Fragile fruits, which are prone to mechanical damage and microbial infection, necessitate protective materials that possess both cushioning and antimicrobial properties. In this study, we present a novel genipin-crosslinked chitosan/gelatin aerogel (CS/GEL/GNP) synthesized through direct mixing and free-drying techniques. The mechanical properties and cushioning capacities of the CS/GEL/GNP aerogel were thoroughly characterized, alongside an evaluation of its antimicrobial efficacy. The composite aerogel demonstrated remarkable compressibility and shape recovery characteristics. In a transportation simulation test, the aerogel effectively protected strawberries from mechanical damage. Furthermore, the composite aerogel exhibited enhanced antimicrobial activities against Escherichia coli, Staphylococcus aureus and Botrytis cinerea in vitro. The quality of strawberries was successfully maintained at ambient temperature when packaged with the CS/GEL/GNP. Notably, the aerogel could be completely degraded in the soil within 21 days and is nontoxic to cells. Consequently, the dual-functional CS/GEL/GNP aerogel presents a promising option for packaging materials aimed at protecting delicate fruits.

The degradation and erosion of wood and its products caused by microorganisms remains a persistent challenge, which leads to significant economic and property losses and poses a potential health threat to users due to the presence of pathogenic microorganisms. In light of the recent COVID-19 pandemic, this issue has become increasingly urgent to address in modern society due to the increasing focus on private health. In this work, the carboxymethyl chitosan nano-silver (CMCS-Ag) was prepared through a microwave-assisted method, where the CMCS-Ag was ultrasonically blended with waterborne paint to obtain a waterborne antimicrobial wood coatings. Compared with commercial nano-silver with the same particle size, due to the unique system, the CMCS-Ag exhibited superior antibacterial efficacy and lower Ag+ release. CMCS-Ag exhibited effective dispersion within waterborne coatings, leading to a significant improvement in both the mechanical and antimicrobial performance of the coatings. With a CMCS-Ag content of 10 wt%, the coating films exhibit high elastic modulus, tensile strength and shore hardness, 78%, 33% and 69% higher than the control, respectively. Moreover, antimicrobial tests confirm that CMCS-Ag wood coatings inhibit Escherichia coli (24 h sterilization rate: 99.99%), Aspergillus niger (28 days without erosion), and soil decay fungi (56 days undecayed), while minimizing wood product appearance deterioration and mass loss from microbial erosion. These findings not only provide valuable insights into enhancing the antimicrobial of wood and its products but also reduce possibilities for people exposed to pathogens.

The pervasive use of petroleum-based food packaging has caused significant ecological damage due to their unsustainability and non-biodegradability. Polysaccharide-based biodegradable materials are promising alternatives, but low hydrophobicity and functional properties limit their practical applications which can be overcome by incorporation of phytochemical(s). Therefore, by leveraging the strong antioxidant and antibacterial potential of pterostilbene (PTB), we have developed PTB nanoemulsion (NE) incorporated chitosan/sodium alginate (CS/SA) film for food packaging applications. The PTBNE was prepared by high pressure homogenization and characterized for particle size distribution and morphology via DLS, TEM and AFM. The PTBNE CS/SA film was developed by solvent casting method and demonstrated improved mechanical, optical, water resistance and oxygen barrier properties as compared to native CS/SA film. The films were characterized via SEM, 3D optical profilometry, FTIR, XRD and TGA analysis to assess morphological and structural variations. Notably, incorporation of PTBNE in CS/SA matrix significantly enhanced the antioxidant and antibacterial potential of film along with biocompatibility in fibroblast cells. The developed PTBNE CS/SA film demonstrated comparable results with polythene in post harvested shiitake mushroom preservation up to 10 days with rapid soil degradation. Overall, the findings suggested that PTBNE CS/SA film can be a promising alternative to conventional petroleum-based packaging materials.

Polyhydroxybutyrate (PHB) has gained attention as an excellent packaging material due to its high crystallinity, biodegradability, low interaction with food matrices, and favorable mechanical properties. This study explores the development of PHB films incorporated with potassium sorbate (KS) and gallic acid (GA) via solvent casting, followed by a 30-day biodegradation test in soil. The films are analyzed for physicochemical and microbiological properties using X-ray diffraction, tensile testing, and disk diffusion assays. The soil-buried PHB films demonstrate accelerated biodegradation, likely driven by increased microbial and fungal activity, as well as moisture absorption. Incorporating KS and GA significantly enhances the antimicrobial efficacy of the films against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, with greater inhibition observed against S. aureus. This difference may stem from the additional lipopolysaccharide membrane in E. coli. Field emission scanning electron microscopy (FESEM) of the films, both pre- and post-biodegradation, provides further insights into their structural changes. These findings underscore the potential of PHB antimicrobial films in advancing sustainable food packaging applications.

