Pickering emulsion has potential as a loading system and a plasticizer in active packaging, and the feasibility of CZGE film in food packaging.

Carbon dots embedded bacterial cellulose membrane as active packaging: Toxicity, in vitro release and application in minced beef packaging

Antimicrobial bacterial cellulose (BC) membranes incorporated with carbon dots (CDs) were developed to improve the shelf life and ensure the safety of minced beef during 9 days of storage at 4 °C. An ex-situ method was used to develop BC-CDs with different CDs loading capacities (16.50, 22.50, and 38.50 mg/cm3). Only BC-CDs38.50 membrane exhibited toxicity in human embryonic kidney cells, and BC-CDs membranes had the slowest release rate of CDs in 95% ethanol. Significant differences were noted in the chemical and sensory attributes of samples packaged with BC-CDs16.50 and BC-CDs22.50, compared to the control. The microbial counts in samples with BC-CDs were significantly lower than those in samples with pristine BC membranes or the control. Notably, the BC-CDs22.50 membrane exhibited a substantial reduction (4.7 log10 CFU/g) in Escherichia coli counts by the end of storage. These findings highlight the potential of BC-CDs membranes as effective antimicrobial materials in meat packaging.

Coated composite paper with nano-chitosan/cinnamon essential oil-nanoemulsion containing grafted CNC@ZnO nanohybrid; synthesis, characterization and inhibitory activity on Escherichia coli biofilm developed on grey zucchini

This investigation aims to highlight the applicability of a potent eco-friendly developed composite film to combat the Escherichia coli biofilm formed in a model food system. ZnO nanoparticles (NPs) synthesized using green methods were anchored on the surface of cellulose nanocrystals (CNCs). Subsequently, nano-chitosan (NCh) solutions were used to disperse the synthesized nanoparticles and cinnamon essential oil (CEO). These solutions, containing various concentrations of CNC@ZnO NPs and CEO, were sequentially coated onto cellulosic papers to inhibit Escherichia coli biofilms on grey zucchini slices. Six films were developed, and Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, biodegradation, and mechanical properties were assessed. The film containing 5 % nano-emulsified CEO + 3 % dispersed CNC@ZnO nano-hybrid in an NCh solution was selected for further testing since it exhibited the largest zone of inhibition (34.32 mm) against E. coli and the highest anti-biofilm activity on biofilms developed on glass surfaces. The efficacy of the film against biofilms on zucchini surfaces was temperature-dependent. During 60 h, the selected film resulted in log reductions of approximately 4.5 logs, 2.85 logs, and 1.57 logs at 10 °C, 25 °C, and 37 °C, respectively. Applying the selected film onto zucchini surfaces containing biofilm structures leads to the disappearance of the distinctive three-dimensional biofilm framework. This innovative anti-biofilm film offers considerable potential in combatting biofilm issues on food surfaces. The film also preserved the sensory quality of zucchini evaluated for up to 60 days.

Recent advances in carboxymethyl cellulose-based active and intelligent packaging materials: A comprehensive review

Researchers have concentrated on innovative approaches to increase the shelf life of perishable food products and monitor their quality during storage and transportation as consumer demand for safe, environmentally friendly, and effective packaging develops. This comprehensive review aims to provide an overview of recent developments in carboxymethyl cellulose (CMC) chemical synthesis and its applications in active and intelligent packaging materials. It explores various methods for modifying cellulose to produce CMC and highlights the unique properties that make it suitable for addressing packaging industry challenges. The integration of CMC into active packaging systems, which helps reduce food waste and enhance food preservation, is discussed in depth. Furthermore, the integration of CMC in smart sensors and indicators for real-time monitoring and quality assurance in intelligent packaging is examined. The chemical synthesis of CMC and strategies to optimise its properties were studied, and the review concluded by examining the challenges and prospects of CMC-based packaging in the industry. This review is intended to serve as a valuable resource for researchers, industry professionals, and policymakers interested in the evolving landscape of CMC and its role in shaping the future of packaging materials.

