Search Results (112)

Phosphorus (P) release from reservoir sediments critically influences water quality and ecosystem stability. This study analyzed surface sediments from four representative zones to investigate phosphorus fraction distribution, key influencing factors, and implications for water quality. Results showed that total phosphorus (TP) content in sediments from main and tributary inflow zones was significantly higher than in open-water and transition zones. Inorganic phosphorus (IP) was the dominant form, with iron-bound phosphorus (Fe-P) accounting for 33.2–42.0% of IP. A strong correlation existed between P release and the Fe/P molar ratio; notably, when the ratio approached 10, phosphorus desorption increased significantly, indicating a shift from sink to source. Sediments with grain sizes <0.01 mm had the highest P release rates, suggesting particle size, Fe content, and hydrodynamics jointly regulate P mobilization. Using the Diffusive Gradients in Thin Films (DGT) technique, phosphorus release in inflow zones exceeded 1 g/m² in all hydrological periods, contributing substantially to internal loading. Sediment-derived P primarily influenced bottom water, while surface water was more affected by external inputs. These findings highlight the spatial heterogeneity of P release and underscore the need for zone-specific management strategies in reservoir systems. Full article

Lactobacillus plantarum exhibits probiotic effects, including regulating the balance of the intestinal microbiota and enhancing immune function. However, this strain often experiences viability loss upon ingestion due to harsh conditions within the human digestive tract. This study aimed to evaluate the efficacy of metal–phenol networks (MPNs) fabricated via three polyphenols—tannic acid (TA), tea polyphenol (TP), and anthocyanin (ACN)—combined with Fe(III) coatings in protecting Lactobacillus plantarum during simulated digestion and storage. The results demonstrated that MPNs formed a protective film on the bacterial surface. While TA and ACN inhibited the growth of Lactobacillus plantarum YJ7, TP stimulated proliferation. Within the MPNs system, only Fe(III)-TA exhibited growth-inhibitory effects. Notably, ACN displayed the highest proliferation rate during the initial 2 h, followed by TP between 3 and 4 h. All MPN-coated groups maintained high bacterial viability at 25 °C and −20 °C, with TP-coated bacteria showing the highest viable cell count, followed by TA and ACN. In vitro digestion experiments further revealed that the Fe(III)-ACN group exhibited the strongest resistance to artificial gastric juice. In conclusion, tea polyphenol and anthocyanin demonstrate superior potential for probiotic encapsulation, offering both protective stability during digestion and enhanced viability under storage conditions. Full article

A novel biodegradable food packaging material based on cassava thermoplastic starch (TPS) and polybutylene adipate terephthalate (PBAT) blends containing food preservatives was successfully developed using blown-film extrusion. This active packaging is designed to enhance the appearance, taste, and color of food products, while delaying quality deterioration. However, the incorporation of food preservatives directly influences consumer perception, as well as health and safety concerns. Therefore, this research aims to assess the risks associated with both intentionally added substances (IAS) and non-intentionally added substances (NIAS) present in the developed active packaging. The migration of both intentionally and non-intentionally added substances (IAS and NIAS) was evaluated using gas chromatography–mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). Fifteen different volatile compounds were detected, with the primary compound identified as 1,6-dioxacyclododecane-7,12-dione, originating from the PBAT component. This compound, along with others, resulted from the polymerization of adipic acid, terephthalic acid, and butanediol, forming linear and cyclic PBAT oligomers. Migration experiments were conducted using three food simulants—95% ethanol, 10% ethanol, and 3% acetic acid—over a period of 10 days at 60 °C. No migration above the detection limits of the analytical methods was observed for 3% acetic acid and 10% ethanol. However, migration studies with 95% ethanol revealed the presence of new compounds formed through interactions between the simulant and PBAT monomers or oligomers, indicating the packaging’s sensitivity to high-polarity food simulants. Nevertheless, the levels of these migrated compounds remained below the regulatory migration limits. Full article

The effect of low-temperature plasma treatment on the surface properties of thermoplastic starch film (TPS) was investigated. The surface layer (SL) modification of polymeric materials is mainly carried out to improve wettability and adhesive properties and to increase surface cleanliness. TPS was modified in an air atmosphere under either atmospheric or reduced pressure. The process parameters for modifying the SL of TPS were determined based on wettability assessment using a goniometer, geometric structure using scanning electron microscopy (SEM), and the degree of oxidation (O/C ratio) using X-ray photoelectron spectroscopy (XPS). Additionally, the effect of plasma treatment on TPS film sterilization was investigated. Full article

