Recent advances in extending the shelf life of fresh Agaricus mushrooms: a review

Pectin-Cellulose Nanofiber Composites: Biodegradable Materials for Modified Atmosphere Packaging

Pectin blended with cellulose nanofiber (CNF) sourced from wood pulp has excellent potential for modified atmosphere packaging (MAP), as demonstrated with refrigerated or sliced fruits enclosed in parchment coated with pectin-CNF composites. Addition of sodium borate (NaB) augments the antioxidant capacity of the composite, most likely through the generation of unsaturated pectic acid units. Packaging materials coated with pectin-CNF-NaB composites demonstrate better humidity regulation in refrigerated spaces over a 3-week period relative to uncoated controls (50% less variation), with improved preservation of strawberries as well as a reduction in the oxidative browning of sliced apples. Pectin-CNF films are both biorenewable and biodegradable as confirmed by their extensive decomposition in soil over several weeks, establishing their potential as a sustainable MAP material. Lastly, self-standing films are mechanically robust at 80% RH with tensile strength and toughness as high as 150 MPa and 8.5 MJ/m2 respectively. These values are on par with other bioplastic composites and support the practical utility of pectin-CNF composites in functional packaging applications.

Metabolomic and Transcriptomic Analyses Revealed Lipid Differentiation Mechanisms in Agaricus bisporus at Ambient Conditions

Agaricus bisporus is one of the most popular mushroom species in the world; however, mushrooms are highly susceptible to browning due to the absence of a protective cuticle layer and high respiration rate. The molecular mechanism underlying the process of mushroom browning needs to be explored. Here, we analyzed the transcriptomic and metabolomic data from A. bisporus at ambient temperature. Specifically, a total of 263 significantly changed metabolites and 4492 differentially expressed genes were identified. Lipid metabolites associated with cell membrane degradation were predominantly up-regulated during ambient storage. Transcriptomic data further revealed the alterations of the expression of membrane lipid metabolism-related enzymes. Additionally, energy metabolic processes and products such as glycolysis and linoleic acid changed significantly during ambient storage, indicating their potential roles in the quality deterioration of A. bisporus. These findings provide new insights into the underlying lipid metabolic mechanisms of A. bisporus during postharvest ambient storage and will provide values for mushroom preservation techniques.

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.

Recent advances and role of melatonin in post-harvest quality preservation of shiitake (Lentinula edodes)

Shiitake mushrooms are renowned for their popularity and robust nutritional value, are susceptible to spoilage due to their inherent biodegradability. Nevertheless, because of their lack of protection, these mushrooms have a short shelf life. Throughout the post-harvest phase, mushrooms experience a persistent decline in quality. This is evidenced by changes such as discoloration, reduced moisture content, texture changes, an increase in microbial count, and the depletion of nutrients and flavor. Ensuring postharvest quality preservation and prolonging mushroom shelf life necessitates the utilization of post-harvest preservation techniques, including physical, chemical, and thermal processes. This review provides a comprehensive overview of the deterioration processes affecting mushroom quality, covering elements such as moisture loss, discoloration, texture alterations, increased microbial count, and the depletion of nutrients and flavor. It also explores the key factors influencing these processes, such as temperature, relative humidity, water activity, and respiration rate. Furthermore, the review delves into recent progress in preserving mushrooms through techniques such as drying, cooling, packaging, irradiation, washing, and coating.

A comprehensive review of the application of ultrasonication in the production and processing of edible mushrooms: Drying, extraction of bioactive compounds, and post-harvest preservation

Edible mushrooms are high in nutrients, low in calories, and contain bioactive substances; thus, they are a valuable food source. However, the high moisture content of edible mushrooms not only restricts their storage and transportation after harvesting, but also leads to a shorter processable cycle, production and processing limitations, and a high risk of deterioration. In recent years, ultrasonic technology has been widely applied to various food production operations, including product cleaning, post-harvest preservation, freezing and thawing, emulsifying, and drying. This paper reviews applications of ultrasonic technology in the production and processing of edible mushrooms in recent years. The effects of ultrasonic technology on the drying, extraction of bioactive substances, post-harvest preservation, shelf life/preservation, freezing and thawing, and frying of edible mushrooms are discussed. In summary, the application of ultrasonic technology in the edible mushroom industry has a positive effect and promotes the development of this industry.

