Properties of soy protein isolate/nano‐silica films and their applications in the preservation of Flammulina velutipes

Photodegradation of chitosan decorated by titanium dioxide: The potential to serve as a responded microcapsule shell

In order to develop the UV responded material, chitosan (CS) was decorated by TiO2, and the mechanism of UV-mediated photodegradation of CS-TiO2 was analyzed. In this study, the changes in color, microstructure, degradation rate, thermal stability, and structure under different treatments were explored. The results showed that CS could be degraded by UV light. With the increase of irradiation time, the degradation rate of CS significantly raised, and was up to 18.41 %. L⁎ value markedly decreased, a⁎ value and b⁎ value significantly increased. The photodegradation process fitted with first-order kinetics. The degradation was improved when reducing scale of TiO2 from 10 nm to 102 nm, increasing TiO2 addition, and increasing UV light power. UV irradiation would promote the breakage of β-1,4 glycosidic bonds and deacetylation of CS. After UV irradiation, the crystalline structure of CS was destroyed and thermal stability was reduced. Tea tree essential oil microcapsules were constructed by using CS-TiO2 as a UV-light-sensitive shell material and could achieve a rapid UV-light-triggered release process, with a significant increase in volatile substances after UV irradiation. Thus, CS decorated by TiO2 could function as a controlled-release shell for microcapsules, while UV light could act as a switch to modulate the release process.

UV responded polyvinyl alcohol bio-active films containing oregano essential oil microcapsules by chitosan-incorporated TiO2: Physical properties, release characterizations, bio-functional performances and applications

In the present study, with oregano essential oil (OEO) as the active ingredient and polyvinyl alcohol/citric acid (PVA/CA) as the composite matrix, ultraviolet (UV) responded PVA bio-active films incorporated with microcapsules, which were established by chitosan-incorporated titanium dioxide (TiO2), were constructed. The UV light-triggered process changed the structure of films, including the degradation of PVA, the fracture of ester bonds and the breaking of glycosidic bonds. UV irradiation reduced the elongation at break, increased the light resistance ability, the surface hydrophobicity and the roughness, and accelerated the release of OEO in films. The release process of films in food simulations and air environment conformed to Fick's second law and the first-order dynamics model, which were attributed to the synergistic effects of the random diffusion and the structural relaxation that were promoted by UV irradiation, leading to the increase of release rate, antioxidant activities and antibacterial capacities of films. Finally, chicken thighs with UV responded PVA bio-active films had better quality and the films could be considered as active packages for preservation.

Chitosan and alginate/Aspergillus flavus-mediated nanocomposite films for preservation of postharvest tomatoes

The isolated Aspergillus flavus NSRN22 was used for green synthesis of silver and selenium nanoparticles (AgNPs and SeNPs). New food packaging films produced by combining each type of NPs with chitosan (CS) or sodium alginate (SA) were characterized. Transmission electron microscopy revealed that the average particle size was lower in case of AgNPs (9 to 14.7 nm) than SeNPS (36.8 to 53.5 nm). FTIR revealed a stronger connection between CS and NPs compared to SA and NPs. Tensile strength of CS (0.55 MPa) or SA (2.42 MPa) increased to 3.82, 4.73, 5.96, and 3.87 MPa for nanocomposite films of CS/AgNPs, CS/SeNPs, SA/AgNPs, and SA/SeNPs, respectively. Contrarily, water vapor pressures of SA (2132.57 g/m2.day) and CS (2021.71 g/m2.day) decreased to 1922.47, 1871.45, 1822.95 and 1795.29 g/m2.day for SA/AgNPs, SA/SeNPs, CS/AgNPs and CS/SeNPs, respectively. The respective statistical minimum inhibitory concentrations for SA/AgNPs, CS/AgNPs, CS/SeNPs, SA/SeNPs, CS and SA were 1000, 1018, 1030, 1055, 1130 and 1135 μg/5 mL. CS/SeNPs were superior in terms of thermal stability (21 % weight loss), antioxidant activity (58.75 %), and normal cells viability (100 %). They demonstrated excellent preservation of tomatoes' natural color and texture, significantly reduced mold growth, and thus are ideal as antimicrobial and safe packaging materials.

