Dried Shiitake Mushroom Research Articles

Effects of combined drying techniques and cellulase hydrolysis on the nutritional value and sensory properties of shiitake mushrooms (Lentinus edodes)

Dried shiitake mushrooms offer rich nutritional value and unique sensory properties, prompting further investigation. The effects of different drying techniques (hot air drying (HAD), infrared hot air drying (IRHAD), pulsed vacuum drying (PVD), vacuum freeze drying (VFD), and natural drying (ND)) combined with enzymatic hydrolysis on the release of flavor compounds and nutrients from shiitake mushrooms were explored. The combination of HAD with cellulase hydrolysis yielded notably high levels of umami amino acids (5.4723 ± 0.1501 mg/g) and 5′-nucleotides (4.0536 ± 0.0062 mg/g), and superior volatile flavors. Combined with cellulase hydrolysis, IRHAD achieved the highest level of total sugars (6.57 ± 0.34 mg/mL), VFD resulted in the greatest soluble protein content (153.21 ± 0.23 μg/mL), PVD yielded the highest total phenolics content (93.20 ± 0.41 μg GAE/mL), and ND produced the maximum reducing sugar content (5.79 ± 0.13 mg/mL). This study addresses crucial gap in the post-drying processing of shiitake mushrooms, offering valuable insights for further product development of shiitake mushrooms.

Automatic Selection of High-Grade Dried Shiitake Mushrooms using Machine Learning

Automatic Selection of High-Grade Dried Shiitake Mushrooms using Machine Learning

Structural analysis of vacuum microwave dried shiitake mushrooms based on X-ray CT images and physical properties

Structural analysis of vacuum microwave dried shiitake mushrooms based on X-ray CT images and physical properties

Dried shiitake mushroom grade recognition using D-VGG network and machine vision.

Grading dried shiitake mushrooms is an indispensable production step, as there are large quality differences between different grades, which affect the product's price and marketability. Dried shiitake mushroom samples have irregular shapes, small morphological differences between different grades of the same species, and they may occur in mixed grades, which causes challenges to the automatic grade recognition using machine vision. In this study, a comprehensive method to solve this problem is provided, including image acquisition, preprocessing, dataset creation, and grade recognition. The osprey optimization algorithm (OOA) is used to improve the computational efficiency of Otsu's threshold binarization and obtain complete mushroom contours samples efficiently. Then, a method for dried shiitake mushroom grade recognition based on the improved VGG network (D-VGG) is proposed. The method uses the VGG16 network as the base framework, optimizes the convolutional layer of the network, and uses a global average pooling layer instead of a fully connected layer to reduce the risk of model overfitting. In addition, a residual module and batch normalization are introduced to enhance the learning effect of texture details, accelerate the convergence of the model, and improve the stability of the training process. An improved channel attention network is proposed to enhance the feature weights of different channels and improve the grading performance of the model. The experimental results show that the improved network model (D-VGG) can recognize different dried shiitake mushroom grades with high accuracy and recognition efficiency, achieving a final grading accuracy of 96.21%, with only 46.77 ms required to process a single image. The dried shiitake mushroom grade recognition method proposed in this study provides a new implementation approach for the dried shiitake mushroom quality grading process, as well as a reference for real-time grade recognition of other agricultural products.

Changes in Physicochemical Characteristics and Antioxidant Activities of Dried Shiitake Mushroom in Dry-Moist-Heat Aging Process.

Shiitake mushrooms are prized for their unique flavor and bioactive properties. While there has been extensive research on drying methods, a comprehensive investigation of the effects of drying parameters in the dry-moist-heat system on shiitake quality is still needed. This study aimed to investigate the effects of dry-moist-heat aging on dried shiitake mushrooms comprehensively. Four aging temperatures, specifically 50, 60, 70, and 80 °C, were applied to the mushrooms, maintaining a constant humidity level of 75% RH and aging duration of 20 days. Color analysis revealed a progressive decrease in measured values as aging temperature increased, indicating noticeable changes in visual characteristics. Regarding amino acid composition, glutamic acid was found to be the predominant amino acid in shiitake mushrooms in the range of 90.29-467.42 mg/100 g. However, aging led to a reduction in overall amino acid content, with higher aging temperatures resulting in greater decline. Similarly, the equivalent umami content (EUC) also decreased (from 123.99 to 7.12 g MSG/100 g) with the increase in aging temperatures up to 80 °C, suggesting a decline in the overall umami taste sensation. Interestingly, despite the reduction in amino acid levels and umami content, the aging process positively impacted the phenolic compounds and the antioxidant activity of dried shiitake mushrooms. The antioxidative abilities of all aged mushroom extracts for DPPH, ABTS, and FRAP ranged from 65.01 to 81.39 µg TE/mL, 87.04 to 258.33 µg GAE/mL, and 184.50 to 287.68 µg FeSO4/mL, respectively. The utilization of aged temperature at 60 °C for 20 days with controlled relative humidity (~75%) should be a suitable aging condition of this edible mushroom with both antioxidant and umami qualities. Nevertheless, the control sample demonstrated higher levels of amino acid content and EUC compared to the aged samples. Conversely, the aged samples exhibited higher polyphenol content and greater antioxidant activity. Depending on specific requirements, these powders can be used in food formulation as flavor enhancers for control samples or as enriching agents for polyphenols and antioxidant activity in matured samples. Therefore, all of the powders obtained have potential applications in the field of nutrition.

