Barrier Properties Of Films Research Articles

The impact of heat‐moisture treatment and pre‐gelatinization on functional, mechanical, and barrier properties of basmati rice starch films

Background and Objectives This study investigated the effect of heat-moisture treatment (HMT) and pre-gelatinization (PG) on the physical, mechanical, barrier, and optical features of films based on starch extracted from the Pakistani well-known variety “Basmati rice.” The thermal disintegration of granules was indicated by Scanning Electron Micrographs for HMT film. Findings The results of the study showed that the solubility of films in water was reduced in the following sequence: Pre-gelatinized rice starch film (33.66%) > Native rice starch (NRS) film (30.42%) > Heat moisture-treated rice starch (HMTRS) film (26.90%). The lowest water-soluble HMTRS film showed increased water transfer resistance and both treatments (HMT and PG) reduced water vapor permeability values of NRS from 2.49 × 10−10 to 1.25 × 10−10 g−1 s−1 Pa−1 and 1.34 × 10−10 g−1 s−1 Pa−1, respectively. Conclusions HMT induced structural deviations that impact higher changes in color parameters and reduced transparency while both modified films had higher elongation at break than NRS films, but PG films had lower TS as compared to the HMT and NRS films. Significance and Novelty The lower water vapor permeability of HMT films makes them suitable for packaging moisture-sensitive food products, while PG films can find use in the packaging of products that are sensitive to light.

Improving the Characteristics of Edible Film Using Modified Cassava Starch Over Ethanol Precipitation

Cassava starch has been widely explored as film forming material, however its hydrophilicity restricts its application. Hydrophobic material such as modified starch can be used in the film elaboration to improve its quality. This study aims to examine the effect of modified cassava starch concentration on the physical, barrier, and mechanical properties of edible films. A completely randomized design was used with 5 concentrations of modified starch at 0%, 5%, 10%, 15%, and 20% and 4 repetitions to obtain a total of 20 experimental combinations. The ANOVA showed that the modified starch concentration affected the compressive strength, thickness, transparency, and solubility of the edible film, but has no effect on its water vapor transmission rate (WVTR). Usage of 20% modified starch gave the product with the best characteristics at 0.22 mm thickness, 89.45 N/m2 strength, 6.484%/mm transparency, 52.19% solubility, and 21.00 g/m2.hour WVTR.

Investigating functional properties of halloysite nanotubes and propolis used in reinforced composite film based on soy protein/basil seed gum for food packaging application

This study aimed to investigate the effect of halloysite nanotubes (HNTs) on the physicochemical characteristics of the soy protein isolated/basil seed gum (SPI/BSG) film activated with propolis (PP). The obtained results of scanning electron microscope (SEM), thermal gravimetric analysis (TGA), and tensile investigations illustrated that the addition of HNTs as nanofiller led to positive changes in the morphology, thermal stability, and mechanical characteristics of SPI/BSG films. The barrier properties of films considerably decreased with incorporation of HNTs. Furthermore, the encapsulation of PP as bioactive agent into the produced films significantly increased (P < 0.05) the antioxidant potential of the samples in DPPH radical-scavenging activity assays. The antibacterial effects of film also significantly increased (P < 0.05) after the encapsulation of PP. In conclusion, the produced films illustrated acceptable efficiency for usage in food packaging system.

Incorporation of oxidized debranched starch/chitosan nanoparticles for enhanced hydrophobicity of corn starch films

Starch films have superior advantages owing to the renewability and low cost of starch; however, their strong inherent hydrophilic character greatly limits their practical application. This study aimed to improve the hydrophobicity of corn starch films by adding a new type of covalently formed, oxidized debranched starch/chitosan nanoparticles (SC-NPs). SC-NPs were obtained by a Schiff-base crosslinking reaction between the aldehyde group of dialdehyde debranched starch and the amino group of chitosan. Corn starch films reinforced with SC-NPs were obtained using a casting method. A mass ratio of dialdehyde debranched starch and chitosan of 3–5 yielded mainly spherical nanoparticles ranging from 50 to 150 nm in diameter determined by transmission electron microscopy. The water contact angle (WCA) of the pure starch film was only 19.4°, whereas the WCA values of the films reinforced with 3 % SC-NPs were greater than 70°, indicating that SC-NPs efficiently improved the hydrophobicity of corn starch films. The ultraviolet and visible light barrier property of starch films with 3 % SC-NPs were significantly enhanced in comparison with pure starch film. The water vapor permeability, water solubility, and swelling ratio were markedly lower in films with 3 % SC-NPs than in neat starch films.

