Search Results (777)

To improve the postharvest preservation of cherry tomatoes and combat pathogenic, both bacterial and fungal contamination (particularly Alternaria alternata), a novel biodegradable coating was developed based on a water-in-water (W/W) Pickering emulsion system. The emulsion was stabilized by L. plantarum (Lactobacillus plantarum), with maltodextrin (MD) as the dispersed phase and hydroxypropyl methylcellulose (HPMC) as the continuous phase. Characterization of emulsions at varying concentrations revealed that the optimized W/W-PL^8 film exhibited superior stability, smooth morphology, and low water vapor permeability (WVP = 220.437 g/(m²·24 h)), making it a promising candidate for fruit and vegetable preservation. Furthermore, the coating demonstrated strong antioxidant activity, with scavenging rates of 58.99% (ABTS) and 94.23% (DPPH), along with potent antimicrobial effects, showing inhibition rates of 12.8% against Escherichia coli and 23.7% against Staphylococcus aureus. Applied to cherry tomatoes, the W/W-PL^8 coating significantly reduced respiration rates, minimized decay incidence, and maintained nutritional quality during storage. Remarkably, the coating successfully controlled Alternaria alternata contamination, enhancing the storage duration of cherry tomatoes. These findings highlight the potential of W/W-PL^8 as an eco-friendly and functional packaging material for fresh produce preservation. Full article

In this study, multicomponent PLA-based biocomposites were developed. In particular, both native fibrous cellulose and cellulose with modified morphology obtained through ball milling treatments were incorporated into the polyester matrix in combination with an oligomeric plasticizer, specifically a lactic acid oligomer (OLA). The resulting materials were analyzed in terms of their morphology, thermal and mechanical properties over time, water vapor permeability, and degradation under soil burial conditions in comparison to neat PLA and unplasticized PLA/cellulose composites. The cellulose phase significantly affected the mechanical properties and enhanced their long-term stability, addressing a common limitation of PLA/plasticizer blends. Additionally, water vapor permeability increased in all composites. Finally, the ternary systems exhibited a significantly higher degradation rate in soil burial conditions compared to PLA, evidenced by larger weight loss and reduction in the molecular weight of the PLA phase. The degradation rate was notably influenced by the morphology of the cellulose phase. Full article

In recent years, active packaging has become a focal point of research and development in the food industry, driven by increasing consumer demand for safe, high-quality, and sustainable food products. In this work, solvent casting processed an active antibacterial multicomponent film based on hydroxypropyl methylcellulose incorporated with ferulic acid and chitin nanofibers. The influences of ferulic acid and different content of chitin nanofibers on the structure, thermal, mechanical, and water vapor stability and antioxidant and antibacterial efficiency of films were studied. It was shown that the inclusion of only ferulic acid did not significantly influence the mechanical, water vapor, and thermal stability of films. In addition, films containing only ferulic acid did not display antibacterial activity. The optimal concentration of chitin nanofibers in hydroxypropyl methylcellulose–ferulic acid films was 5 wt%, providing a tensile strength of 15 MPa, plasticity of 52%, and water vapor permeability of 0.94 × 10⁻⁹ g/m s Pa. With further increase of chitin nanofibers content, films with layered and discontinuous phases are obtained, which negatively influence tensile strength and water vapor permeability. Moreover, only films containing both ferulic acid and chitin nanofibers demonstrated antibacterial activity toward E. coli and S. aureus, suggesting that the presence of fibers allows easier release of ferulic acid from the matrix. These results imply that the investigated three-component systems have potential applicability as sustainable active food packaging materials. Full article

