Low Water Vapor Research Articles

Preparation and Characterization of Lithraea molleoides Gum Flour and Its Blend Films

Lithraea molleoides fruit gum (LMFG) is a valuable product obtained from the total hydrolysis of the fruit. The hydrolysis process involves three methods: thermal (LMFGT), alkaline (LMFGB), and acid (LMFGA). Through these methods, the aim is to break bonds and de-esterify polysaccharides, resulting in increased solubility and decreased molecular weight. The resulting hydrolysates are then combined with pectins in a 1:2 ratio to form films. In this study, the focus is on utilizing the hydrolysates of Lithraea molleoides gums for film applications, with an evaluation of their structural and physicochemical characteristics. The films produced exhibit excellent mechanical properties and low water vapor permeability, as well as exceptional thermal stability. These properties make them highly suitable for industrial films in pharmaceutical and food applications. This research highlights the potential of LMFG-based films as a viable solution for various industrial needs due to their outstanding performance across multiple parameters.

Reversible Photo-Responsive Hydrophobic Coating Synthesized from Lignin-Derivable Molecules on Nanocellulose Films for Packaging Applications.

Paper-based packaging can offer a sustainable replacement for plastics. However, paper provides a poor barrier to water, oxygen and moisture. This study presents a novel renewable lignocellulosic composite made from a hydrophobic photo-reversible coating deposited onto a cellulose nanofiber film that has improved barrier properties and can be reprocessed. Diglycerol and lignin-derivable aldehyde were reacted to form a tetra-functional monomer with photo-responsive unsaturated double bonds that can be converted to covalent cyclobutane rings to create reversibly crosslinkable network upon UV-irradiation. The photo-responsive compound was applied as a thin coating of thickness 2.7±0.4 μm over cellulose nanofiber (CNF) films of thickness 80±19 μm. The surface of the coated films became hydrophobic with a contact angle (CA) of 93.1±1.7° and displayed a low water vapour transmission rate (WVTR) of 16±2 g/m2/day vs. 30.7±1.5° CA and 81±11 g/m2/day WVTR for uncoated CNF films. The coated film is also oleophobic, an attractive feature for food packaging applications. The reversible photo-reaction enables the crosslinked covalent network to be broken down to unsaturated double bonds once exposed to a higher-energy UV irradiation, allowing reprocessing and recycling. The novel coating was developed using a sustainable green synthesis method (process simple E factor 0.9).

Water Vapor-Impermeable AlON/HfOx Bilayer Films Deposited by Hybrid High-Power Impulse Magnetron Sputtering/Radio-Frequency Magnetron Sputtering Processes

Water vapor-impermeable AlON/HfOx bilayer films were constructed through a hybrid high-power impulse magnetron sputtering (HiPIMS) and radio-frequency magnetron sputtering process (RFMS), applied as an encapsulation of flexible electronics such as organic photovoltaics. The deposition of monolithic and amorphous AlON films through HiPIMS was investigated by varying the duty cycles from 5% to 20%. At an accelerated test condition, 60 °C, and 90% relative humidity, a 100 nm thick monolithic AlON film prepared using a duty cycle of 20% exhibited a low water vapor transmission rate (WVTR) of 0.0903 g m−2 day−1 after testing for 336 h. Furthermore, after introducing a nanocrystalline HfOx film through RFMS, a 214 nm thick AlON/HfOx bilayer film reached the lowest WVTR of 0.0126 g m−2 day−1.

