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Although polyvinyl alcohol (PVA) is a promising biodegradable packaging material, it presents some disadvantages for food packaging such as poor ultraviolet (UV) and water vapor barrier properties, low mechanical strength, poor water resistance, and lack of antimicrobial properties. To overcome these limitations, novel PVA/cellulose nanocrystals (CNC)/titanium dioxide (TiO 2 ) nanocomposites were developed, characterized, and demonstrated for potential food packaging applications. The mechanical strength, water vapor barrier, and UV barrier properties of PVA/CNC/TiO 2 5 % film (5 wt% TiO 2 in the PVA/CNC matrix with 5 wt% of CNCs) increased by 55.8 %, 45.2 %, and 70,056.8 %, respectively, compared to those of a PVA film. In the antibacterial simulation test, PVA/CNC/TiO 2 5 % film could limit the growth of microorganisms for 14 days. In packaging tests with fresh garlic, PVA/CNC/TiO 2 films effectively prevented weight loss and spoilage by external influences, indicating the potential of the PVA/CNC/TiO 2 nanocomposites for food-packaging applications., Competing Interests: Declaration of interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

To improve the performance of potato starch films and solve the problems of high volatility and low stability of thymol (Thy), thymol was loaded into the channel of SBA-15 to prepare Thy-SBA-15, and the Thy-SBA-15/potato starch film was prepared. The results showed thymol was successfully loaded into the pores of SBA-15. The addition of Thy-SBA-15 enhanced the tensile strength of potato starch film (3.93 Mpa), reduced the water vapor permeability (1.56 × 10 -12  g·d -1  m -1  Pa -1 , WVP) and moisture absorption (80.97%, MA), which enhanced the barrier properties of the films. Thy-SBA-15 had good compatibility with potato starch films. Notably, the thymol released from Thy-SBA-15/potato starch film was initially explosive, and then continuous, which showed this film could effectively slow down the release rate of thymol and prolong the fresh-keeping period of food. The Korsmeyer-Peppas model M t M ∞ = k t n (R 2  > .96) had the best fit for the release curve of thymol. PRACTICAL APPLICATIONS: This work offers a new method for the preparation of potato starch sustained-release antibacterial film, and provides a theoretical basis and technical support for the development of intelligent packaging., (© 2022 Wiley Periodicals LLC.)

In this study, nanocomposites of polylactic acid (PLA) with clove essential oil (CEO) and alkali treated halloysite nanotubes (NHNT) as fillers were synthesized by using simple solvent casting method. The treatment of halloysite nanotubes with NaOH increased the surface area from 50.16 m 2 ⋅g -1 to 57.01 m 2 ⋅g -1 and pore volume from 0.25 cm 3 ⋅g -1 to 0.32 cm 3 ⋅g -1 . The as-synthesized nanocomposite films were characterized for physical, thermal, mechanical and water vapor barrier properties towards their use as food packaging material. The nanocomposite film PCOH0.5 (consisting 0.5 wt% NHNT and 200 μL CEO) possessed the best physical properties with percentage enhancements over PLA as: surface hydrophobicity (20.2 %), water vapor barrier (42.1 %), thermal stability (3.2 %), flexibility (682 %), tensile strength (20 %), elastic modulus (38 %), UV barrier property (62 %). In addition, a practical packaging test was performed on cut apples stored at room temperature for 6 days. The PCOH0.5 films showed substantially improved results (as compared to PLA) as follows: weight loss (40.5 %), mesophilic count (4.0 %), firmness (116.6 %), titratable acidity (110.8 %), pH (2.9 %) and total soluble solids (8.9 %). The results clearly indicate the efficiency of PLA/CEO/NHNT nanocomposite films as potential active food packaging material., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Our living environment is being increasingly polluted by petroleum-based plastics and there is an increasing demand for biodegradable food packaging. In this study, the effect of various ultrahigh-pressure (UHP) treatments (0, 200 and 400 MPa) on the microstructure and thermal, barrier and mechanical properties of poly(lactic acid) (PLA)/ZnO nanocomposite films was studied., Results: The film-forming solution was processed using UHP technology. The crystallinity, strength and stiffness of the composite film after UHP treatment increased. In addition, barrier property analysis showed that the UHP treatment significantly (P < 0.05) reduced the oxygen permeability and water vapor permeability (WVP) coefficient of the PLA/ZnO nanocomposite film. Furthermore, the WVP value of the film treated at 400 MPa (50 g kg -1 nano-ZnO content) was the lowest and reduced by 47.3% compared with that of pure PLA film. The improvement in these properties might be due to the interaction between nano-ZnO and PLA matrix promoted by UHP treatment., Conclusions: Therefore, the application of UHP technology on the film-forming solution could improve the crystallinity and functional properties of the nanocomposite film, and has great potential in the production of food packaging films with ideal functions. © 2021 Society of Chemical Industry., (© 2021 Society of Chemical Industry.)