Development of innovative antioxidant food packaging systems based on natural extracts from food industry waste and Moringa oleifera leaves

Active packaging that prolongs food shelf life, maintaining its quality and safety, is an increasing industrial demand, especially if integrated in a circular economy model. In this study, the fabrication and characterization of sustainable cellulose-based active packaging using food-industry waste and natural extracts as antioxidant agents was assessed. Grape marc, olive pomace and moringa leaf extracts obtained by supercritical fluid, antisolvent and maceration extraction in different solvents were compared for their antioxidant power and phenolic content. Grape and moringa macerates in acetone and methanol, as the most efficient and cost-effective extracts, were incorporated in the packaging as coatings or in-between layers. Both systems showed significant free-radical protection in vitro (antioxidant power 50%) and more than 50% prevention of ground beef lipid peroxidation over 16 days by indirect TBARS and direct in situ Raman microspectroscopy measurements. Therefore, these systems are promising for industrial applications and more sustainable farm-to-fork food production systems.

Electrospun plant protein-based nanofibers in food packaging

Electrospinning is a relatively simple technology capable to produce nano- and micron-scale fibers with different properties depending on the electrospinning conditions. This review critically investigates the fabrication of electrospun plant protein nanofibers (EPPNFs) that can be used in food and food packaging applications. Recent progress in the development and optimization of electrospinning techniques for production of EPPNFs is discussed. Finally, current challenges to the implementation of EPPNFs in food and food packaging applications are highlighted, including potential safety and scalability issues. The production of plant protein nanofibers and microfibers is likely to increase in the future as many industries wish to replace synthetic materials with more sustainable, renewable, and environmentally friendly biopolymers. It is therefore likely that EPPNFs will find increasing applications in various fields including active food packaging and drug delivery.

Properties of active packaging of PLA-PCL film integrated with chitosan as an antibacterial agent and syzygium cumini seed extract as an antioxidant agent

Active packaging is becoming increasingly significant in the food industry. The present study aims to explore the use of Syzygium Cumini Seed Extract (SCSE) as an antioxidant and chitosan as an antibacterial agent to produce active packaging based on polylactic acid (PLA), poly ε-caprolactone (PCL), and polyethylene glycol (PEG) blend. Using advanced characterization techniques, active packaging (PLA/PCL/PEG) incorporating with 0.5 g chitosan-0.5 mL SCSE was evaluated for its mechanical, physical, structural, and antibacterial-antioxidant properties. The addition of chitosan-SCSE caused an 18.57 % increase in tensile strength and decreased the Water Vapor Transmission Rate (WVTR) by up to 52 %, whereas smooth surface microscopy indicated good compatibility between polymers and active agents. Active packaging incorporating chitosan-SCSE reduced 96.66 % of Gram-positive bacteria Staphylococcus aureus and 73.98 % of Gram-negative bacteria, Escherichia coli. During 15 days of storage, the active packaging was able to slow the increase in Total Volatile Basic Nitrogen (TVBN) in beef and prevent the decrease in vitamin C contents in pineapple.

Carboxymethyl cellulose/poly (vinyl alcohol) based active film incorporated with tamarind seed coat waste extract for food packaging application

Incorporating a bioactive food waste extract into biodegradable polymers is a promising green approach to producing active films with antioxidant and antibacterial activity for food packaging. Active packaging films from carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) incorporated with tamarind seed coat waste extract (TS) were prepared by solvent casting method using citric acid as a crosslinking agent. The effect of TS content on the film properties was determined by measuring the optical, morphology, mechanical, water vapor transmission rate (WVTR), antioxidant, and antimicrobial attributes. The CMC/PVA-TS films were also tested on fresh pork. The addition of TS did not significantly affect the film structure and WVTR but it improved the mechanical and UV barrier properties. The films possessed antioxidant and antimicrobial ability against bacteria (S. aureus and E. coli). Thus, CMC/PVA packaging was successfully prepared, and the incorporation of TS enhanced the antioxidant and antimicrobial properties of the film, which extended the shelf-life of fresh pork.

