Bilayer edible films with tunable humidity regulating property for inhibiting browning of Agaricus bisporus

Troxerutin associated with Agaricus blazei Murill polysaccharides in films improves full-thickness wound healing

The present study aimed to associate troxerutin (TRX) with polysaccharides from Agaricus blazei Murill mushroom (PolyAb) in alginate/PVA films and evaluate their effect on wound healing. The physicochemical, mechanical, morphological, and water vapor barrier properties of the films were studied, and their biological potential was analyzed in vivo using the full-thickness wound healing model. The association between TRX and PolyAb present in the polymeric film contributed to increased thermal stability, mechanical resistance, and elasticity when compared to films without TRX, which indicated good miscibility of the excipients. In the in vivo tests, the TRX films promoted greater collagen deposition and repair of epidermis and dermis layers. The 0.25 % TRX film showed an increase in reduced glutathione levels, while the 1.0 % TRX film reduced lipid peroxidation and production of the pro-inflammatory cytokine IL-1β, demonstrating the anti-inflammatory and antioxidant effect of TRX films. Therefore, it is estimated that the film containing 1 % TRX can be used as biocurative for wound dressing applications.

Ultralong luminescence lifetime imaging of edible plant tissue for humidity sensing in food packaging by a smartphone

The safety of luminescence sensors and probes used in food packaging should be seriously considered, while most luminescence sensors were artificially synthesized with unclear toxicity, and cannot be directly used as indicators that were in contact with food. To overcome this problem, a humidity indicator based on an edible plant tissue was developed without any chemical processing. We found that garlic bulbs could emit significant persistent luminescence after drying at room temperature. The luminescence lifetime decreases from hundreds of milliseconds to tens of milliseconds as humidity increases. The long-lived luminescence could easily be detected through smartphones without any sophisticated instruments. The edible garlic is expected to be used as a humidity indicator in food packaging without worrying about food safety. Furthermore, the interference of scattered light and short-lived fluorescence from foods and packages can be eliminated in time-resolved luminescence imaging, greatly increasing the signal-to-noise ratio.

A 3R-MYB transcription factor is involved in Methyl Jasmonate-Induced disease resistance in Agaricus bisporus and has implications for disease resistance in Arabidopsis

INTRODUCTION

Methyl jasmonate (MeJA) and MYB transcription factors (TFs) play important roles in pathogen resistance in several plants, but MYB TFs in conjunction with MeJA-induced defense against Pseudomonas tolaasii in edible mushrooms remain unknown.

OBJECTIVES

To investigate the role of a novel 3R-MYB transcription factor (AbMYB11) in MeJA-induced disease resistance of Agaricus bisporus and in the resistance of transgenic Arabidopsis to P. tolaasii.

METHODS

Mushrooms were treated with MeJA alone or in combination with phenylpropanoid pathway inhibitors, and the effects of the treatments on the disease-related and physiological indicators of the mushrooms were determined to assess the role of MeJA in inducing resistance and the importance of the phenylpropanoid pathway involved. Subcellular localization, gene expression analysis, dual-luciferase reporter assay, electrophoretic mobility shift assay, and transgenic Arabidopsis experiments were performed to elucidate the molecular mechanism of AbMYB11 in regulating disease resistance.

RESULTS

MeJA application greatly improved mushroom resistance to P. tolaasii infection, and suppression of the phenylpropanoid pathway significantly weakened this effect. MeJA treatment stimulated the accumulation of phenylpropanoid metabolites, which was accompanied by increased the activities of biosynthetic enzymes and the expression of phenylpropanoid pathway-related genes (AbPAL1, Ab4CL1, AbC4H1) and an AbPR-like gene, further confirming the critical role of the phenylpropanoid pathway in MeJA-induced responses to P. tolaasii. Importantly, AbMYB11, localized in the nucleus, was rapidly induced by MeJA treatment under P. tolaasii infection; it transcriptionally activated the phenylpropanoid pathway-related and AbPR-like genes, and AbMYB11 overexpression in Arabidopsis significantly increased the transcription of phenylpropanoid-related genes, the accumulation of total phenolics and flavonoids, and improved resistance to P. tolaasii.

