Sustainable utilization of fruit and vegetable waste bioresources for bioplastics production.

Nowadays, rapidly increasing production, use and disposable of plastic products has become one of the utmost environmental issues. Our current circumstances in which the food supply chain is demonstrated as containing plastic particles and other plastic-based impurities, represents a significant health risk to humans, animals, and environmental alike. According to this point of view, biodegradable plastic material aims to produce a more sustainable and greener world with a lower ecological impact. Bioplastics are being investigated as an environmentally friendly candidate to address this problem and hence global bioplastic production has seen significant growth and expansion in recent years. This article focuses on a few critical issues that must be addressed for bioplastic production to become commercially viable. Although the reduction of fruit and vegetable waste biomass has an apparent value in terms of environmental benefits and sustainability, commercial success at industrial scale has remained flat. This is due to various factors, including biomass feedstocks, pretreatment technologies, enzymatic hydrolysis, and scale-up issues in the industry, all of which contribute to high capital and operating costs. This review paper summarizes the global overview of bioplastics derived from fruit and vegetable waste biomass. Furthermore, economic and technical challenges associated with industrialization and diverse applications of bioplastics in biomedical, agricultural, and food-packaging fields due to their excellent biocompatibility properties are reviewed.HighlightsReview of the diverse types and characteristics of sustainability of biobased plasticsImproved pretreatment technologies can develop to enhance greater yieldEnzyme hydrolysis process used for bioplastic extraction & hasten industrial scale-upFocus on technical challenges facing commercialized the bioplasticsDetailed discussion on the application for sustainability of biodegradable plastics.

Plastic pollution in croplands threatens long-term food security.

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta-analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%-42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of -3% for every additional 100 kg/ha of film residue), plant height (-2%) and root weight (-5%), and soil properties including soil water evaporation capacity (-2%), soil water infiltration rate (-8%), soil organic matter (-0.8%) and soil available phosphorus (-5%) based on meta-regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%-10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands.

Fabrication of antimicrobial packaging based on polyaminopropyl biguanide incorporated pectin/polyvinyl alcohol films for fruit preservation.

Pectin (PEC)/polyvinyl alcohol (PVA), plasticizers, and polyaminopropyl biguanide (Pb) (0.125%-1%) were used to prepare the film solution. The results demonstrated significantly enhanced tensile strength and elongation at break of PEC/PVA/Pb 0.25% film than PEC/PVA film. Scanning electron microscopy was carried out to investigate the continuous and dense structure of the PEC/PVA/ Pb0.25% film. FTIR, XPS, and XRD revealed that Pb addition to the PEC/PVA film matrix changed its physicochemical properties by forming new hydrogen and CN bonds. Moreover, the composite films exhibited strong antimicrobial activity against food-borne microorganisms (E. coli and S. aureus), and post-harvest pathogens (P. italicum and F. proliferatum) in vitro. The composite film effectively inhibited P. italicum growth during citrus experiments, while maintaining nutritional components (vitamin C, total flavonoid, and total polyphenol content). Overall, the antimicrobial composite film presented promising applicability in food packaging.

Defective UiO-66/cellulose nanocomposite aerogel for the adsorption of heterocyclic aromatic amines.

Heterocyclic aromatic amines (HAAs), arising as chemical derivatives during the high-temperature culinary treatment of proteinaceous comestibles, exhibit notable carcinogenic potential. In this paper, a composite aerogel (AGD-UiO-66) with high-capacity and fast adsorption of HAAs was made with anchoring defective UiO-66 (D-UiO-66) mediated by lauric acid on the backbone of cellulose nanofibers (CNF). AGD-UiO-66 with hierarchical porosity reduced the mass transfer efficiency for the adsorption of HAAs and achieved high adsorption amount (0.84-1.05 µmol/g) and fast adsorption (15 min). The isothermal adsorption model demonstrated that AGD-UiO-66 belonged to a multilayer adsorption mechanism for HAAs. Furthermore, AGD-UiO-66 was successfully used to adsorb 12 HAAs in different food (roasted beef, roasted pork, roasted salmon and marinade) with high recoveries of 94.65%-104.43%. The intrinsic potential of AGD-UiO-66 demonstrated that it could be widely applicable to the adsorption of HAAs in foods.

In-situ growth of metal-organic frameworks on cellulose nanofiber aerogels for rapid adsorption of heterocyclic aromatic amines.

Heterocyclic aromatic amines (HAAs) are the main carcinogens produced during thermal processing of protein-rich foods. In this paper, a composite aerogel (TOCNFCa) with a stabilized dual-network structure was prepared via a template for the in-situ synthesis of UiO-66 on cellulose for the adsorption of HAAs in food. The dual-network structure of TOCNFCa provides the composite aerogel with excellent wet strength, maintaining excellent compressive properties. With the in-situ grown UiO-66 content up to 71.89 wt%, the hierarchical porosity endowed TOCNFCa@UiO-66 with the ability to rapidly adsorb HAAs molecules with high capacity (1.44-5.82 µmol/g). Based on excellent thermal stability, adsorption capacity and anti-interference, TOCNFCa@UiO-66 achieved satisfactory recoveries of HAAs in the boiled marinade, which is faster and more economical than the conventional SPE method. Moreover, TOCNFCa@UiO-66 could maintain 84.55 % of the initial adsorption capacity after 5 times of reuse.