Influence of Storage Temperature on Levels of Bioactive Compounds in Shiitake Mushrooms (Lentinula edodes)

Shiitake mushroom (Lentinula edodes) hold high nutritional and medicinal value as they contain an abundance of health-promoting compounds. However, the effect of long-term postharvest storage on the variation in the levels of health-promoting compounds has not been extensively studied. In this study, we investigated the changes in the levels of phenolic compounds, antioxidants, eritadenine, and ergothioneine in shiitake mushrooms stored at three different temperatures (1, 3, and 5 °C) for 4 weeks. Compared to mushrooms stored at lower temperatures, those stored at 5 °C exhibited a higher level of total phenolics in their pileus after 2 weeks of storage; however, storage at 5 °C also increased the deterioration of the fruiting body of these mushrooms. In mushrooms stored at all temperatures, the eritadenine content in the pilei tended to increase up to 2 weeks of storage. In contrast, the ergothioneine content in the pileus decreased during storage, with a significantly lower level detected in mushrooms stored at 5 °C for 4 weeks. Together, these results suggest that the mechanisms underlying the accumulation of phenolics and eritadenine may be related to mushroom deterioration during storage. Our findings indicate that the levels of health-promoting compounds in shiitake mushrooms are influenced by storage temperature, suggesting the potential to control adjustments of specific bioactive compounds by regulating storage conditions.

Cell wall composition and enzyme-related activities in eggplant as affected by hot water, 1-MCP and calcium chloride treatments

The effects of postharvest applications of hot water (HWT) (45, 50, and 55 °C), 1-MCP (1, 5, and 10 μL/L), and CaCl2 (1, 2, and 3%) on polygalacturonase (PG), pectin methylesterase (PME), α-galactosidase (α-Gal), β-galactosidase (β-Gal) and β-1,4-glucanase (β-1,4-Glu) activities, and the fruit firmness and cell wall composition of eggplant fruit were investigated. The results showed that the decrease in the eggplants firmness was delayed by HWT, 1-MCP, and CaCl2 treatments during storage compared with the control. However, HWTs were less effective than the 1-MCP and CaCl2 treatments. The results show that 1-MCP and CaCl2 treatments inhibited the depolymerization of water (WSP), CDTA (CSP), and sodium carbonate (SSP) soluble polyuronides. The results suggest that 1-MCP (5 and 10 μL/L) and CaCl2 (1, 2, and 3%) could prevent eggplant softening by inhibiting hydrolase enzymes and reducing the disintegration of the polysaccharides. In addition, 1-MCP and CaCl2 were more effective than hot water treatment in extending postharvest storage life. There is a significantly high correlation between firmness, polyuronide content and cell wall enzyme activity.

Changes in the Physical Properties and Volatile Odor Characteristics of Shiitake Mushrooms (Lentinula edodes) in Far Infrared Radiation Drying

The effects of far infrared radiation drying (FID) on physical properties (drying kinetics, color, shrinkage ratio, rehydration ratio, and microstructural characterization) and volatile odor characteristics (volatile odor profile distinction and volatile compounds) of shiitake mushrooms were evaluated in this study. During the FID, the drying time decreased with the increase in drying temperature, and it had a less significant effect in the lower temperature range. The increase in drying temperature led to increasing shrinkage and collapse in the microstructure, resulting in a decreased rehydration rate and highlighting the influence of microstructure characteristics on macroscopic properties. Higher drying temperatures employed in the FID process were found to be associated with a decreasing L* value and an increasing ΔE value. The application of principal component analysis can effectively distinguish the significant effect of FID on the volatile odor profiles of shiitake mushrooms. Compared to raw shiitake mushrooms, FID treatment has endowed samples with a greater variety of volatile compounds. After processing with FID, there have been increases in volatile components such as sulfur compounds, acids, nitrogen compounds, and aldehydes, while volatile components like alcohols, ketones, and hydrocarbons have shown decreases.

