Integrated application of nitric oxide and modified atmosphere packaging to improve quality retention of button mushroom (Agaricus bisporus)

The Concentrations of Phenolic Compounds and Vitamin C in Japanese Quince (Chaenomeles japonica) Preserves

The aim of this study is to characterize a range of the Japanese quince (Chaenomeles japonica) fruit preserves in terms of the content of vitamin C and phenolic compounds, as well as to discuss the effects of processing on the concentrations of these compounds in Japanese quince fruit. Research materials consisted of seven different products: a 100% Japanese quince fruit pressed juice, syrups with added honey, cane sugar, and xylitol, and three products sweetened with white sugar: jam, fruits in syrup, and candied fruits. The content of vitamin C and polyphenolic compounds (phenolic acids and flavonoids) was determined by high-performance liquid chromatographic method. The study confirmed that the Japanese quince fruit preserves can be considered a rich source of vitamin C and selected phenolics. At the same time, the tested products differed significantly in terms of the levels of the analyzed phenolic compounds, e.g., the syrups sweetened with xylitol were characterized by significantly higher concentrations of the analyzed phenolics than the syrups sweetened with other sweeteners. It is noteworthy to explore the possibilities for quince fruit processing, taking into account various processing methods and conditions, and using sweeteners alternative to white sugar.

Hydrogen Gas Fumigation Combined with Nano-Film Packaging Extend the Storage of Button Mushrooms (Agaricus bisporus)

To extend the shelf life of button mushrooms, the optimal fumigation doses for hydrogen gas treatment were screened through sensory evaluation, combined with browning index and weight loss rate in this study. Then, using H2 fumigation combined with polyethylene film packaging as a control, changes in the sensory quality, reactive oxygen species, browning-related enzyme activity and the nutritional quality of mushrooms treated by H2 fumigation combined with nano-film packaging (H2 + NA) during low-temperature storage were dynamically tracked. The preservation effect of H2 + NA on mushrooms after harvest was investigated, and its mechanism was also analyzed. The storage validation test showed that the optimum H2 fumigation time was 2 h, and the H2 + NA-treated mushrooms had a fuller appearance, maintained whiteness well, showed a slow increase in reactive oxygen species, antioxidant enzyme activities remained at high levels, a high retention rate of protein content was observed, and there was a good antibacterial effect. This study indicates that H2 fumigation combined with nano-film packaging can improve the storage quality of button mushrooms and may prolong low-temperature shelf life by 4-5 d compared to conventional commercial polyethylene film packaging.

Effects of chestnut shell extract and citric acid on the properties of navel orange pomace/chitosan composite films

The improper use of citrus peel and nondegradable plastic film can cause substantial issues, such as environmental pollution and resource waste. Herein, navel orange pomace powder (NOPP) and chitosan (CS) were used as the raw material and film-forming additive, respectively, to prepare biobased composite films. Chestnut shell extract (CHE) and citric acid (CA) were added to the prepared NOPP/CS biobased multifunctional films. Based on ensuring the tensile strength of the film above 10 MPa, the elongation at break of the film can be increased from 19.11 % to 34.93 %, the water contact angle can reach 60°, and the water vapor transmittance can be significantly reduced to approximately 1.1 × 10-10 gs-1m-1Pa-1. Additionally, the antibacterial ability and antioxidant capacity of the composite film were improved. We observed that the multifunctional film could significantly inhibit the browning of fresh-cut apples, where the browning index was maintained between 60 and 65, which was 25 % lower than that of the control. The newly developed film therefore possesses the potential to replace the traditional plastic cling film. This research contributes to the literature regarding the source of raw materials for biobased materials and highlights the value of navel orange processing by-products.