Amino carboxymethyl chitosan//dialdehyde starch/polyvinyl alcohol double-layer film loaded with ε-polylysine.

To develop food packaging with good antibacterial activity and mechanical performance, four amino carboxymethyl chitosan (ACC)//dialdehyde starch (DAS) /polyvinyl alcohol (PVA) films were prepared by Schiff base and hydrogen bond interactions for efficient loading and release of ε-polylysine (ε-PL). The effects of the Schiff base reaction on the physicochemical properties of the films were explored based on the different aldehyde group contents in DAS. The ACC//DAS4/PVA film exhibited a tensile strength of 62.5 MPa, and the water vapor and oxygen permeability was 8.77 × 10-3·g·mm/m2·d·kPa and 0.15 × 103·cm3·mm/m2·d, respectively. By leveraging the Schiff base reaction, the film swelling properties were improved by adjusting the cross-link density, mesh size, and molecular mass between the cross-links. The ACC//DAS4/PVA film could efficiently load ε-PL with a value of 98.44% and long-term release in a food simulant of 10% ethanol at 25 °C for 120 min. Moreover, the ACC-ε-PL//DAS4/PVA film was successfully used for salmon preservation.

Hyaluronic Acid-Coated Bovine Milk Exosomes for Achieving Tumor-Specific Intracellular Delivery of miRNA-204.

Cell type-specific drug delivery is a straightforward strategy to achieve targeted cancer therapy and reduce side effects. Hyaluronic acid (HA), an U.S. Food and Drug Administration (FDA)-approved biocompatible carbohydrate polymer, has been extensively employed as a targeting ligand for a drug delivery system due to its natural ability to bind to tumor cells overexpressing cluster of differentiation 44 (CD44) receptors. Here, we report the preparation and antitumor efficacy of HA-coated bovine milk exosomes (HA-mExo) for tumor-specific delivery of microRNA-204-5p mimics (miR-204). The exosome-based delivery formulation was prepared with miR-204 encapsulated inside the lumen and HA displayed outside the membrane. The resultant formulation of HA-mExo-miR204 was able to specifically target CD44-positive cancer cells, with a concomitant increase in the intracellular uptake of miR-204. Compared to the uncoated mExo-miR204 formulation, HA-mExo-miR204 showed significantly increased antitumor efficacy both in vitro and in vivo. Importantly, HA-mExo-miR204 showed excellent biocompatibility and did not cause significant systemic toxicity. Given that both HA and bovine milk exosomes are low-cost and highly accessible biogenic materials with broad biomedical applications, HA-decorated bovine milk exosomes can be proven to be a practical drug delivery system of RNA drugs for targeted cancer therapy.

Preparation of chitosan-cellulose-benzyl isothiocyanate nanocomposite film for food packaging applications.

To improve the mechanical and barrier properties of cellulose and chitosan (CS) and to allow the application of volatile antibacterial benzyl isothiocyanate (BITC) in active packaging, a double-layer nanocomposite film was prepared. Cellulose nanofibers (CNF) were crosslinked with CS via genipin to build the substrate. Quaternized cellulose nanocrystals (QCNC) were synthesized for carrying BITC as the coating material. By the layer-by-layer self-assembly approach, CS-CNF/QCNC-BITC film was fabricated. This film possessed the tensile strength of 33.75 MPa, low permeabilities of oxygen (6.9 × 10-17 m3/s·m·Pa) and moisture (1.2 × 10-11 g/s·m·Pa), and good antibacterial activity with the inhibition zone diameters of 4.9, 4.2 and 2.7 cm against Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. The total viable count, total volatile basic nitrogen and thiobarbituric acid-reactive substances of the chicken wrapped CS-CNF/QCNC-BITC were only 4.4 log CFU/g, 17.7 mg/100 g and 0.44 mg/kg at 14 days, indicating a potential application of CS-CNF/QCNC-BITC for food packaging.

Dinitrophenol-Hyaluronan Conjugates as Multivalent Antibody-Recruiting Glycopolymers for Targeted Cancer Immunotherapy.

Multivalent antibody-recruiting glycopolymers (MARGs) composed of hyaluronic acid (HA) grafted with multiple copies of dinitrophenol (DNP) were developed for targeted cancer immunotherapy. Structure-activity studies demonstrated that the MARGs were able to specifically recognize CD44-positive cancer cells and displayed remarkable antibody-recruiting capacities and tumor cell killing activities dependent on the introduced multivalent effect and the length of PEG linker. One of the MARGs, HA-[PEG3 -DNP]8 , showed the best capacity for clustering anti-DNP antibodies onto CD44-positive cancer cells and displayed potent in vitro anti-cancer activity by triggering complement dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC). Moreover, we found that HA-[PEG3 -DNP]8 significantly inhibited the xenograft tumor growth of Babl/c nude mice bearing triple negative breast cancer cells, while it did not cause detectable histological cytotoxicity. Given the easy access of this type of natural glycopolymer and the practical synthesis approach, these MARGs provide promising immunotherapeutics for cancer immunotherapy.