Microbiological Assessment of White Button Mushrooms with an Edible Film Coating

The development of edible coatings incorporating bioextracts from mushrooms native to Portuguese forests aims to enhance the value of the endogenous forest and mycological resources by harnessing their potential as a source of antimicrobial and antioxidant compounds. Edible coatings represent an important pathway to decreasing food waste and contributing to implementing a circular bioeconomy. The coating should result in product valorization through improved preservation/conservation, increased shelf life, as well as enhancement of its antioxidant and enzymatic properties. To evaluate the effectiveness of an edible coating on fungal food matrices, a 14-day shelf-life study was conducted, wherein both coated and untreated mushrooms were examined under controlled storage temperatures of 4 °C and 9.3 °C. Agaricus bisporus was chosen as the food matrix for its bioeconomy significance, and Pleurotus eryngii was selected for the preparation of the food-based coating due to its profile of bioactive compounds. Microbiological analysis and physicochemical monitoring were conducted on the food matrices and the coating. Coated mushrooms had less mass loss and color change, and had better texture after 14 days. Microbiological analysis revealed that the coating had no antimicrobial activity. Overall, the coating improved the shelf life of the coated mushrooms but had less effect on the microbial community.

Rapid and Accurate Authentication of Porcini Mushroom Species Using Fourier Transform Near-Infrared Spectra Combined with Machine Learning and Chemometrics

Porcini mushrooms have high nutritional value and great potential, but different species are easily confused, so it is essential to identify them rapidly and precisely. The diversity of nutrients in stipe and cap will lead to differences in spectral information. In this research, Fourier transform near-infrared (FT-NIR) spectral information about imparity species of porcini mushroom stipe and cap was collected and combined into four data matrices. FT-NIR spectra of four data sets were combined with chemometric methods and machine learning for accurate evaluation and identification of different porcini mushroom species. From the results: (1) improved visualization level of t-distributed stochastic neighbor embedding (t-SNE) results after the second derivative preprocessing compared with raw spectra; (2) after using multiple pretreatment combinations to process the four data matrices, the model accuracies based on support vector machine and partial least-square discriminant analysis (PLS-DA) under the best preprocessing method were 98.73-99.04% and 98.73-99.68%, respectively; (3) by comparing the modeling results of FT-NIR spectra with different data matrices, it was found that the PLS-DA model based on low-level data fusion has the highest accuracy (99.68%), but residual neural network (ResNet) model based on the stipe, cap, and average spectral data matrix worked better (100% accuracy). The above results suggest that distinct models should be selected for dissimilar spectral data matrices of porcini mushrooms. Additionally, FT-NIR spectra have the advantages of being nondevastate and fast; this method is expected to be a promising analytical tool in food safety control.

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.

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.

Advances in Postharvest Storage and Preservation Strategies for Pleurotus eryngii

The king oyster mushroom (Pleurotus eryngii) is a delicious edible mushroom that is highly prized for its unique flavor and excellent medicinal properties. Its enzymes, phenolic compounds and reactive oxygen species are the keys to its browning and aging and result in its loss of nutrition and flavor. However, there is a lack of reviews on the preservation of Pl. eryngii to summarize and compare different storage and preservation methods. This paper reviews postharvest preservation techniques, including physical and chemical methods, to better understand the mechanisms of browning and the storage effects of different preservation methods, extend the storage life of mushrooms and present future perspectives on technical aspects in the storage and preservation of Pl. eryngii. This will provide important research directions for the processing and product development of this mushroom.

Advances in the Role and Mechanisms of Essential Oils and Plant Extracts as Natural Preservatives to Extend the Postharvest Shelf Life of Edible Mushrooms

China has a large variety of edible mushrooms and ranks first in the world in terms of production and variety. Nevertheless, due to their high moisture content and rapid respiration rate, they experience constant quality deterioration, browning of color, loss of moisture, changes in texture, increases in microbial populations, and loss of nutrition and flavor during postharvest storage. Therefore, this paper reviews the effects of essential oils and plant extracts on the preservation of edible mushrooms and summarizes their mechanisms of action to better understand their effects during the storage of mushrooms. The quality degradation process of edible mushrooms is complex and influenced by internal and external factors. Essential oils and plant extracts are considered environmentally friendly preservation methods for better postharvest quality. This review aims to provide a reference for the development of new green and safe preservation and provides research directions for the postharvest processing and product development of edible mushrooms.