Role of Tropical Disturbances along the South Asian Monsoon Trough in the 2022 Pakistan Floods and the Implications for Interannual Variability

Abstract This study examined the atmospheric circulation patterns that were responsible for the severe flooding that occurred in Pakistan in 2022. It focused on the role of westward-propagating tropical disturbances (TDs) along the South Asian monsoon trough, which are associated with flood-related precipitation events. The study also investigated the interannual precipitation variation in Pakistan over 23 years from 2000 to 2022, using satellite-derived precipitation and atmospheric reanalysis. The results showed high precipitation in southern and central Pakistan, implying tropical influences. The precipitation was the highest in the past 23 years. The massive rainfall was brought by several TDs under the highest water vapor conditions, although a TD of South Asia climatologically tends to weaken before affecting Pakistan. Enhanced easterlies along the Indo-Gangetic Plain, part of the enhanced monsoon trough, supported high water vapor conditions over Pakistan. The high water vapor was also partly supported by the long-lasting active phase of the South Asian monsoon intraseasonal oscillation in 2022. Moreover, the La Niña condition increased moisture transport as a background. On an interannual time scale, the enhanced moisture flux over the Indo-Gangetic Plain resulted in higher precipitation over Pakistan, as occurred in 2022. These high (low) water vapor and precipitation can be partly explained by La Niña (El Niño). However, La Niña and El Niño may not control the TD activity over South Asia. Thus, for 2022, the high water vapor is somewhat empirically predictable, but the active TD activity can be coincidental. Significance Statement In 2022, Pakistan was hit by catastrophic flooding that affected 15% of the population. The analysis of the atmospheric circulation associated with the flooding indicates that weak but rain-bearing tropical disturbances played a significant role in flooding. Several tropical disturbances stayed or moved into Pakistan, bringing massive rainfall although, usually, they tend to weaken before hitting Pakistan. In the past 23 years, La Niña–related weather patterns have partly explained the year-to-year precipitation variation in Pakistan. However, in 2022, the unusually heavy flooding was due to the combined La Niña effect and tropical disturbance activity. Because it is still difficult to predict the seasonal tropical disturbance activity from La Niña, El Niño, and other climatic conditions, seasonal prediction of these floods remains challenging.

Preparation of active films with antioxidant and antimicrobial properties by combining ginger essential oil nanoemulsion with xylan and polyvinyl alcohol

Due to the environmental challenges of petroleum-based packaging, new biodegradable and active food packaging has garnered significant attention. In this work, active films were generated with xylan/polyvinyl alcohol (PVA) as the film-forming matrix, combined with ginger essential oil nanoemulsions (GEO-NEs) at varying concentrations (2.0 %, 4.0 %, 6.0 %, and 8.0 % w/w). The GEO-NEs, produced via ultrasound, had a mean particle size measuring 176.4 ± 1.2 nm and demonstrated excellent stability for up to 28 d. FTIR and XRD analyses revealed that interactions between GEO-NEs and the film matrix occurred through hydrogen bonding, indicating good compatibility between the components. Incorporating GEO-NEs significantly enhanced the UV shielding performance and mechanical characteristics of the composite films, achieving mechanical characteristics comparable to those of commercial packaging materials such as high-density polyethylene (HDPE). Additionally, composite films with 2 % and 4 % GEO-NEs exhibited lower water vapor permeability (WVP) than the control film, indicating improved water barrier performance. GEO-NEs also significantly improved the antioxidant activity of the composite films and imparted certain antimicrobial properties. As a result, these films hold promise for applications in active food packaging.

Enhanced wound healing with biogenic zinc oxide nanoparticle-incorporated carboxymethyl cellulose/polyvinylpyrrolidone nanocomposite hydrogels.

Contemporary wound dressings lack antibacterial properties, exhibit a low water vapour transmission rate, and demonstrate inadequate porosity. In order to overcome these limitations, scientists have employed water hyacinth to produce carboxymethyl cellulose (CMC). CMC/PVP nanocomposite films containing biogenic zinc oxide nanoparticles (nZnOs) were synthesised using cost effective solution-casting technique. As the proportion of nZnOs in the film increased, swelling and water permeability decreased, whereas mechanical stability improved. Dynamic light scattering testing and transmission electron microscopy confirmed that the particle size was around 50.7 nm. Field emission scanning electron microscopy (FESEM) images showed that nZnOs were distributed uniformly in the polymer matrix. Cell viability against Vero cells was greater than 94%, and a substantial zone of inhibition against S. aureus and E. coli bacteria was observed. Wounds of albino mice were treated with CMC/PVP and CMC/PVP/nZnO (6%) nanocomposite hydrogels and healed in 20 and 12 days, respectively, as demonstrated by wound healing assay and histological staining. In vitro and in vivo studies revealed that the novel nanocomposite hydrogels exhibit improved cell viability and wound healing features. Therefore, they could be exploited as promising skin wound dressing materials.

