•Green synthesis of silver nanoparticles (AgNPs) from Nigella sativa extract.•Development of functional CS based AgNPs nano-composite films.•Improved the physicochemical, antimicrobial and ...antioxidant properties of the film.•Exhibit a pH-dependent sustained release of AgNPs and Ag+ ions.
In this study, biogenic AgNPs were synthesize using Nigella sativa extract (NSE) with potential antioxidant activity. The transmission electron microscopy (TEM) image showed spherical AgNPs with biphasic nature and an average particle size 8 nm. AgNPs was then evaluated for their effect on sustained release and film-forming capacity of chitosan. Characterization of the films was done to analyze their physical, mechanical as well as antibacterial properties. The structural change in the films was indicated by FTIR spectra which showed the shift of characteristics peak and modification of the absorbance intensity. Scanning electron micrographs (SEM) showed an uneven distribution of AgNPs all over the CS polymer matrix. Moreover, the mechanical and barrier properties of CS/ Ag nanocomposite films were influenced by the intercalation of AgNPs. The tensile strength and elongation of the films were improved by 8.4–22.5% and 4.4–9.2%, whereas water vapor permeability reduced by 15.23% depending on the concentration of AgNPs. Further, the films showed a pH-dependent sustained release of AgNPs and Ag+ ions and significant antibacterial activity. Largely, the excellent antibacterial activity and biocompatibility mark CS-AgNPs composite films a promising material for packaging of food, pharmaceutical, and allied products.
Summary
A tannins‐rich chestnut extract was used to enhance the antioxidant and antibacterial properties of chitosan‐based film materials. The favourable mechanical properties of the novel material ...enabled its application in the preparation of the sachets that were used for packing and storage of filled fresh pasta. The fresh pasta ageing progressed in conventional refrigerated storage conditions of 8 °C with 60 ± 2% relative humidity in the absence of light for 60 days. The rapid moisture mobility between a starchy food and sachets during the first 9 days of storage induced retrogradation of the fresh pasta, whereby total phenolic content show dependency on moisture throughout the shelf life. Active components within the sachet prevented microbial growth on the food surface during the entire 60 days.
Chestnut extract was successfully used as an active component in chitosan‐based films used as a fresh pasta packaging in a 60 days shelf life study.
Covalent Organic Frameworks (COFs) have attracted extensive attention for the photocatalytic degradation of emerging organic contaminants. The difficulty in separation and recovery after use yet ...would hinder the practical application of COFs in powder form. In present study, COFs in film form were fabricated via using chitosan as the film-substrate to support COFs (CSCF). We found that CSCF could effectively degrade two types of emerging organic contaminants under visible light irradiation. Particularly, CSCF could effectively degrade 99.8% of paracetamol (PCT) and 94.0% of bisphenol A (BPA) within 180 min under visible light irradiation. •O2- and h+ played dominant roles during the photocatalytic degradation process. Hydroxylation and cleavage were the main degradation processes. CSCF exhibited good photocatalytic degradation performance in a broad range of ionic strengths, in the presence of common coexisting ions including Cl-, NO3- and SO42-, in a wide range of pH (5−11), and in real water samples including tap water, river water and lake water. Moreover, CSCF could be easily collected after use and exhibited excellent degradation performance in five successive cycles. CSCF has potential applications to treat water with either PCT or BPA contamination. This study provided a new insight into the practical application of COFs.
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•CSCF exhibited excellent photocatalytic degradation performance of PCT and BPA.••O2- and h+ were the major reactive species in the photocatalytic processes.•CSCF exhibited good photocatalytic performance in complex water conditions.•Excellent degradation performance in tap water, river water and lake water.•CSCF displayed outstanding reusability.
Ethylene (C2H4) and pathogenic microorganisms are the two major causes of the deterioration of postharvest fruits and vegetables (F&V). Hence, the development of active packaging with C2H4 scavenging ...and bactericidal activities is urgently desirable. Herein, a novel photocatalytic active film (CS-PC-AC) is developed for banana preservation by incorporating WO3/AgBr/Ag photocatalyst (PC) and activated carbon (AC) into chitosan (CS). The fabricated PC is a ternary Z-scheme heterojunction and its high photocatalytic activity is achieved by the bridge of Ag between WO3 and AgBr through rapid transfer and separation of photogenerated electrons and holes. AC plays an indispensable role in the photocatalytic reaction through molecule adsorption and transport. PC and AC are hydrogen bonded with chitosan and their incorporation has slight effect on film's thermal stability but decreases the film's mechanical and barrier properties to some extent. CS-PC-AC exhibits strong bactericidal activity (killing ~100 % of Escherichia coli and Staphylococcus aureus within 3 h) and good C2H4 scavenging activity (C2H4 scavenging rate of 49 ± 2 %) under visible light irradiation, which can extend the banana shelf-life by at least 50 % at 25 °C. These results indicate the good perspective of CS-PC-AC in the delay of the deterioration of postharvest F&V.