Effects of argon dielectric barrier discharge (DBD) cold plasma treatment on mechanical, barrier and antimicrobial properties of chitosan film

SummaryThis research studied the effects of argon dielectric barrier discharge (DBD) plasma on properties of chitosan film to be used as active food packaging. The effects of plasma treatment time (0, 30, 60, 90 and 120 s) on tensile strength (TS), elongation at break (EAB), colour, water vapour permeability (WVP), oxygen transmission rate (OTR), contact angle and antimicrobial activity of films were investigated. Depending on the plasma treatment time, the TS values of plasma‐treated film increased, but there were no significant differences between the EAB of control and treated films. The formation of the oxygen‐containing groups and the occurrence of etching affected the WVP, contact angle, roughness and antimicrobial activity of plasma‐treated film. Chitosan film treated with 60 s of DBD plasma had good OTR (&lt;0.05 cc m−2 day−1), hydrophilicity and antimicrobial activity against various kinds of bacteria. However, it may need longer than 60 s of the treatment time to increase the WVP of the films. Overall, these results implied that plasma treatment can be used as an alternative non‐thermal approach for improving the characteristics of film packaging.

Promising nanocomposites for food packaging based on cellulose – PCL films reinforced by using ZnO nanoparticles in an ionic liquid

The fact that most composites consist of polluting synthetic materials has prompted a search for biodegradable replacements based on cellulose fibers and polycaprolactone as potential packaging materials. In this work, we developed a green, efficient approach to rendering hydrophobic polycaprolactone (PCL) compatible with hydrophilic cellulose fibers by using an ionic liquid as a nanowelding agent in the presence of zinc oxide nanoparticles (ZnONPs). Transparent biobased nanocomposite films were thus directly obtained by in situ ring-opening polymerization (ROP) of ε-caprolactone (CL) monomers onto the dissolved cellulose matrix by using the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac). [EMIM]Ac and ZnONPs were efficiently catalyzed ε-caprolactone ROP under mild conditions. Cellulose-grafted PCL nanocomposite films were obtained by adding variable amounts of CL and ZnONPs to the cellulose matrix. The maximum grafting of 40% was achieved by using 5▒wt% ZnONPs and 70% CL. FTIR spectra confirmed the presence of PCL in the nanocomposites. Also, FE-SEM revealed uniform dispersion of ZnONPs and PCL in the regenerated cellulose matrix, and trapping of nanoparticles in nanofibrils after the cellulose matrix was regenerated. X-ray diffraction (XRD) spectra showed a decreased apparent crystallinity and crystallite size. The XRD results also confirmed that the crystal properties of the nanocomposite films and an all-cellulose composite (ACC) were almost identical. The mechanical, barrier and optical properties of the nanocomposite films were significantly better than those of the ACC film by effect of the incorporation of ZnONPs and PCL especially with 5▒wt% ZnONPs and 70% CL). The nanocomposite films exhibited acceptable antioxidant activity and UV-light barrier properties, so they hold promise for used in food packaging. Nanocomposite films are in fact multifunctional materials with the potential for use in cellulose-based food packaging by virtue of their being transparent and bio-based, and possessing very good water vapor and oxygen barrier properties.

Starch-based environment friendly, edible and antimicrobial films reinforced with medicinal plants.