Nanofillers in Novel Food Packaging Systems and Their Toxicity Issues

Background: Environmental concerns about petroleum-based plastic packaging materials and the growing demand for food have inspired researchers and the food industry to develop food packaging with better food preservation and biodegradability. Nanocomposites consisting of nanofillers, and synthetic/biopolymers can be applied to improve the physiochemical and antimicrobial properties and sustainability of food packaging. Scope and approach: This review summarized the recent advances in nanofiller and their applications in improved food packaging systems (e.g., nanoclay, carbon nanotubes), active food packaging (e.g., silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs)), intelligent food packaging, and degradable packaging (e.g., titanium dioxide nanoparticles (e.g., TiO2 NPs)). Additionally, the migration processes and related assessment methods for nanofillers were considered, as well as the use of nanofillers to reduce migration. The potential cytotoxicity and ecotoxicity of nanofillers were also reviewed. Key findings: The incorporation of nanofillers may increase Young's modulus (YM) while decreasing the elongation at break (EAB) (y = -1.55x + 1.38, R2 = 0.128, r = -0.358, p = 0.018) and decreasing the water vapor (WVP) and oxygen permeability (OP) (y = 0.30x - 0.57, R2 = 0.039, r = 0.197, p = 0.065). Meanwhile, the addition of metal-based NPs could also extend the shelf-life of food products by lowering lipid oxidation by an average of approx. 350.74% and weight loss by approx. 28.39% during the longest storage period, and significantly increasing antibacterial efficacy against S. aureus compared to the neat polymer films (p = 0.034). Moreover, the migration process of nanofillers may be negligible but still requires further research. Additionally, the ecotoxicity of nanofillers is unclear, as the final distribution of nanocomposites in the environment is unknown. Conclusions: Nanotechnology helps to overcome the challenges associated with traditional packaging materials. Strong regulatory frameworks and safety standards are needed to ensure the appropriate use of nanocomposites. There is also a need to explore how to realize the economic and technical requirements for large-scale implementation of nanocomposite technologies.

Developing a Prolamin-Based Gel for Food Packaging: In-Vitro Assessment of Cytocompatibility

Growing environmental concerns drive efforts to reduce packaging waste by adopting biodegradable polymers, coatings, and films. However, biodegradable materials used in packaging face challenges related to barrier properties, mechanical strength, and processing compatibility. A composite gel was developed using biodegradable compounds (prolamin, d-mannose, citric acid), as a coating to increase the oxygen barrier of food packaging materials. To improve gel stability and mechanical properties, the gels were physically cross-linked with particles synthesized from tetraethyl orthosilicate and tetramethyl orthosilicate precursors. Additionally, biocompatibility assessments were performed on human keratinocytes and fibroblasts, demonstrating the safety of the gels for consumer contact. The gel properties were characterized, including molecular structure, morphology, and topography. Biocompatibility of the gels was assessed using bioluminescent ATP assay to detect cell viability, lactate dehydrogenase assay to determine cell cytotoxicity, and a leukocyte stimulation test to detect inflammatory potential. A composite gel with strong oxygen barrier properties in low-humidity environments was prepared. Increasing the silane precursor to 50 wt% during gel preparation slowed degradation in water. The addition of citric acid decreased gel solubility. However, higher precursor amounts increased surface roughness, making the gel more brittle yet mechanically resistant. The increase of precursor in the gel also increased gel viscosity. Importantly, the gels showed no cytotoxicity on human keratinocytes or fibroblasts and had no inflammatory effects on leukocytes. This composite gel holds promise for oxygen barrier food packaging and is safe for consumer contact. Further research should focus on optimizing the stability of the oxygen barrier in humid environments and investigate the potential sensitizing effects of biodegradable materials on consumers.