Multifunctional electrospun nanofibrous film integrated with cinnamon essential oil emulsion stabilized by dealkali lignin for active packaging material

Cinnamon essential oil (CEO) has good antibacterial properties, but its volatility, hydrophobicity and bad odor limit its use in food preservation. In this study, a dealkali lignin (DAL) stabilized emulsion loaded with CEO was encapsulated into poly (vinyl alcohol) (PVA) and zein using an emulsion electrospinning technique. With the existence of DAL, the PVA/zein/DAL/CEO nanofibrous film (PVA/zein/DAL/CEO NF) exhibited good antioxidant properties. Moreover, higher antibacterial activity was achieved owing to the nanosized structure and enhanced stability compared to DAL/CEO emulsion and pure CEO. Scanning electron microscopy (SEM) revealed uniformly produced PVA/zein/DAL/CEO NF with an average diameter of 295 nm. The interactions among the nanofibrous film's components were confirmed using attenuated total internal reflectance fourier transform infrared spectroscopy (ATR-FTIR). The nanofibrous film demonstrated a low water vapor permeability (WVP) of 5.07 mm∙g/(m2∙h∙kPa), which was beneficial for reducing moisture transfer from the external environment to the interior of the packaging. Additionally, the PVA/zein/DAL/CEO NF also exhibited a marked enhancement in antioxidant activity, neutralizing 94.54 % of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The nanofibrous film also demonstrated potent antibacterial effects, with inhibition zones measuring 19.47 mm for Escherichia coli (E. coli) and 30.37 mm for Staphylococcus aureus (S. aureus), respectively. This study provided a reference for preparing a multifunctional electrospun nanofibrous film integrated with CEO as an active packaging material.

Urban surface-emitted longwave radiation estimation from high spatial resolution thermal infrared images using a hybrid method

Accurate estimation of the surface-emitted longwave radiation (SELR) has important scientific value in understanding its spatiotemporal dynamics and surface thermal environment. Thermal infrared (TIR) images with high spatial resolution offer enhanced data support for studying SELR of complex surfaces, such as urban surface. This study proposes a new urban-oriented hybrid (UoHy) method, which considers multiple scattering and adjacent effects of urban pixel using the term sky view factor, to estimate urban SELR from the top-of-atmosphere radiance of TIR images with high spatial resolution, and performs sensitivity analysis and application. The experimental results for the thermal images of GF-5/VIMS as an example showed that the UoHy method has relatively high accuracy, and obtains SELR errors of less than 12.0 W/m2 under low atmospheric water vapor conditions and less than 17.0 W/m2 under high atmospheric water vapor conditions. The application of the method during daytime and nighttime also demonstrated the method's validity and effectiveness. Compared with the natural surface-oriented hybrid method, the UoHy method obtains an improvement of about 7.0–10.0 W/m2 in SELR estimation, which indicates that it has the potential for practical SELR estimation over urban surface with TIR images of high spatial resolution.