Pleurotus ostreatus Grown on Agro-Industrial Residues: Studies on Microbial Contamination and Shelf-Life Prediction under Different Packaging Types and Storage Temperatures

The short shelf-life of mushrooms, due to water loss and microbial spoilage, is the main constraint for commercialization and consumption. The effect of substrate type combined with different temperatures and packaging conditions on the shelf-life of fresh Pleurotus ostreatus is scantily researched. The current study investigated the shelf-life of fresh oyster mushrooms grown on low (0.3, 0.3, 0.17) and high (0.7, 0.7, 0.33) rates of olive pruning residues (OLPR), spent coffee grounds (SCG), and both combined residues (OLPR/SCG) with wheat straw (WS), respectively, at ambient (20 °C) and 4 °C temperatures under no packaging, polyethylene plastic bag packaging (PBP), and polypropylene vacuum bag packaging (VBP). Results showed that at ambient temperature OLPR/SCG mushrooms PBP-bagged had an increased shelf-life by 0.5-1.2 days in comparison with WS ones. The predictive models adopted to optimize mushroom shelf-life at ambient temperature set rates of 0.289 and 0.303 of OLPR and OLPR/SCG, respectively, and PBP as the most suitable conditions (9.18 and 9.14 days, respectively). At 4 °C, OLPR/SCG mushrooms VBP-bagged had a longer shelf-life of 2.6-4.4 days compared to WS ones. Predictive models noted a maximized shelf-life of VBP-bagged mushrooms (26.26 days) when a rate of 0.22 OLPR/SCG is incorporated into the initial substrate. The combination of OLPR and SCG increased the shelf-life of fresh Pleurotus ostreatus by decreasing the total microbial count (TMC) while delaying weight loss and veil opening, and maintaining carbohydrate content, good firmness, and considerable protein, in comparison with WS regardless the storage temperature and packaging type.

Recent Advances in Postharvest Irradiation Preservation Technology of Edible Fungi: A Review

Edible fungi have high edible, medicinal and economic value. Rapid development of the edible fungi industry can meet people's consumption demands. However, due to lack of suitable preservation technology after harvest, edible fungi are susceptible to mechanical damage, microbial infection, and discoloration, which could affect the quality and shelf life of fresh edible fungi. Many techniques have been developed to extend the postharvest storage time of fresh edible fungi and irradiation technology has been proven to be one of the potential technologies. This review summarizes the internal and external factors affecting the postharvest quality deterioration of edible fungi, introduces the types of irradiation preservation technology and describes comprehensive advances in the effects of irradiation on shelf life, microbiology, organoleptic qualities, nutritional qualities (proteins, fats, sugars and vitamins) and enzymatic activities of edible fungi from different regions and of different species worldwide. This review uncovers that the postharvest quality decay of edible fungi is a complex process. The irradiation preservation of edible fungi is affected not only by the edible fungus itself and the storage environment but also by the radiation type, radiation dose and radiation source conditions. Future studies need to consider the combined application of irradiation and other novel technologies to further improve the preservation effect of edible fungi, in particular in the area of irradiation's influence on the flavor of edible fungus.

Widely Targeted Metabolomics Analysis of the Changes to Key Non-volatile Taste Components in Stropharia rugosoannulata Under Different Drying Methods

Stropharia rugosoannulata is an extremely perishable edible fungi product, and drying can delay its deterioration, however, drying will affect its flavor, especially the non-volatile taste substances dominated by amino acids, nucleotides, organic acids and carbohydrates. Currently, which drying method is the most suitable for the drying of S. rugosoannulata remains unknown, we need to fully consider the economic efficiency of the method and the impact on flavor. But we have limited comprehensive knowledge of the changed non-volatile taste metabolites as caused by drying processes. Here, an LC-MS/MS-based widely targeted metabolome analysis was conducted to investigate the transformation mechanism of S. rugosoannulata non-volatile taste components after undergoing hot air drying (HAD), vacuum freeze drying (VFD), and microwave vacuum drying (MVD). A total of 826 metabolites were identified, 89 of which—48 amino acids, 25 nucleotides, 8 organic acids, and 8 carbohydrates—were related to non-volatile taste. The drying method used and the parts of S. rugosoannulata (stipe and pileus) influenced the differences found in these metabolites. The possible mechanisms responsible for such chemical alterations by different drying methods were also investigated by a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Amino acid metabolism (alanine, aspartate, and glutamate metabolism; glycine, serine, and threonine metabolism; arginine and proline metabolism; valine, leucine, and isoleucine biosynthesis) was the main metabolic pathway involved. Pathway enrichment analysis also identified differences in non-volatile taste components among three drying methods that may be closely related to the applied drying temperature. Altogether, the results indicated that as an economical and convenient drying method, HAD is conducive to improving the flavor of S. rugosoannulata and thus it harbors promising potential for practical applications.