In the current study, cornstarch-based antimicrobial and edible films were designed using solution-casting methods. The medicinal plants (Acontium heterophyllum, Artemisia annua, and Thymus serpyllum) reinforced the gelatinized solution in different concentrations as fillers. The effect of plant extracts on antimicrobial and antioxidant potential, microstructure, barrier, thermal and mechanical properties of cornstarch-based films (SBFs) was investigated using antimicrobial activity, DPPH free radical scavenging values, scanning electron microscopy, X-ray diffraction, water vapor transmission rate, differential scanning calorimetry, and tensile strength. Likewise, it was depicted that the geometric and crystalline structures of medicinal plants' reinforced films remained the same even after processing. The mechanical tests indicated that the plant extracts effects are associated with reduced elongation, increasing tensile strength, and Young's modulus. Morphological analysis revealed the generation of uniform and the compact surfaces. However, films with 10% concentration of plant extracts have the lowest water vapor permeability values, and emerged better barrier properties. Moreover, these films showed the significant antioxidant potential and antimicrobial activity.

Characterization of Biodegradable Films Made from Taro Peel (Colocasia esculenta) Starch.

Studies of renewable polymers have highlighted starch's role to replace petroleum-based components to produce biodegradable films with plastic-like qualities. In this study, the novelty of taro peel starch (TPS) to produce such films using the casting technique is reported for the first time. A response surface method (RSM) approach was employed to optimize different concentrations of TPS (2.5-3.5%, w/w) and glycerol (25-35%, w/w) and investigate their effects on the physico-mechanical and water barrier properties of TPS films. TPS films showed a positive linear effect (p &lt; 0.05) for thickness (0.058-0.088 mm), opacity (1.95-2.67), water vapor permeability (0.06-0.09 g∙m/m2∙kPa∙h), and cubic effect (p &lt; 0.05) for moisture content (0.58-1.57%), which were linked to high starch concentrations when plasticized with glycerol. X-ray diffraction analysis of TPS films depicted "amorphous"-type crystalline structure peaks at 19.88°, while the thermogravimetric analysis of the film samples exhibited 75-80% of the weight loss of TPS film in the second phase between temperatures of 300 °C to 400 °C. All films exhibited homogenous, transparent surfaces with flexibility, and completely degraded in 5 days in simulated river water and composting soil environments, which confirmed TPS as a promising film polymer in food packaging.

Oxidative treatment and nanofibrillation softwood kraft fibres with lytic polysaccharide monooxygenases from Trichoderma reesei and Podospora anserina

Cellulose oxidation and enzymatic treatments can be employed to reduce the energy consumption in production of cellulose nanofibrils (CNFs). Lytic polysaccharide monooxygenases (LPMOs) offer new biocatalytic tools for oxidative pretreatment of cellulosic fibres in this process. In this work the capability of LPMO enzymes to enhance fibrillation of bleached softwood kraft fibres was studied using two LPMO enzymes, i.e. C1/C4-oxidising AA9A from Trichoderma reesei (Tr AA9A) and C1-oxidising AA9E from Podospora anserina (Pa AA9E). The enzymatic treatments were carried out after mechanical pre-refining (grinding) of the pulp, which resulted in clear reduction of the intrinsic viscosity of the refined fibres compared to the previously published work, presumably due to better access of the enzymes on the fibre polysaccharides. The Tr AA9A treatments were carried out using different enzyme dosages (0.25–10 mg/g dry fibre) and fixed reaction time (24 h), resulting in fibres characterized by increased aldehyde content, which is in line with the C1/C4 oxidising activity of this enzyme. Comparison of the Tr AA9A to Pa AA9E with fixed enzyme dosage (2 mg/g dry fibre) and reaction time (24 h), showed that no remarkable increase in total charge of the cellulosic fibres could be obtained with either of the LPMO enzymes in these conditions. All the LPMO pretreatments improved fibrillation of mechanically refined fibres in microfluidization, seen as clearly lower residual fibre content and higher proportion nanosized material. In comparison of the Pa AA9E to Tr AA9A, clearly faster fibrillation was achieved with the Pa AA9E pretreatment. The mechanical and oxygen barrier properties of CNF films prepared from LPMO pretreated fibres were very similar to the reference CNF films while water vapour transmission rate was somewhat higher.