Effectiveness of combined catalytic infrared radiation and holding time for decontamination Aspergillus niger on dried shiitake mushrooms (Lentinus edodes) with different moisture contents

This paper investigated the effect of catalytic infrared radiation (CIR) only and CIR coupled with holding time (CIRH) on decontamination of damp-returning dried shiitake mushrooms contaminated with Aspergillus niger (A. niger). The effect of initial moisture content (IMC) of the samples on CIR/CIRH operation layout was also investigated. Analysis of surface color, observations of electron microscopy and evaluation of quality (retention rate of total sugar, crude protein and total phenolics) directly manifested that CIRH treatment had the outstanding potential to maintain the original appearance and microstructure compared to CIR (p < 0.05). Meanwhile, the envisaged model (Log-Linear + tail) achieved expected results for the inactivation of A. niger with R2 = 0.9790–0.9977, which can well predict the changes in A. niger of dried shiitake mushrooms with different IMCs in the holding process. Therefore, the present work could pave the way for future production of good quality dried shiitake mushrooms using CIRH.

Dynamic changes of non-volatile compounds and evaluation on umami during infrared assisted spouted bed drying of shiitake mushrooms

The present study was carried out to report the dynamic changes of non-volatile components and the evaluation on umami of shiitake mushrooms during infrared assisted spouted bed drying (IRSBD) under different temperatures (45, 50, 55, and 60 °C) and airflow speeds (7.0, 7.5, 8.0, and 8.5 m/s). In addition, the drying characteristics and dried product rehydration ratio of shiitake mushrooms were also analyzed. Results demonstrated that compared with airflow speeds, drying temperature has a more significant effect on the drying characteristics of shiitake mushroom during IRSBD. Of all the drying process, the contents of flavor nucleotides, organic acids (tartaric acid, malic acid, succinic acid and citric acid), free amino acids (Asp, Glu and Ser) and equivalent umami concentration (EUC) value of Shiitake mushrooms are constantly increasing. The contents of soluble sugar and free amino acids such as polyol, acetic acid and fumaric acid increased significantly in the early and middle stage of drying, while decreased in the late stage of drying. The increase of temperature and airflow speed have a positive effect on retaining the flavor components of dried products. The condition of IRSBD with 55 °C and 8.0–8.5 m/s airflow speed is suitable for the dehydration process of Shiitake mushrooms to maintain better dried samples structure and yield high quality dried products with rich flavor in industry. • IRSBD was used to improve dried Shiitake mushrooms product quality. • Non-volatile compounds of Shiitake mushrooms were dynamic changed during IRSBD. • 55 °C and 8.0–8.5 m/s airflow speed is suitable for yielding rich flavor product.

Optimization of a variable-temperature heat pump drying process of shiitake mushrooms using response surface methodology

Quality, energy consumption, and production efficiency are paramount factors for optimizing a shiitake mushroom drying process, which are often mutually restrained. This paper adopts the response surface methodology to optimize a variable-temperature drying process of shiitake mushrooms based on a comprehensive score considering the above three aspects. A mode-switchable heat pump drying system is specially built to implement a variable-temperature drying process including four stages in which drying temperatures are 35 °C, 45 °C, 55 °C, and 65 °C, respectively. It is demonstrated that the drying time at 55 °C is the most important factor affecting the rehydration ratio of dried shiitake mushrooms, and the drying time at 35 °C is the key factor affecting the coefficient of performance of the heat pump. Moreover, according to the comprehensive score, the optimal drying time at 35 °C, 45 °C, 55 °C, and 65 °C are 2.4 h, 3.3 h, 5.6 h, and 2.6 h, respectively. The comprehensive score of the optimal drying process is 0.837 which is 49% higher than that of constant-temperature drying at 65 °C. One striking fact is that a valuable theoretical and experimental guideline is provided for future research on heat pump drying of shiitake mushrooms.

