Innovations in food packaging systems could meet the evolving needs of the market; emerging concepts of non-migrating technologies reduce the negative migration of preservatives from packaging materials, extend shelf life, and improve food quality and safety. Non-migratory packaging activates the surface of inert materials through pretreatment to generate different active groups. The preservative is covalently grafted with the resin of the pretreated packaging substrate through the graft polymerization of the monomer and the coupling reaction of the polymer chain. The covalent link not only provides the required surface properties of the material for a long time but also retains the inherent properties of the polymer. This technique is applied to the processing for durable, stable, and easily controllable packaging widely. This article reviews the principles of various techniques for packaging materials, surface graft modification, and performance characterization of materials after grafting modification. Potential applications in the food industry and future research trends are also discussed.

In this study, Pickering emulsion (PE) containing zein/Tannic acid (TA) nanoparticles (ZTNPs) and oregano oil (OEO) was incorporated into konjac glucomannan (KGM) film for developing active film with antioxidant and antimicrobial properties. TA anchored the amino group of zein to form covalent bond, and self-assembled to form nanoparticles via the antisolvent precipitation method. The interactions between TA and zein were characterized through FT-IR and molecular docking. The physicochemical properties and morphological characterization of ZTNPs under different zein/TA mass ratios were investigated, significant changes were observed in the Zeta-potential and particle size. ZTNP-0.2 exhibited a uniform and smooth surface (particle size≈126 nm), demonstrating exceptional antioxidant activity and highlighting the enhanced bioavailability of TA. High-speed shearing formed PE loading ZTNP-0.2 and OEO, which was applied to the preparation of active films. The oil phase was evenly distributed in the film matrix, the presence of interfaces between nanoparticles prevented flocculation and aggregation between OEO droplets, and maintained the mechanical and barrier properties of the KGM-P film. The KGM-P film demonstrated remarkable inhibitory effects against S. aureus, E. coli, and A. niger, with inhibition area diameters measuring 39.7 ± 0.46 mm, 19.92 ± 0.45 mm, and 18.70 ± 0.8 mm respectively. Furthermore, the composite KGM-P film exhibited substantial scavenging rates of 87.5% for DPPH and 89.8% for ABTS, underscoring its exceptional antibacterial and antioxidant activities. In conclusion, the active KGM film holds promise for application in food packaging, effectively extending the shelf life of products by retarding oxidation and mitigating microbial intrusion.

Neonicotinoids (NEOs) and fipronil (FIP) are ubiquitous in aquatic environment, yet the transformation and water-sediment exchange are largely unknown for these systemic insecticides and their transformation products (TPs). Herein, occurrence, field-based partitioning coefficients, and fugacity fractions (ff) of NEOs, FIP, and their TPs were analyzed in the drainage and receiving rivers near a rice paddy field. NEOs and FIPs were frequently detected in the sediments with concentrations of TPs being often higher than the parent compounds. Average ff values of NEOs (0.944-1.00) were larger than those of FIPs (0.399-0.716), indicating NEOs had a greater tendency to diffuse from sediment into water. Similar as well-studied hydrophobic compounds, hydrophobicity was the main factor impacting the water-sediment exchange of moderately hydrophobic FIPs. Alternatively, electrostatic interactions governed the fate of hydrophilic NEOs in water-sediment system. The log Kd values of NEOs were positively correlated with their N/C ratios (p < 0.05), possibly because the negatively charged sediments (zeta potential were from-19.1 & PLUSMN; 0.6 to-5.84 & PLUSMN; 0.57 mV) generated electrostatic attraction with amino functional group. Our study highlighted the ubiquitousness of TPs and distinct water-sediment interaction for moderately hydrophobic and hydrophilic insecticides in an agriculture-dominated watershed.