Novel active edible food packaging films based entirely on citrus peel wastes

This is the first report on mobilizing three value-added compounds from citrus peel wastes to fabricate novel/cost-effective active edible films with multiple functionalities. Pectin extracted from grapefruit peels (GFP) with improved recovery yields (48.35%), displayed better thermal stability and superior physico-chemical properties to commercial citrus pectin ( CPec ) with regard to methoxylation degree, anhydrouronic acid and moisture contents. Active films plasticized with PEG 400 (25% w/w of polymer) were prepared by solution casting upon incorporating 0.04% (w/v) of grapefruit peel methanolic extract (GFPE) and maltodextrin-encapsulated lemon peel extract (MD-LPE) into grapefruit pectin ( GFPec ; 3% w/v) matrix. The bioactive ingredients and the optimally active ( GFPec -GFPE/MD-LPE) film-forming solutions exhibited strong radical scavenging and antimicrobial activities against foodborne pathogens. SEM micrographs of the optimal active film revealed good dispersion and compatibility of ingredients in agreement with the FTIR data that confirmed no modifications in the film's functional groups. GFPE and MD-LPE capsules synergistically enhanced the tensile strength, thermal, water vapor/UV barrier properties and soil biodegradability of the elaborated transparent flexible films compared to CPec -based films. Wrapping of artificially contaminated cherry tomatoes with optimal active films inhibited the growth of a four-strain cocktail suspension of E. coli O157:H7 by ∼1.6 log units after 6 days of chilled storage. Overall, the study highlights the benefits of citrus wastes valorization, provides evidence of potential applicability of the fabricated novel edible GFPec -based films as candidates for antimicrobial food packaging, shelf life extension of fresh-cut produce, and supports their consideration as promising eco-friendly alternatives to synthetic food packaging materials. • Three value-added compounds were mobilized from citrus peels for film fabrication. • High methoxyl grapefruit pectin showed superiority to commercial citrus pectin. • Free and encapsulated extracts had remarkable antioxidant and cytotoxic activities. • Incorporating both ingredients enhanced thermal and barrier properties of films. • The novel active film inhibited E. coli O157:H7 growth on wrapped cherry tomatoes.

Improving barrier and antibacterial properties of chitosan composite films by incorporating lignin nanoparticles and acylated soy protein isolate nanogel

Chitosan (CS) films have demonstrated strong antibacterial properties, excellent biocompatibility and biodegradability, but poor UV blocking, oxygen and water barrier and mechanical properties limit their application in antimicrobial food packaging. In this study, CS films were incorporated with nanofillers, including lignin nanoparticles (LNP, 1–5 wt %) and acylated soy protein isolate nanogel (ASPNG, 3–7 wt %) to improve their tensile strength, oxygen and water barrier, UV blocking and antibacterial properties. SEM images illustrated that the addition of LNP and ASPNG significantly affected the surface morphology of the CS film. Meanwhile, LNP incorporation improved UV blocking property of composite film, while an improved sustained antibacterial property was achieved with ASPNG incorporation. Interestingly, CS composite film incorporated with 3% LNP and 5% ASPNG showed a remarkable increase in tensile strength (37.29–54.29 MPa) and decreased oxygen barrier property (5.73–2.83 cm 3 /m 2 ·24h MPa) relative to pure CS film. It is worth mentioning that the bacterial counts in samples treated by 3% LNP/5% ASPNG-CS composite film decreased approximately 2.37 log CFU/mL, which exhibited higher antibacterial activity than other composite films. However, this study also demonstrated that incorporation of LNP and ASPNG slightly decreased the light transmission and increased surface roughness of CS film. All in all, the CS composite film with enhanced mechanical, barriers, antibacterial properties were obtained by incorporating an appropriate proportion of LNP and ASPNG and could further be utilized as a promising antibacterial food packaging material. • Lignin nanoparticles (LNP) and acylated soy protein isolate nanogel (ASPNG) were fabricated. • LNP and ASPNG incorporation improved tensile strength and elongation at break of the film. • LNP and ASPNG incorporation improved oxygen and water vapor barrier properties of the film. • 3% LNP/5% ASPNG enhanced CS film's potassium sorbate sustained release ability. • 3% LNP/5% ASPNG-CS film had higher antibacterial activity than pure chitosan film.