Characteristics and properties of co-precipitated protein and film based on Bambara groundnut protein isolate and fish skin acid-soluble collagen

Co-precipitated protein (CPP) from Bambara groundnut protein isolate (BGPI) and fish skin acid-soluble collagen (ASC) at different BGPI/ASC ratios (100:0, 75:25, 50:50, 25:75 and 0:100 (v/v)) were prepared and characterized. CPP of BGPI/ASC at ratio of 75:25 had higher solubility at acidic and alkaline pHs, compared to other CPP samples. All CPPs had good emulsifying properties. Based on protein patterns, the combination of major bands from BGPI and ASC in the resulting CPP sample was observed. CPP with BGPI/ASC at ratio of 75:25 showed higher surface hydrophobicity than those of other CPP samples. When the films from CPPs were fabricated, similar tensile strength (p > 0.05) was observed, regardless of BGPI/ASC ratios. Nevertheless, film from CPP with BGPI/ASC ratio of 25:75 had higher elongation at break along with lower water vapor permeability (p < 0.05), compared to other CPP films. All CPP films had bright-yellowish color. Increasing ASC ratio augmented (p < 0.05) light transmission of resulting CPP films. FTIR spectra revealed that all CPP films had the similar pattern and functional groups. Therefore, the co-precipitated BGPI and ASC at appropriate ratio could improve properties of resulting proteins, especially for film forming ability.

Pioneering high barrier packaging for pressure assisted thermal sterilization of low-acid food products

Pressure-assisted thermal sterilization (PATS) utilizes flexible packaging with low oxygen and water vapor transmission rates (OTRs, WVTRs). In this study, pouches made from metal oxide (MO)-coated (A–D) and ethylene vinyl alcohol (EVOH)-containing (E, F) multilayer films were filled with water and mashed potatoes (MP), preheated at 98 ± 0.5 °C for 10 min, and processed using a pilot-scale high-pressure processing machine (HPP) at 600 ± 5 MPa for 300 s. The initial vessel temperature and the fluid medium were 90 °C, and during processing, the temperature of the fluid medium increased to approximately 120 °C. After processing, the water-filled pouches were emptied, refilled with a novel oxygen indicator, and stored at 40 ± 0.2 °C for 80 days. The MP-filled pouches were stored at 49 ± 1 °C for 60 days. MO-coated film D contained fewer defects, had ultra-low OTRs and WVTRs, showed insignificant (p > 0.05) moisture absorption and changes in crystallinity after PATS processing, and exhibited minimal color change in both the oxygen indicator and the packaged MP during the 60 days of storage. The ultra-high barrier of film D could be attributed to the presence of multiple AlOx-coated PET layers that successfully prevented oxygen ingress, even after exposure to high temperature and pressure conditions during PATS processing. Among the EVOH-based structures, the Film F showed a 22.3 % lower OTR than Film E (p < 0.05), due to a 16.7 % greater EVOH-layer thickness, despite having a lower overall thickness than Film E. Overall, this study can assist packaging manufacturers in designing and developing high-barrier flexible packaging suitable for in-package, shelf-stable food products.

Extending The Calendar Life of Fiber Lithium-Ion Batteries to 200 Days with Ultra-High Barrier Polymer Tubes.

Scalable fiber lithium-ion batteries (FLIBs) have garnered significant attention due to huge potential applications in wearable technology. However, their widespread applications have been limited by inadequate cycle and calendar life, primarily due to the high permeability of the encapsulation layer to water vapor in ambient air. To address this challenge, an ultra-high barrier composite tube is developed by blending polytrifluorochloroethylene (PCTFE) with organically modified montmorillonite (OMMT) for the continuous packaging of FLIBs. Due to the high crystallinity (≈40.21%) and small free volume (103.443 Å3), the PCTFE tube exhibited a low water vapor transmission rate (WVTR) of 0.123 mgday-1pkg-1. Furthermore, through the melt extrusion, OMMT with its plate-like morphology are fully exfoliated and dispersed within the PCTFE matrix. This created more complex pathways for water, increasing the diffusion path length and thereby reducing WVTR to 0.006 mgday-1pkg-1. This innovation enabled an ultra-long calendar life of 200 days and cycle life of 870 cycles for FLIBs, with over 80% capacity retention in ambient air. Additionally, 2%OMMT-PCTFE-FLIBs exhibited excellent flexibility, retaining an impressive 85.31% capacity after 10000 bending cycles. This research presents a simple yet effective approach to enhance the lifetime and practicality of FLIBs through building a high-performance polymer-based encapsulation layer.