Gamma radiation crosslinking of PVA/myrrh resin thin film for improving the post-harvest time of lemon fruits

Preparation of a thin film of polyvinyl alcohol (PVA)/myrrh natural resin using a low gamma irradiation dose (1 kGy) was investigated towards increasing the post-harvest time of lemon fruit. Different analytical techniques, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and mapping techniques were used to characterize the prepared thin film. This investigation was carried out to evaluate the effect of different concentrations of myrrh as an edible coating in prolonging shelf life and preserving the quality of lemon fruits (Citrus aurantifolia). Lemons were immersed directly in PVA solution containing 1%, 2%, and 3% concentrations of myrrh and then stored at ambient (25 ± 1 °C) and low (4 ± 1 °C) temperatures. The disease severity, acidity, total soluble solids (TSS), and ascorbic acid contents were tested after the coating with the PVA/myrrh thin film at different temperatures (4 °C and 25 °C) for different storage times (7 and 14 days). The application of different concentrations of the synthesized PVA/myrrh thin film (1%, 2%, and 3%) significantly reduced green mold disease symptoms and disease severity in the lemon fruits. The acidity value (pH value) was the lowest for the 2% myrrh treatment after 7 °C days at 25 °C, followed by the 1% myrrh treatment under the same conditions. The highest TSS was observed after the treatment for 7 days at 25 °C, with a value of 8.1 g dL-1. A high ascorbic acid concentration (33.5 mg dL-1) was noted after coating the lemons with the 1% PVA/myrrh thin film for 7 days at 25 °C. The results show that the application of a PVA/myrrh thin film extends the shelf-life and maintains the quality of lemon fruits by decreasing the levels of evaporation from the fruits and loss of weight due to the delay of the complete ripening stage of the lemon fruits.

The effect of carbon dioxide on the quality of the mushrooms

Mushrooms' quality may be significantly changing depending on their type, strain, growing cycle, packing, cooling, postharvest handling (PHH), and conditions of storage. This work aimed to define the influence of the type and mushrooms' strain, the regime of the PHH by carbon dioxide on their preservation (marketability, loss of weight (LW)), changes in the chemical substances, and physiological activity (intensity respiration (IR) and heat release (HR)). Mushrooms Agaricus bisporus (AB) (strains ІБК-25 and ІБК-15) and Pleurotus ostreatus (PO) (strains НК-35 and Amycel 3000) were used for testing. Three regimes of treatment by CO2 with a concentration of 20% were applied: 2 h; 12 h and 22 h. The control was the mushrooms without treatment by CO2. Changes in the chemical substances such as dry matters (DM), protein nitrogen (PN), and ascorbic acid (AA) in the researched mushrooms were observed. The best result of mushroom preservation was provided by the regime of CO2 treatment during 12 h. The yield of marketable AB was 94.9% (IBK-25) and 94.2% (IBK-15) comparison to control 93.5%, and 92.5%, respectively. The regime of PHH 2 h almost has no influence but 22 h harmed this indicator. PHH of mushrooms by carbon dioxide was promoted to preserve the DM and increasing concentration of CO2 was supplied better results. Thus, DM at the end of storage in the AB of strain IBK-25 depend on the regime were 8.5, 8.6, and 8.4%, against – 8.3% in the control variant. Significant quantitative changes in the PN and AA as a result of treatment by CO2 were not established. PHH also affected the IR and HR. The increased duration of treatment by CO2 inhibited the intensity of physiological processes in the mushrooms. But, as in previous cases, the best result was provided PHH by 20% CO2 during 12 h. Similar trends of treatments effect by carbon dioxide were observed in the mushrooms of PO.

Fresh Mushroom Preservation Techniques

The production and consumption of fresh mushrooms has experienced a significant increase in recent decades. This trend has been driven mainly by their nutritional value and by the presence of bioactive and nutraceutical components that are associated with health benefits, which has led some to consider them a functional food. Mushrooms represent an attractive food for vegetarian and vegan consumers due to their high contents of high-biological-value proteins and vitamin D. However, due to their high respiratory rate, high water content, and lack of a cuticular structure, mushrooms rapidly lose quality and have a short shelf life after harvest, which limits their commercialization in the fresh state. Several traditional preservation methods are used to maintain their quality and extend their shelf life. This article reviews some preservation methods that are commonly used to preserve fresh mushrooms and promising new preservation techniques, highlighting the use of new packaging systems and regulations aimed at the development of more sustainable packaging.