This research developed a biodegradable absorbent pad using polybutylene adipate terephthalate (PBAT) and thermoplastic starch (TPS) films, combined with hairy basil (Ocimum basilicum) seed powder (HBP) to extend the shelf life of fresh pork during cold storage. To form the biocomposite film, PBAT was blended with TPS in ratios of 100:0, 90:10, 70:30, and 50:50. The PBAT:TPS ratio of 70:30 (PB7T3) was the most suitable in terms of mechanical properties and water permeation. Therefore, PB7T3 was selected to fabricate the absorbent pad for extending the shelf life of fresh pork during cold storage. For the storage test, 100 g of pork pieces was placed in PET trays (12 cm × 12 cm), each containing a different absorbent: the control (no pad), a commercial absorbent pad, and the PB7T3 absorbent pad. The pork samples were stored at 4 °C for 8 days and analyzed for color change, total plate count (TPC), total volatile basic nitrogen (TVB-N), pH, and drip loss on days 0, 2, 4, 6, and 8. The results indicated that the PB7T3 absorbent pad effectively extended the shelf life of fresh pork compared to the control, with no significant difference compared to the commercial absorbent pad made from plastic. This research opens new avenues for developing sustainable absorbent pads, contributing to reduced reliance on conventional non-biodegradable plastics. Full article

Obtaining active extracts from beet root leaves and stems (BLS) is an alternative for the valorization of this agricultural waste. Subcritical water extraction (SWE) at 150 °C and 170 °C has been used to obtain these extracts, which were incorporated (6% wt.) into polymer matrices to produce antioxidant films of thermoplastic starch (TPS) and polylactic acid (PLA) for the preservation of sunflower oil. A high extraction yield (67–60% solubilized solids) was achieved, and the extracts contained high levels of total phenols (51–73 mg GAE·g⁻¹ extract) and betalains and great radical scavenging capacity (EC₅₀: 30–22 mg mg⁻¹ DPPH). The highest temperature promoted the extract’s phenolic richness and antioxidant capacity. The TPS and PLA films containing extracts exhibited color and UV-light blocking effects. The extracts reduced the oxygen permeability (OP) and water vapor permeability of PLA films while promoting those of the TPS films. The capacity of the films to preserve sunflower oil from oxidation was mainly controlled by the OP values of the films, which were very high in TPS films with low OP values. However, in the PLA films (which were more permeable to oxygen), the antioxidant extracts provided significant protection against sunflower oil oxidation. Full article

The environmental impact of conventional plastics has spurred interest in biopolymers as sustainable alternatives, yet their performance under abiotic degradation conditions still remain unclear. This study investigated the effects of ultraviolet C (UV-C) irradiation and its combination with water immersion (UV-C/H₂O) on films of commercial poly(butylene adipate-co-terephthalate)-thermoplastic starch (PBAT/TPS) blends. Changes in structural, chemical, morphological, and thermal properties, as well as molar mass, were analyzed. The results showed distinct degradation mechanisms during exposure to UV-C irradiation either in dry or during water-immersion conditions. UV-C irradiation disrupted PBAT ester linkages, inducing photodegradation and chain scission, leading to a more pronounced molar mass decrease compared to that under water immersion, where a more restrained impact on the molar mass was ascribed to diffuse attenuation coefficient of irradiation. Nevertheless, under UV-C/H₂O conditions, erosion and disintegration were enhanced by dissolving and leaching of mainly the TPS fraction, creating a porous structure that facilitated the degradation of the film. Blends with higher TPS content exhibited greater susceptibility, with pronounced reductions in PBAT molar mass. In conclusion, exposure of films of PBAT/TPS blends to ultraviolet/water-assisted environments effectively initiated abiotic degradation, in which fragmentation was accentuated by the contribution of water immersion. Full article

Microplastics (MPs) resulting from plastic fragmentation with a size less than 5 mm have become one of the main pollutants endangering the water environment. Therefore, it is necessary to know about the abundance and size distribution of MPs in sewage waters and their relationship with water quality. In this study, water samples are collected from 20 sewage outlets in Guilin, China to analyze the abundance and morphology of the MPs and their hydrochemical characteristics. Multivariate statistical analyses are conducted to identify the major factors related to the MP distribution in sewage water samples. Results showed that MPs in sewage water samples are mainly composed of fiber and film, and about 67.8% are sized <0.3 mm. The abundance is in the range of 6 (±1)–47 (±3) items/L. The correlation analysis presents that the abundance of MPs is weakly correlated with hydrochemical parameters and metal ions due to the complexity of the abundance data. The redundancy analysis indicates that the MP morphology distribution is significantly affected by NO₃–N, Zn, Ca, and Cu contents, and the MP size distribution is mainly related to Zn, Ca, and Cu contents. Adsorption kinetics are analyzed using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, revealing that the adsorption process is predominantly governed by chemisorption for smaller MPs (0.3–0.5 mm), while larger MPs (1.0–5.0 mm) are constrained by internal diffusion. Isothermal adsorption experiments are fitted using Langmuir and Freundlich models, indicating that the adsorption of nutrients (NH₃–N, TN, TP) and metal ions (Ca, Mg, Cu, Pb, Zn) on MPs follows a monolayer adsorption mechanism, with smaller MPs showing higher adsorption capacities due to their larger specific surface areas. This study highlights the occurrence characteristics and environmental influencing factors of MPs in sewage water, which may be significant for future studies on the pollution control of MPs. Full article