Irrational use of fipronil for rice pest control often occurred, resulting in high concentrations of fipronil and its transformation products (TPs) (collectively termed fiproles) in aquatic sediment, calling for a better understanding of the migration and transformation of fipronil in surface water as well as efficient methods for source identification. Herein, the fate and transport of fiproles from a paddy field to receiving rivers were assessed in Poyang Lake basin, Jiangxi, China using polar organic chemical integrative samplers with mixed-mode adsorbents (POCIS-MMA). Average concentrations of fiproles in water were 6.16 ± 6.32 ng/L, with median, minimum, and maximum values being 2.99 ± 0.67, 0.40 ± 0.08, and 18.6 ± 3.1 ng/L, respectively. In all samples, over half of fiproles (55.9 %-90.8 %) presented in the form of TPs and fipronil desulfinyl was the dominant TP. Two approaches were applied for source identification, including the change of molar concentration ratios of fipronil to its TPs and the relative attenuation values of fiproles normalized to a reference compound (acetamiprid) that was stable in aquatic environment. While the paddy field upstream was the main source of waterborne fiproles, additional input sources in the downstream region were identified. The present study indicated that the combination of attenuation of molar concentration ratios of micro-pollutants to their respective TPs and relative attenuation values of micro-pollutants' concentrations normalized to a reference compound measured by POCIS is an effective means to study the migration and transformation of micro-pollutants in field.

Bananas are susceptible to the effects of endogenous enzymatic, leading to their rapid decay and deterioration. In order to mitigate economic losses and prolong the shelf life of bananas, the objective of this study was to develop a new and green gas-regulating packaging film. In this study, an active gas-regulating packaging film was prepared by extrusion, with mobil composition of matter (MCM)-41 loaded with salicylic acid (SA) as the active agent and poly (lactic acid) (PLA), poly (butylene adipate-co-terephthalate) (PBAT), and thermoplastic starch (TPS) as the base materials. The obtained films included PLA/PBAT/TPS, PLA/PBAT/TPS-SA, and PLA/PBAT/TPS-MCSA. These films were subsequently applied to banana preservation. The study focused on the variations in soluble solid content (SSC), rate of weight loss (RWL), malondialdehyde (MDA) content, and polyphenol oxidase (PPO) activity of bananas during the preservation process. The results showed that, compared with the PLA/PBAT/TPS film, the oxygen transmission rate of the PLA/PBAT/TPS-MCSA film increased from 384.36 ± 22.06 cm3·m−2·24 h−1·0.1 MPa−1 to 543.10 ± 3.47 cm3·m−2·24 h−1·0.1 MPa−1. Throughout the preservation period, the PLA/PBAT/TPS-MCSA film exhibited superior performance, effectively retarding the increase in banana SSC, RWL, and MDA while inhibiting the elevation of PPO activity and prolonging the shelf life of bananas by 4–5 days. However, this study needs to further investigate the mechanism of function of MCM-41 loaded with SA in banana preservation.

The loading and delivery of nanomaterials have attracted considerable interest. In this study, the organic-inorganic hybrid antimicrobial materials of clove essential oil (CEO) intercalated organic montmorillonite (MMT) were prepared using a facile and novel cryogenic ball milling technology and characterized. Fourier transform infrared spectroscopy, powder X-ray diffraction, and transmission electron micrograph analysis confirmed the successful preparation of the hybrid antimicrobial materials, and thermogravimetric analysis further demonstrated the thermal stability. In a novel application, hybrid antimicrobial materials were extruded with thermoplastic starch (TPS), polylactic acid (PLA), and poly (butylene adipate-co-terephthalate) (PBAT) to prepare active packaging films. The film release experiments showed that the CEO in the film, containing hybrid antimicrobial materials, was in a sustained release state, and its equilibrium release was higher than that of other films. The prepared films were used to preserve fresh abalone （Haliotis discus hannai Ino）, physicochemical changes and microbiological counts were determined. The results showed that the shelf life of fresh abalone packed in films containing hybrid antimicrobial materials was extended by 3–5 days, indicating that cryogenic ball milling is a simple and effective method for preparing organic-inorganic hybrid antimicrobial materials for active packaging.