A tailored slow-release film with synergistic antibacterial and antioxidant activities for ultra-persistent preservation of perishable products

Rapid decrease in antibacterial efficacy of existing active packages is difficult to promisingly prevent microbial infection during the storage of perishable products. Here, we pioneered an advanced ZnO-doped hollow carbon-encapsulated curcumin (ZHC-Cur)-chitosan (CS) slow-release film (ZHC-Cur-CS) with "nano-barricade" structure through demand-oriented tailoring of the structure and components of zeolitic imidazolate framework-8 (ZIF-8) carrier. Such an exquisite structure realized the effective sustained release of Curcumin through the dual complexity of diffusion pathway by the disordered hierarchical pore structure and steric hindrance. Prepared ZHC-Cur-CS film exhibited boosting bactericidal and antioxidant abilities by virtue of the functional synergy between curcumin and ZnO. Thus, ZHC-Cur-CS film demonstrated excellent preservation performance by significantly prolonging the shelf life of Citrus (∼2.4 times). Furthermore, the upgraded mechanical strength, improved barrier ability, and proven safety laid the foundation for its practical application. These satisfactory properties underscore the applicability of ZHC-Cur-CS film for the efficient preservation of perishable products.

Thymol incorporation within chitosan/polyethylene oxide nanofibers by concurrent coaxial electrospinning and in-situ crosslinking from core-out for active antibacterial packaging

Active packaging systems that are sustainable and capable of delivering antimicrobial agents are in demand in food industry. In this work, Thymol (Thy) was encapsulated into Polyethylene oxide (PEO)/Chitosan (CS) to form core-shell nanofibers via coaxial electrospinning. Various dose of the crosslinker-genipin (GP) were encapsulated into the core layer to achieve in-situ etching crosslink with the CS of shell layer during the electrospinning process. The core-shell structure of the nanofiber was confirmed by transmission electron microscopy. The microstructures, mechanical properties, water vapor permeability, swelling ratios, wettability, thermal stability, biocompatibility and antibacterial properties of the crosslinked films were characterized. The results showed that the crosslinked films had compact structures, strong water resistance, better mechanical property and thermal stability, the sustained release profiles and antioxidant activity were also improved. More importantly, the antibacterial assays indicated that the Thy loaded nanofiber films could effectively inhibit the growth of two common food spoilage bacteria-E. coli and S. aureus.

Construction of carboxymethyl chitosan/PVA/chitin nanowhiskers multicomponent film activated with Cotylelobium lanceolatum phenolics and in situ SeNP for enhanced packaging application

This work focused on the construction of bioactive packaging films based on carboxymethyl chitosan and poly(vinyl alcohol) (CMP) as polymeric matrix and fortified with chitin nanowhiskers, Cotylelobium lanceolatum phenolic extract (CL) and in situ synthesized nano selenium. Extensive morphological, microstructural, physical and mechanical analysis revealed that the nanofillers were well-dispersed and integrated into CMP matrix. Incorporation of the extract and nano selenium produced excellent UV blocking properties without seriously compromising the transparency of the composite (CMP/CNW/CLNS1) film. Moreover, blending of CMP with the filler materials significantly elevated (p < 0.05) the surface hydrophobicity (WCA by 35.4°), water barrier (by 53.86 %), tensile strength (from 29.35 to 33.09 MPa), elongation at break (from 64.28 to 96.48 %), and thermal properties of the resultant CMP/CNW/CLNS1 film, with concomitant reduction in water solubility and swellability. Furthermore, the CMP/CNW/CLNS films exhibited remarkable improvement in antioxidant properties. When used for packaging of peeled fresh garlic cloves, the CMP/CNW/CLNS1 film pouch, not the plain CMP or CMP/CNW film pouches, inhibited weight loss, oxidative browning, and the emergence of black mold on the packaged cloves. The developed CMP/CNW/CLNS1 film demonstrated enhanced capacity to safeguard the quality of packaged food and improved shelf life. Therefore, the present study suggests that incorporation of CNW/CLNS into carboxymethyl chitosan/PVA films is a suitable and facile strategy for the fabrication of films with improved mechanical, physico-chemical and functional properties with great potential for application as a sustainable active packaging material in the food industry.