Comparison of different drying techniques for shiitake mushroom (Lentinus edodes): Changes in volatile compounds, taste properties, and texture qualities

The impact of heat pump dehumidifier drying (HPD) on the sensory qualities of shiitake mushroom was comprehensively evaluated in comparison with hot air drying (HAD) and vacuum freeze drying (VFD). The data showed that HPD substantially improved the characteristic flavors (volatile sulfide levels and equivalent umami concentration) of dried mushrooms by partially inhibiting enzymatic and Maillard reactions. The rehydration, shrinkage, and microstructural characteristics of HPD mushrooms were intermediate between VFD and HAD mushrooms. Results of sensory quality analysis indicated that HPD mushrooms outperformed HAD and VFD mushrooms in terms of overall quality. Additionally, HPD (0.85 kWh kg−1) had significantly (P < 0.05) lower energy consumption than HAD (2.65 kWh kg−1) and VFD (6.67 kWh kg−1). It can be concluded that HPD is a commercially attractive low-energy technique for the production of high sensory caliber dried shiitake mushrooms.

Investigation on the rehydration mechanism of freeze-dried and hot-air dried shiitake mushrooms from pores and cell wall fibrous material

Shiitake mushrooms are unique in their porous structure, which could be affected by various chemical/physical changes during freeze-drying process. In this work, rehydration characteristics of freeze-dried products which were pre-frozen at −20 ℃, −40 ℃, −80 ℃, and −196 ℃ (by liquid nitrogen) were explored from aspects of pores and cell wall fibrous material. Although the appearance and rehydration rate of freeze-dried samples was better than hot-air dried samples with drying temperature ranging from 30 ℃ to 90 ℃, the final rehydration ratio was still less than hot-air dried samples dried at low temperature (30 ℃ and 40 ℃) due to the more serious structural damage by freeze-drying. Hydration capacity of the cell wall fiber was increased by freeze-drying, which might be ascribed to the loosen structure of cell wall instead of composition changes. Thus, hot-air drying at low temperature is still recommend and freeze-drying should be further optimized.

ANALYSIS OF THE EXISTING METHODS AND SPECIFIC FEATURES OF DRYING SHIITAKE MUSHROOMS

The paper reviews and analyses the advantages and disadvantages of the existing technologies of drying shiitake mushrooms, which are a valuable source of bioactive polysaccharides, vitamins, antioxidants, etc. The findings presented in the paper show how various drying methods and their thermotechnological operating parameters affect the mechanostructural properties, chemical composition, content of aromatic substances and other compounds of mushrooms. It has been demonstrated that the traditional convection drying of shiitake in the temperature range 50–60°C allows maximum preservation of phenolic compounds, organic acids, nucleotides, sulphuric aromatic substances, and enhances the unique aroma of the mushroom. Radiation drying has such advantages as lower shrinkage of dried shiitake mushrooms, a higher coefficient of rehydration and higher hardness, and the drying time reduced by 66% compared with freeze-drying. Vacuum drying makes it possible to obtain high quality products, but significantly increases the duration of the process and reduces the content of aromatics. Radiation drying combined with hot air allows obtaining a dry form of shiitake rich in protein and bioactive polysaccharides and having high physicochemical properties, and reduces the duration of the process by 37.5% compared with convection drying. Spray drying of shiitake mushrooms is highly practical economically and allows organising industrial manufacture of high-quality dry mushroom powder in large volumes. It is characteristic of this drying method that its temperature effect on the product is slight, which makes it possible to preserve thermolabile bioactive substances. When using spray drying, it is advisable to add dextrin additives. This improves the structuring and moisture-conducting properties of the suspensions and their thermal stability, and helps preserve the unique aroma of shiitake mushrooms due to encapsulation of aromatic compounds. Studying the effect of various drying methods on the physicochemical properties of shiitake will lead to improving the existing technological processes and will make it possible to obtain products with desired properties.