Method Superior to Traditional Spectral Identification: FT-NIR Two-Dimensional Correlation Spectroscopy Combined with Deep Learning to Identify the Shelf Life of Fresh Phlebopus portentosus

The taste of fresh mushrooms is always appealing. Phlebopus portentosus is the only porcini that can be cultivated artificially in the world, with a daily output of up to 2 tons and a large sales market. Fresh mushrooms are very susceptible to microbial attacks when stored at 0-2 °C for more than 5 days. Therefore, the freshness of P. portentosus must be evaluated during its refrigeration to ensure food safety. According to their freshness, the samples were divided into three categories, namely, category I (1-2 days, 0-48 h, recommended for consumption), category II (3-4 days, 48-96 h, recommended for consumption), and category III (5-6 days, 96-144 h, not recommended). In our study, a fast and reliable shelf life identification method was established through Fourier transform near-infrared (FT-NIR) spectroscopy combined with a machine learning method. Deep learning (DL) is a new focus in the field of food research, so we established a deep learning classification model, traditional support-vector machine (SVM), partial least-squares discriminant analysis (PLS-DA), and an extreme learning machine (ELM) model to identify the shelf life of P. portentosus. The results showed that FT-NIR two-dimensional correlation spectroscopy (2DCOS) combined with the deep learning model was more suitable for the identification of fresh mushroom shelf life and the model had the best robustness. In conclusion, FT-NIR combined with machine learning had the advantages of being nondestructive, fast, and highly accurate in identifying the shelf life of P. portentosus. This method may become a promising rapid analysis tool, which can quickly identify the shelf life of fresh edible mushrooms.

Effects of power ultrasound treatment on the shelf life of button mushrooms: Digital image processing and microbial counting can reveal the effects

Edible button mushroom (Agaricus bisporus) is the most common commercial-grade mushroom in the world. The shelf life of button mushrooms is limited to a range between two and four days because of enzymatic browning at medium ambient temperature if it is minimally processed. This study aimed to investigate the effects of power ultrasonics and its interaction with several treatments including H2O2 and O3 on increasing the storage quality of edible button mushroom by controlling enzymatic browning. A 100 W ultrasonic bath with a frequency between 20 and 35 kHz was used during the experiments. The storage quality was studied by examining the changes in color and microbial content over 12 days. The results obtained from the digital image processing and total microbial counting showed that the ultrasonic treatment for 6 min is an appropriate method for controlling the color preservation of mushrooms to improve their shelf life. The maximum changes in RGB band, HSV band, L*a*b* band, and microbial content of the mushroom samples under the ultrasonic treatment were equal to 7%, 12%, 10%, and 11%, respectively. Furthermore, having the color properties and microbial content of the samples, the artificial neural network (ANN) was capable of predicting their storage period with an MSE of 0.011.

Packaging of Fresh Sliced Mushrooms with Essential Oils Vapours: A New Technology for Maintaining Quality and Extending Shelf Life

The use of vapour of essential oils (EOs) through an innovative pilot-plant packaging device was studied to preserve the quality of sliced mushrooms during storage. A mix of EOs (eugenol, bergamot EO, and grapefruit EO) was vaporized (100 and 125 µL L⁻¹) and applied during packaging of sliced mushrooms under modified atmosphere packaging (MAP); then, the product quality was studied during cold storage up to 12 days. The highest colour changes of EOs125 samples, which were observed in the mushroom stipe, were not observed with the EOs100 atmosphere. Thus, the high polyphenoloxidase activity observed in untreated samples after 5–7 days was highly controlled with the vapour EOs atmospheres. Furthermore, the visual appearance scores of EOs100 samples were still over the limit of usability, while untreated samples were already below this threshold after 5 days of storage. A strong bacteriostatic effect was achieved with vapour EOs, reducing the Pseudomonas spp. (the main microbial genus in cultivated mushrooms) growth by ≈1.7 log CFU g⁻¹, regardless of the EOs dose, after 12 days. The activity of phenyl ammonia lyase was also reduced up to ≈0.4 enzymatic units with the EOs100 treatment. Conclusively, packaging of sliced mushrooms under an atmosphere enriched with 100 µL L⁻¹ EOs vapour highly controlled the quality loss of sliced mushrooms owing to their enzymatic inhibition and high bacteriostatic effect.

