A synergistic method for improving the quality of frozen edible mushrooms

Abstract

A kind of synergistic method for improving the quality of frozen edible mushroom, the main steps are as follows: after selecting fresh raw materials, washing, removing roots, slicing, first through atmospheric pressure cold plasma (ACP) and high voltage electric field (HVEF) for pre-freezing treatment, then through static magnetic field assisted quick freezing, prepare the complex thawing color protection liquid based on L-cysteine, GABA, cyclodextrin and ascorbic acid, carry out ultrasonic micro-rehydration thawing treatment in the color protection liquid. After the edible mushroom treated by the method of the application, the ACP and HVEF enzyme inactivation effect before freezing and the pre-freezing pre-dehydration by HVEFD non-thermal drying can maximize the sensory quality and nutritional value of the sample during frozen storage period, the static magnetic field assisted quick freezing technology during freezing can effectively reduce the ice crystal size and reduce the damage to the tissue structure of edible mushroom, and the ultrasonic assisted technology after freezing can improve the thawing rate while promoting the action of thawing color protection liquid and reducing juice loss.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food freezing processing, and particularly relates to a synergistic method for improving the quality of frozen edible mushrooms. BACKGROUND

[0002] Mushrooms contain polysaccharides, minerals, dietary fiber, essential amino acids and polyphenols, and are low in fat and calories, delicious in taste, and widely consumed in the world, and are favored by consumers. However, fresh mushrooms have high water content, strong respiration and metabolism, and are prone to browning and rotting, which leads to rapid decline in mushroom quality after harvesting, and can only be stored for 3-4 days at room temperature. These characteristics result in a soft texture, water loss, opening of the cap, generation of an odor, browning and rotting, which seriously restricts its commercial value. At the same time, due to the high water content, the frozen mushrooms are greatly affected by ice crystal formation, resulting in destruction of the tissue structure, severe browning of the mushrooms, high juice loss rate, and difficulty in maintaining good sensory properties. Current research is mainly focused on postharvest fresh preservation of mushrooms, but the storage time is still very limited. Therefore, the research on frozen mushrooms is the key to breaking through the shelf life of mushrooms and expanding the industrial development of mushrooms, and it is imperative to explore the technology for effectively improving the quality of frozen mushrooms.

[0003] Zhao Jinshan et al. (Publication No. CN109497512A) disclose a "production process of quick-frozen yellow mushrooms", which mainly uses warm water soaking and physiological saline soaking for pretreatment, uses atomized ice hanging and precooling for freezing. Physiological saline makes the yellow mushrooms full under the action of osmosis, the atomized ice hanging method makes the yellow mushrooms harden, reduces water loss and mechanical wear, avoids mutual adhesion and freezing of the yellow mushrooms, and precooling of the yellow mushrooms before quick-freezing processing avoids damage to the internal structure of the yellow mushrooms. After processing, the quality, nutritional value and taste of the quick-frozen yellow mushrooms are improved. However, the problem of browning protection of mushrooms is not considered, and it is not suitable for white edible fungi such as double-spore mushrooms.

[0004] Traditional color protection methods for white edible fungi usually use color protection agents, and are mostly focused on exploring heat processing, drying and canning application scenarios. Wang Qingping et al. (Publication No. CN109169884A) disclosed a "mushroom preservation process", which used 0.6% sodium chloride solution for color protection, soaked for 8-9 minutes, then pre-cooked at 40-60°C for 5 minutes, and then sealed with 0.6% sodium chloride solution as soup. Through this method, the mushroom processed has good preservation effect, but the pre-cooking uses heat processing to destroy the structure of the mushroom, so that its sensory quality except fresh taste is not well maintained. Yang Wenjian et al. (Publication No. CN108576196A) disclosed a "high-quality quick-frozen double-spore mushroom freezing and thawing method", which used a compound color protection agent (0.15% L-cysteine, 1.0% citric acid, 0.3% erythorbic acid and 0.04% ascorbic acid) for color protection, soaked in the color protection agent for 20-30 minutes, then frozen at-80°C, stored at-20°C, and thawed at 4°C to obtain a quick-frozen double-spore mushroom with low browning degree and less juice loss. However, this method uses pre-freezing soaking, which affects the subsequent freezing and thawing due to the residual water in the color protection liquid, and the long thawing time at 4°C causes long browning time and low thawing efficiency. In addition, it does not involve improving the freezing and thawing environment through physical field assistance.