Nowadays, using biodegradable and active packaging as an alternative to oil-based plastics become a trend. Thus, we aimed in this study to develop and generally evaluate chitosan-based films ...(CH-film) incorporating C. zeylanicum and E. caryophyllus essential oils (EOs) for eventual utilization as food active-packaging. Experimental data revealed that the film thickness and opacity increased from 2.2- to 6-folds, and from 2.6- to 4.5-folds respectively, following the addition of EOs. Moreover, the treated materials revealed a significant drop in hydrophobicity, elongation at break, moisture content, and swelling degree, especially in the case of cinnamon EO treatment. A correlation was observed between the antioxidant property and total phenolic content. The DPPH inhibitory behavior and release of phenolic compounds of the treated CH-films increased over time, reaching third-day values higher than 15 mg gallic acid/g sample, and 80% of DPPH inhibition, respectively. Finally, the introduction of clove and cinnamon EOs significantly promotes the antibacterial and antibiofilm properties of the material against Escherichia coli, Enterococcus hirae, Staphylococcus aureus, and Pseudomonas aeruginosa. Biofilm inhibition values ranged from 69.76 to 96.97% depending on the bacterial species.
These promising findings encourage the potential utilization of CH-films supplemented with EOs such as cinnamon and clove EOs to replace plastic-based films as packaging, especially in the agri-food industry.
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•The incorporation of clove and cinnamon essential oil modifies the mechanical characteristics of the material.•The physical and physicochemical properties of the chitosan-based film were improved by the addition of essential oils.•The treated films showed greater antioxidant, antibacterial and antibiofilm activities against the four studied strains.•The treated films could potentially be applied as active packaging that maintains food quality and extends its shelf-life.
•The CFS of L. paracasei ALAC-4 confers significant antifungal activities.•Optimized CS-CFS film exhibits excellent antifungal, mechanical, and structural properties.•CS-CFS film promises ...applications to Mongolian cheese preservation.
Fungal spoilage of food is a worldwide concern prompting the development of many antimicrobial agents and applications. In this study, the cell-free supernatant (CFS) of Lacticaseibacillus paracasei ALAC-4 had a significant inhibition effect on fungi. The CFS with antifungal activities were combined with chitosan (CS) matrix to prepare an active packaging CS-CFS films by using a solvent casting method and used for the packaging of Mongolian cheese for 15 days during storage at 4 ± 1℃. The optimized formulation of the film were 1.25% (w/v) chitosan, 1.75% (w/v) gelatin, 0.3% (v/v) glycerol, and 9.6% (w/v) CFS. It was found that CS-CFS films exhibited strong antifungal activities against molds and yeasts, especially Candida albicans, and also had excellent mechanical properties. Additionally, FTIR spectroscopy indicated that hydrogen bonds between the CFS and CS formed, and there was a smooth surface, compact cross-section observed in SEM morphologies of CS-CFS films. Furthermore, CS-CFS film also displayed a strong antifungal effect against molds and yeasts on cheese surface. These results suggest that the chitosan-based CS-CFS film has a promising application for Mongolian cheese and food preservation.
Four different types of chitosan-based nanocomposite films were prepared using a solvent-casting method by incorporation with four types of nanoparticles, that is, an unmodified montmorillonite ...(Na-MMT), an organically modified montmorillonite (Cloisite 30B), a Nano-silver, and a Ag-zeolite (Ag-Ion). X-ray diffraction patterns of the nanocomposite films indicated that a certain degree of intercalation was formed in the nanocomposite films, with the highest intercalation in the Na-MMT-incorporated films followed by films with Cloisite 30B and Ag-Ion. Scanning electron micrographs showed that in all of the nanocomposite films, except the Nano-silver-incorporated one, nanoparticles were dispersed homogeneously throughout the chitosan polymer matrix. Consequently, mechanical and barrier properties of chitosan films were affected through intercalation of nanoparticles, that is, tensile strength increased by 7-16%, whereas water vapor permeability decreased by 25-30% depending on the nanoparticle material tested. In addition, chitosan-based nanocomposite films, especially silver-containing ones, showed a promising range of antimicrobial activity.