Composite films with properties improved by increasing the compatibility of sodium caseinate and zein in a heated 60% ethanol solvent

To improve the mechanical and barrier properties of zein films, sodium caseinate (CN) was combined with zein to fabricate composite films, by achieving co-dispersion of the two proteins in a newly developed film-forming solvent mixture (60% v/v aqueous ethanol, at 65 °C). The synergistic interactions between CN and zein at various ratios in the films were evaluated. Incorporation of CN into zein-based films increased elongation at break, tensile strength and water contact angle, and decreased water vapor permeability. The film with a CN/zein ratio of 0.75:1 had the lowest water vapor permeability (2.53 ± 0.07 × 10 −12 g/(m·s·Pa)), and that with a ratio of 1.25:1 had high elasticity, with an elongation at break 4.11 times that of a pure zein film. CN addition also increased the thermal stability of the composite films, such that films with a CN to zein ratio of 0.75:1 had the highest glass-transition temperature (105.3 °C). Infrared spectral analysis confirmed the high compatibility and strong interactions between CN and zein, and scanning electron microscopy indicated that the microstructure of the composite films was more compact and homogeneous than pure zein films. However, atomic force microscopy revealed that the composite films had a rougher surface. This study provides new perspectives for the development and application of protein-based films as food packaging materials. • CN and zein can be well co-dispersed in hot (65 °C) 60% aqueous ethanol. • The CN/zein composite films showed improved barrier and water resistance. • Addition of CN reduced the brittleness of zein-based films. • Compact structure and rough surface of CN/zein composite films were observed. • The CN/zein ratio of 0.75 is the best for synergistic interactions of both.

Rheology of nano ZnO - Hydroxypropyl Methylcellulose (HPMC) based suspensions and structural properties of resulting films

Effect of polyethylene glycol (PEG) and ZnO nanoparticles concentration on rheological properties of the hydroxypropyl methylcellulose (HPMC) based film forming suspensions (FFS) and, on the structural properties of the resulting films were characterized. Rheological properties of FFS were not significantly affected by PEG concentration and ZnO NPs incorporation. Intrinsic viscosity [η] of aqueous HPMC solution obtained from extrapolation of Huggins and Kraemer plot was 0.115–0.118 (L/g). Coating thickness calculated as a function of coating solution viscosity, concentration and draining time for strawberry coating was 1.26–1.49 μm. Tensile strength (TS) of HPMC film decreased while water vapour permeability (WVP) increased with increasing PEG concentration. Elongation at break (%E) increased up to 25% PEG concentration and decreased afterward. Incorporation of ZnO NPs improved the tensile strength and barrier properties of HPMC film. Relaxation percentage and stress decay rate increased with increasing plasticizer concentration while decreased with incorporation of ZnO NPs. • Rheological behaviour of aqueous HPMC solution (4% w/v) was Newtonian. • Calculated Intrinsic viscosity [η] of aqueous HPMC solution was 0.115–0.118 (L/g). • Relaxation % and stress decay rate showed positive correlation with PEG concentration. • Added ZnO nanoparticles improves the HPMC film properties.

Additives in Edible Soy Protein Film Incorporation of Polysaccharides, Nano Polysaccharides, Vegetable Oils and Phenolic Additives in Edible Soy Protein Film

Soy protein isolate (SPI) is one such plant derived protein that holds significant potential for fabrication of edible films and packaging materials owing to its smooth, flexible and fair film forming abilities. However, native SPI suffers from several limitations such as poor water resistance, tensile strength, and susceptibility towards microbial attack. Many plants and animal derived compounds have been tried and tested to improve the material properties of these films. Incorporation of polysaccharides, nano polysaccharides, vegetable oils and polyphenolic compounds are explored to attain desirable properties in prepared films. Phenolic compounds are generally targeted to increase the tensile strength and resistance towards microbial attack as they possess rigid planar aromatic ring and hydroxyl groups that make them suitable candidate of choice. Polysaccharides or nanopolysaccharides and vegetable oils are reported to enhance the oxygen, carbon dioxide gas barrier properties of edible films that could delay putrefaction of packaged food items. Moreover, polyphenols and polysaccharide compound also exhibit bacteriostatic and bactericidal effect against S. aureus, L. monocytogenes and E. coli. This review paper summarizes the incorporation of polyphenolics, polysaccharides, nanopolysaccharides and vegetable oils in SPI films followed by their material and antibacterial characterization.