[0005] Fan Liuping et al. (Publication No. CN105341631A) developed a "heat-processed white mushroom color protection agent and its application", which configured a color protection agent containing 3-5% calcium ascorbate, 0.55-2% calcium propionate, 0.8-1.5% sodium chloride, 0.1-0.3% L-cysteine, and 0.02-0.03% disodium ethylenediaminetetraacetate. Before heat treatment of white mushrooms, the color protection agent was used for color protection treatment, which can effectively solve the problem of browning during heat processing of white mushroom products, affecting the nutrition and quality of the products, and the health hazards of the current market mainstream color protection agent, sulfite. However, the color protection agent of this invention is mainly for color protection before heat treatment, but does not involve color protection for freezing and thawing.

[0006] Li Suliang et al. (Publication No: CN107753579A) discloses a fresh processing method for white peony root, which uses a citric acid aqueous solution to protect color and prevent browning. Then, high-voltage electric field treatment is used to dry the white peony root slices, which also inactivates or passivates the enzymes. This method shows that high-voltage electric field has the effects of non-thermal drying and enzyme passivation, and the use of chemical color protectants extends the storage time of white peony root slices. However, the difference between this invention and the present invention is the degree of micro-drying and drying, and the present invention can maintain good sensory quality of frozen and thawed mushrooms through micro-rehydration technology. Jiang Hao et al. (Publication No: CN116420774A) discloses the application of low-temperature plasma in the preparation of banana slices. This invention confirms the positive effect of low-temperature plasma in enzyme passivation. After treatment, the activities of polyphenol oxidase (PPO) and peroxidase (POD) in banana slices significantly decrease with increasing treatment time.

[0007] Tian Changqing et al. (CN116941722A) developed a magnetic field assisted freezing device, freezing equipment and magnetic field assisted freezing method. The application of this invention can reduce the size of ice crystals formed during food freezing through magnetic field assistance, thereby improving the quality of frozen food. This invention demonstrates the wide application prospects of magnetic field assisted freezing.

[0008] White edible mushrooms such as Agaricus bisporus are prone to browning and other quality deterioration during storage and processing due to their high water content. Using a single method often cannot achieve the effect of overall improvement of frozen quality. Therefore, the present invention combines physical field assistance and chemical treatment to intervene in all aspects of mushroom freezing, freezing, and post-freezing, to improve the quality of frozen and thawed products. SUMMARY

[0009] Technical problems solved: In order to solve the technical problems of color browning, texture softening, and juice loss of frozen and thawed edible mushrooms, the present invention provides a synergistic method for improving the quality of frozen edible mushrooms.

[0010] Technical solution: A synergistic method for improving the quality of frozen edible mushrooms, comprising the following steps: (1) raw material selection: selecting fresh edible mushrooms as raw materials; (2) pretreatment: washing and removing the roots of the selected edible mushrooms, and slicing them to 6mm±2mm thick; (3) atmospheric pressure cold plasma (ACP) treatment: placing the pretreated edible mushrooms in the gap between two plates and treating for 5 minutes; (4) high voltage electric field (HVEF) treatment: treating the edible mushroom slices treated in step (3) with 10-40kV for 1-4h; (5) static magnetic field assisted quick freezing: quick freezing the edible mushroom slices treated in step (4) at a magnetic field strength of 0-10mT to -20℃, and storing them in a -20℃ freezer after freezing is completed; (6) thawing color protection liquid preparation: preparing a complex thawing color protection liquid containing L-cysteine, GABA, cyclodextrin and ascorbic acid; (7) ultrasonic assisted thawing: immersing the quick frozen edible mushroom slices in the thawing color protection liquid and performing ultrasonic assisted micro-rehydration thawing under ultrasonic power of 200-600W; (8) draining: draining the surface moisture of the edible mushroom slices after thawing in step (7) is completed.