Variation in cell membrane integrity and enzyme activity of the button mushroom (Agaricus bisporus) during storage and transportation

Button mushrooms (Agaricus bisporus) were put under stimulated storage and transportation environments with different amounts of phase-change materials (PCM). Results showed that the addition of PCM effectively maintained a cooler environment and delayed a rise in temperature. And the addition of PCM, especially in a ratio 1:2 PCM:mushroom, had a significant effect on delaying the increase in cell membrane permeability, malondialdehyde and H2O2 levels, and also delayed superoxide dismutase and catalase activity. These results suggest that PCM may be candidate in postharvest mushroom during storage and transportation.

Impact of post-harvest processing or thermal dehydration on physiochemical, nutritional and sensory quality of shiitake mushrooms

Shiitake mushrooms are one of the most popular and highly consumed mushrooms worldwide both in fresh and dry forms. However, it rapidly starts losing its quality immediately after harvest which necessitates processing and/or proper storage before being distributed. However, the processes used for preserving other mushrooms (e.g., Agaricus) become unviable for shiitake due to its uniqueness (higher respiration rate, varied biochemicals, growth, etc.) which demands individual studies on shiitake. This review starts by listing the factors and their interdependence leading to a quality decline in shiitake after harvest. Understanding well about these factors, numerous post-harvest operations preserve shiitake as fresh form for a shorter period and as dried forms for a longer shelf-life. These processes also affect the intrinsic quality and nutrients of shiitake. This review comprehensively summarizes and discusses the effects of chemical processing (washing, fumigation, coating, and ozone), modified atmosphere packaging (including irradiation) on the quality of fresh shiitake while discussing their efficiency in extending their shelf-life by inhibiting microbial spoilage and deterioration in quality including texture, appearance, nutrients, and favor. It also reviews the impact of thermal dehydration on the quality of dried shiitake mushrooms, especially the acquired unique textural, nutritional, and aromatic properties along with their merits and limitations. Since shiitake are preferred to be low-cost consumer products, the applicability of freeze-drying and sophisticated novel methodologies, which prove to be expensive and/or complex, are discussed. The review also outlines the challenges and proposes the subsequent future directives, which either retains/enhances the desirable quality in shiitake mushrooms.

The microperforated packaging design and evaluation of shelf life of fresh-sliced mushrooms

Fresh mushrooms have a very short shelf life, of 1 – 3 days because of their high respiration rate and lack of cuticles that protect the plant from external factors. In the case of fresh-sliced mushrooms, they will be more susceptible to spoilage reactions due to the increase in respiration rate as a result of a broader surface area. Conventional packaging materials can not meet the requirements for modified atmosphere packaging of fresh-sliced mushrooms. One of the techniques to extend the fresh-cut produce shelf life is the passive modification of modified atmosphere packaging technology. For highly respiring fresh-cut produce such as fresh-sliced mushrooms, the permeability properties of the polymeric materials might not be enough to provide an equilibrium gas concentration in the passive modification of modified atmosphere technology. In this case, the microperforated packaging materials can be used for passive modification of fresh-cut produce. But the microperforation process needs a design for the application of the appropriate number and diameter of microholes to meet the requirements of passive modified atmosphere packaging. For this reason in this research, the design of the microperforation process to be used in passive modified atmosphere packaging was based on the diameter and the number of microholes, and the shelf life of fresh-sliced mushrooms was determined. The samples were stored at 15 °C/80% RH, and pH, color, weight loss, textural, sensorial, and microbial analysis were performed periodically during storage. It was determined that the empirical equation used in this research can be applied to microperforated packaging design for fresh-sliced mushrooms. The shelf life of the fresh-sliced mushrooms packaged with microperforated packaging material was 8 days, while it was less than 7 days (4, 5, or 6 days) when packaged with non-microperforated packaging material. This result shows that the use of microperforated packaging material is effective in extending the shelf life of fresh-sliced mushrooms.