To address the increasingly diverse demands for biodegradable packaging materials, such as for their physical properties and antioxidant properties, this study incorporated tea polyphenols (TPs) into soybean oil body emulsions (SOBs) and added a certain proportion of sodium alginate (SA) and octenyl succinic starch sodium (SSOS) to prepare a biodegradable soybean oil body–tea polyphenol (ST) emulsion film. The study systematically evaluated the effects of different concentrations of TP (0–6 wt.%) on the structure, physicochemical properties, antioxidant activity, and antibacterial activity of ST films. The results showed that the physical properties, such as tensile strength and elongation at break, of the films increased significantly with the addition of TP, and the antioxidant and antibacterial activity also increased with the increase in TP concentration. When TP concentration was 2.5 wt.%, the barrier properties of the film (ST-2.5) significantly improved (p < 0.05), while water content and water solubility decreased. The Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis results showed that the structure of ST films became tighter at this point. The addition of TP also affected the sensory properties of ST films, such as with an increase in the opacity of the film. Compared with the control, the light transmittance of ST-6.0 decreased by 23.68% at a wavelength of 600 nm, indicating a significant reduction in film transparency. Moreover, the biodegradability test showed that ST films have good degradability. Therefore, the ST film, as a functional edible film, has broad application prospects in the food packaging industry. Full article

This article provides a brief overview of the research on localized optical states called Tamm plasmons (TPs) and their potential applications, which have been extensively studied in recent decades. These states arise under the influence of incident light at the interface between a metal film and a medium with the properties of a Bragg mirror, or between two media with the properties of a Bragg mirror. The localization of the states in the interfacial region is a consequence of the negative dielectric constant of the metal and the presence of a photonic band gap of the Bragg reflector. Optically, TPs appear as resonant reflection dips or peaks in the transmission and absorption spectra in the region corresponding to the photonic band gap. The relative simplicity of creating a Tamm structure and the significant sensitivity of TPs to its parameters make them attractive for applications. The formation of broadband and tunable TP modes in hybrid structures containing, in particular, rugate filters and porous distributed Bragg reflectors are considered. Considerable attention is paid to TP designs that include liquid crystals, which allow for the remote tuning of the TP spectrum without the mechanical restructuring of the system. The application of TPs in sensors, thermal emitters, absorbers, laser generation, and the experimental capabilities of TP-liquid crystal devices are also discussed. Full article

The transient plane heat source method (TPS), also known as the hot disc method, is an experimental method for determining the thermal transport properties of materials. The method’s main element is a sensor made of a nickel metal strip in the shape of a double helix, which is inserted into an insulating polymer film. In this work, we used the finite element method to create a three-dimensional model of the sensors and compared the simulated and experimentally recorded mean temperature rise data. The volume mean temperature rise of the sensor, as determined through simulation, exhibits a high level of resemblance with the corresponding experimental data. Additionally, temperature rise curves of several other materials are also simulated based on the model and the thermal performance parameters are calculated from these data. In the meantime, this paper presents an evaluation and discussion of the current density distribution of the sensor and the temperature distribution during the testing of the sample. This simulation has the potential to be utilized for future geometry and parameter estimate optimization, and provides a theoretical reference for detector design. Full article

The study investigated the effect of Vinnex^® (vinyl acetate polymer) and Joncryl^® (epoxy-based copolymer) as compatibilizers on the mechanical properties of thermoplastic starch (TPS) and polybutylene adipate-co-terephthalate (PBAT) and polybutylene succinate-co-adipate (PBSA) films. Due to TPS’s hydrophilicity and brittleness, blending it with biodegradable polyesters like PBAT enhances its properties but may introduce compatibility challenges. This research evaluated three formulations (TPS/PBAT with Vinnex, TPS/PBAT with Joncryl, and TPS/PBAT with both additives) along with the inclusion of a polybutadiene succinate-co-adipate (PBSA) matrix to further improve performance. Mechanical testing (tensile strength, elongation at break, Young’s modulus) reveals that Vinnex and Joncryl enhance plasticization and polymer compatibility, positively impacting TPS/PBAT’s mechanical properties. The introduction of the PBSA matrix further improves tensile strength and elongation. Scanning electron microscopy (SEM) confirms better additive dispersion and interfacial adhesion within the blend. Complementary analysis includes melt flow index, melt density, DSC, and TGA, providing a comprehensive understanding of how these additives optimize TPS/PBAT compounds for sustainable applications. Mechanically, the compatibilized blends showed improved performance: Vinnex mainly enhanced stiffness, Joncryl primarily improved elongation, and a synergistic effect was observed with their combination. Full article