[0011] The atmospheric pressure cold plasma (ACP) treatment in step (3) above uses dielectric barrier discharge, with an adjusted voltage of 30V, a gap between the two quartz dielectric plates of 10mm, and a treatment time of 5min at room temperature.

[0012] The static electric field strength in step (4) is 30kV, the sample stage is 10cm away from the electrode plate, and the field strength acting on the edible mushroom sample is 3kV / cm, treated at 4℃ for 2h.

[0013] The static magnetic field assisted quick freezing environment in step (5) above is provided by a static magnetic field assisted quick freezing device, and the static magnetic field is provided by a pair of Helmholtz coils placed on both sides of the quick freezing cabinet; the magnetic field strength is set to 8mT.

[0014] The composition of the complex thawing color protection liquid in step (6) above is 0.15wt.% L-cysteine, 0.06wt.% GABA, 0.5wt.% cyclodextrin and 0.1wt.% ascorbic acid, with the rest being water; after thorough stirring and dissolution, the thawing color protection liquid is prepared.

[0015] The ultrasonic frequency in step (7) above is 28kHz, and the power is 300W; when the center temperature of the sample reaches 4℃, the thawing is completed.

[0016] Beneficial effects: (1) The application provides a high-voltage electrostatic field assisted pretreatment method for improving the quality of frozen edible mushrooms, which has a positive effect on enzyme inactivation and micro-drying. Polyphenol oxidase (PPO) is considered to be the main enzyme that causes the browning of white mushroom such as Agaricus bisporus. It includes tyrosinase, catechol oxidase and laccase. Phenolic substrates are oxidized by PPO to form quinones that can easily polymerize to form melanin, accelerating the browning of Agaricus bisporus. HVEF can inhibit browning by inactivating enzymes, ensuring the color quality stability of Agaricus bisporus during frozen storage. At the same time, HVEF treatment has a non-thermal drying effect. By forming an ionic wind, the saturation boundary layer of the material is disturbed, and the polarized water is subjected to the action of the electric field force to achieve effective drying. By controlling the HVEF treatment time, the enzyme inactivation effect is ensured, and the drying degree of micro-drying is achieved.

[0017] (2) The application provides a magnetic field assisted quick freezing method for improving the quality of frozen edible mushrooms. Under the action of the magnetic field, the material is subjected to the action of the magnetic force, the spin and vibration of the molecules change, and the thermodynamic change occurs, thereby forming fine and uniform intracellular ice crystals, reducing the damage to the tissue structure of the mushroom.

[0018] (3) The application provides a complex agent color protection method for improving the quality of frozen edible mushrooms, which has outstanding effects in inhibiting enzyme browning of mushrooms and maintaining good sensory quality. A complex color protection agent based on L-cysteine, GABA, cyclodextrin and ascorbic acid is used. The application of the color protection agent is different from the conventional color protection agent, which is designed in the thawing step. The reasons are as follows: first, the residual water of the color protection agent can affect the subsequent freeze-thaw link; second, the color change of Agaricus bisporus is only slightly yellow during freezing and frozen storage, and the enzyme inactivation effect of HVEF treatment ensures the color quality during freezing and frozen storage. Browing mainly occurs after thawing, so color protection during thawing can achieve timely inhibition and double the effect.

[0019] (4) The application provides an ultrasonic assisted thawing method for improving the quality of frozen edible mushrooms. Liquid is used as a medium, and high-frequency sound waves are used to penetrate energy to the center of the sample, accelerating the dissolution of internal ice crystals. However, unlike traditional ultrasonic assisted thawing, the liquid medium used in the application is a thawing color protection agent, so it can achieve the dual effect of promoting thawing efficiency and increasing the effect of color protection.