Preparation and characterization of water vapor-responsive methylcellulose-polyethylene glycol-400 composite membranes and an indication of freshness of shiitake mushrooms

Intelligent packaging with freshness indication capability can help consumers purchase fresh food. However, current research primarily focuses on carbon dioxide-sensitive intelligent packaging, with limited research on water vapor-sensitive indication packaging. In this study, the water vapor-sensitive indicator membrane was prepared and used to determine the freshness of mushrooms. The results of this study showed that the water permeability of the indicator membrane decreased from 33.17 % to 21.59 % with the increase of Polyethylene glycol-400(PEG-400) content in methylcellulose(MC) membrane, and the contact angle of the indicator membrane increased from 87 % to 98 % with the addition of PEG-400. The addition of plasticizer PEG-400 increased the hydrophobicity of the indicator film, which could be attributed to the improvement of the molecular arrangement and crystallinity of the indicator film by the addition of PEG-400. After encountering water, the transparency of the indicator membrane changes from completely opaque (white) to transparent. Addition of PEG-400 reduces the rate of change in the transparency of the indicator membrane. The indicator membrane was successfully used to indicate the freshness of mushrooms and effectively reflected the freshness of mushrooms during storage. This technology could be applied to measure the freshness of other foods.

Epsilon-poly-l-lysine alleviates brown blotch disease of postharvest Agaricus bisporus mushrooms by directly inhibiting Pseudomonas tolaasii and inducing mushroom disease resistance

The natural antimicrobial peptide, epsilon-poly-l-lysine (ε-PL), is widely acknowledged as a food preservative. However, its potential in managing bacterial brown blotch disease in postharvest edible mushrooms and the associated mechanism remain unexplored. In this study, concentrations of ε-PL ≥ 150 mg L-1 demonstrated significant inhibition effects, restraining over 80% of growth and killed over 99% of Pseudomonas tolaasii (P. tolaasii). This inhibition effect occurred in a concentration-dependent manner. The in vivo findings revealed that treatment with 150 mg L-1 ε-PL effectively inhibited P. tolaasii-caused brown blotch disease in Agaricus bisporus (A. bisporus) mushrooms. Plausible mechanisms underlying ε-PL's action against P. tolaasii in A. bisporus involve: (i) damaging the cell morphology and membrane integrity, and increasing uptake of propidium iodide and leakage of cellular components of P. tolaasii; (ii) interaction with intracellular proteins and DNA of P. tolaasii; (iii) inhibition of P. tolaasii-induced activation of polyphenol oxidase, elevation of antioxidative enzyme activities, stimulation of phenylpropanoid biosynthetic enzyme activities and metabolite production, and augmentation of pathogenesis-related protein contents in A. bisporus mushrooms. These findings suggest promising prospects for the application of ε-PL in controlling bacterial brown blotch disease in A. bisporus.

The improvement of freezing time and functional quality of frozen mushrooms by application of probe-type power ultrasound

The study proposes a novel ultrasound-assisted freezing method for button mushrooms, which combines probe-type ultrasonication and immersion freezing. The effects of power ultrasound in both continuous and pulse modes (at five levels of 50, 100, 200, 300, and 400 W) on the freezing process and quality attributes of frozen mushrooms were investigated. Results showed that ultrasound-assisted freezing significantly reduced freezing time compared to immersion freezing, potentially due to the formation of abundant cavitation bubbles that enhanced heat and mass transfer rates. The lowest weight loss was achieved by the continuous mode of 200 W ultrasound (UC200), which may be attributed to the formation of smaller ice crystals during ultrasonication. Ultrasound also prevented acidification and resulted in the retention of the samples' pH and higher total solid solution than immersion freezing. The optimal ultrasound power and duty cycle for different freezing outcomes were determined using the TOPSIS method. UC200 was found to be the best treatment for total freezing time and minimizing weight loss, while a combination of UC200 and UC400 was optimal for gumminess and chewiness. The proposed ultrasound-assisted freezing method shows promise as an environmentally friendly and safe technique for commercial use in the future.