Development and characterization of antioxidant bilayer film based on poly lactic acid-bitter vetch (Vicia ervilia) seed protein incorporated with Pistacia terebinthus extract for active food packaging

This study focuses on designing an active bilayer food package film based on polylactic acid (PLA) and bitter vetch seed protein incorporated with Pistacia terebinthus extract (PTE). The effect of PTE on the physicochemical, barrier, structural, mechanical, and antioxidant properties of the active film was determined. Moisture content, water solubility, and water vapor permeability (WVP) of the active films indicated that the addition of PTE increased its suitability for food packaging. FE-SEM micrographs illustrated that the resulting films had a smooth and dense surface, describing a continuous network of protein molecules within the film structure. FTIR analysis displayed the physical interaction between PTE and the film polymer. XRD revealed an increase in the crystallinity of the active films. The resulting active film had a low migration rate (<7%) of phenolic compounds into fatty food simulant. Notably, the addition of PTE significantly (P ≤ 0.05) decreased the tensile strength and Young's modulus (from 15.13 and 315.98 MPa to 14.07 and 254.07 MPa, respectively). Concurrently, there was an increase in the elongation at break of the active films (from 23.19 to 75.60%), indicating higher flexibility compared to control films. Additionally, the incorporation of PTE improved the thermal properties of active films. The antioxidant capacity of the designed films was measured based on their DPPH radical scavenging activity, revealing that the antioxidant capacity of the control film increased from 44.65% to 59.72% in the active film containing 15% PTE. In conclusion, the prepared bilayer film can effectively be used as an active food package for sensitive foods to oxidation.

Effects of physical crosslinking methods on digestibility &lt;i&gt;in vitro&lt;/i&gt; and safety of edible packaging: A primary study on collagen films

Crosslinking is often used to improve the mechanical strength and barrier properties of edible films. However, the effects on films’ digestibility and edible safety are still unknown. Herein, four crosslinking methods were utilized to crosslink collagen films, including UV irradiation, dehydrothermal treatment (DHT), tannin and glutaraldehyde. The crosslinked samples were then researched via <italic>in vitro</italic> digestion and cell culture model. With the INFOGEST method, the results of dry matter loss, degree of hydrolysis and absorbed collagen content have significantly correlated relation and showed the excellent digestive ability of UV treated and DHT films. The results of the FTIR suggest that the crosslinking affects the structure of digestion and absorption. The toxicity and nutrition of the hydrolytes of collagen films were measured in Caco-2 and HepG-2 cells, and the collagen films, especially UV treated and tannin treated films, can promote cell growth while the glutaraldehyde treated one reduced cell viability presumably due to its residual in the films.

Improving the active food packaging function of poly(lactic acid) film coated by poly(vinyl alcohol) based on proanthocyanidin functionalized layered clay

In this paper, natural plant polyphenol-proanthocyanidin (PAC) and layered clay-layered double hydroxides (LDHs) were firstly introduced into poly(vinyl alcohol) (PVA) based coatings to construct PAC/PVA and PAC functionalized LDHs (LDHs@PAC-Cu)/PVA dual active coatings, and further successively coated on the surface of PLA base films to develop PLA active films. The results showed that PAC and copper ions were successfully loading on the LDHs surface through adsorption and complexation. After a certain amount (≥3 wt%) of LDHs@PAC-Cu was added, active packaging functions and gas barrier properties of PLA active films were improved markedly. When 5 wt% LDHs@PAC-Cu was added, antioxidant and antibacterial properties of PLA active films reached 84.31% and 95.5%, oxygen and water vapor transmission rate decreased by 99.4% and 62.6% compared with PLA base film, and the shelf life of pasteurized milk was extended from 60 h to 96 h. Active substances release test indicated that LDHs@PAC-Cu could not only delay the release of active substances in the early stage, but also supplement the release of active substances in the later stage, thus extending the shelf life of food more effectively. Therefore, PLA active films have good application potential in the field of active food packaging.