[0020] The present application adopts micro-drying and micro-rehydration combined technology, realizes effective control on juice loss through HVEFD and ultrasonic technology, and the traditional control on juice loss mainly starts from quick freezing technology, reduces the size of ice crystal, has certain effect but limited control. The micro-drying and micro-rehydration are different from the traditional drying and rehydration technology, and the processing degree is limited to the free water in the dried and rehydrated mushroom tissue. The part of free water is the most important component of juice loss, the present application first micro-dries the part of water through HVEFD, adopts magnetic field assistance to form small ice crystals when other water is frozen, and then realizes efficient rehydration through ultrasonic assistance, and the effect of reducing juice loss is extremely obvious. And the present application does not affect the tissue structure of the mushroom, so that the mushroom still has good sensory quality and nutritional value after thawing and rehydration.

[0021] The present application realizes the color protection effect through the combined action of physical field assistance and chemical treatment. The HVEF passivates the activity of polyphenol oxidase and other enzymes, so that the mushroom maintains a good color state during the low-temperature period of freezing and frozen storage. The color protection agent restrains the browning degree during the obvious thawing process, and the ultrasonic assistance promotes the action of the effective color protection factor in the color protection agent, so that the HVEF-color protection agent-ultrasonic assistance combined color protection effect is realized.

[0022] The edible mushroom treated by the method of the present application can maintain the sensory quality and nutritional value of the sample to the greatest extent during the frozen storage period through the HVEF non-thermal drying and enzyme passivation effect before freezing, the ice crystal size can be effectively reduced through the static magnetic field assisted quick freezing technology during freezing, the damage to the tissue structure of the mushroom is reduced, and the thawing rate can be improved through the ultrasonic assistance technology after freezing, the thawing color protection liquid is promoted, and the juice loss is reduced. That is, the quality of the frozen edible mushroom is improved in all aspects through the whole-process control before, during and after freezing, and the actual production requirements are met. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The freezing time and thawing time of the samples treated in the control example 1 and the example 1 of the present application;

[0024] Figure 2 The color difference change of the samples treated in the control example 1 and the example 1 of the present application;

[0025] Figure 3 The juice loss rate of the samples treated in the control example 1 and the example 1 of the present application;

[0026] Figure 4 The freezing time and thawing time of the samples treated in the control example 2 and the example 2 of the present application;

[0027] Figure 5 The color difference change of the samples treated in the control example 2 and the example 2 of the present application;

[0028] Figure 6 Juice loss rate of the sample after treatment of Comparative Example 2 and Example 2 of the present application;

[0029] Figure 7 Freezing time and thawing time of the sample after treatment of Comparative Example 3 and Example 3 of the present application;

[0030] Figure 8 Color difference change of the sample after treatment of Comparative Example 3 and Example 3 of the present application;

[0031] Figure 9 Juice loss rate of the sample after treatment of Comparative Example 3 and Example 3 of the present application. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application.

[0033] Example 1

[0034] A synergistic method for improving the quality of frozen Agaricus bisporus, comprising the following steps:

[0035] (1) Raw material selection: selecting fresh, intact, no mechanical damage, uniform size, uniform color, and round mushroom cap Agaricus bisporus as raw material;

[0036] (2) Pretreatment: washing the selected Agaricus bisporus, removing the roots, and slicing to 6mm±2mm thick;

[0037] (3) Atmospheric pressure cold plasma (ACP, Energetically Balanced (Germany)) treatment: placing the pretreated mushroom in the gap between the two plates, using dielectric barrier discharge, setting the adjustment voltage to 30V, the gap between the two quartz dielectric plates is 10mm, and treating for 5min at room temperature;

[0038] (4) High voltage electric field (HVEF, Indus (Wuxi)) treatment: placing the mushroom slices treated in step (3) flat in the high voltage electrostatic field device, setting the electrostatic field strength to 30kV, the sample stage is 10cm away from the electrode plate, the field strength acting on the mushroom sample is 3kV / cm, and treating for 2h at 4℃, thereby inactivating enzymes through HVEF, inhibiting the generation of enzyme browning in the mushroom. At the same time, part of the free water in the mushroom is dried through high voltage electric field drying (HVEFD) technology;