Using the NAMA as a Natural Integrator to Quantify the Convective Contribution to Lower Stratospheric Water Vapor Over North America

AbstractThe dynamical environment of the stratosphere, during the summer over North America, provides a natural integrator of the impact of convection in the lower stratosphere, as air can be confined for periods of a few days to more than a week. In situ data obtained during the NASA Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) field campaign show increasing water vapor mixing ratios in background air as a function of time the air parcel spent within the North American Monsoon Anticyclone region. We find that water vapor added to the stratosphere by convection decreases with altitude and tends to drop below detectable limits by the 415 K isentrope in 2021 and the 430 K isentrope in 2022. Integrating between potential temperatures of 380 and 460 K we find that convection added between 20 and 32 Tg per summer to the stratosphere in 2021 and 2022. While the total amount is only 1%–4% of the amount ascending in the tropics across the tropical tropopause, small changes in the annual flux of water can have a significant effect on the radiation budget of the atmosphere. Locally, over North America we find that convection increased the water vapor mixing ratio at 380 K by as much as 40%. Tropopause‐penetrating convection is part of the yearly cycle of stratospheric water vapor and we suggest that it must be included in extratropical models to accurately predict future trends in stratospheric water vapor.

Development of fish gelatin film for anti-fogging mushroom packaging

Mushrooms are extremely perspiring and transpiring commodities. The commonly used plastic films for packaging fresh mushrooms have lower water vapour permeability compared to the rate at which mushrooms transpire, resulting in excessive moisture accumulation inside the package which leads to fogging. This study aimed to investigate the properties of a fish scale gelatin-based film and its correlation with antifogging properties. To produce the gelatin-based film, gelatin was extracted from fish scales using chemical pretreatment and thermal denaturation of collagen. A film-forming solution (FFS) was prepared by dissolving 2% (w/v) gelatin in a solvent, with the addition of glycerol. The solution was then cast to form the film, which underwent tests for mechanical strength, thermal behaviour, barrier properties, and antifogging performance. The resulting film (G-Gly) exhibited reduced tensile strength (13.21 MPa) but increased elongation at break (82.4%). Differential scanning calorimetry revealed a lower glass transition temperature (59.91 °C) for G-Gly. Both gelatin films displayed high water vapour permeability (1.69–3.09x10-6 g m/m2.day.Pa), preventing condensation. Notably, the G and G-Gly films remained fog-free even under varying temperatures, unlike linear low-density polyethylene film (LLDPE). In conclusion, the gelatin-based films demonstrated strong barrier properties and effective antifogging capabilities, making them suitable for moisture-sensitive commodities like mushrooms.

Tilapia gelatin films by incorporating metal-polyphenol network formed by procyanidin and zinc ion for pork preservation

There is a lack of information about the application of metal polyphenol networks (MPN) in the food industry nowadays. Herein, the MPN was prepared by procyanidin (PC) and zinc ion (Zn2+), and introduced into tilapia gelatin films. The MPN-modified films showed broader thickness, higher UV-Vis light barrier property, and lower water sensitivity and water vapor property than PC-modified films. When the molar ratio of Zn2+ to PC being 3:8, the incorporation of MPN induced the highest tensile strength of films reaching 82.47 MPa, good activity against oxidation, and improved inhibition activity to Staphylococcus aureus and Escherichia coli. The MPN-modified gelatin films could suppress the bacteria growth, and attenuate the generation of total volatile basic nitrogen and thiobarbituric acid reactive substances, causing the shelf life of pork extended by five and three days compared with the control and PC-modified films, respectively. The results suggested that MPN provided great potential in the application of food packaging.