Rapid fabrication of micro-nanofibers from grapevine leaf extract and gelatine via electroblowing: A novel approach for edible active food packaging

The objective of this study was to develop novel micro-nanofibers for food packaging using grapevine extract (GLP) and gelatine using electroblowing technique. The identified components of GLP were dominated by the flavone group phenolics, as analyzed by LC-MS/MS. SBS was used to fabricate gelatine micro-nanofiber mats loaded with three different concentrations of GLP, which were subsequently cross-linked. The micro-nanofibers were characterized by their morphology, chemistry, thermal properties, and bioactivity. The in-vitro antioxidant and antimicrobial effects of the nanofiber mats were determined using various methods, which showed an increase in effectiveness with increasing GLP concentration. The in-situ assessment, where the nanofibers were applied to cheese, also showed a consistent improvement in shelf life with the use of GLP-loaded gelatin electroblown fibers.

Characterization of active films of chitosan containing nettle Urtica dioica L. extract: Spectral and water properties, microstructure, and antioxidant activity

Chitosan films enriched with aqueous nettle extract (Urtica dioica L.) were evaluated by measuring their solubility, equilibrium moisture, water vapor permeability, spectral and antioxidant properties, and microstructure. Nettle extract showed a significant effect on the analyzed film properties. The addition of nettle extract manifested a sharp decrease in water vapor permeability, decreasing from 5.64 · 10-11 to 2.22 · 10-11 g/m·s·Pa. The chitosan- nettle extract films exhibited a high free-radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Incorporation of nettle extract into the chitosan matrix was successfully carried out to obtain antioxidant films. The results obtained showed that the incorporation of nettle extract allowed obtaining chitosan films with antioxidant properties, including a total phenolic content up to 1.57 mg GAE/g film. Furthermore, the films with nettle extract boast an UV shielding ability with transmittance values close to zero in the UV region and a water solubility up to 1 %. The inherent biodegradability is also a strong advantage of the developed active films.

Development of biobased multifunctional films incorporated with essential oils@polydopamine nanocapsules for food preservation applications

A novel multifunctional soy protein isolate-carboxymethyl cellulose (SPI-CMC) based nanocomposite film was successfully prepared by introducing the polydopamine encapsulated essential oils (EOs@PDA) nanocapsules for food packaging. The EOs@PDA nanocapsules possessed smooth spherical morphology with good dispersion, and the particle size was about 283 nm. The influence of EOs@PDA nanocapsules on the physical, chemical and biological properties of EOs@PDA/SPI-CMC nanocomposite film was investigated. The EOs@PDA nanocapsules were crosslinked with SPI-CMC matrix and distributed uniformly in the matrix. The nanocomposite film with 1 wt% nanocapsules (EP/S-C) also showed excellent antioxidant activity (66.6 ± 0.3 % on DPPH and 98.6 ± 0.1 % on ABTS), superior UV-blocking properties (100 %), advanced antibacterial ability against E. coli and S. aureus, favorable biodegradability (>90 %) and relatively low In vitro cytotoxicity. Also, the EP/S-C nanocomposite film displayed potential to extend the shelf life of fresh cut apple slices (>24 h), perishable cherry tomatoes and blueberries (>6 days). The results suggested that the EOs@PDA/SPI-CMC nanocomposite film had a great possibility in the field of biodegradable and antimicrobial materials for food packaging.