Exploring the mechanism of browning of Rosa roxburghii juice based on nontargeted metabolomics

To explore the mechanism of Rosa roxburghii juice browning, this experiment was based on nontargeted metabolomics to study the effects of browning on the nutrition, flavor, metabolites, and metabolic pathways of R. roxburghii juice before and after storage. The results showed that the total soluble solids, superoxide dismutase (SOD), vitamin C (V_C ), total phenol, and total flavonoid of R. roxburghii juice decreased significantly before and after storage. The color difference value ∆E, browning index, and flavor and taste of R. roxburghii juice changed significantly (p < 0.05). A total of 541 metabolites were detected before and after browning of R. roxburghii juice by nontargeted metabolomics, including 435 differential metabolites, of which 221 were upregulated, and 214 were downregulated. The differential metabolites were mainly amino acids and peptides, carbohydrates, and carbohydrate conjugates. There were a total of 76 metabolic pathways enriched by differential metabolites, involving mainly galactose metabolism; alanine, aspartate and glutamate metabolism; and pantothenate and CoA biosynthesis. The experimental results showed that after browning of R. roxburghii juice, V_C , total phenol, total flavonoid, and SOD activity were seriously lost, and the flavor deteriorated. The contribution of differential metabolites and metabolic pathways to the browning of R. roxburghii juice was sugar metabolism > amino acid metabolism > ascorbate and aldarate metabolism > phenols.

One-Step Synthesis of Poly(L-Lactic Acid)-Based Soft Films with Gas Permselectivity for White Mushrooms (Agaricus bisporus) Preservation

Proper packaging can extend the shelf life and maintain the quality of mushrooms during storage. The purpose of this study is to investigate the preservation of Agaricus bisporus using copolymer-modified poly (L-lactide-co-butylene fumarate) and poly (L-lactide-co-glycolic acid) (PLBF and PLGA) packaging. Shelf life and quality were evaluated over 15 days of storage of Agaricus bisporus at 4 ± 1 °C and 90% relative humidity, including weight loss, browning index (BI), total phenolics (TP), ascorbic acid (AA), malondialdehyde content (MDA), electrolyte leakage rate (EC), and superoxide dismutase (SOD) and catalase (CAT). The results showed that mushrooms packaged in PLBF films exhibited better retention in BI, TP, and AA than those with PLLA, PLGA, or polyethylene (PE) films. They can reduce the rate of weight loss, EC, and MDA, which in turn increases the activity of SOD and CAT. PLBF and PLGA have substantially improved flexibility in comparison with PLLA. They also significantly reduced oxygen (O₂) and carbon dioxide (CO₂) permeability and changed the gas permeability ratio. These positive effects resulted in the effective restriction of O₂ and CO₂ in these packages, extending the post-harvest storage period of white mushrooms.

The Emergence and Impact of Ethylene Scavengers Techniques in Delaying the Ripening of Fruits and Vegetables

As the top grocery list priorities, the primary challenge when purchasing fruits and vegetables from supermarkets is obtaining fresh, minimally processed perishable goods. This source of diet is critical for obtaining vitamins, minerals, antioxidants, and fibres. However, the short shelf life caused by moisture content in rapid deterioration and decay caused by microbial growth, results in unappealing appearances. Fruits and vegetables undergo ripening and eventually the ageing process, in which the tissues of the plants degrade. Even after harvesting, numerous biological processes occur, generating a significant variation of ethylene production along with respiration rates between fruits and vegetables. Thus, the utilization of ethylene scavengers in food packaging or films has been revealed to be beneficial. The synergistic effects of these biomaterials have been demonstrated to reduce microorganisms and prolong the shelf life of greens due to antimicrobial activity, oxygen scavenging capacity, enzyme immobilization, texture enhancers, and nutraceuticals. The current review fills this void by discussing the most recent advances in research on ethylene scavengers and removal mechanisms of ethylene, including oxidation in fruit and vegetable packaging. The application and advantages of ethylene scavengers in packaging are then discussed with the addition of how the efficiency related to ethylene scavengers can be increased through atmospheric packaging tools. In this context, the article discusses characteristics, types of applications, and efficacy of ethylene control strategies for perishable commodities with the inclusion of future implications.