Effect of nanopackaging on the quality of edible mushrooms and its action mechanism: A review

With higher demands for food packaging and the development of nanotechnology, nanopackaging is becoming a research hotspot in the field of food packaging because of its superb preservation effect, and it can effectively resist oxidation and regulates energy metabolism to maintain the quality and prolong the shelf life of mushrooms. Furthermore, under the background of SARS-CoV-2 pandemic, nanomaterials could be a potential tool to prevent virus transmission because of their excellent antiviral activities. However, the investigation and application of nanopackaging are facing many challenges including costs, environmental pollution, poor in-depth genetic research for mechanisms and so on. This article reviews the preservation effect and mechanisms of nanopackaging on the quality of mushrooms and discusses the trends and challenges of using these materials in food packaging technologies with the focus on nanotechnology and based on recent studies.

New preservation and detection technologies for edible mushrooms: A review

Edible mushrooms are nutritious, tasty, and have medicinal value, which makes them very popular. Fresh mushrooms have a high water content and a crisp texture. They demonstrate strong metabolic activity after harvesting. However, they are prone to textural changes, microbial infestation, and nutritional and flavor loss, and they therefore require appropriate post-harvest processing and preservation. Important factors affecting safety and quality during their processing and storage include their quality, source, microbial contamination, physical damage, and chemical residues. Thus, these aspects should be tested carefully to ensure safety. In recent years, many new techniques have been used to preserve mushrooms, including electrofluidic drying and cold plasma treatment, as well as new packaging and coating technologies. In terms of detection, many new detection techniques, such as nuclear magnetic resonance (NMR), imaging technology, and spectroscopy can be used as rapid and effective means of detection. This paper reviews the new technological methods for processing and detecting the quality of mainstream edible mushrooms. It mainly introduces their working principles and application, and highlights the future direction of preservation, processing, and quality detection technologies for edible mushrooms. Adopting appropriate post-harvest processing and preservation techniques can maintain the organoleptic properties, nutrition, and flavor of mushrooms effectively. The use of rapid, accurate, and non-destructive testing methods can provide a strong assurance of food safety. At present, these new processing, preservation and testing methods have achieved good results but at the same time there are certain shortcomings. So it is recommended that they also be continuously researched and improved, for example through the use of new technologies and combinations of different technologies. © 2023 Society of Chemical Industry.

Storage Quality Variation of Mushrooms (Flammulina velutipes) after Cold Plasma Treatment

Flammulina velutipes is susceptible to mechanical damage, water loss, microbial growth, and other factors that lead to postharvest deterioration, thereby shortening the storage period. The purpose of this study was to analyze the effects of cold plasma treatment on the physicochemical properties and antioxidant capacity of F. velutipes during storage at 4 °C for 21 days. Compared to the control group, cold plasma cold sterilization (CPCS) treatment (150 Hz, 95 kV for 150 s) effectively inhibited the growth and multiplication of microorganisms on the surface of F. velutipes, with no significant effect on the fresh weight change and the superoxide anion generation rate, but with a higher postharvest 1,1-dephenyl-2-picrylhydrzyl (DPPH) clearance rate. Moreover, CPCS increased antioxidant enzyme activities, delayed both malondialdehyde (MDA) accumulation and vitamin C loss, inhibited the browning reaction and polyphenol oxidases (PPO) activity and protected F. velutipes cell membrane from disruption. In general, CPCS not only achieved bacteriostatic effects on F. velutipes during storage, but also reduced cell damage from free radical oxidation, resulting in better postharvest quality and longer shelf life.