Green interconnected network structure of chitosan-microcrystalline cellulose-lignin biopolymer film for active packaging applications

As an excellent alternative to petroleum-based food packaging materials, a novel green hybrid composite film with an excellent interconnected network structure was successfully fabricated by integrating chitosan (chi), microcrystalline cellulose (MCC), and lignin nanoparticles (LNP), including the desired amount of plasticizer glycerol (gly). Overall, 36 combinations were developed and investigated for superior biocomposite film formation. Among the various concentration ratios, the 40:35:25 chi-MCC-gly film provided well-organized film formation, good physicochemical properties, mechanical stability, efficient water contact angle, reduced water solubility, and lower water vapor permeability (11.43 ± 0.55 × 10-11 g.m-1.s-1.Pa-1). The performance of the chi-MCC-gly film further enhanced by the homogeneous incorporation of ∼100 nm LNP. With 1 % LNP addition, the tensile strength of the film increased (28.09 MPa, 47.10 % increase) and the water vapor permeability reached a minimum of 11.43 × 10-11 g.m-1.s-1.Pa-1, which proved the impact of LNP in composite films. Moreover, the films showed excellent resistance to thermal shrinkage even at 100 °C and exhibited nearly 100 % UV blocking efficiency at higher LNP concentrations. Interestingly, the green composite films extended the shelf life of freshly cut cherry tomatoes to seven days without spoilage. Overall, the facile synthesis of strong, insoluble, UV-blocking, and thermally stable green composite films realized for food packaging applications.

Chitosan-based films blended with moringa leaves and MgO nanoparticles for application in active food packaging

This study aims to address the issue of environmental pollution caused by non-biodegradable petroleum-based food packaging by exploring the application of biodegradable films. Film casting was employed to fabricate food packaging films from chitosan (CS) and polyvinyl alcohol (PVA) polymers blended with moringa extract (MoE) and various concentrations of magnesium oxide nanoparticles (MgO NPs). The films were characterized through multiple techniques, including UV spectroscopy, Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Fourier-transform Infrared Spectroscopy (FTIR). The study investigated the physicomechanical properties, water solubility, water vapor transmission rate, oxygen permeability, migration test, biodegradability, contact angle, anti-fogging, antibacterial and antifungal activity, and application of the films for food packaging. The results showed that blending CS/PVA films with MoE and MgO NPs significantly improved their mechanical properties. The highest tensile strength of 98 MPa was observed in the CPMMgO-0.5 film. The solubility of the films was low, with CPMMgO-0 and CPMMgO-0.25 demonstrating the lowest solubility as weight decreased by 3.41 % and 3.47 %, respectively. The water vapor transmission rate and oxygen permeability decreased with increasing MgO NP concentrations, with the CPMMgO-0.5 film exhibiting the lowest values. The films also demonstrated good biodegradability, anti-fogging ability, antibacterial and antifungal activity, and low water solubility, enabling bead encapsulation over 14 days in good condition. Moreover, the thermal stability of the films was improved, extending the shelf life of bread. Therefore, the fabricated films provide a promising alternative to non-degradable plastic packaging, which heavily contributes to environmental pollution.

Alginate based films integrated with nitrogen-functionalized carbon dots and layered clay for active food packaging applications

The applications of alginate derived from seaweed polysaccharide in food packaging are restricted due to their inherent deficient antibacterial, antioxidant and UV barrier properties. In this study, nitrogen-functionalized carbon dots (NCDs) with active functions (0.5-3 %) and layered clay (1 %) with barrier property were introduced to construct alginate based active films via solution casting method. The results showed that the synthesized spherical NCDs had a particle size of 2-3 nm, and the internal structure of NCDs was similar to graphene, with a large number of active groups (-NH2, -OH, etc.) on the surface. Infrared analysis revealed that NCDs could form strong hydrogen bonds with alginate matrix, which slowed down the deterioration of mechanical properties and reduced the surface wettability. With the addition of NCDs, active functions and surface hydrophobicity of the active films were enhanced significantly (P < 0.05). When the amount of NCDs reached 3 %, UV barrier, antioxidant and antibacterial properties of the active films were increased by 50.0 %, 61.1 % and 70.1 %, respectively. The addition of NCDs could enhance the anti-browning ability of alginate based coatings and extend the shelf life of banana significantly. Therefore, a suitable amount of NCDs (1-2 %) and layered clay (1 %) can synergistically improve comprehensive performance of alginate based films and promote their food packaging application used as active films/inner coatings.