[0039] (5) Static magnetic field assisted quick-freezing: The processed mushroom slices are laid flat in a static magnetic field assisted quick-freezing device. The static magnetic field assisted quick-freezing environment is provided by the device, and the static magnetic field is provided by a pair of Helmholtz coils placed on both sides of the quick-freezing cabinet. The magnetic field strength is set to 8mT, and the freezing is carried out at -20℃. After freezing, the mushroom slices are stored in a -20℃ freezer.

[0040] (6) Preparation of thawing and color protection solution: The compound thawing and color protection solution consists of 0.15 wt.% L-cysteine, 0.06 wt.% GABA, 0.5 wt.% cyclodextrin and 0.1 wt.% ascorbic acid, with the remainder being water. After thorough stirring and dissolution, it is prepared as the ultrasonic liquid environment in step (7) below.

[0041] (7) Ultrasonic-assisted thawing: At room temperature (25℃), using the thawing and color-protecting solution as a medium, high-frequency sound waves propagate energy to penetrate into the center of the sample, accelerating the dissolution of internal ice crystals, thereby achieving the purpose of assisting thawing and promoting the effect of color-protecting active factors. The ultrasonic equipment is set to a frequency of 28kHz and a power of 300W. Thawing is considered complete when the sample center temperature reaches 4℃.

[0042] (8) Drain: Take out the thawed mushroom slices and drain the surface water.

[0043] Compare with Example 1

[0044] The following control experiment was set up to demonstrate the effectiveness of the present invention in improving the quality of frozen button mushrooms. At the same time, by applying a single technology of the invention as a control, the comprehensive application effect of the present invention was demonstrated.

[0045] Control 1: Button mushrooms that were washed, sliced, and frozen at -20°C without any treatment according to the present invention, and then thawed at room temperature were used as Control 1;

[0046] Control 2: Button mushrooms that were not treated with the ACP and HVEF of this invention, but were frozen with magnetic field assistance, protected with color-protecting solution, and thawed with ultrasound assistance at room temperature were used as Control 2;

[0047] Control 3: Button mushrooms that were not treated with the magnetic field of this invention, but were pretreated with ACP and HVEF, protected with color-protecting solution, and thawed with ultrasound at room temperature were used as Control 3;

[0048] Control 4: Button mushrooms that were not treated with the color-protecting solution of this invention, but were pretreated with ACP and HVEF, frozen with magnetic field assistance, and thawed with ultrasound assistance at room temperature were used as Control 4;

[0049] Control 5: Button mushrooms that were thawed in a color-protecting thawing solution at room temperature without undergoing the ultrasonic-assisted thawing treatment of this invention, but were pretreated with ACP and HVEF, frozen with magnetic field assistance, and without undergoing ultrasonic-assisted thawing treatment, were Control 5.

[0050] The freezing time and thawing time, color change, juice loss and other indicators of the frozen Agaricus bisporus samples under different treatments were determined to compare and illustrate the beneficial effects and results of the present application. The experimental results are shown in Table 1. Figures 1-3 As shown in Table 1, the freezing time and thawing time of the frozen Agaricus bisporus treated by the present application are significantly less than those of the control group samples (P<0.05), and the color protection treatment can effectively inhibit the browning of Agaricus bisporus during freezing and thawing, and significantly reduce the juice loss of the samples. At the same time, the superiority of the present application in the synergistic method for improving the quality of frozen Agaricus bisporus is verified by comparative experiments, and the effect is significantly better than that of ordinary freezing and thawing method or single treatment technology.