Bio-nanocomposites based on poly (vinyl alcohol) (PVA) and cellulosic nanostructures are favorable for active food packaging applications. The current study systematically investigates the mechanical properties, gas permeation, and swelling parameters of PVA composites with cellulose nanocrystals (CNC) or nano lignocellulose (NLC) fibers. Alterations in these macroscopic properties, which are critical for food packaging applications, are correlated with structural information at the molecular level. Strong interactions between the fillers and polymer host matrix were observed, while the PVA crystallinity exhibited a maximum at ~1% loading. Finally, the orientation of the PVA nanocrystals in the uniaxially stretched samples was found to depend non-monotonically on the CNC loading and draw ratio. Concerning the macroscopic properties of the composites, the swelling properties were reduced for the D1 food simulant, while for water, a considerable decrease was observed only when high NLC loadings were involved. Furthermore, although the water vapor transmission rates are roughly similar for all samples, the CO₂, N₂, and O₂ gas permeabilities are low, exhibiting further decrease in the 1% and 1–5% loading for CNC and NLC composites, respectively. The mechanical properties were considerably altered as a consequence of the good dispersion of the filler, increased crystallinity of the polymer matrix, and morphology of the filler. Thus, up to ~50%/~170% enhancement of the Young’s modulus and up to ~20%/~50% enhancement of the tensile strength are observed for the CNC/NLC composites. Interestingly, the elongation at break is also increased by ~20% for CNC composites, while it is reduced by ~40% for the NLC composites, signifying the favorable/unfavorable interactions of cellulose/lignin with the matrix. Full article

The purpose of this paper is to evaluate the thermophysiological comfort of pineapple bio-based nonwoven material as a sustainable alternative to natural leather and synthetic polymer-coated materials by analyzing both the objective parameters of the material and subjective user feedback by wearing a skirt made from the same material. Considering the increasing demand for sustainable materials alternatives, the study aims to determine whether this material can offer acceptable comfort during wear. The research included two commercially available pineapple, bio-based, nonwoven materials that differed in their finishing. Sample S1 contained 5% Bio-PU and 5% conventional PU, and sample S2 contained 10% conventional PU. Objective parameters such as thermal resistance (R_ct), water vapor resistance (Ret) and air permeability were measured. For the subjective evaluation, ten female subjects wore the pineapple bio-based material skirts under controlled environmental conditions. Sample S1 showed lower R_ct values and slightly lower Ret combined with higher air permeability, which correlated with better subjective comfort evaluation. Although both samples showed high R_et values (S1 = 60.57 Pa²/W; S2 = 84.80 m²K/W) indicating limited vapor transfer, sample S1 was perceived as more comfortable, which was effected by better air permeability (S1 = 11.3 mm/s; S2 = 2.65 mm/s). Overall, S1 is more suitable for indoor use and for a shorter wear duration, while S2 may be better for cooler outdoor environments. Full article

This work presents a comprehensive evaluation of the heat-sealability of films developed from chañar brea gum (CBG), a biopolymer with potential for packaging applications. Heat sealability is a critical property in the packaging industry, as it directly determines the integrity and functionality of the final product. The films were prepared by the 10% casting method with the addition of glycerin, and heat sealing was performed at 140 °C using a heat sealer. Heat sealing was performed on 2 cm × 10 cm strips of chañar gum in the horizontal (CBG-H) and vertical (CBG-V) directions. This study employs a joint determination to explore the fundamental properties of the films, including proximate analysis, antioxidant capacity, FTIR, DSC, TGA-DTGA, XRD, mechanical testing, water vapor permeability, sorption, and biodegradability. By integrating the results of all these determinations, this study seeks to evaluate and explain the “intimate relationships”—i.e., the complex interconnections among the molecular structure, composition, thermal behavior, mechanical properties, and barrier properties of channier gum films—and how these fundamental properties dictate and control their heat sealability. The thermal stability of CBG is up to 200 °C, with a melting point of 152.48 °C. The interstrand spacing was very similar at 4.88 nm for CBG and 4.66 nm for CBG-H. The SEM images of the heat seal show rounded shapes on the surface, while in the cross section, it is homogeneous and almost without gaps. The WVP decreased from 1.7 to 0.37 for CBG and CBG-H, respectively. The Young’s modulus decreased from 132 MPa for CBG to 96.5 MPa for CBG-H. The heat sealability is 656 N/m, with a biodegradability of 4 days. This comprehensive approach is crucial for optimizing the sealing process and designing functional and efficient biodegradable packages. Full article