The present study aimed to develop a new bio-nanocomposite film based on gum arabic (GA) reinforced with cellulose nanocrystals (CNC). CNC was successfully fabricated and its microstructure was characterized. Subsequently, the effects of CNC on the rheological, physicochemical and functional properties of GA-based films were systematically evaluated. Results showed that the tensile strength (2.21 MPa) and elongation at break (62.79%) of film incorporated with 4% (w/w) CNC were effectively increased compared with the GA film (1.08 MPa and 42.50%). Additionally, 4% CNC reduced the water vapor and oxygen permeability by 10.61% and 25.30% respectively, while improved the ultraviolet light barrier and thermal stability of film. The well dispersion and filling effect of nanofiller contributed to form a compact and homogeneous film structure. Furthermore, the film containing 4% CNC decreased the weight loss of strawberries by 23.80% compared with the control group, thus delaying the deterioration of strawberry quality during storage., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Electrosprayed zein nanoparticles containing 10% (w/w) of clove essential oil (CEO) were prepared and then with different levels (5, 10, and 15% w/w) in the starch matrix were used. The incorporation of zein nanoparticles in the structure of starch-based bio-nanocomposites films was confirmed by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Increasing the level of application of zein bio-nanofillers in the starch film matrix increased thickness and contact angle. However, the use of electrosprayed zein nanoparticles loaded by CEO (EZN-CEO) up to 10% significantly (p < 0.05) reduced the water vapor permeability (WVP), but using 15% of the nanoparticles increased the WVP of the films significantly (p < 0.05). Increasing the EZN-CEO up to 10% significantly (p < 0.05) increased the tensile strength and Young's modulus and reduced the elongation at break of the films. Sustained release of CEO from the bio-nanocomposites showed that the most release of the CEO occurs in 10% ethanol medium. The Fickian diffusion was the predominant mechanism in the release of the CEO, and the Peleg model was selected as the best one to explain the release behavior. The structures designed in this study can be used as an edible coating and bio-preservative in perishable food products., Competing Interests: Declaration of competing interest The authors wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2021. Published by Elsevier B.V.)

The research in eco-friendly and sustainable materials for packaging applications with enhanced barrier, thermo-mechanical, rheological and anti-bacterial properties has accelerated in the last decade. Last decade has witnessed immense interest in employing nanocellulose (NC) as a sustainable and biodegradable alternative to the current synthetic packaging barrier films. This review article gathers the research information on NC as a choice for food packaging material. It reviews on the employment of NC and its various forms including its chemico-physical treatments into bio/polymers and its impact on the performance of nanocomposites for food packaging application. The review reveals the fact that the research trends towards NC based materials are quite promising for Active Packaging (AP) applications, including the Controlled Release Packaging (CRP) and Responsive Packaging (RP). Finally, it summarizes with the challenges of sustainable packaging, gray areas that need an improvement/focus in order to commercially exploit this wonderful material for packaging application., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Alginate nanocomposite films incorporating sepiolite (Sep) modified with myrtle berries extract (MBE) rich in polyphenols were prepared by solution casting method. The effects of different extract concentrations on the film properties were determined by measuring physicochemical, mechanical and antioxidant properties of the films. Fourier transform infrared (FTIR) spectra indicated that strong interactions between the polyphenols present in the MBE and sepiolite were involved in the films. The results suggested that incorporation of Sep-MBE hybrids into the films improved elongation at break, tensile strength, water vapor and UV barrier properties compared to the control film. The antioxidant activity of the films was significantly improved and raised with increasing content of MBE. The release kinetics results of MBE polyphenols from the active films into alcoholic food simulant indicated that the addition of Sep-MBE hybrids to alginate film is able to slow the release of MBE polyphenols. This study revealed the benefits of incorporation of Sep-MBE hybrids into the alginate films and their potential application as active packaging films or coating material., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Chitosan (CHI) and whey protein are usually used to prepare edible films for food preservation. However, the composite film composed of the two components does not yield satisfactory properties for chestnut preservation. In this study, nano-cellulose and cinnamaldehyde (CMA) were added to CHI and whey protein, creating a new composite film with strong water retention, bacteriostatic, and mechanical properties. The water vapor permeability (WVP) of the film decreased by 21.61% with the addition of 0.5% (w/v) nano-cellulose, and 23.02% with the addition of 0.3% (w/v) CMA. Furthermore, water solubility (WS) decreased 22.05%, and the density of the film was significantly improved with the addition of 0.3% (w/v) CMA. The optimized formula of the film was CHI 2.5% (w/v), whey protein 3.0% (w/v), nano-cellulose 0.5% (w/v), CMA 0.3% (w/v), and pH 3.8, as determined by orthogonal testing L9(3 4 ), with fuzzy comprehensive assessment, of WVP, WS, tensile strength, and elongation at break. The film clearly inhibited the growth of E. coli, S. aureus, and Chinese chestnut fungus, destroying the mycelial structure of the fungus. In addition, coating effectively reduced the weight loss, mildew rate, and calcification index during 16 days of storage of chestnuts at 25 °C., (© 2020 Institute of Food Technologists®.)