Polymorphism, Nanostructures, and Barrier Properties of Ceramide-Based Lipid Films.

Ceramides belong to sphingolipids, an important group of cellular and extracellular lipids. Their physiological functions range from cell signaling to participation in the formation of barriers against water evaporation. In the skin, they are essential for the permeability barrier, together with free fatty acids and cholesterol. We examined the periodical structure and permeability of lipid films composed of ceramides (Cer; namely, N-lignoceroyl 6-hydroxysphingosine, CerNH24, and N-lignoceroyl sphingosine, CerNS24), lignoceric acid (LIG; 24:0), and cholesterol (Chol). X-ray diffraction experiments showed that the CerNH24-based samples form either a short lamellar phase (SLP, d ∼ 5.4 nm) or a medium lamellar phase (MLP, d = 10.63-10.78 nm) depending on the annealing conditions. The proposed molecular arrangement of the MLP based on extended Cer molecules also agreed with the relative neutron scattering length density profiles obtained from the neutron diffraction data. The presence of MLP increased the lipid film permeability to the lipophilic model permeant (indomethacin) relative to the CerNS24-based control samples and the samples that had the same lipid composition but formed an SLP. Thus, the arrangement of lipids in various nanostructures is responsive to external conditions during sample preparation. This polymorphic behavior directly affects the barrier properties, which could also be (patho)physiologically relevant.

Rheological performance of film-forming solutions and barrier properties of films fabricated from cold plasma-treated high methoxyl apple pectin and crosslinked by Ca2+: Impact of plasma treatment voltage

Sustainable and “green” technologies, such as cold plasma are gaining attention in recent times for improving the functional properties of hydrocolloids. Chemical modifications of hydrocolloids require several chemicals and solvents, which are not environment-friendly. The major objective of the study was to understand the impact of plasma treatment (170–230 V|15 min) on the rheology of film-forming solutions (FFS) and the barrier properties of pectin films. The film-forming properties of plasma-treated pectin were investigated in the presence of two plasticizers, namely, glycerol and polyethylene glycol (PEG) 400. The effects of cross-linking by CaCl2 on the rheology of FFS and barrier properties of the films were discussed. A voltage-dependent decrease in the apparent viscosity of FFS was observed. The viscoelastic properties of the FFS were enhanced due to cross-linking. Glycerol exhibited a better plasticizing effect than PEG. Cross-linking and increasing voltage synergistically contributed towards lower oxygen and carbon dioxide transmission rates. The moisture sorption rate and capacity of the films increased with the voltage of the treatment. The resistance to extension of the films made from glycerol and PEG decreased with voltage, with no significant change in extensibility. On the other hand, the cross-linking by Ca2+ and plasma treatment enhanced the resistance to extension for the films made from both the plasticizers. While the increasing hydrophilicity and opacity of the films were a major drawback of plasma modification, the increase in UV barrier property of the films was an advantage of the modification.

Production, characterization, and antimicrobial activity of almond gum/polyvinyl alcohol/chitosan composite films containing thyme essential oil nanoemulsion for extending the shelf-life of chicken breast fillets

In this study, thyme essential oil (TEO) nanoemulsion was immobilized within composite films based on almond gum (AG), polyvinyl alcohol (PVA), and chitosan (CS). The physical, mechanical, water barrier, microstructural and antimicrobial properties of composite films were assessed. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the intermolecular interactions in the composite film matrix. The results indicated that the incorporation of TEO into the composite films increased thickness, moisture content, and water vapor permeability, while it reduced light transmittance and transparency value. The antimicrobial activity of films against gram-negative and gram-positive bacteria was tested using a disc diffusion method. The effect of composite on the microbiological properties of chicken breast fillets was investigated during refrigerated storage for 21 days. The microbial populations of total mesophilic, psychrotrophic, and lactic acid bacteria of the samples that were coated with the composite containing TEO were lower than the permitted limit after 21 days while for blank samples they were higher than 7 log CFU/g after 7 days which is considered as the maximum acceptable total count limit. Results disclosed that AG/PVA/CS composite films containing TEO nanoemulsion can be applied as eco-friendly active food packaging to enhance the shelf-life of food products.