The packaging industry has made efforts to reduce food waste and improve the resilience of food systems worldwide. Active food packaging, which incorporates active agents, represents a dynamic area where industry and academia have developed new strategies to produce innovative and sustainable packaging solutions that are more compatible with conventional options. Due to health and environmental concerns, industries have sought alternatives to petroleum-based materials and have found biopolymers to be a viable option because of their biodegradable and safe nature. The combination of PLA/TPS has emerged as an effective system for packaging film; however, they are thermodynamically immiscible. This work highlights the development of a starch-based compatibilizer to connect the PLA and TPS phases by functionalizing maize starch with glycidyl methacrylate, glycerol, or garlic oil. Garlic oil was chosen for its plasticizing ability and antioxidant properties. The films produced exhibited excellent compatibility, with enhanced interfacial adhesion between PLA and TPS components. The introduction of compatibilizers also increased the systems’ crystallinity and improved their mechanical properties. The wettability of the films significantly increased with higher garlic oil content, along with enhanced antioxidant properties. These advancements will enable the production of a compatible PLA/TPS system with improved properties for application in the packaging industry. Full article

The development of biodegradable active packaging is a relevant topic demanding the development of film properties, biodegradability, and the potential to preserve food quality. This study aimed to develop thermoplastic starch (TPS) blended with polybutylene adipate-co-terephthalate (PBAT) films via blown-film extrusion containing ascorbyl palmitate (AP) and sodium ascorbyl phosphate (SAP) as antioxidants. The morphology, mechanism, and barrier and antioxidant properties of the films were analyzed to determine the presence of AP, SAP, and their interaction effect on the film properties. SEM showed that increasing AP and SAP content increased fibrous-like morphology, improving the TPS dispersion. AP slightly decreased mechanical properties, while SAP increased the tensile properties and seal strength of the films. All of the YM values were increased by adding AP and SAP content. The addition of AP and SAP content enhanced the interaction with TPS/PBAT networks due to increasing C-O stretching of ester bonds, compatibility, and hydrophobicity of the polymer. Both water vapor and the oxygen barrier were insignificantly affected by AP and SAP up to 1%, while the permeabilities greatly increased at higher AP and SAP contents due to non-homogeneous and void spaces between the film matrix. TPS/PBAT containing AP and SAP (≥0.5%) effectively enhanced antioxidant capacity in 95% ethanol as a food simulant and reduced the UV light transmission of the films. Finding, the interaction between AP, SAP, and TPS/PBAT matrices effectively changed the microstructures and properties as functionalized antioxidant biodegradable packaging. Full article

The development of thermoplastic starch (TPS) films is crucial for fabricating sustainable and compostable plastics with desirable mechanical properties. However, traditional design of experiments (DOE) methods used in TPS development are often inefficient. They require extensive time and resources while frequently failing to identify optimal material formulations. As an alternative, adaptive experimental design methods based on Bayesian optimization (BO) principles have been recently proposed to streamline material development by iteratively refining experiments based on prior results. However, most implementations are not suited to manage the heteroscedastic noise inherently present in physical experiments. This work introduces a heteroscedastic Gaussian process (HGP) model within the BO framework to account for varying levels of uncertainty in the data, improve the accuracy of the predictions, and increase the overall experimental efficiency. The aim is to find the optimal TPS film composition that maximizes its elongation at break and tensile strength. To demonstrate the effectiveness of this approach, TPS films were prepared by mixing potato starch, distilled water, glycerol as a plasticizer, and acetic acid as a catalyst. After gelation, the mixture was degassed via centrifugation and molded into films, which were dried at room temperature. Tensile tests were conducted according to ASTM D638 standards. After five iterations and 30 experiments, the films containing 4.5 wt% plasticizer and 2.0 wt% starch exhibited the highest elongation at break (M = 96.7%, SD = 5.6%), while the films with 0.5 wt% plasticizer and 7.0 wt% starch demonstrated the highest tensile strength (M = 2.77 MPa, SD = 1.54 MPa). These results demonstrate the potential of the HGP model within a BO framework to improve material development efficiency and performance in TPS film and other potential material formulations. Full article