In this study, various amounts of nanoclay montmorillonite (MMT) and ZnO nanopowders were used to analyze the properties of biodegradable nanocomposites of cationic starch (CS). Nanocomposites are produced by solvent casting method. The structure of CS-MMT nanocomposite films that contain 3% montmorillonite was exfoliated and was proved by XRD test. New hydrogen bonds were successfully formed between the CS hydroxyl groups and nanofillers and this was proved by FTIR test. The water vapor permeability and the UV light transmittance of the nanocomposites reduced after the contents of MMT and ZnO increased. ∆E and opacity of the nanocomposites enhanced after the amount of ZnO increased. Tensile strength (TS) of nanocomposites increased after the incorporation of ZnO and MMT nanoparticles although the elongation at break was diminished. Results showed that the 3 and 0.7 wt% amounts of montmorillonite and ZnO nanopowders were sufficient in order to acquire a well-moderated mechanical behavior in plastic and elastic regions, and they also cause good improvements in barrier and optical properties., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In current study, starch/TiO 2 bionanocomposites were produced by photochemical reactions as a biodegradable food packaging material. Physical, mechanical, thermal and water-vapor permeability properties were investigated. Then, the photo-degradation properties of nanocomposite films were studied. This is the first report of the photo-producible and photo-degradable bionanocomposite as a food packaging material. Film-forming solutions were exposed to ultraviolet A (UV-A) for different times. Our results showed that UV-A irradiation increased the hydrophobicity of starch films. With increasing UV-A exposure time, tensile strength and Young's modulus of the specimens were decreased. On the other hand, elongation at break of the films was increased with increasing UV-A irradiation. The glass transition temperature and melting point of the films were increased by increasing UV-A exposure time. Nevertheless, the results showed that photo-degradation properties of photo-produced starch/TiO 2 nanocomposite were significantly higher than virgin starch and virgin starch/TiO 2 films. According to obtain results and bibliography a schema was developed to describe the mechanism of photo-production and photo-degradation of starch/TiO 2 by UV-A ray. It can be concluded, the modification of starch based biopolymer by UV-A and nano-TiO 2 , is an easy and accessible process to improve the packaging properties and photo-degradability of biopolymer based films., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In this study, ternary potato starch (PS) bionanocomposite films containing two types of nanoparticles, sodium montmorillonite (MMT), one-dimensional (1D) clay platelets, (3 and 5wt%) and TiO2, three-dimensional (3D) nanospheres, (0.5, 1 and 2wt%), are prepared using solvent casting method. X-ray diffraction (XRD) test confirms the completely exfoliated structure formed in the PS-MMT nanocomposites containing 3 and 5% MMT. The success of the formation of new hydrogen bonds between the hydroxyl groups of starch and nanofillers is confirmed by Fourier transform infrared (FTIR) spectroscopy. Tensile strength (TS), elongation at break (EB), glass transition temperature (Tg), and melting point (Tm) of the films are also enhanced after MMT and TiO2 incorporation. The water vapor permeability (WVP) and the visible, UVA, UVB and UVC lights transmittance decreases upon TiO2 and MMT content increasing. Generally, a synergistic effect is observed between MMT and TiO2 at lower concentrations of MMT., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this research, potato starch and TiO2 nanoparticles (0.5, 1 and 2wt%) films were developed. Influences of different concentrations of TiO2 on the functional properties of nanocomposite films (water-related properties, mechanical characteristics, and UV transmittance) were investigated. XRD, FTIR, and DSC analyses were used to characterize the morphology and thermal properties of the films. The results revealed that TiO2 nanoparticles dramatically decreased the values of water-related properties (water vapor permeability: 11-34%; water solubility: 1.88-9.26%; moisture uptake: 2.15-11.18%). Incorporation of TiO2 led to a slight increment of contact angle and tensile strength, and a decrease in elongation at break of the films. TiO2 successfully blocked more than 90% of UV light, while opacity and white index of the films were enhanced. Glass transition temperature and melting point of the films were positively affected by the addition of TiO2 nanoparticles. The result of XRD study exhibited that due to a limited agglomeration of TiO2 nanoparticles, the mean crystal size of TiO2 increased. Formation of new hydrogen bonds between the hydroxyl groups of starch and nanoparticles was confirmed by FTIR spectroscopy. In conclusion, TiO2 nanoparticles improved the functional properties of potato starch film and extended the potential for food packaging applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