CONCLUSION

This study clarified the pivotal role of AbMYB11 as a regulator in disease resistance by modulating the phenylpropanoid pathway, providing a novel idea for the breeding of highly disease-resistant edible mushrooms and plants.

Chitosan/zein-based sustained-release composite films: Fabrication, physicochemical properties and release kinetics of tea polyphenols from polymer matrix

This study investigated the properties of chitosan/zein/tea polyphenols (C/Z/T) films and analyzed the release kinetics of tea polyphenols (TP) in various food simulants to enhance the sustainability and functionality of food packaging. The results revealed that TP addition enhanced the hydrophilicity, opacity and mechanical properties of film, and improved the compatibility between film matrix. 1.5 % TP film showed the lowest lightness (76.4) and the highest chroma (29.1), while 2 % TP film had the highest hue angle (1.5). However, the excessive TP (above 1 % concentration) led to a decrease in compatibility and mechanical properties of film. The TP concentration (2 %) resulted in the highest swelling degree in aqueous (750.6 %), alcoholic (451.1 %), and fatty (6.4 %) food simulants. The cumulative release of TP decreased to 16.32 %, 47.13 %, and 5.87 % with the increase of TP load in the aqueous, alcoholic, and fatty food simulants, respectively. The Peleg model best described TP release kinetics. The 2 % TP-loaded film showed the highest DPPH (97.13 %) and ABTS (97.86 %) free radical scavenging activity. The results showed TP release influenced by many factors and obeyed Fick's law of diffusion. This study offered valuable insights and theoretical support for the practical application of active films.

Properties of modified chitosan-based films and coatings and their application in the preservation of edible mushrooms: A review

Edible mushrooms are prone to deteriorate during storage. A Single chitosan film or coating has limitations in preservation. Therefore, this article focused on the improvement of modified chitosan-based films and coatings on properties related to storage quality of edible mushrooms (e.g.: safety, barrier, mechanical, antioxidant and antibacterial properties). Besides, the application of chitosan-based materials in the preservation of mushrooms was also discussed. The modified chitosan film and coating can slow down the respiration of mushrooms, inhibit the growth of microorganisms, protect antioxidant compositions, and regulate the activity of related enzymes, thus improving the quality and prolonging the shelf life of mushrooms. Meanwhile, the added ingredients improve the water and gas barrier properties of chitosan through volume and group occupation, and reduce the light transmittance of chitosan through light transmission, scattering and absorption. Essential oils and polyphenolic compounds had a better enhancement of antioxidant and antimicrobial properties of chitosan.

Novel Post-Harvest Preservation Techniques for Edible Fungi: A Review

Edible fungi are well known for their rich nutrition and unique flavor. However, their post-harvest shelf-life is relatively short, and effective post-harvest preservation techniques are crucial for maintaining their quality. In recent years, many new technologies have been used for the preservation of edible fungi. These technologies include cold plasma treatment, electrostatic field treatment, active packaging, edible coatings, antimicrobial photodynamic therapy, and genetic editing, among others. This paper reviews the new methods for post-harvest preservation of mainstream edible fungi. By comprehensively evaluating the relative advantages and limitations of these new technologies, their potential and challenges in practical applications are inferred. The paper also proposes directions and suggestions for the future development of edible fungi preservation, aiming to provide reference and guidance for improving the quality of edible fungi products and extending their shelf-life.

Deep eutectic solvents (DESs) films based on gelatin as active packaging for moisture regulation in fruit preservation

To develop a novel active packaging for fruit preservation, two different deep eutectic solvents (DESs) comprising choline chloride, betaine and glycerol [ChCl:Gly (1:2) and Be:Gly (1:2)] were prepared and the corresponding DESs-based films (DES@Gel) using gelatin as polymer matrix were fabricated. DES@Gel showed smoother morphologies and better optical and mechanical properties as compared with Gel. Moisture sorption isotherm curves, the enhancement of water vapour permeability (WVP) and the excellent moisture absorption-desorption cyclist performance illustrated the moisture regulation hypothesis mechanism of DES@Gel. Furthermore, cherry tomato preservation experiment was carried out and the groups treated with DES@Gel showed better performances. The moisture regulation property of DES@Gel could broaden new avenues for active packaging.