Biodegradable blend films of poly(ε-caprolactone)/poly(propylene carbonate) for shelf life extension of whole white button mushrooms

Blend films with poly(ε-caprolactone)(PCL) and poly(propylene carbonate)(PPC)with thickness of approximately 40 μm and 60 μm, respectively, were prepared using a uniaxial-stretching extrusion process to modify the property of PCL. PCL/PPC blend films with better comprehensive properties with thickness about 60 μm were used for equilibrium-modified atmosphere packaging of button mushrooms at 5 °C. The gas barrier property together with water vapor permeability were evaluated as well as its effects on the shelf life button mushrooms. The results showed that the PCL/PPC20 and PCL/PPC50 blend films have suitable gas barrier property and water vapor permeability, which was helpful to generate an appropriate storage environment and more importantly no condensation occurred in these two packages. The lower weight loss of button mushrooms was observed for PCL/PPC20 and PCL/PPC50 blend films 4.43 and 4.46, respectively. The PCL/PPC blend films was more effective in decreasing the activity of PPO and preserving the color of the button mushrooms. The over market acceptability of button mushrooms packaged in PCL/PPC blend films still maintained good and within the limit of marketability after 17 days of storage.

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.

Development of Active Packaging to Extend the Shelf Life of Agaricus bisporus by Using Plasma Technology

In this study, a preservation package that can extend the shelf life of Agaricus bisporus was developed using plasma modification combined with low-density polyethylene (LDPE), collagen (COL), and carboxymethyl cellulose (CMC). Out results showed that the selectivity of LDPE to gas can be controlled by plasma modification combined with coating of different concentrations of CMC and COL. Packaging test results applied to A. bisporus showed that 3% and 5% of CMC and COL did not significantly inhibit polyphenol oxidase and β-1,3-glucanase, indicating no significant effect on structural integrity and oxidative browning. The use of 0.5% and 1.0% CMC and COL can effectively inhibit the polyphenol oxidase and β-1,3-glucanase activity of A. bisporus, leading to improved effects in browning inhibition and structural integrity maintenance. P-1.0COL can effectively maintain gas composition in the package (carbon dioxide: 10–15% and oxygen: 8–15%) and catalase activity during storage, thereby reducing the oxidative damage caused by respiration of A. bisporus. The current study confirmed that the use of plasma modification technology combined with 1.0% COL can be used in preservation packaging by regulating the respiration of A. bisporus, thus extending its shelf life from 7 to 21 days.

Investigating the Nano-Films Effect on Physical, Mechanical Properties, Chemical Changes, and Microbial Load Contamination of White Button Mushrooms during Storage

Nutrient-rich edible white button mushrooms were coated with Chitosan (1%), Chitosan/nano-silica, and Chitosan/nano-titanium and then stored at 4 °C to investigate the physical, mechanical properties, chemical changes, and microbial load contamination at an interval of 3 days up to a 12 days storage period. It was noticed that Chitosan/nano-titanium and Chitosan/nano-silica preserved the weight loss percentages as 11.80% and 12.69%, respectively. Treatment with Chitosan/nano-silica coating was found to have positive impacts on the overall color parameters. Both of the nano-coating films enhanced headspace gas compositions and firmness. Chitosan/nano-silica samples recorded the least electrolyte leakage value (24.44%), as low oxygen gas concentration can reduce the respiration rate, weight loss, and cap opening. Chitosan/nano-titanium treatment showed the lowest cap opening value (19.58%), PPO activity (16.98 mg−1 protein), and microbial load contamination (6.12 log CFU/g) at the end of the whole storage period, suggesting that nano-films are a promising preservation method for prolonging the white button mushroom’s shelf-life.

Preservation of Agaricus bisporus freshness with using innovative ethylene manipulating active packaging paper

Agaricus bisporus produces substantial ethylene during storage and transportation, which accelerates ripening and senescence, thereby shortening the shelf-life. In this study, a novel food packaging material with ethylene removal property was prepared to increase storage time of Agaricus bisporus. 1-Methylcyclopropen and molecular sieves loaded with potassium permanganate were used as ethylene scavengers to coat the fresh-keeping paper. SEM, FT-IR and DSC analyses proved that these functional components were successfully coated on the fresh-keeping paper. The qualities of the mushrooms packed by prepared functional paper were then determined. The results showed that this prepared functional paper could delay the softening, browning and weight loss of mushrooms during storage by inhibiting ethylene synthesis-related enzymes and gene expression in the mushroom fruiting body, and continuous adsorption and removal of the exogenous ethylene. Consequently, the functional paper could reduce the biochemical and physicochemical quality loss of Agaricus bisporus, thus prolonging its shelf-life.