[0051] Example 2

[0052] A synergistic method for improving the quality of frozen Agaricus bisporus, comprising the following steps:

[0053] (1) Raw material selection: selecting fresh and complete Agaricus bisporus without mechanical damage, uniform size, consistent color, and round Agaricus bisporus as raw material;

[0054] (2) Pretreatment: washing the selected Agaricus bisporus, removing the roots, and slicing the Agaricus bisporus into slices with a thickness of 6 mm ± 2 mm;

[0055] (3) Atmospheric pressure cold plasma (ACP) treatment: placing the pretreated Agaricus bisporus in the gap between the two plates, using dielectric barrier discharge, setting the adjustment voltage to 30 V, the gap between the two quartz dielectric plates is 10 mm, and treating for 5 min at room temperature;

[0056] (4) High voltage electric field (HVEF) treatment: placing the Agaricus bisporus slices treated in step (3) in a high voltage electrostatic field device, setting the electrostatic field strength to 30 kV, the sample stage is 10 cm away from the electrode plate, the field strength acting on the Agaricus bisporus sample is 3 kV / cm, and treating for 2 h at 4℃. The HVEF blunts the enzymes, inhibiting the production of enzyme browning in Agaricus bisporus. At the same time, the high voltage electric field drying (HVEFD) technology is used to dry part of the free water in the Agaricus bisporus;

[0057] (5) Static magnetic field assisted quick freezing: placing the treated Agaricus bisporus slices in a static magnetic field assisted quick freezing device, the static magnetic field assisted quick freezing environment is provided by the static magnetic field assisted quick freezing device, and the static magnetic field is provided by a pair of Helmholtz coils placed on both sides of the quick freezing cabinet. The magnetic field strength is set to 8 mT, and the freezing is carried out at -20℃ environment. After freezing, the Agaricus bisporus is stored in a -20℃ freezing room;

[0058] (6) Preparation of thawing color protection solution: the composition of the thawing color protection solution is 0.15wt.% L-cysteine, 0.06wt.% GABA, 0.5wt.% cyclodextrin and 0.1wt.% ascorbic acid, and the rest is water. After being fully stirred and dissolved, the thawing color protection solution is prepared as the ultrasonic liquid environment in the following step (7).

[0059] (7) ultrasonic assisted thawing: at room temperature (25℃), using thawing color protection liquid as medium, energy is penetrated to the center of the sample through high frequency sound wave propagation to accelerate the dissolution of internal ice crystals, so as to achieve the purpose of assisting thawing and promoting the effect of color protection. The frequency of the ultrasonic device is set to 28 kHz, and the power is 300 W. When the temperature of the center of the sample reaches 4℃, it is considered that the thawing is completed;

[0060] (8) draining: the mushroom slices after thawing are fished out and drained of surface water.

[0061] Comparative Example 2

[0062] The following comparative experiments are set up to prove the effective effect of the application in improving the quality of frozen amanita caesarea. At the same time, by applying a single technology in the application as a control, the effect of the comprehensive application of the application is embodied.

[0063] Control 1: the amanita caesarea thawed at room temperature without any treatment in the application is control 1;

[0064] Control 2: the amanita caesarea thawed at room temperature with magnetic field assisted freezing and color protection liquid color protection without ACP and HVEF treatment in the application is control 2;

[0065] Control 3: the amanita caesarea thawed at room temperature with color protection liquid color protection and ACP and HVEF pretreatment without magnetic field treatment in the application is control 3;

[0066] Control 4: the amanita caesarea thawed at room temperature with ultrasonic assisted thawing and ACP and HVEF pretreatment without color protection liquid treatment in the application is control 4;

[0067] Control 5: the amanita caesarea thawed at room temperature with color protection liquid thawing and ACP and HVEF pretreatment without ultrasonic assisted thawing treatment in the application is control 5.

[0068] The freezing time and thawing time, color difference change, juice loss and other indicators of the frozen amanita caesarea samples under different treatments are determined to compare and illustrate the beneficial effects and effects of the patent. The experimental results are shown in Table 1. Figures 4-6 The freezing time and thawing time of the frozen amanita caesarea treated by the application are significantly less than those of the control group samples (P<0.05), the color protection treatment can effectively inhibit the browning of amanita caesarea during freezing and thawing, and significantly reduce the juice loss of the sample. At the same time, the superiority of the synergistic method of the application in improving the quality of frozen amanita caesarea is verified through comparative experiments, and the effect is significantly better than that of ordinary freezing and thawing method or single treatment technology.