The objective of this work was to produce and characterize active gelatin–acerola packaging films based on gelatin incorporated with different concentrations of acerola pulp and applied to evaluate the stability of meat products in packaging. The active films were produced by casting using gelatin (5%), sorbitol (0,1%), and acerola pulp (60, 70, 80, and 90%). The characterization of the acerola pulp was carried out. Visual aspects, thickness, pH, water vapor permeability, and total phenolic compounds were characterized in the films. The commercial acerola pulp presented the characteristics within the identity and quality standards. A good film formation capacity was obtained in all formulations, presenting the color parameters tending to red coloration, characteristic of the acerola pulp. The total phenolic compounds content ranged from 2.88 ± 70.24 to 3.94 ± 96.05 mg GAE/100 g, with 90 g of acerola pulp per 100 g of filmogenic solution. This film formulation was selected to apply in a vacuum pack of beef and chicken samples, analyzing the weight loss, color parameters, pH, water holding capacity, shear strength after 9 days of refrigeration storage, and soil biodegradability. Additionally, beef and chicken (in nature) were stored under the same conditions without using the wrapping film. The beef and chicken samples showed greater water retention capacity and color maintenance over the storage period compared to the control (without film addition). This way, active gelatin–acerola films can be considered a sustainable packaging alternative to preserve meat products. Full article

This study aimed to improve the hydrophobicity of cellulose nanofibril (CNF) films using a natural wax coating. For this purpose, firstly, the selection, extraction and characterization of a natural wax and fatty acids were carried out. These compounds were extracted from the aerial part of the Halimium viscosum plant. The chromatogram resulting from the chemical analysis of the extract revealed the presence of 15 compounds, with nonacosane being the major compound present. For film production, two different chemical pulps gels (sulfite and sulfate) were first characterized in terms of solids content, rheology and Fourier transform infrared spectroscopy (FTIR). The CNF films were produced by the solvent casting method, coated on one side with the extracted wax and subsequently characterized by wettability, surface energy, differential scanning calorimetry (DSC), FTIR, structural properties and water vapor permeability. The results showed that the wax-coated films exhibited a significant increase in water resistance, with a water contact angle exceeding 100°, demonstrating improved hydrophobicity. Also, the water vapor transmission rate (WVTR) of the films was drastically reduced after wax coating. Furthermore, the coated films maintained good transparency, making them a viable alternative to synthetic plastic. This study highlights the potential of natural wax coatings to improve the moisture barrier properties of biodegradable CNF films, promoting their application in sustainable packaging solutions. Full article

Film-forming solutions were prepared using Tara gum (TG), with glycerol (GL) as a plasticizer and orange peel powder (OP) as a filler. A TG stock solution (10 g/L) was initially prepared to facilitate homogenization, from which appropriate dilutions were made to obtain final concentrations of 0.6%, 0.8%, and 1.0% (w/v). GL (30% and 50%) and OP (0%, 20%, and 50%) were incorporated based on the dry weight of TG, meaning their amounts were calculated relative to TG content to ensure consistent formulation ratios. Rheological parameters, including the flow behavior index, consistency coefficient, storage modulus (G′), and loss modulus (G″), were characterized via steady shear and oscillatory rheometry. Mechanical properties, such as the Young’s modulus, tensile strength, and elongation at break, were also evaluated. A strong positive correlation (R² = 0.840) was observed between G′ and the Young’s modulus, indicating that solutions with higher internal network strength yield films with greater stiffness. The synergistic interaction between TG and OP was critical: TG primarily enhanced stiffness and mechanical reinforcement, whereas OP improved structural cohesion and stability. GL functioned as a plasticizer, increasing film flexibility while reducing stiffness. These interactions led to a reduction in film solubility by up to 62.43%, particularly in formulations without orange peel powder. In contrast, mechanical strength increased by up to 50.21% in films containing orange peel powder, as those without it exhibited significantly lower tensile strength. Flexibility, expressed as elongation at break, was enhanced by up to 78.86% in formulations with higher glycerol content. Barrier properties were also improved, demonstrated by decreased water vapor permeability and increased hydrophobicity, attributed to the TG–OP synergy. A regression model (R² = 0.928) substantiated the contributions of TG to stiffness, OP to matrix reinforcement, and GL to flexibility modulation. This study underscores the pivotal role of rheological behavior in defining film performance and presents a novel analytical framework applicable to the design of sustainable, high-performance biopolymeric materials. Full article