Protein-based natural antibacterial materials and their applications in food preservation

Plastics materials used for food packaging are recalcitrant, leading to a growing global environmental problem, which arouses the attention of environmental protection departments in many countries. Therefore, to meet the increasing demand for sustainable and environment-friendly consumer products, it is necessary for the food industry to develop natural antibacterial materials for food preservation. This review summarizes the common biodegradable natural antimicrobial agents and their applications in food preservation; as well as an overview of five commonly used biodegradable protein-based polymers, such as zein, soy protein isolate, gelatin and whey protein, with special emphasis on the advantages of protein-based biopolymers and their applications in food packaging industry.

Characterization and antioxidant properties of chitosan film incorporated with modified silica nanoparticles as an active food packaging

In this study, two modified silica nanoparticles (SiO₂-GA NPs) were successfully obtained by covalently grafting gallic acid onto silica nanoparticles. The mean particle diameters of their were 112.7 ± 0.55 nm (1-SiO₂-GA NPs) and 408.7 ± 3.20 nm (4-SiO₂-GA NPs), respectively. Novel antioxidant active packaging composite films were prepared by incorporation of 1-SiO₂-GA NPs or 4-SiO₂-GA NPs into chitosan. The structure analysis of the composite films showed that intermolecular hydrogen bonds were formed between the two modified silica nanoparticles and chitosan. Compared with the chitosan film, the mechanical properties, water vapor barrier property and UV light barrier ability of the composite films were significantly improved. Moreover, the incorporated of the two modified silica nanoparticles significantly increased antioxidant activity of the composite films. This study indicates that composite films incorporated with modified silica nanoparticles, especially the incorporation of 1-SiO₂-GA NPs can be used as novel antioxidant food packaging composite films.

Sustainable nanocomposite films based on SiO2 and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) for food packaging

Sustainable nanocomposites with transparent, biodegradable, and enhanced mechanical and barrier properties were prepared by the incorporation of SiO2 into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) films and subsequent solvent casting. The crystallinity of composites could be increased by 67% with appropriate contents of SiO2, which proved that SiO2 were effective nucleating agents for PHBH. And it was worth mentioning that the contributions of SiO2 to the crystallization and thermal stability of composites are proved effectively by Avrami relationship and Horowitz and Metzger method. More importantly, compared with PHBH, it had not only an enhancement about 40% and 60% on the tensile strength and elastic modulus, respectively, but also half the reduction of the moisture and oxygen permeability which were much higher than the values of conventional plastics. The above, in conjunction with the low migration rate measured in food substitutes, illustrated unambiguously that the nanocomposites might be suitable for potential application in food packaging.

Preparation and Characterization of Double-Layered Microcapsules Containing Nano-SiO2

The double-layered microencapsulation technology has been used in many fields. In this study, the double-layered microencapsulated anthocyanin of Passiflora edulis shells (APESs) was prepared via complex coacervation using gelatin and gum Arabic as the first wall materials (single-layered microcapsules (SMs)) and using gum Arabic containing nano-SiO2 as the second wall material (double-layered microcapsules (DMs)/nano-SiO2) to enhance the stability of the core material. Properties of microcapsules were analyzed on the basis of EE, morphology, scanning electron microscopy (SEM), droplet size, moisture content, and differential scanning calorimetry (DSC). The results showed that the EE values of SMs, DMs, and DMs/nano-SiO2 were 96.12%, 97.24%, and 97.85%, respectively. DMs/nano-SiO2 had the lowest moisture content (2.17%). The average droplet size of DMs/nano-SiO2 (34.93 μm) was higher than those of SMs and DMs. DSC indicated that the melting temperature of DMs/nano-SiO2 was 73.61°C and 45.33°C higher than those of SMs and DMs, respectively. SEM demonstrated that DMs/nano-SiO2 had the smoothest surface compared with the other two kinds of microcapsules. The storage stability of APESs and their microcapsules indicated that the stability of the microcapsules was improved by adding DMs/nano-SiO2 into the wall material of microcapsules. These results indicated double-layered microcapsules containing silica nanoparticles contribute to the stability of the core material.