Prolonging the shelf life of fresh-cut guava (Psidium guajaya L.) by coating with chitosan and cinnamon essential oil

This study investigated the effect of a coating of chitosan (CH) and cinnamon essential oil (CEO; 0-1 %) on the quality attributes of fresh-cut guava (Psidium guajaya L.) during storage at 4 ± 1 °C for 17 days, with uncoated fresh-cut guava used as control. The CH coating significantly (p < 0.05) delayed changes in weight loss, firmness, colour, total soluble solids and titratable acidity compared to the control sample. Furthermore, the effects were more prominent with the incorporation of higher CEO concentrations. The bacterial, yeast and mould counts were also significantly lower (p < 0.05) in the CH-coated samples than in the control, with the coating containing 1 % CEO exhibiting the best quality preservation effect. In addition, CH and CEO coatings extended the shelf life of fresh-cut guava up to 17 days compared to the control sample (shelf life of only 3 days). In conclusion, combining CH and CEO as a coating matrix effectively preserves the quality and enhances fresh-cut guava's shelf life.

Multifunctional food packaging materials: Lactoferrin loaded Cr-MOF in films-based gelatin/κ-carrageenan for food packaging applications

In this study, antimicrobial biocomposite films based on gelatin-κ-carrageenan (Gκ) with 1, 2 and 4 % lactoferrin (L) loaded chromium-based metal-organic frameworks (L@Cr-MOFs) nanoparticles were synthesized by casting methods. The addition of L loaded Cr-MOFs into Gκ based films increased elongation at break from 2.19 to 14.92 % and decreased the tensile strength from 65.1 to 31.22 MPa. L@Cr-MOFs addition reduced swelling index (from 105 to 70.8 %), water solubility (from 61.3 to 34.63 %) and water vapor permeability (from 2.46 to 2.19 × 10-11 g. m/m2. s). When the additional amount was 4 wt%, the Gκ/L@Cr-MOFs films showed antibacterial effects against Escherichia coli and Staphylococcus aureus with the inhibition zone of 19.7 mm and 20.2 mm, respectively. In addition, strawberries preservation trial shown that the Gκ/L@Cr-MOFs films delayed the growth of spoilage molds on the surface of fruits. This research indicated that Gκ/L@Cr-MOFs are promising active packaging materials for the preservation of perishable fruits.

Impact of nitrite-embedded packaging film on quality and sensory attributes of alternatively-cured and nitrite-free bologna

The objectives were to determine the effects of post-thermal processing nitrite-embedded film (NEF) packaging on the quality attributes of alternatively-cured (nitrite from celery juice powder (AC)) and nitrite-free bologna. Attributes evaluated included lipid oxidation, instrumental color, pigment concentration, and sensory properties such as cured meat flavor, aroma, and color. Three bologna formulations, each packaged with two packaging films were produced. A conventionally-cured control formulation (with nitrite from sodium nitrite; CON), a nitrite-free formulation (UCC), and an alternatively cured formulation (nitrite from cultured celery juice powder; AC) were packaged in conventional (CF) or nitrite-embedded (NEF) film. Instrumental a* values (measured during both light and dark storage at intervals of 7 or 14 days over 126 days of storage) and cured pigment concentration (measured at 14-day intervals over 84 days of storage) were significantly greater (P < 0.05) for the UCC-NEF treatment compared to its conventional film counterpart, UCC-CF. No significant differences (P > 0.05) for lipid oxidation (TBARS values) were observed with NEF. Trained sensory panelists, who evaluated samples at 14-day intervals over 70 days of storage, found significantly greater (P < 0.05) cured aroma, cured flavor, pink color and less off-flavor for uncured bologna packaged in NEF compared to conventional film. For the uncured bologna formulation, NEF packaging provided cured meat attributes comparable to the control formulation that included nitrite. This is the first time that cured aroma and flavor have been observed when nitrite from packaging film is added to a cooked meat product under anaerobic conditions.