Optimizing the Nutritional Composition of a Meat Substitute Intended to Replace Meat in Observed Diet Results in Marked Improvement of the Diet Quality of French Adults

ObjectivesWhile consumers’ demand is growing, meat substitutes have much varied composition, raising questions about their nutritional interest. We aimed to identify the composition of a meat substitute that would best improve diet quality, and analyze the impact on nutrient adequacy. MethodsWe aimed at maximizing the overall diet quality of an average individual representing the nutrient intake of the French adult population (INCA3, n = 1125) by modeling the composition of a meat substitute intended to replace meat, using non-linear optimization (using SAS, proc optmodel). The diet quality was assessed using the PANDiet scoring system, which assesses the probability of adequate nutrient intake. Nutritional constraints were applied in order to not increase the risk of overt deficiency for 12 nutrients. A list of 159 ingredients was used to compose the meat replacer and technological constraints were defined so as to take into account the feasibility of the formulation. The impacts on diet quality of the modelled meat substitute were analyzed and compared with those of 43 meat substitutes on the market. ResultsThe optimized meat substitute was composed of 13 ingredients (such as coco bean, yellow sweet pepper, rapeseed oil, dried shiitake mushroom, wheat bran and thyme) and this formulation proved to be relatively robust to variations in the model constraints, as shown by a sensitivity analysis. Meat substitution with this optimized meat substitute largely increased the PANDiet, by 5.5 points above its initial value before substitution (73.7/100). In particular, it led to better adequacies for nutrients that are currently insufficiently consumed (e.g., alpha-linolenic acid, fiber, linoleic acid). It also allowed to compensate for loss of some nutrients partly provided by meat (e.g., vitamin B6, potassium and, to a certain extent, bioavailable iron), but was not sufficient to compensate for bioavailable zinc and vitamin B12. The optimized meat substitute proved to be dramatically more nutritionally efficient than the available meat substitutes, whose individual impact on the PANDiet ranged from –3.1 to +1.5 points. ConclusionsWe proved that it is possible to select appropriate ingredients resulting in a meat substitute that could be a fairly good nutritional lever when substituting meat. Funding SourcesPartly funded by a PhD fellowship from Terres Univia.

Study on the Rehydration Quality Improvement of shiitake Mushroom by Combined Drying Methods.

The aim of study is to improve the rehydration quality of dried shiitake mushrooms for their instant food manufacturers and fast restaurants. Serial combined drying methods were investigated to achieve this objective: either instant controlled pressure drop drying (DIC) or freeze drying (FD) was used as the treatments for microstructure improvement, and they were applied either before or after an additional drying step at low (35 °C) or high (65 °C) temperatures. Dried mushrooms were assessed for quality indicators like relative volume, rehydration rate, dry matter loss and sensory scores. Microstructure properties were inferred to understand the physical mechanisms of quality changes. Principal component analysis (PCA) was used to cluster treatments and to identify combinations of drying techniques, rendering improved quality. Consequently, it was shown that DIC treatment before hot air drying at 35 °C was shown to be the most promising combined drying method to enhance the rehydration quality, leading to a high volume recovery ratio, low dry matter loss after rehydration, and high rehydration rates. This good performance could be explained by the retention of pore interconnectivity resulting from the slight expansion of porous structure during DIC and the retention of cell membrane integrity.

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.

Ultraviolet Irradiation Increased the Concentration of Vitamin D2 and Decreased the Concentration of Ergosterol in Shiitake Mushroom (Lentinus edodes) and Oyster Mushroom (Pleurotus ostreatus) Powder in Ethanol Suspension.

Vitamin D deficiency is a serious global health problem. Edible mushrooms are a good source of vitamin D for human health. The objective of this experiment was to investigate the efficiency of converting its precursor ergosterol to vitamin D2 in shiitake mushroom (Lentinus edodes) and oyster mushroom (Pleurotus ostreatus) powder in ethanol suspension under ultraviolet (UV) irradiation. UV irradiation conditions were optimized for several parameters, such as material form, wavelength, wavelength combination, and exposure time. Under the optimal conditions, UV irradiation increased the concentrations of vitamin D2 from undetectable to 40.59 ± 1.16 μg/g (dw) in dry shiitake mushroom powder and to 677.28 ± 40.42 μg/g (dw) (an approximately 16.69-fold increase) in ethanol suspension. The concentration of vitamin D2 increased from undetectable to 23.71 ± 5.72 μg/g (dw) in the dry oyster mushroom powder upon UV irradiation, whereas UV irradiation increased the concentration to 275.32 ± 48.45 μg/g (dw) (an approximately 11.61-fold increase) in the ethanol suspension. Comparing the effects of varying combinations of wavelengths showed that irradiation with UV-A, UV-C, or a combination of both is more effective than UV-B irradiation. In addition, the increase in vitamin D2 in shiitake mushrooms irradiated by UV-C was time-dependent, that is, dose-dependent. Nevertheless, the increase rates decreased with time. The concentration of ergosterol decreased with the increase in vitamin D2, but ergosterol was only partially converted to vitamin D2, whereas most of the ergosterol was probably UV-degraded. Exposure to ultraviolet light in ethanol suspension offers an effective way to increase the concentration of vitamin D2 and thus improve the nutritional value of edible mushrooms, as well as make them more functional as a source of vitamin D to improve the consumer health.