Effects of nitric oxide treatment on flavour compounds and antioxidant enzyme activities of button mushroom (Agaricus bisporus) during storage

Button mushroom (Agaricus bisporus) is sold well for its unique flavour and nutritional benefits. However, the mushroom flavour deteriorates quickly during storage because of its delicate structure and high moisture. In this study, the effects of nitric oxide (NO) application on flavour compounds and antioxidant enzyme activities of stored button mushrooms were investigated. The button mushrooms were immersed in the NO donor sodium nitroprusside (15 μmol/L) for 3 min and then stored under the condition of 4 °C, 90% relative humidity for 12 days. Results showed that the treated mushrooms have reduced weight loss rate, uniform white colour, and higher firmness during storage. Compared to the control, the ketones, alcohols, esters, and aldehydes in the NO-treated button mushroom increased sharply at 3 days of storage and then showed a continuing decline trend, except ester compounds which reached the peak value at 6 days of storage. In addition, NO treatment increased the total phenolics and catalase activity and inhibited the polyphenol oxidase activity in the stored button mushroom. These results indicated that NO treatment is an alternative storage technology to enhance antioxidant capacity and maintain flavour and consumer acceptance of stored button mushroom.

Application of non-thermal pretreatment techniques on agricultural products prior to drying: a review

BACKGROUND

Most agricultural crops contain high moisture content (80-95% wet basis (wb)) which makes them very susceptible to microbial damage leading to shorter shelf-life and high postharvest losses. The high perishability of these agricultural products requires preservation techniques to prolong their shelf-lives. Drying remains an important component of processing in this regard. Therefore, any pretreatment methods for drying agricultural product that decreases the moisture content and minimizes drying time by conserving the quality of the crop product is of prime significance. This article is a comprehensive review of recent developments of non-thermal pretreatment (NTP) methods. A summary of their significance, emerging and innovative methods of this technology together with its applications and limitations are discussed. This article further examines the environmental impact of NTP techniques.

RESULTS

NTP techniques, such as high pressure, ultrasound, pulsed electric field and osmotic dehydration methods are essential operations for pre-dehydration of agricultural products prior to drying. These techniques can avoid the deleterious effects of heat on nutritive value, colour and flavour of agricultural products compared to thermal pretreatments. They also enhance the inactivation of the enzymes, improve energy efficiency and mass transfer, reduce processing time, preserve bioactive compounds, improve drying kinetics and drying rate, minimize enzymatic browning, and enhance product quality.

CONCLUSION

These findings will provide a better understanding of different NTP methods and also make available more information for selecting pretreatment techniques for drying of agricultural products. © 2020 Society of Chemical Industry.

Investigating the effect of chitosan, nanopackaging, and modified atmosphere packaging on physical, chemical, and mechanical properties of button mushroom during storage

This study investigated the effect of chitosan coating, nanopackaging, and modified atmosphere packaging (MAP) to increase the shelf life and improve the quality of the white button mushroom. Uncoated and coated button mushrooms were stacked in three types of packages (normal, nano, and nano + MAP). The atmosphere inside the nano + MAP packages contained 10% oxygen and 10% carbon dioxide. The physical, chemical, mechanical properties and the evolution of oxygen and carbon dioxide inside the packages were investigated. The results showed that the triple interaction had significant effect (at 1% and 5% levels) on physical, mechanical properties and gas composition. The use of nanofilm (due to the low permeability to oxygen and carbon dioxide), as well as the modification of atmosphere had a positive effect on the control of mushroom respiration rate and the improvement in its physical, chemical, and mechanical properties.