Functionalized cellulose nanofiber films as potential substitutes for Japanese paper

Japanese papers (JPs) are among the most common materials used for the restoration of historical papers. However, they have low transparency and may structure the paper surface. To overcome the limitations of JPs, in the present work, films of cellulose nanofibers with and without lignin (LCNFs and CNFs, respectively) were explored. For this, chemically different LCNFs (carboxylated by TEMPO-mediated oxidation using variable oxidant amount and sulfated with deep eutectic solvent) and two reference CNFs were produced from Eucalyptus kraft pulps. Lignin hindered slightly the introduction of carboxyl groups into the cellulose structure, but did not affect the incorporation of sulfate groups. (L)CNFs gave films with better mechanical properties than those determined for three types of JP (tensile strength of 79–142 MPa (±11) vs 3.5–13.0 MPa (±0.4) and Young's modulus of 4900–5900 MPa (±300) vs 200–1800 MPa (±70)). Additionally, the (L)CNF films exhibited lower water vapor transmission rates (132–312 g.m−2.day−1) compared to the JPs (685–719 g.m−2.day−1), and a higher transparency (up to 89% and ≤82% for JPs). Besides thermal stability, all properties studied favored (L)CNF films over JPs, indicating their strong potential for restoration/conservation applications. This systematic comparison between the properties of (L)CNF films and JPs has never been conducted before.

Self-powered sensors utilizing single-pillar thermocells with pyrolytic graphite sheet electrodes: harvesting body heat and solar thermal energy

This study investigates the development of self-powered sensors employing single-pillar thermocells to harness body heat and solar thermal energy. A pyrolytic graphite sheet was selected for its low water vapor permeability, and its surface was modified to be hydrophilic to minimize interfacial resistance. Two types of DC–DC converters, Asahi Kasei Microdevices AP4473 and matrix mercury, underwent evaluation for compatibility with these thermocells. The compact 1.5 cm3 (1 cm × 1 cm × 1.5 cm) device effectively powered the AP4473 converter, illuminating a light-emitting diode. A larger device (2.5 cm × 2.5 cm × 1.5 cm) efficiently drove the matrix mercury converter, enabling the operation of bluetooth low-power sensors. These self-powered sensors wirelessly provided humidity and temperature data using solar thermal energy for approximately 4 h per day during peak temperature differences in January. This study showcases the potential of thermocells for sustainable energy harvesting and suggests avenues for future research, such as exploring alternative heat sources like geothermal energy to power these sensors.

Anthocyanin modified by chondroitin sulphate and tannic acid improved the quality-indicating properties of gelatin-based intelligent film

A highly pH-responsive gelatin film incorporating purple cabbage anthocyanin (PCA) and chondroitin sulphate (CS)/tannic acid (TA) was developed. Co-pigmentation of PCA via CS/TA improved its photothermal stability and visibility of color change in gelatin film. The morphological and structural properties of CS-PCA and TA-PCA films revealed that a more stable network was formed as new hydrogen bonds were generated by the co-pigmentation. Meanwhile, the co-pigmentation improved film's mechanical and hydrophobic properties, expressed as higher tensile strength (16.65 and 17.97 Mpa) and lower water vapor permeability (1.45 and 1.41) in CS-PCA and TA-PCA films, compared to PCA film. CS-PCA and TA-PCA films showed distinct color transitions for chilled fish fillets during storage. Total color difference (ΔE) of CS-PCA and TA-PCA films correlated well with the deterioration indexes of total volatile base nitrogen (TVB-N). All the results provided a novel pH-sensitive intelligent packaging strategy by co-pigmenting CS/TA with PCA for freshness monitoring.