[0069] Example 3

[0070] A synergistic method for improving the quality of frozen Agaricus blazei, comprising the following steps:

[0071] (1) Raw material selection: selecting fresh, intact, no mechanical damage, uniform size, uniform color, and round Agaricus blazei as raw material;

[0072] (2) Pretreatment: washing the selected Agaricus blazei, removing the roots, and slicing to 6mm±2mm thick;

[0073] (3) Atmospheric pressure cold plasma (ACP) treatment: placing the pretreated mushrooms in the gap between the two plates, using dielectric barrier discharge, setting the adjustment voltage to 30V, the gap between the two quartz dielectric plates is 10mm, and treating for 5min at room temperature;

[0074] (4) High voltage electric field (HVEF) treatment: placing the mushroom slices treated in step (3) in the high voltage electrostatic field device, setting the electrostatic field strength to 30kV, the sample stage is 10cm away from the electrode plate, the field strength acting on the mushroom sample is 3kV / cm, and treating for 2h at 4℃, thereby blunting the enzymes and inhibiting the generation of enzymatic browning in the mushrooms. At the same time, part of the free water in the mushrooms is dried by high voltage electric field drying (HVEFD) technology;

[0075] (5) Static magnetic field assisted quick freezing: placing the treated mushroom slices in the static magnetic field assisted quick freezing device, the static magnetic field assisted quick freezing environment is provided by the static magnetic field assisted quick freezing device, and the static magnetic field is provided by a pair of Helmholtz coils placed on both sides of the quick freezing cabinet. The magnetic field strength is set to 8mT, and the freezing is carried out at-20℃, and after the freezing is completed, the mushrooms are stored in a-20℃ freezing room;

[0076] (6) Preparation of thawing color protection liquid: the composition of the prepared thawing color protection liquid is 0.15wt.% L-cysteine, 0.06wt.% GABA, 0.5wt.% cyclodextrin and 0.1wt.% ascorbic acid, and the rest is water. After being fully stirred and dissolved, the thawing color protection liquid is prepared as the ultrasonic liquid environment in the following step (7);

[0077] (7) Ultrasonic assisted thawing: at room temperature (25℃), the thawing color protection liquid is used as the medium, high frequency sound waves are used to penetrate the energy to the center of the sample, so as to accelerate the dissolution of internal ice crystals, thereby achieving the purpose of assisting thawing and promoting the effect of color protection effective factor. The frequency of the ultrasonic device is set to 28kHz, and the power is 300W. When the temperature of the center of the sample reaches 4℃, it is considered that the thawing is completed;

[0078] (8) Drainage: the thawed mushroom slices are taken out and drained.

[0079] Comparative example 3

[0080] The following control experiment was set up to compare and demonstrate the effectiveness of the present invention in improving the quality of frozen Ferula aspera. At the same time, by applying a single technology of the invention as a control, the comprehensive application effect of the present invention was demonstrated.

[0081] Control 1: The *Ferula* mushrooms that were washed, sliced, and frozen at -20°C without any treatment according to this invention, and then thawed at room temperature, were Control 1;

[0082] Control 2: Ferula asperata without the ACP and HVEF treatment of this invention, but frozen with magnetic field assistance, protected with color-protecting solution, and thawed with ultrasound assistance at room temperature;

[0083] Control 3: Ferula asperata without magnetic field treatment of the present invention, but pretreated with ACP and HVEF, protected with color-protecting solution, and thawed with ultrasound at room temperature;

[0084] Control 4: Ferula asperata without the color-protecting solution of this invention, but pretreated with ACP and HVEF, frozen with magnetic field assistance, and thawed with ultrasound assistance at room temperature;

[0085] Control 5: The *Ferula asperata* that was thawed in a color-protecting solution at room temperature without undergoing the ultrasonic-assisted thawing treatment of this invention, but was pretreated with ACP and HVEF, frozen with magnetic field assistance, and without undergoing ultrasonic-assisted thawing treatment, was Control 5.