Microflora of fresh white button mushrooms (Agaricus bisporus) during cold storage revealed by high-throughput sequencing and MALDI-TOF mass spectrometry fingerprinting

BACKGROUND

Fresh Agaricus bisporus is popular and consumed throughout the world because of its taste, as well as its nutritional and medicinal properties, but it is also prone to microbial growth. There is very limited information about the dynamic changes of microbial communities during storage. The present study aimed to analyze the microbial diversity of button mushroom during cold storage using Illumina HiSeq sequencing. Bacteria isolated from the later storage period were identified by MALDI-TOF mass spectrometry and a bioassay of pathogenicity was carried out.

RESULTS

High-throughput sequencing showed that Pseudomonas was the predominant genus throughout the storage period. Pedobacter and Flavobacterium grew prolifically on the eighth day, while the relative abundance of Oscillospira continued to decrease. Pseudomonas, Ewingella and Chryseobacterium were isolated at the later period of mushroom storage. A pathogenicity bioassay on the cap of mushrooms showing brown blotch indicated an infection by Pseudomonas tolaasii. However, Ewingella americana did not have a pathogenic effect in our study.

CONCLUSION

Bacterial communities of fresh Agaricus bisporus during cold storage were characterized by high-throughput sequencing. MALDI-TOF MS provides a good analytical procedure, in addition to 16S rRNA gene sequencing. © 2019 Society of Chemical Industry.

Mass transfer characteristics during ultrasound-assisted osmotic dehydration of button mushroom (Agaricus bisporus)

Button mushroom (Agaricus bisporus) slices were dehydrated using ultrasound-assisted osmotic dehydration (UOD), and three osmotic agents including sucrose, glucose and sodium chloride were investigated for their effects on the mass transfer characteristics, average density and microstructure. Different mathematical models were selected to describe the osmotic behaviours, and the effective moisture (D _m) as well as solid diffusivities (D _s) during UOD were also calculated. The results showed that, during UOD, button mushrooms had the highest D _m values in the sodium chloride solutions, and they had the highest D _s values in the glucose solutions, which indicated that faster moisture and solid transfers could occur in these two osmotic solutions, respectively. Moreover, the Weibull model provided the best fit for the UOD curves of button mushrooms under the study's operating conditions, which showed good predictability for the moisture and solid contents of the button mushrooms during UOD. In addition, sucrose agents were suggested for use in the UOD of button mushrooms due to the better microstructure of the products as well as the appropriate rates of effective moisture and solid diffusivities during UOD. This study provides a theoretical basis for the deep processing of mushrooms and other food products.

Efficiency of Tragacanth gum coating enriched with two different essential oils for deceleration of enzymatic browning and senescence of button mushroom (Agaricus bisporus)

The effect of Tragacanth gum (T) coating containing (100, 500, and 1,000 mg/L) Satureja khuzistanica essential oil (S), Zataria multiflora Boiss. essential oil (Z), and (1,000 mg/L) sodium metabisulfite (M) on mushroom (Agaricus bisporus) enzymatic browning and postharvest quality was examined throughout 16 days of cold storage. Mushroom respiration rate, soluble solids content (SSC), percentage of open caps, and sensory quality as well as factors related to browning such polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and peroxidase (POD) activities were figured out. The significant decrease in respiration rate, cap opening delay, and SSC enhancement was observed after treating mushrooms with TZ and TS. Moreover, TZ- and TS-treated mushrooms prevented enzymatic browning through inhibiting PPO and POD activities and increasing activity of PAL over the storing term. Additionally, the influence of TZ5 and TS5 (containing 500 mg/L essential oil) coatings was validated by sensory evaluation through protecting the overall quality of button mushrooms over the storage. Thus, Tragacanth coating enriched with essential oils might be an encouraging nomination for improving the modality of button mushroom and expanding its shelf life.