PurposeThe present work aims to prepare biocomposites blend based on linear low density polyethylene/ starch without using harmful chemicals to improve the adhesion between two phases. Also, the efficiency of essential oils as green plasticizers and natural antimicrobial agents were evaluated.Design/methodology/approachBarrier properties and biodegradation behavior of linear low density polyethylene/starch (LLDPE/starch) blends plasticized with different essential oils including moringa oleifera and castor oils wereassessed as a comparison with traditional plasticizer such as glycerol. Biodegradation behavior forLLDPE/starch blends was monitored by soil burial test. The composted samples were recovered then washed followed by drying, and weighting samples after 30, 60, and 90 days to assess the change in weight loss. Also, mechanical properties including retention values of tensile strength and elongation at break were measured before and after composting. Furthermore, scanning electron microscope (SEM) was used to evaluate the change in the morphology of the polymeric blends. In addition to, the antimicrobial activity of plasticized LLDPE/starch blends films was evaluated using a standard plate counting technique.FindingsThe results illustrate that the water vapor transition rate increases from 2.5 g m-2 24 h-1 for LLDPE/5starch to 4.21 g m-2 24 h-1 and 4.43 g m-2 24 h-1 for castor and moringa oleifera respectively. Also, the retained tensile strength values of all blends decrease gradually with increasing composting period. Unplasticized LLDPE/5starch showed highest tensile strength retention of 91.6% compared to the other blends that were 89.61, 88.49 and 86.91 for the plasticized LLDPE/5starch with glycerol, castor and M. oleifera oils respectively. As well as, the presence of essential oils in LLDPE/ starch blends increase the inhibition growth of escherichia coli, candida albicans and staphylococcus aureus.Originality/valueThe objective of this work is to develop cost-effective and environmentally-friendly methods for preparing biodegradable polymers suitable for packaging applications.

Pyroligneous acids (PAs) amendments could reduce soil antibiotic resistance genes (ARGs) pollution, but their impacts on horizontal transformation of extracellular ARGs (eARGs) remain unclear. Here, a wood residues derived PA was selected to investigate its effect on ARG dissemination via transformation using a soil microcosm experiment and an in vitro transformation system. The PA application effectively decreased the abundances of representative ARGs and mobile genetic elements, demonstrating that the weakened horizontal gene transfer alleviated ARG pollution in the soil. PA showed an amount-dependent inhibition on the transformation as well as the three distilled fractions and chemical components, proving that their important roles in inhibiting eARG transformation. The relatively low-amount (1 mu L mL-1) of PA suppressed the transformation mainly by destroying the plasmid pBR322 structure, while the high-amount (10-100 mu L mL-1) of PA inhibited the transformation due to the inactivation of recipient Escherichia coli DH5 alpha by inducing oxidative stress and destroying cell membrane, and damages of plasmid by reducing eARGs abundance and broking the base deoxyribose, and phosphate skeletons. These findings expand the understanding of PA amendments mitigating ARG pollution in agricultural soils via inhibiting horizontal gene transformation, and also provide a practical strategy to remediate soil ARG pollution.

Biochar is a solid substance with a charcoal-like appearances. It is highly flammable and is made from the burning of agricultural and forest-based organic wastes by various controlled processes like pyrolysis. Biochar is rich in carbon and storage of the same in soil is highly recommended to ease off climate change by sequestration of carbon along with enhancing agricultural yield and production of energy. According to the World Health Organization, one of the biggest threats to human life in the present century is livestock water contamination. Among different contaminants, microbial contamination is responsible for several harmful diseases many of which are fatal. The current disinfectant methods are quite useful but they produce harmful by-products which can cause more hazards to human health. Magnetic biochar which is a modification of normal biochar is a green, facile, and cost-effective bacteriocide that has immense antimicrobial potential against water-borne pathogens. Magnetic biochar in conjugation with quaternary phosphonium salt produces Magnetic Biochar-Quaternary phosphonium salt [MBQ], which is a further modification of magnetic biochar that holds much better antimicrobial properties than biochar or magnetic biochar. It can successfully undergo inhibition of water-borne pathogens like Escherichia coli and Staphylococcus aureus. MBQ can disrupt the bacterial membrane and induce oxidative damage inside the bacteria, causing their inactivation and inhibition. MBQ also shows biocidal effects. In this review, we will discuss biochar, its properties, various methods of synthesis of biochar, different methods of modification of biochar, antimicrobial and antibacterial properties of biochar, magnetic biochar, and MBQ. Synthesis, Characterization, and antimicrobial properties of MBQ against waterborne microorganisms are also discussed in detail.