In this study, chitosan (CS) was grafted onto the surface of polylactic acid (PLA) film by covalent immobilization to prepare four kinds of CS-grafted PLA (CS-g-PLA) films with different molecular weights. The properties of the films were characterized, and their antibacterial effect and mechanism of action against Staphylococcus aureus (S. aureus) were explored. After being treated with CS-g-PLA films, the cell morphology was destroyed, the permeability of the cell membrane changed, and malate dehydrogenase (MDH) activity decreased. Furthermore, the large yellow croaker fillets were packaged by the films mentioned above and stored at 4 degrees C, the physicochemical changes and microbial counts were measured. The results showed that the CS-g-PLA films could effectively delay the decay of fish fillets for 1-4 days. Overall, this study demonstrated that grafted films showed great application potential in aquatic product packaging and preservation.

Non-migrating active packaging can provide long-lasting and safe antibacterial effects; however, the underlying antibacterial mechanism remains unclear. In this study, chitosan (CS) and lysozyme (LYS) were covalently immobilized on a polylactic acid (PLA) film to produce functional packaging films, chitosan-graft-polylactic acid (CS-g-PLA) and lysozyme-graft-polylactic acid (LYS-g-PLA). The antimicrobial effects and mechanisms of action of these films against Staphylococcus aureus and Escherichia coli were investigated. The minimum inhibitory concentrations (MICs) of the CS and LYS against S. aureus were both 1.25 mg/mL; the MIC against E. coli was 1.25 mg/mL for CS and 2.5 mg/mL for LYS. Scanning and transmission electron microscopy revealed physical damage, significant morphological changes, and intracellular component leakage from bacterial cells after treatment with antimicrobial agents. Cell integrity and conductivity tests showed that bacterial cell membrane integrity was destroyed, and its permeability changed. The gel retardation assay showed that the CS-g-PLA film affected the bacteria by binding to genomic DNA. The results showed that the grafted films effectively inhibited S. aureus and E. coli. CS-g-PLA and LYS-g-PLA films inhibited bacterial growth by destroying the integrity of bacterial cell membranes and promoting changes in membrane wall permeability. In addition, immobilized CS can enter bacterial cells and bind with DNA, thus inhibiting the growth and reproduction of bacteria.

To explore new, green and effective low-temperature preservation technology, β-cyclodextrin (β-CD) embedded Elsholtzia essential oil (EEO) was used as an antibacterial agent, and polybutylene adipate-co-terephthalate (PBAT) and polylactic acid (PLA) were used as the base material to extend grass carp fillets shelf life. Active antibacterial PBAT/PLA, PBAT/PLA-EEO, and PBAT/PLA-β-CDels films were prepared using a casting film-forming process. The changes in total viable count (TVC), pH, total volatile basic nitrogen (TVB-N), and thiobarbituric acid-reactive substances values of grass carp fillets during storage at 4 °C were studied. The results showed that, compared with the PBAT/PLA film, the oxygen transmission rate of PBAT/PLA-β-CDels decreased from 868.02 to 566.80 cm3 m2•24 h•0.1 MPa−1. During preservation, compared with the PBAT/PLA film, the PBAT/PLA-β-CDels film effectively lowered TVC and delayed TVB-N production. The results revealed that PBAT/PLA-β-CDels film with β-CD-embedded EEO positively affected grass carp quality maintenance and extended its shelf life.

当前研究显示污水处理厂出水是地表水体中新烟碱类杀虫剂的重要来源之一,但其具体检测与水生态风险评估工作却相对匮乏.本文测定了广州5个污水处理厂出水中的新烟碱类杀虫剂及其转化产物残留,并对其存在的水生态风险进行了评估.结果表明:新烟碱类杀虫剂母体化合物及其转化产物在广州污水处理厂出水中普遍检出,母体化合物和转化产物检出总浓度范围分别为(217±18)～(599±31)ng/L和(63.0±3.0)～(131±9)ng/L.广州污水处理厂出水中的吡虫啉及其转化产物吡虫啉胍和吡虫啉烯烃会对当地水生态系统构成风险.