This study was aimed to develop bio-nanocomposite films of carboxymethyl cellulose (CMC)/starch (ST) polysaccharide matrix reinforced with cellulose nanocrystals (CNC) using the solution casting method. The CNC were extracted at the nanometric scale from sugarcane bagasse via sulfuric acid hydrolysis and used as reinforcing phase to produce CMC/ST-CNC bio-nanocomposite films at different CNC loading levels (0.5-5.0 wt%). Steady shear viscosity and dynamic viscoelastic measurements of film-forming solution (FFS) of neat CMC, CMC/ST blend and CMC/ST-CNC bio-nanocomposites were evaluated. Viscosity measurements revealed that a transition from Newtonian behavior to shear thinning occurred when CNC were added. The dynamic tests confirmed that all FFS have a viscoelastic behavior with an entanglement network structure, induced by the hydrogen bonding. In regard to the cast film quality, the rheological data showed that all FFS were suitable for casting of films at ambient temperature. The effect of CNC addition on the optical transparency, water vapor permeability (WVP) and tensile properties of bio-nanocomposite films was studied. It was found that bio-nanocomposite films remain transparent due to CNC dispersion at the nanoscale. The WVP was significantly reduced and the elastic modulus and tensile strength were increased gradually with the addition of CNC. Herein, the steps to form new eco-friendly bio-nanocomposite films were described by taking advantage of the combination of CMC, ST and CNC. The as-produced films exhibited good optical transparency, reduced WVP and enhanced tensile properties, which are the main properties required for packaging applications., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Crystallized nanocellulose (CNC) was separated from paper-mulberry (Broussonetia kazinoki Siebold) bast pulp by sulfuric acid hydrolysis method and they were blended with agar to prepare bionanocomposite films. The effect of CNC content (1, 3, 5 and 10 wt% based on agar) on the mechanical, water vapor permeability (WVP), and thermal properties of the nanocomposites were studied. Changes of the cellulose fibers in structure, morphology, crystallinity, and thermal properties of the films were evaluated using FT-IR, TEM, SEM, XRD, and TGA analysis methods. The CNC was composed of fibrous and spherical or elliptic granules of nano-cellulose with sizes of 50-60 nm. Properties of agar film such as mechanical and water vapor barrier properties were improved significantly (p<0.05) by blending with the CNC. The tensile modulus and tensile strength of agar film increased by 40% and 25%, respectively, in the composite film with 5 wt% of CNC, and the WVP of agar film decreased by 25% after formation of nanocomposite with 3 wt% of CNC. The CNC obtained from the paper-mulberry bast pulp can be used as a reinforcing agent for the preparation of bio-nanocomposites, and they have a high potential for the development of completely biodegradable food packaging materials., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Adsorption isotherms of agar and agar/clay nanocomposite films prepared with different types of nanoclays, that is, a natural montmorillonite (Cloisite Na(+) ) and 2 organically modified montmorillonites (Cloisite 30B and Cloisite 20A), were determined at 3 different temperatures (10, 25, and 40 °C). The water vapor adsorption behavior of the nanocomposite films was found to be greatly influenced with the type of clay. The Guggenheim-Anderson-de Boer (GAB) isotherm model parameters were estimated by using both polynomial regression and nonlinear regression methods and it was found that the GAB model fitted adequately for describing experimental adsorption isotherm data for the film samples. The monolayer moisture content (m(o) ) of the film samples was also greatly affected by the type of nanoclay used, that is, m(o) of nanocomposite films was significantly lower than that of the neat agar film. Nanocomposite films prepared with hydrophobic nanoclays (Cloisite 30B and Cloisite 20A) exhibited lower m(o) values than those prepared with hydrophilic nanoclay (Cloisite Na(+) )., (© 2011 Institute of Food Technologists®)