[0086] Freezing and thawing times, color difference changes, and juice loss were measured in frozen *Ferula asperata* samples under different treatments to compare and illustrate the beneficial effects of this patent. Experimental results are as follows: Figures 7-9 As shown, the freezing and thawing times of *Ferula asperata* treated with this invention were significantly shorter than those of the control group (P<0.05). The color-protecting treatment effectively inhibited browning of *Ferula asperata* during freeze-thaw cycles and significantly reduced juice loss. Furthermore, comparative experiments verified the superiority of this invention as a synergistic method for improving the quality of frozen *Ferula asperata*, demonstrating that its effects are significantly better than ordinary freeze-thaw methods or single-treatment techniques.

[0087] The foregoing illustrative description of the invention and its embodiments is not restrictive. Therefore, if those skilled in the art are inspired by it and design similar structural methods and embodiments without departing from the spirit of the invention, they should all fall within the protection scope of the invention.

Claims

1. A synergistic method for improving the quality of frozen edible mushrooms, characterized by, The method comprises the following steps: (1) raw material selection: selecting fresh edible mushrooms as raw materials; (2) pretreatment: washing and removing roots of the selected edible mushrooms, and slicing the mushrooms into pieces with a thickness of 6 mm ± 2 mm; (3) atmospheric pressure cold plasma treatment: placing the pretreated edible mushrooms in a gap between two plates, and treating for 5 min; (4) high-voltage electric field treatment: treating the edible mushroom pieces treated in step (3) at a high-voltage electric field of 10-40 kV for 1-4 h; (5) static magnetic field assisted quick freezing: quick freezing the edible mushroom pieces treated in step (4) at a magnetic field strength of 8-10 mT to-20 °C, and storing the frozen edible mushroom pieces in a-20 °C freezer; (6) thawing color protection liquid preparation: preparing a thawing color protection liquid containing L-cysteine, GABA, cyclodextrin and ascorbic acid; (7) ultrasonic assisted thawing: immersing the quick-frozen edible mushroom pieces in the thawing color protection liquid, and performing ultrasonic assisted micro-rehydration thawing under ultrasonic power of 200-600 W; and (8) draining: draining the surface water of the edible mushroom pieces after thawing in step (7).

2. The synergistic method for improving the quality of frozen edible mushrooms according to claim 1, characterized in that, In step (3), the atmospheric pressure cold plasma treatment is performed by dielectric barrier discharge, a voltage of 30 V is set, the gap between the two quartz dielectric plates is 10 mm, and the treatment is performed at room temperature for 5 min.

3. The synergistic method for improving the quality of frozen edible mushrooms according to claim 1, characterized in that, In step (4), the high-voltage electric field strength is 30 kV, the sample table is 10 cm away from the electrode plate, the field strength acting on the edible mushroom sample is 3 kV / cm, and the treatment is performed at 4 °C for 2 h.

4. The synergistic method for improving the quality of frozen edible mushrooms according to claim 1, characterized in that, In step (5), the static magnetic field assisted quick freezing environment is provided by a static magnetic field assisted quick freezing device, and the static magnetic field is provided by a pair of Helmholtz coils placed on both sides of the quick freezing cabinet; the magnetic field strength is set to 8 mT.

5. The synergistic method of improving the quality of frozen edible mushroom according to claim 1, characterized in that, In step (6), the thawing color protection liquid comprises 0.15 wt.% L-cysteine, 0.06 wt.% GABA, 0.5 wt.% cyclodextrin and 0.1 wt.% ascorbic acid, and the rest is water; after being fully stirred and dissolved, the thawing color protection liquid is prepared.

6. The synergistic method of improving the quality of frozen edible mushroom according to claim 1, characterized in that, In step (7), the ultrasonic frequency is 28 kHz, the power is 300 W, and the thawing is completed when the center temperature of the sample reaches 4 °C.

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