Preparation of chitosan/gelatin-based functional films integrated with carbon dots from banana peel for active packaging application

Carbon dots (CDs) were manufactured with banana peels using a hydrothermal method (200 °C for 6 h). The synthesized CDs were spherical particles with a size of 1-3 nm having carboxyl groups and amine groups on the surface. CDs have been impregnated into chitosan/gelatin films to synthesize multifunctional packaging films. The composite film showed a slight decrease in transparency but a significant increase in UV protection properties. The fabricated film displayed strong antioxidant efficacy showing >74 % DPPH and 99 % ABTS radical scavenging potential. The film also unveiled substantial antibacterial activity against the foodborne pathogenic bacteria, Listeria monocytogenes, fully eliminating the growth of these bacteria within 6 h of exposure. The chitosan/gelatin film containing CD was used for minced meat packaging, and the film delayed bacterial growth (< 1 Log CFU/g after 24 h) and maintained the meat color even after 24 h of storage at 20 °C. The CD-added chitosan/gelatin functional film has a high probability of application in active food packaging, especially for extending the shelf life of packaged meat and maintaining its aesthetic quality.

An edible coating utilizing Malva sylvestris seed polysaccharide mucilage and postbiotic from Saccharomyces cerevisiae var. boulardii for the preservation of lamb meat

Currently, microbial bioactive substances (postbiotics) are considered a promising tool for achieving customer demand for natural preservatives. This study aimed to investigate the effectiveness of an edible coating developed by Malva sylvestris seed polysaccharide mucilage (MSM) and postbiotics from Saccharomyces cerevisiae var. boulardii ATCC MYA-796 (PSB) for the preservation of lamb meat. PSB were synthesized, and a gas chromatograph connected to a mass spectrometer and a Fourier transform infrared spectrometer were used to determine their chemical components and main functional groups, respectively. The Folin-Ciocalteu and aluminium chloride techniques were utilized to assess the total flavonoid and phenolic levels of PSB. Following that, PSB has been incorporated into the coating mixture, which contains MSM, and its potential radical scavenging and antibacterial activities on lamb meat samples were determined after 10 days of 4 °C storage. PSB contains 2-Methyldecane, 2-Methylpiperidine, phenol, 2,4-bis (1,1-dimethyl ethyl), 5,10-Diethoxy-2,3,7,8- tetrahydro-1H,6H-dipyrrolo[1,2-a:1',2'-d] pyrazine, and Ergotaman-3',6',18-trione, 12'-hydroxy-2'-methyl-5'-(phenylmethyl)-, (5'alpha) as well as various organic acids with significant radical scavenging activity (84.60 ± 0.62 %) and antibacterial action toward Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Staphylococcus aureus, and Listeria innocua as foodborne pathogens. The edible PSB-MSM coating effectively reduced microbial growth and increased meat shelf life (> 10 days). When PSB solutions were added to the edible coating, the moisture content, pH value, and hardness of the samples were also more successfully maintained (P < 0.05). The PSB-MSM coating inhibited lipid oxidation in meat samples considerably and diminished the formation of primary as well as secondary oxidation intermediates (P < 0.05). Additionally, when MSM + 10 % PSB edible coating was utilized, the sensory properties of the samples were maintained more well during preservation. As a significance, the use of edible coatings based on PSB and MSM is efficient in decreasing microbiological and chemical degradation in lamb meat during preservation.