Effects of Gamma Irradiation on Microbial Load and Chemical Properties for Preserve Dried Shiitake Mushroom Powder

Effects of Gamma Irradiation on Microbial Load and Chemical Properties for Preserve Dried Shiitake Mushroom Powder

Evaluation of sensory, textural, and nutritional attributes of shiitake mushrooms (Lentinula edodes) as prepared by five types of drying methods

AbstractThe effect of freeze drying (FD), far‐infrared radiation drying (FIRD), heat pump drying (HPD), hot air drying (HAD), and hot air combined instant controlled pressure drop drying (DIC) were compared on the drying efficiency and quality attributes of dried shiitake mushrooms. The results showed that in comparison with the HPD, HAD, and DIC, the FIRD shiitake mushroom exhibited better appearance with less shrinkage and lower ΔE (6.10), lower hardness (34.82 N), and higher rehydration ratio (7.55), which were more resemble to those of the FD sample. Besides, a significantly higher (p &lt; 0.05) retention of protein was found in the FD and FIRD sample (2.47 mg/g and 2.30 mg/g), as well as higher retention of polysaccharide (1.79 mg/g and 1.39 mg/g). In addition, FIRD shiitake mushroom were superior to FD product in terms of saving drying time as 66.25% and exhibiting maximum numbers of flavor components, among which specific sulfides showed the highest percentage (24.59%). Therefore, the FIRD dried shiitake mushroom obtained a better overall quality among the products dried by the five drying methods.Practical applicationsShiitake mushrooms are wildly planted edible fungi, which are consumed mostly in dried form around the word. Recently, the demand of efficient application have promoted an increasingly use of novel drying technologies in mushroom processing. This study presents comprehensive evaluations on some vital quality attributes of shiitake mushrooms using five drying methods that already commercialized in China. FIRD was more suitable to produce dried shiitake mushrooms with desirable appearance and texture, as well as relatively rich flavor and nutrients.

Effects of high-temperature pre-drying on the quality of air-dried shiitake mushrooms (Lentinula edodes)

We investigated the relationship between the pre-drying temperature and overall quality of dried shiitake mushrooms (Lentinula edodes). Results showed that high-temperature pre-drying significantly increased the rehydration ratio and hardness of dried shiitake mushrooms, but decreased the degree of shrinkage, degree of browning, and formaldehyde content. The levels of enzyme activity were high throughout the pre-drying process and benefitted the formation of flavoured substances. Furthermore, high-temperatures pre-drying also resulted in a higher content of sulfur compounds. These results indicated that the pre-drying processing had significant impacts on the overall quality of dried shiitake mushrooms. This may pave the way for increasing the economic value of dried shiitake mushrooms.

Improving of texture and rehydration properties by ultrasound pretreatment for infrared-dried shiitake mushroom slices

ABSTRACTShiitake mushrooms are mostly used in the forms of dried products, and the pretreatments could help to improve the product quality. The effects of ultrasound pretreatment on water diffusion during short- and medium-wave infrared drying and overall product quality of shiitake mushroom were investigated. Shiitake mushroom slices were pretreated with ultrasonic wave at 28 kHz and 600 W for 15 min and then conducted infrared dried at 1350 W and 60°C. The results demonstrated that the drying time of the samples previously subjected to ultrasound pretreatment was remarkably reduced by 21.43%, as compared to the samples without pretreatment. Moreover, homogenous porous microstructure was obtained by dried mushrooms pretreated by ultrasound. In addition, the honeycomb-like microstructure pointed to superior texture, which also lead to reduce hardness and increase crispness of dried products. Furthermore, the dried products exhibited higher lightness (78.46) and better shape than those of the other pretreatment samples. In conclusion, ultrasound pretreatment coupled with infrared drying might be a potential method to produce high-quality dried shiitake mushrooms slices.

Current Status and Issues of Dry Shiitake Mushroom Production on Sado Island

Current Status and Issues of Dry Shiitake Mushroom Production on Sado Island