Influence of cellulose nanocrystals gellan gum-based coating on color and respiration rate of Agaricus bisporus mushrooms

The edible coating has been used for covering fruits and vegetables, bringing surface protection, and extending product shelf-life. Due to the outstanding properties, nanomaterials have become a part of the packaging/coating new generation, demonstrating improvements in the barrier capacity of materials starting from construction products to the food industry. In the food industry, on the other hand, Agaricus bisporus mushrooms have a limited shelf-life from 1 to 3 days because of their high respiration rate and enzymatic browning. With the aim to reduce these two parameters and prevent rapid senescence, the objective of this study was to incorporate a natural source of nanomaterials (cellulose nanocrystals (CNCs) into a gellan gum-based coating and sprayed the surface of the mushrooms with the coating material. To evaluate the effect of CNCs, oxygen consumption, carbon dioxide production rate, and color change were recorded during the mushroom storage at 4 ± 1 °C. Results showed that all coatings were able to decrease total color change (ΔE) of mushrooms from 12 to 8 at day 10 when the coating was applied in all samples compared to control. In addition, significant differences were observed in the respiration rate when CNCs were added to the mushrooms. Oxygen consumption results exhibited a 44 mL O2 /kg · day production at day 5 with 20% CNCs compared to 269 mL O2 /kg · day observed in noncoated samples. This trend was similarly observed in the carbon dioxide production rate. PRACTICAL APPLICATION: With this research, it was remarkable to see the presence of CNCs in the coating solution reduced the respiration rate and increased the shelf-life of mushrooms. Similar applications can be industrially scaled-up to protect fruits and vegetables by CNCs-based coating or packaging materials. A variety of sustainable materials are available nowadays that serve as packaging matrix, and scientists are working on expanding the compatibility of these nanomaterials. In addition, it has been studied that CNCs enhance the degradation of polymers, an effort that many companies are making to reduce the environmental impact in their products.

Melatonin retards senescence via regulation of the electron leakage of postharvest white mushroom (Agaricus bisporus)

Currently, melatonin (N-acetyl-5-methoxytrytamine) is recognized as a potential scavenger of free radicals. In this study, the effect of exogenous melatonin at various concentrations (0.05, 0.1, and 0.2 mM) on the texture, sensory qualities, and electron leakage in white mushrooms was evaluated at 3 ± 1 °C. It was observed that mushrooms treated with 0.1 mM melatonin were of good quality and their electron leakage was dramatically dampened. The results showed that 0.1 mM melatonin retained a higher adenosine triphosphate level and also prevented the release of cytochrome c into the cytoplasm. More significantly, it prominently inhibited electron leakage by increasing the activities of complexes I and III by the upregulation of AbNdufB9 and AbRIP1. It also regulated respiratory states in mushrooms; delayed the decline of respiratory state 3; enhanced respiratory state 4; boosted the oxidative phosphorylation and efficiency of mitochondria; and ultimately retarded the senescence of the white mushrooms.

Postharvest biochemical characteristics and ultrastructure of Coprinus comatus

BACKGROUND

Coprinus comatus is a novel cultivated edible fungus, hailed as a new preeminent breed of mushroom. However, C. comatus is difficult to keep fresh at room temperature after harvest due to high respiration, browning, self-dissolve and lack of physical protection.

METHODS

In order to extend the shelf life of C. comatus and reduce its loss in storage, changes in quality, biochemical content, cell wall metabolism and ultrastructure of C. comatus (C.c77) under 4 °C and 90% RH storage regimes were investigated in this study.

RESULTS

The results showed that: (1) After 10 days of storage, mushrooms appeared acutely browning, cap opening and flowing black juice, rendering the mushrooms commercially unacceptable. (2) The activity of SOD, CAT, POD gradually increased, peaked at the day 10, up to 31.62 U g-1 FW, 16.51 U g-1 FW, 0.33 U g-1 FW, respectively. High SOD, CAT, POD activity could be beneficial in protecting cells from ROS-induced injuries, alleviating lipid peroxidation and stabilizing membrane integrity. (3) The activities of chitinase, β-1,3-glucanase were significantly increased. Higher degrees of cell wall degradation observed during storage might be due to those enzymes' high activities. (4) The fresh C. comatus had dense tissue and every single cell had the number of intracellular organelles which structure can be observed clearly. After 10 d storage, the number of intracellular organelles was declined and the structure was fuzzy, the nucleus disappeared. After 20 d storage, C. comatus's organization was completely lost, many cells were stacked together and the cell wall was badly damaged.