Novel procyanidins-loaded chitosan-graft-polyvinyl alcohol film with sustained antibacterial activity for food packaging.

Active food packaging materials containing procyanidins (PC) exhibits outstanding antimicrobial activity, but PC is easy to be hydrolyzed by acid. A novel water-soluble chitosan (CS)-based copolymer was prepared to be used as a carrier to provide a pH-stable environment for loading PC. CS was copolymerized with polyvinyl alcohol (PVA) via a coupling reagent-mediated approach. The CS-graft-PVA film exhibited a desirable PC encapsulation efficiency of over 95% and excellent long-term release sustainability, which was better than the conventional CS and CS-blend-PVA films. Moreover, CS-graft-PVA film had satisfactory mechanical properties and barrier properties, as well possessed a desirable antibacterial activity and biofilm inhibition against foodborne pathogenic microbes and spoilage bacteria. The film was also applied in the salmon muscle perseveration and showed a potential ability to prevent microorganism contamination and texture deterioration in 10 days. These results suggested that the CS-graft-PVA film has an excellent promise for future food packaging applications.

Characterization of PLA-P3,4HB active film incorporated with essential oil: Application in peach preservation.

This study aimed to develop an active film by using biodegradable materials and antioxidant essential oils to improve gas and water vapor permeability during peach preservation. O2 and CO2 volume fractions and water status were investigated by using an oxygen meter and conducting low-field nuclear magnetic resonance (LF-NMR), respectively. Results revealed that the film added with angelica essential oil (AEO) had a 49.4% increase in 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and high O2 and CO2 transmission rates and water vapor permeability. The film added with AEO showed the best preservation effect, effectively delaying the oxidation of peach, maintained the combined water, and extended the shelf life of peaches to more than 15 days. This study provided a relatively new LF-NMR method for tracking the internal water status of packaged peaches and served as an effective reference for the development of active food packaging.

Effects of Different Carbon Sources on Fumonisin Production and FUM Gene Expression by Fusarium proliferatum.

Fusarium proliferatum can infect many crops and then produce fumonisins that are very harmful to humans and animals. Previous study indicates that carbon sources play important roles in regulating the fumonisin biosynthesis. Unfortunately, there is limited information on the effects of carbon starvation in comparison with the carbon sources present in the host of fumonisin production in F. proliferatum. Our results indicated that F. proliferatum cultivated in the Czapek's broth (CB) medium in the absence of sucrose could greatly induce production of fumonisin, while an additional supplementation of sucrose to the culture medium significantly reduced the fumonisin production. Furthermore, cellulose and hemicellulose, and polysaccharide extracted from banana peel, which replaced sucrose as the carbon source, can reduce the production of fumonisin by F. proliferatum. Further work showed that these genes related to the synthesis of fumonisin, such as FUM1 and FUM8, were significantly up-regulated in the culture medium in the absence of sucrose. Consistent with fumonisin production, the expressions of FUM gene cluster and ZFR1 gene decreased after the addition of sucrose. Moreover, these genes were also significantly down-regulated in the presence of cellulose, hemicellulose or polysaccharide extracted from peel. Altogether, our results suggested that fumonisin production was regulated in F. proliferatum in response to different carbon source conditions, and this regulation might be mainly via the transcriptional level. Future work on these expressions of the fumonisin biosynthesis-related genes is needed to further clarify the response under different carbon conditions during the infection of F. proliferatum on banana fruit hosts. The findings in this study will provide a new clue regarding the biological effect of the fumonisin production in response to environmental stress.

[A clinical observation of therapeutic alliance of orthodontics and implant prosthodontics for dentition defect with malocclusion].

OBJECTIVE: To explore the clinical effect of the multidisciplinary treatment combined orthodontics with implant prosthodontics for cases of dentition defect with malocclusion. METHODS: Seventeen cases of dentition defect with malocclusion were observed. All the cases accepted the orthodontic treatment in order to establish normal occlusion and achieve adequate space for implants. After that, the missing teeth were replaced by implant-supported denture. The clinical effect was evaluated by clinical examination and radiographic examination. RESULTS: Satisfactory esthetic and functional results were achieved for all the cases. The follow-up time ranged from 12 months to 48 months. 76 implants were inserted totally. Two of them were extracted due to peri-implantitis. However, the other 74 implants were stable with an average loading time of 32 months. The cumulative survival rate was 97.4%. CONCLUSION: The multidisciplinary approach combined orthodontics with implant prosthodontics was an effective treatment option for cases of dentiton defect with malocclusion.