Humidity-adjustable functional gelatin hydrogel/ethyl cellulose bilayer films for active food packaging application

A sustainable functional bilayer film composed of gelatin hydrogel/ethyl cellulose was fabricated using a simple LBL casting method. The outer layer was hydrophobic ethyl cellulose (EC), while the inner layer was hydrophilic gelatin (GEL) hydrogel. Tannic acid (TA) served as a green cross-linker for GEL hydrogel preparation and as a reductant for AgNPs synthesis in-situ within the hydrogel network. Physicochemical and functional properties of the bilayer films containing different TA content were studied. When 3 wt% TA was added, the AgNPs@GT-3/EC bilayer film exhibited superior UV-light barrier, possessed desirable humidity-adjustable capability and oxygen barrier due to denser hydrogel network structure, and effectively inactivated foodborne pathogens S. aureus and E. coli with bacteriostatic rates of 99 %. The application results indicated that this bilayer film effectively maintained the postharvest quality of white button mushrooms and prolonged their shelf-life to 7 days under ambient storage, demonstrating its promising potential for fresh food packaging.

Chitosan-based hydrogels: From preparation to applications, a review

Chitosan, derived from the deacetylation of chitin, is an abundant natural biopolymer on earth. Chitosan and its derivatives have become promising biological materials because of their unique molecular structure and excellent biological activities. The reactive functional groups of chitosan such as the amino and hydroxyl groups play a crucial role in facilitating the synthesis of three-dimensional hydrogel. Chitosan-based hydrogels have been widely used in medical, pharmaceutical, and environmental fields for years. Nowadays, chitosan-based hydrogels have been found in a wide range of applications in the food industry such as food sensors, dye adsorbents and nutrient carriers. In this review, recently developed methods for the preparation of chitosan-based hydrogels were given, and the biological activities of chitosan-based hydrogels were systematically introduced. Additionally, the recent progress in food sensors, packaging, dye adsorbents, and nutrient carriers was discussed. Finally, the challenges and prospects for the future development of chitosan-based hydrogels were discussed.

Nanocellulose-based antimicrobial aerogels with humidity-triggered release of cinnamaldehyde

Active food packaging with controlled release behavior of volatile antimicrobials is highly desirable for enhancing the quality of fresh produce. In this study, humidity-responsive antimicrobial aerogels were developed using chitosan and dialdehyde nanocellulose, loading with cyclodextrin-cinnamaldehyde inclusion complexes (ICs) for achieving humidity-triggered release of the encapsulated antimicrobial agent. Results showed that the prepared aerogels had capable water absorption ability, which could be served as absorbent pads to take in excessive exudate from packaged fresh produce. More importantly, the accumulative release rate of cinnamaldehyde from the antimicrobial aerogels was significantly improved at RH 98 % compared to that at RH 70 %, which accordingly inactivated all the inoculated Escherichia coli, Staphylococcus aureus and Botrytis cinerea. Additionally, strawberries packaged with the antimicrobial aerogels remained in good conditions after 5 d of storage at 22 ± 1 °C. The prepared composite aerogels had the potential to extend the shelf life of fresh strawberries.

Polylactic acid-based microcapsules for moisture-triggered release of chlorine dioxide and its application in cherry tomatoes preservation

Polylactic acid (PLA)-based microcapsules, capable of releasing chlorine dioxide (ClO2) upon exposure to moisture, have been developed for fruits and vegetables preservation. The microcapsules were prepared by emulsion solvent evaporation, utilizing PLA as the wall material, and NaClO2 as the core material. After optimization, NaClO2 microcapsules exhibited an encapsulation efficiency of 55.75% and an average particle size of 498.08 μm. Citric acid microcapsules were prepared using the same process, but with citric acid as the core material. When the two kinds of microcapsules were mixed, gaseous ClO2 was released in a highly humid environment. The release rate could be adjusted by temperature and the ratio between the two microcapsules, and the release period could be as long as 17 days at 20 °C. With a certain amount of microcapsules placed in the package of cherry tomatoes, the decay rate and weight loss rate of the fruits were reduced by 63 % and 34 %, respectively, compared to the control group. The microcapsules also helped to maintain the good appearance, hardness, and the content of total soluble solid content and titratable acid content of cherry tomatoes. Therefore, the PLA-based microcapsules have satisfied convenience and effectiveness for application in fruit and vegetables preservation.