A study on preparation of low-cost environment-friendly self-assembled nanocellulose membrane from waste paper

In the context of green development, different types of waste paper were used in this study to prepare environment-friendly nanocellulose membrane by using different pretreatment processes. The results showed that all nanocellulose membranes had a novel microscopic composite morphology: nanocellulose fibers in the middle were tightly arranged and had a certain direction, while nanocellulose fibers at the edge were arranged randomly. Moreover, the type of waste paper affected the formation and property of nanocellulose membranes deeply compared with the pretreatment process. Nanocellulose membrane prepared from office waste paper had a high transmittance (50.8 %) and low oxygen transmission rate (1.548·10−3/cm3mm/(m2·d·KPa)) while that prepared from waste corrugated paper had a high yield (50.63 %), high folding number (81 times), and low water vapor transmission rate (1550.24 g·m−2·day−1). Meanwhile, nanocellulose membrane prepared without any deinking treatment had a significant performance advantage in terms of water vapor barrier and folding resistance. Therefore, in actual application, deinking treatment can be selectivity omitted, which will simplify the preparation process flow and reduce the production cost of nanocellulose membrane. Furthermore, in order to satisfy different application requirements, the appropriate raw materials and treatment processes can be chosen to prepare nanocellulose membranes with different properties. This study provides a simple and low-cost way to prepare high-performance environment-friendly self-assembled nano membrane material, and also achieves the high value utilization of waste paper, which has a certain ecological, economic, and social benefits.

Plant-Based Films for Food Packaging as a Plastic Waste Management Alternative: Potato and Cassava Starch Case.

The escalating environmental impact of plastic packaging waste necessitates sustainable alternatives in food packaging. This study explores starch-based films derived from cassava and potato as viable substitutes, aiming to mitigate plastic pollution and enhance environmental sustainability. Utilizing a casting method, formulations optimized by CCRD were characterized for their physical, physicochemical, and morphological properties. Comprehensive analysis revealed both cassava and potato starch films to exhibit robust structural integrity, high tensile strength (up to 32.6 MPa for cassava starch films), and semi-crystalline morphology. These films demonstrated low water vapor permeability and moderate solubility, akin to conventional low-density polyethylene used in packaging. Differential scanning calorimetry indicated glass transition temperatures between 116.36 °C and 119.35 °C, affirming thermal stability suitable for packaging applications. Scanning electron microscopy confirmed homogeneous film surfaces, with cassava starch films (C4-15) exhibiting superior transparency and uniformity. X-ray diffraction corroborated the films' semi-crystalline nature, unaffected by sorbitol content variations. Despite their mechanical and thermal suitability, further enhancements in thermal degradation resistance are essential for broader thermoprocessing applicability. These findings underscore the potential of starch-based films to be used as lids or other part of a food package, decreasing the plastic dependency in food packaging, contributing decisively to waste reduction and environmental preservation.

Antimicrobial multi-crosslinking tamarind xyloglucan/protein-chitosan coating packaging films with self-recovery and biocompatible properties

Natural and high-quality biomass-based coating films are considered promising packaging to consumers. However, the poor mechanical properties and weak antimicrobial activity of biomass materials have limited their practical application. A cleaner and low-cost strategy is used to prepare antimicrobial, self-recovery, and biocompatible coating films using tamarind kernel powder (TKP) and chitosan (CS). The TKP protein and chitosan chains were covalently cross-linked with tetrakis(hydroxymethyl)phosphonium chloride (THPC) to form a three-dimensional network based on THPC-amine dynamic bonds, and act as a sacrificial bond. Then, the hydrogen bond forms an interpenetrating network to build a strong multi-network film. Thus, the THPC multi-crosslinking TKP based films showed enhanced stretchable property (increased from 3.23 % to 77.54 %), and self-recovery after 30 min of recovery. Additionally, the film has been found to exhibit low water vapor permeability, low oxygen transmittance rate, and excellent antimicrobial efficiency (maximum inhibition zones: 24.39 mm). Moreover, the prepared films were demonstrated to be biocompatible and non-hemolytic based on cell viability and hemolytic activity assays. The method described herein could broaden the scope of biomass-based materials in the realm of antimicrobial coating films.