Sclerotinia sclerotiorum is one of the fungi that cause plant diseases. It damages plants by secreting large amounts of oxalic acid and cell wall-degrading enzymes. To meet this challenge, we designed a new pH/enzyme dual-responsive nanopesticide Pro@ZnO@Pectin (PZP). This nanopesticide uses zinc oxide (ZnO) as a carrier of prochloraz (Pro) and is encapsulated with pectin. When encountering oxalic acid released by Sclerotinia sclerotiorum, the acidic environment promotes the decomposition of ZnO; at the same time, the pectinase produced by Sclerotinia sclerotiorum can also decompose the outer pectin layer of PZP, thereby promoting the effective release of the active ingredient. Experimental data showed that PZP was able to achieve an efficient release rate of 57.25% and 68.46% when pectinase was added or under acidic conditions, respectively. In addition, in vitro tests showed that the antifungal effect of PZP was comparable to that of the commercial Pro (Pro SC) on the market, and its efficacy was 1.40 times and 1.32 times that of the Pro original drug (Pro TC), respectively. Crucially, the application of PZP significantly alleviated the detrimental impacts of Pro on wheat development. Soil wetting experiments have proved that PZP primarily remained in the soil, thereby decreasing its likelihood of contaminating water sources and reducing potential risks to non-target organisms. Moreover, PZP improved the foliar wettability of Pro, lowering the contact angle to 75.06 degrees. Residue analyses indicated that PZP did not elevate prochloraz residue levels in tomato fruits compared to conventional applications, indicating that the nanopesticide formulation does not lead to excessive pesticide buildup. In summary, the nanopesticide PZP shows great promise for effectively managing Sclerotinia sclerotiorum while minimizing environmental impact.

The paper reports new hydrogels based on quaternary ammonium salts of chitosan designed as biocidal products. The chitosan derivative was crosslinked with salicylaldehyde via reversible imine bonds and supramolecular selfassemble to give dynamic hydrogels which respond to environmental stimuli. The crosslinking mechanism was demonstrated by 1H NMR and FTIR spectroscopy, and X-ray diffraction and polarized light microscopy. The hydrogel nature, self-healing and thixotropy were proved by rheological investigation and visual observation, and their morphology was assessed by scanning electron microscopy. The relevant properties for application as biocidal products, such as swelling, dissolution, bioadhesiveness, antimicrobial activity and ex-vivo hemocompatibility and in vivo local toxicity and biocompatibility on experimental mice were measured and analyzed in relationship with the imination degree and the influence of each component. It was found that the hydrogels are superabsorbent, have good adhesivity to skin and various surfaces and antimicrobial activity against relevant gram-positive and gram-negative bacteria, while being hemocompatible and biocompatible. Besides, the hydrogels are easily biodegraded in soil. All these properties recommend the studied hydrogels as ecofriendly biocidal agents for living tissues and surfaces, but also open the perspectives of their use as platform for in vivo applications in tissue engineering, wound healing, or drug delivery systems.

This study targets explicitly finding an alternative to petroleum-based plastic films that burden the environment, which is a high priority. Hence, polymeric films were prepared with carboxymethyl cellulose (CMC) (4%), pectin (2%), and polyhydroxybutyrate (PHB) (0.5%) with different concentrations of thymol (0.3%, 0.9%, 1.8%, 3%, and 5%) and glycerol as a plasticizer by solution casting technique. The prepared films were tested for mechanical, optical, antimicrobial, and antioxidant properties. Film F5 (CMC + P + PHB + 0.9%thymol) showed an excellent tensile strength of 15 MPa, Young's modulus of 395 MPa, antioxidant activity (AA) (92%), rapid soil biodegradation (21 days), and strong antimicrobial activity against bacterial and fungal cultures such as Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Aspergillus flavus. The thymol content increase in films F6 (1.8%), F7 (3%), and F8 (5%) displayed a decrease in mechanical properties due to thymol's hydrophobicity. For shelf life studies on tomatoes, F2, a film without thymol (poor antimicrobial and antioxidant activities), F5 (film with superior mechanical, optical, antimicrobial, and antioxidant properties), and F7 (film with low mechanical properties) were selected. Film F5 coatings on tomato fruit enhanced the shelf life of up to 15 days by preventing weight loss, preserving firmness, and delaying changes in biochemical constituents like lycopene, phenols, and AA. Based on the mechanical, optical, antimicrobial, antioxidant, and shelf life results, the film F5 is suitable for active food packaging and preservation.