Multibranched flower-like ZnO anchored on pectin/cellulose nanofiber aerogel skeleton for enhanced comprehensive antibacterial capabilities

In this study, F-ZnO NPs were used as antibacterial agents, mussel bionic dopamine exerted its adhesive action to immobilize F-ZnO NPs on the pectin/CNF aerogel skeleton. Fruit and vegetable antimicrobial mats with safety, long duration of action and high efficiency were prepared and its potential application has been investigated. The results showed that a dopamine layer was deposited on the surface of the CNF, which promoted the tight adhesion of the F-ZnO NPs to the aerogel skeleton. The F-ZnO@D-CNF aerogel exhibited a slow release of zinc ions, with the first two days being 0.40 ± 0.16 and 1.01 ± 0.13 mg/mL. The aerogel was light, can stand on the petals without collapsing, has regular and uniform pore structure, good tensile/compressive properties and high antibacterial/anti-fungal properties. Strawberries packaged with F-ZnO@D-CNF aerogel exhibited an extended shelf life of 5 days. Additionally, the strawberries maintained a soluble solid content of 6.9 ± 0.82 % and a Vc content of 44.67 ± 3.51 mg/100 g. The weight loss, color and firmness were also notably superior to the other four groups. The final concentration of zinc ions in strawberries was 3.71 ± 0.28 μg/g, which is far below the recommended dietary intake.

Emerging technologies for preservation and quality evaluation of postharvest edible mushrooms: A review

Edible mushrooms are the highly demanded foods of which production and consumption have been steadily increasing globally. Owing to the quality loss and short shelf-life in harvested mushrooms, it is necessary for the implementation of effective preservation and intelligent evaluation technologies to alleviate this issue. The aim of this review was to analyze the development and innovation thematic lines, topics, and trends by bibliometric analysis and review of the literature methods. The challenges faced in researching these topics were proposed and the mechanisms of quality loss in mushrooms during storage were updated. This review summarized the effects of chemical processing (antioxidants, ozone, and coatings), physical treatments (non-thermal plasma, packaging and latent thermal storage) and other emerging application on the quality of fresh mushrooms while discussing the efficiency in extending the shelf-life. It also discussed the emerging evaluation techniques based on the various chemometric methods and computer vision system in monitoring the freshness and predicting the shelf-life of mushrooms which have been developed. Preservation technology optimization and dynamic quality evaluation are vital for achieving mushroom quality control. This review can provide a comprehensive research reference for reducing mushroom quality loss and extending shelf-life, along with optimizing efficiency of storage and transportation operations.

Effect of Fermentation Humidity on Quality of Congou Black Tea

This study investigated the effect of different fermentation humidities (55%, 65%, 75%, 85% and 95%) on congou black tea quality and bioactivity. Fermentation humidity mainly affected the tea's appearance, aroma and taste quality. The tea fermented at low humidity (75% or below) showed a decrease in tightness, evenness and moistening degree, as well as a heavy grassy and greenish scent, plus a green, astringent and bitter taste. The tea fermented at a high humidity (85% or above) presented a sweet and pure aroma, as well as a mellow taste, plus an increase of sweetness and umami. With increasing fermentation humidity, the tea exhibited a drop in the content of flavones, tea polyphenols, catechins (EGCG, ECG) and theaflavins (TF, TF-3-G), contrasted by a rise in the content of soluble sugars, thearubigins and theabrownins, contributing to the development of a sweet and mellow taste. Additionally, the tea showed a gradual increase in the total amount of volatile compounds and in the content of alcohols, alkanes, alkenes, aldehydes, ketones and acids. Moreover, the tea fermented at a low humidity had stronger antioxidant activity against 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and a higher inhibiting capability on the activities of α-amylase and α-glucosidase. Overall results indicated the desirable fermentation humidity of congou black tea should be 85% or above.