Ammonia (NH₃) detection in liquids and biological fluids is essential for monitoring environmental contamination and industrial processes, ensuring food safety, and diagnosing health conditions. Existing detection techniques are often unsuitable for point-of-care (POC) use due to limitations including complex sample handling, lack of portability, and poor compatibility with miniaturized systems. This study introduces a proof-of-concept for a compact, portable device tailored for POC detection of gaseous ammonia released from liquid samples. The device combines a polyaniline (PANI)-based chemoresistive sensor with interdigitated electrodes and a resistance readout circuit, enclosed in a gas-permeable hydrophobic membrane that permits ammonia in the vapor phase only to reach the sensing layer, ensuring selectivity and protection from liquid interference. The ink formulation was optimized. PANI nanoparticle suspension exhibited a monomodal, narrow particle size distribution with an average size of 120 nm and no evidence of larger aggregates. A key advancement of this device is its ability to limit the impact of water vapor, a known source of interference in PANI-based sensors, while maintaining a simple sensor design. A tailored signal processing strategy was implemented, extracting the slope of resistance variation over time as a robust metric for ammonia quantification. The sensor demonstrated reliable performance across a concentration range of 1.7 to 170 ppm with strong logarithmic correlation (R² = 0.99), and very good linear correlations in low (R² = 0.96) and high (R² = 0.97) subranges. These findings validate the feasibility of this POC platform for sensitive, selective, and practical ammonia detection in clinical and environmental applications. Full article

Carboxymethyl chitosan (CMCS) exhibits excellent film-forming capability but suffers from limited water resistance. To enhance hydrophobicity and antimicrobial properties, citrus essential oil was emulsified directly with citrus pectin and dispersed into the CMCS matrix. This study investigated the effects of varying emulsion concentrations (0, 1, 3, 5, and 7 wt%) on film performance. FT-IR, XRD, and SEM analyses confirmed uniform emulsion distribution within the CMCS matrix with favorable compatibility. Increased emulsion loading improved water resistance, antioxidant activity, and antimicrobial efficacy of the CMCS-based films, with the 3% emulsion concentration achieving optimal mechanical strength (TS: 4.09 MPa, EAB: 144.47%) and water vapor permeability (1.30 × 10⁻¹⁰ g·m·(Pa·s·m²)⁻¹). Applied to grape preservation, the films significantly delayed quality deterioration of grapes. Furthermore, by modulating the activity of enzymes involved in anthocyanin metabolism, the films could effectively extend the shelf life of grapes by suppressing the oxidative degradation of anthocyanins. Full article

This study develops a sustainable biopolymer film derived from potato peel waste (PW), enhanced with low- and high-viscosity sodium alginate (SA) through a solution casting method. The effect of calcium chloride crosslinking on the PW/SA composites was also evaluated. Scanning electron microscopy (SEM) analysis revealed that SA incorporation improved the film’s cohesion and uniformity, with both low- and high-viscosity SA showing nearly similar effects. Both the addition of SA and crosslinking led to enhanced tensile strength, as well as improved moisture barrier properties, by lowering the water vapor permeability (WVP) factor. The inclusion of high-viscosity SA (hvSA) resulted in superior mechanical and moisture barrier properties compared to the low-viscosity SA (lvSA), achieving a tensile strength of 5.34 MPa, with a 68% improvement compared to the pure PW film. The WVP analysis showed that hvSA had a superior impact, leading to a 32% reduction in WVP compared to the pure film. Crosslinking further boosted the tensile strength and moisture barrier properties. The crosslinked hvSA/PW composite shows the highest tensile strength among all samples, measuring 6.47 MPa, which accounts for a 104% enhancement compared to the pure film. It also led to a 34% reduction in WVP, reaching a value of 1.58 × 10⁻¹² g/(Pa·cm·s). The findings demonstrate that PW/SA composites, especially the crosslinked hvSA/PW, offer the highest mechanical and barrier properties, making them suitable for biodegradable packaging and biomedical applications. Full article