Hydrogen-rich water increases postharvest quality by enhancing antioxidant capacity in Hypsizygus marmoreus

In the present study, we aimed to assess the effect of hydrogen-rich water (HRW) on the physicochemical characteristics and antioxidant capacity of Hypsizygus marmoreus during 12 days of postharvest storage at 4 °C. Different concentrations of HRW (25, 50 and 100%) were tested, and our data showed that 25% HRW treatment had the most significant effect on preservation of nutrients in H. marmoreus compared with the control group. In addition, 25% HRW treatment significantly reduced the relative electrolyte leakage rate and malonaldehyde (MDA) content (P < 0.05) and increased anti-superoxide-radical (O₂^-) activity compared with the control group. The activities of antioxidants, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) were activated by 25% HRW treatment, and the expression levels of these genes were also induced. These results suggested that HRW treatment could delay rot incidence in mushrooms during storage by regulating antioxidant defense ability. This study supplies a new and simple method to maintain the quality and extend the shelf life of mushrooms.

Total quality index of Agaricus bisporus mushrooms packed in modified atmosphere

BACKGROUND

The aim of this study was to develop a total quality index and examine the effects of modified atmosphere packaging (MAP) on the quality of Agaricus bisporus mushrooms stored for 22 days at 4 °C. Mushrooms were packaged under three MAPs: high nitrogen packaging (HNP), low carbon dioxide packaging (LCP) and low oxygen packaging (LOP). Passive MAP with air inside initially was used as the atmosphere treatment (AIR).

RESULTS

This research revealed two phases in quality deterioration of A. bisporus mushrooms. During the first week, most of the quality parameters were not statistically different. Thereafter, odor intensities were stronger for all four types of packaging. Color difference and browning index values showed significantly lower color changes for AIR and LOP compared with HNP and LCP mushrooms.

CONCLUSION

The best total quality index was calculated for LOP, followed by LCP and AIR. The findings of this study are useful with respect to examining two-component MAPs, separating the limiting factors (O₂ and CO₂ ) and evaluating quality deterioration effects and the total quality index of A. bisporus mushrooms. © 2016 Society of Chemical Industry.

Exogenous nitric oxide induces disease resistance against Monilinia fructicola through activating the phenylpropanoid pathway in peach fruit

BACKGROUND

Nitric oxide (NO) is a multifunctional signaling molecule involved in plant-induced resistance to disease. The present study aimed to investigate the relationship between disease resistance induced by NO and the phenylpropanoid pathway in peach fruit. The present study investigated the effect of NO on the main enzymes and metabolites of the phenylpropanoid pathway of harvested peach, which are probably related to disease resistance against Monilinia fructicola.

RESULTS

The results showed that treatment with 15 µmol L^-1 NO significantly (P < 0.05) enhanced the activities of phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumaroyl-CoA ligase, chalcone synthase and chalcone isomerase and the expression of their genes. Furthermore, NO treatment significantly (P < 0.05) increased the contents of total phenolics, flavonoids and lignin over the entire storage period and maintained higher total anthocyanin, phenolic acid and anthocyanin contents during the earlier storage period.

CONCLUSION

These results suggest that NO treatment could activate the phenylpropanoid pathway to enhance the activity of related enzymes and the contents of phenylpropanoid metabolites in peach to improve disease resistance and prevent pathogenic invasion. © 2016 Society of Chemical Industry.

Changes in non-volatile taste components of button mushroom (Agaricus bisporus) during different stages of freeze drying and freeze drying combined with microwave vacuum drying

Button mushroom slices were dehydrated using freeze drying (FD) or FD combined with microwave vacuum drying (FMVD), and the non-volatile component profiles were studied. The results showed that the level of non-volatile components in button mushroom firstly increased during sublimation of FD/FMVD process and then fell during desorption in FD process and MVD in FMVD process. Compared to FD products, the contents of soluble sugars and polyols in FMVD products were relatively low, whereas the contents of total free amino acids were significantly higher, close to the level of fresh mushroom. However, there was no significant difference in the contents of 5'-nucleotides and organic acids between FD and FMVD products. The equivalent umami concentration (EUC) values for FD and FMVD products did not differ from fresh, indicating that both drying methods could effectively preserve MSG (monosodium glutamate)-like components in button mushroom.