Recent advance in quality preservation of non-thermal preservation technology of fresh mushroom: a review

Fresh mushrooms have a long history of cultivation and consumption, but high postharvest losses are a concern in the commercial production of mushrooms worldwide. Thermal dehydration is widely used in the preservation of commercial mushrooms, but the flavor and taste of mushrooms are significantly altered after dehydration. Non-thermal preservation technology, which effectively maintains the characteristics of mushrooms, is a viable alternative to thermal dehydration. The objective of this review was to critically assess the factors affecting fresh mushroom quality after preservation is remarkable, with the ultimate goal of developing and promoting non-thermal preservation technology for preserving fresh mushroom quality, effectively extending the shelf life of fresh mushrooms. The factors influencing the quality degradation process of fresh mushrooms discussed herein include the internal factors associated with the mushroom itself and the external factors associated with the storage environment. We present a comprehensive discussion of the effects of different non-thermal preservation technologies on the quality and shelf life of fresh mushrooms. To prevent quality loss and extend the shelf life after postharvest, hybrid methods, such as physical or chemical techniques combined with chemical techniques, and novel nonthermal technologies are highly recommended.

Characterization of an active film prepared with Lentinus edodes (shiitake) polysaccharide and its effect on post-harvest quality and storage of shiitake

The aim of this study was to prepare a film based on shiitake (Lentinus edodes) stalk polysaccharides (LEP) for mushroom preservation. The effects of different LEP concentrations on physical, mechanical, antioxidant, and antimicrobial properties of the prepared film were evaluated. Using scanning electron microscopy, it was revealed that the addition of 1.5 % LEP resulted in homogeneous distribution in the prepared film, as well as greatly improved its antimicrobial properties. Moreover, LEP film resulted in superior mushroom preservation by regulating enzyme activities related to mushroom browning and softening, thereby decaying these processes. In addition, the prepared film maintained mushroom quality by reducing the accumulation of H₂O₂ and activating the regulatory system against oxidative stress. Collectively, the findings of the present study highlight the potential benefits of LEP films as a strategy to improve mushroom quality and prevent post-harvest spoilage, hence constituting a novel prospect for the development of shiitake by-products.

Facile fabrication of multifunctional citrus pectin aerogel fortified with cellulose nanofiber as controlled packaging of edible fungi

Citrus pectin was used as a precursor and cellulose nanofibers as a reinforcing agent, a mixed aerogel with enhanced structural properties was prepared. Pickering emulsion was a template for aerogel formation, embedding thymol. Its potential application in humidity regulating packaging has been investigated. Results showed that emulsion gel containing cellulose nanofibers has slightly larger droplet diameter, better viscoelasticity and emulsification. Composite aerogel has larger pore size and thinner pore wall. Additionally, its tensile and compressive properties have been significantly improved. Moisture absorption was close to 100% of its own weight, thymol was released slowly. Compared with Escherichia coli, aerogel has better resistance to Staphylococcus aureus. When applied on fresh Agaricus bisporus. It was found that relative humidity in package can be stabilized at about 97%. Hardness, color, total phenol content, cell membrane integrity and total antioxidant capacity of Agaricus bisporus were maintained and fresh-keeping period was extended to 5 days.

Development and characterization of fish myofibrillar protein/chitosan/rosemary extract composite edible films and the improvement of lipid oxidation stability during the grass carp fillets storage

Biofilm composition from fish myofibrillar protein (FMP) and chitosan solution (CS) incorporated with rosemary extract (RE) was developed and applied to monitor the freshness of fish fillets. The effects of different concentrations of RE as well as physical, mechanical, structural and functional properties of FMP/CS films were investigated. Films containing RE showed reduced water solubility and water vapor permeability and enhanced tensile strength and elongation at break. Results also showed good compatibility of the components and good dispersion of RE in the matrix. However, the content of RE (0.2%, v/v) added in the composite films produced aggregations and had negative effects on their film-forming properties. The antioxidant capacity of composite films was related to the level of RE and demonstrated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. Chilled grass carp fillets wrapped with different films to evaluate the preservative effect. Results of thiobarbituric acid reactive substances, pH value, Free amino acid and total volatile basic nitrogen indicated that FMP/CS/RE composite film could protect the fish fillet well and inhibit the lipid oxidation. The developed FMP/CS/RE composite films possess the potential to be applied as edible films in the food packaging industry and food cold chain transportation.