This study aimed to design and optimize an edible antimicrobial film incorporating thermally modified starches using a systematic experimental approach. A comprehensive analysis of six starch types—both native and dry heat–modified—was conducted to evaluate their gelatinization clarity, freeze–thaw stability, microstructure (CLSM), and in vitro digestibility. Corn and cassava starches were selected as optimal components based on their physicochemical performance. A series of single-factor experiments and a Box–Behnken design were employed to assess the influence of starch concentration, gelatinization time, glycerol, and chitosan content on film properties including tensile strength, elongation at break, water vapor permeability (WVP), and transparency. The optimized formulation (5.0% starch, 28.2 min gelatinization, 2.6% glycerol, 1.4% chitosan) yielded a transparent (77.64%), mechanically stable (10.92 MPa tensile strength; 50.0% elongation), and moisture-resistant film. Structural and thermal analyses (SEM, AFM, DSC, TGA) confirmed the film’s homogeneity and stability. Furthermore, the film exhibited moderate antioxidant activity and antibacterial efficacy against Escherichia coli and Staphylococcus aureus. These findings demonstrate the feasibility of using dry heat–modified Kazakhstani starches to develop sustainable antimicrobial packaging materials. However, further studies are needed to explore sensory attributes, long-term storage performance, and compatibility with different food matrices. Full article

Blackseed oil supplemented with caseinate (CA)–carboxymethyl chitosan (CMCH) composite membranes were evaluated for their functional properties and as edible coating for extending the shelf life of grape tomatoes. Composite films were prepared from equal parts of (CaCa or NaCa) and (CMCH) with or without supplemented 3% blackseed oil (BO) and evaluated for their functional properties. Subsequently, the edible membrane coating was evaluated to extend the shelf life of grape tomatoes (Solanum lycopersicum L.). The water vapor permeability (WVP) of the films was the lowest for the calcium caseinate–carboxymethyl chitosan–blackseed oil (CaCa-CMCH-BO) film (3.01 g kPa⁻¹ h⁻¹ m⁻²). Adding blackseed oil to the edible film matrix also led to a significant increase in its mechanical properties, resulting in tensile strength values of 12.5 MPa and 10.2 MPa and elongation at break values of 90.5% and 100% for NaCa-CMCH-BO and CaCa-CMCH-BO, respectively. The composite films also exhibited good compatibility through hydrogen bonding and hydrophobic interactions, as confirmed by FTIR spectroscopy. The particle size and zeta potential of CaCa-CMCM-BO were 117 nm and −40.73 mV, respectively, while for NaCa-CMCH-BO, they were 294.70 nm and −25.10 mV, respectively. The incorporation of BO into the films resulted in greater antioxidant activity. When applied as an edible film membrane on grape tomatoes, the coating effectively delayed the deterioration of tomatoes by reducing weight loss, microbial spoilage, and oxidative degradation. Compared to the control, the coated fruits had delayed ripening, with a shelf life of up to 30 days, and reduced microbial growth over the entire storage period. Full article

In this study, polyvinyl alcohol (PVA) films were reinforced with lignocellulosic nanofibers (LCNFs) extracted from bamboo shoot shells using a choline chloride-based deep eutectic solvent (DES). A filler loading of 10 wt% was identified as the optimal condition for enhancing film performance. To improve interfacial compatibility between the PVA matrix and LCNFs, three surface modification treatments were applied to the nanofibers: hydrochloric acid (HCl) hydrolysis, citric acid (CA) crosslinking, and a dual modification combining both methods (HCl&CA). Among all formulations, films incorporating dual-modified LCNF at 10 wt% loading exhibited the most significant improvements. Compared to neat PVA, these composites showed a 79.2% increase in tensile strength, a 15.1% increase in elongation at break, and a 33.1% enhancement in Young’s modulus. Additionally, thermal stability and barrier properties were improved, while water swelling and solubility were reduced. Specifically, the modified films achieved a thermal residue of 9.21% and the lowest degradation rate of 10.81%/min. Water vapor transmission rate and oxygen permeability decreased by 18.8% and 18.6%, respectively, and swelling and solubility dropped to 14.26% and 3.21%. These results highlight the synergistic effect of HCl hydrolysis and CA crosslinking in promoting uniform filler dispersion and strong interfacial adhesion, offering an effective approach to valorizing bamboo shoot shell waste into high-performance, eco-friendly packaging materials. Full article