Recently, the concept of biodegradable and bioactive packaging and surface coating has become a trend. In this work, the bioactive films of chitosan were elaborated following the casting method. ...Contrary to the films containing the Cinnamomum zeylanicum Blume, Thymus satureioides Cosson, and Syzygium aromaticum essential oils (EOs) mixtures, the control film was thin, colorless, and showed high moisture content, swelling degree, and elongation at break. Concerning the physicochemical parameters, the incorporation of the EOs mixtures minimized the hydrophobicity of the material (θw < 65°) and modified randomly its surface free energy components (γ−; γ+; γLW). The theoretical prediction of Aspergillus sp. and Rhizopus sp. adherence to the chitosan-based films was relatively correlated to the experimental results (r = −0.601). The latter showed that 6.80 % and 19.02 % of the control film surface was covered by Aspergillus sp. and Rhizopus sp. spores, respectively. In contrast, no fungal adherence was noticed in the case of the film incorporating the triple EOs mixture. These promising results revealed that chitosan film containing C. zeylanicum, T. satureioides, and S. aromaticum EOs mixtures could be utilized as a surface coating or bioactive packaging in the food industry.
An active chitosan-based film, blended with the hydrolysable tannin-rich extract obtained from fibrous chestnut wood (Castanea sativa Mill.), underwent a simultaneous engineering optimization in ...terms of measured moisture content (MC), tensile strength (TS), elongation at break (EB), and total phenolic content (TPC). The optimal product formulation for a homogeneous film-forming solution was sought by designing an empirical Box–Behnken model simulation, based on three independent variables: the concentrations of chitosan (1.5–2.0% (w/v)), extracted powder-form chestnut extract (0.5–1.0% (w/v)) and plasticizer glycerol (30.0–90.0% (w/w); determined per mass of polysaccharide). Obtained linear (MC), quadratic (TS or EB), and two-factor interaction (TPC) sets were found to be significant (p < 0.05), to fit well with characteristic experimental data (0.969 < R2 < 0.992), and could be considered predictive. Although all system parameters were influential, the level of polyol played a vital continuous role in defining EB, MC, and TS, while the variation of the chestnut extract caused an expected connected change in affecting TPC. The component relationship formula of chemical mixture fractions (1.93% (w/v) of chitosan, 0.97% (w/v) chestnut extract and 30.0% (w/w) of glycerol) yielded the final applicable material of adequate physico-mechanical properties (MC = 17.0%, TS = 16.7 MPa, EB = 10.4%, and TPC = 19.4 mgGAE gfilm−1). Further statistical validation of the concept revealed a sufficient specific accuracy with the computed maximal absolute residual error up to 22.2%. Herein-proposed design methodology can thus be translated to smart packaging fabrication generally.
•Chitosan-based film developed using chestnut extract as an active component.•Composition of the film-forming solution linked to properties of the final film materials by RSM.•Box–Behnken design was an effective tool in the formulation of the optimal film-forming solution.•Level of plasticizer influenced moisture content and mechanical properties of the film material.•Level of active component influenced the antioxidant properties of the film material.
Numerous endeavours have been developed bio-based polymer packaging films to replace the use of petroleum-based packaging. In this study, as a response and support to the enduring research issues, we ...have developed the optimization composite film formulation based on chitosan (2%), Dioscorea alata starch (0.5%), and glycerol (1.5%) had satisfactory result on several parameters consisting thickness (0.45 mm), solubility (472.1%), moisture content (29.872%), biodegradability (38.346%), elastic modulus (971.2 N/m2) and tensile strength (98.71 N/m). Further, the optimized chitosan film (CF) formulation was enriched with several essential oils (EO), i.e., lemongrass, garlic and aloe vera oil. Upon the addition of EO, the solubility, biodegradable tests, and elongation to break of CF tended to decrease whereas the contact angle and mechanical properties significantly increased. Finally, the antibacterial properties of CF against Escherichia coli, Salmonella typhi, Staphylococcus aureus and Staphylococcus epidermidis dramatically increased by the addition of EO. These impressive results are expected to be applied in the food packaging industry to maintain the quality of food products.
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•Chitosan film modified by Dioscorea alata incorporated essential oils were prepared by following response surface methodology•Essential oils play a role in maintaining the surface morphology of CF, improve the physical, mechanical and antimicrobial activity•Chitosan film formulations have potential to be applied as natural food package
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