Method for assisting preservation of shiitake mushrooms by combining magnetic field and coating preservative

Abstract

The invention discloses a method for assisting in shiitake mushroom preservation by combining a magnetic field and a coating preservative. The method comprises the following steps: S1, removing dust and impurities on stems and surfaces of shiitake mushrooms; s2, precooling the shiitake mushrooms for 30 minutes, and preparing a coating preservative; s3, soaking the pre-cooled shiitake mushrooms in a coating preservative for 1-3 minutes, then fishing out the shiitake mushrooms, and waiting for natural air drying in a room temperature environment; s4, sub-packaging the naturally air-dried shiitake mushrooms coated with the film, and sealing the shiitake mushrooms in self-sealing bags; s5, storing in a magnetic field constant-temperature and constant-humidity refrigerating box, the magnetic field being a static magnetic field of 1 mT, 3 mT and 5 mT and the magnetic field being an alternating magnetic field of 1 mT. The coating preservative is prepared from the following raw materials in percentage by weight: 0.03 to 0.045 percent of chitosan, 0.03 to 0.05 percent of glycerol, 0.03 to 0.045 percent of sodium alginate, 0.03 to 0.045 percent of konjaku flour, 0.025 to 0.04 percent of vitamin, 0.025 to 0.035 percent of tea polyphenol and the balance of purified water. The method can slow down moisture loss of the shiitake mushrooms, delay generation of hydrolase of the shiitake mushrooms, help to reduce the rotting rate of the shiitake mushrooms in the storage period and maintain the quality of the shiitake mushrooms, and is safer and more efficient.

Description

Technical Field

[0001] The invention relates to the technical field of shiitake mushroom preservation, and in particular to a method for assisting shiitake mushroom preservation by combining a magnetic field and a coating preservative. Background Art

[0002] Shiitake mushrooms, also known as flower mushrooms, fragrant mushrooms, thick mushrooms, and flower mushrooms, originated in my country. It is the second largest mushroom in the world and is also a long-standing precious edible mushroom in my country. Shiitake mushroom fruiting bodies grow alone, in clusters or in groups. Its flesh is white, slightly thick or thick, fine and fragrant, and the surface is diamond-colored, light brown, and dark brown. The edible part of shiitake mushrooms accounts for 72%. Every 100 grams of edible part contains 1.8g of fat, 7.8g of crude fiber, 4.9g of ash, 124mg of calcium, 415mg of phosphorus, 25.3mg of iron, 0.07mg of vitamin B1, and 1.13mg of vitamin B2. Shiitake mushrooms contain a variety of vitamins, minerals, amino acids and other substances, which have many functions in promoting metabolism, treating diseases such as diabetes and tuberculosis, inducing the production of interferon, and anti-virus.

[0003] Fresh shiitake mushrooms are difficult to store after harvesting. Shiitake mushrooms have strong water absorption and are easily oxidized and moldy. The temperature of shiitake mushrooms is relatively low, and they are prone to oxidation and deterioration. At present, the technology for long-term preservation of shiitake mushrooms in the market is not perfect, and the preservation effect of shiitake mushrooms is poor.

[0004] Therefore, it is necessary to provide a method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to provide a method for assisting the preservation of shiitake mushrooms to extend their storage period and quality. The present invention provides a method for assisting the preservation of shiitake mushrooms by combining a magnetic field and a coating preservative.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative, comprising the following steps:

[0008] S1: remove dust and impurities from the stem part and the surface of shiitake mushrooms;

[0009] S2: pre-cooling the mushrooms for 30 minutes and preparing the coating liquid;

[0010] S3: soaking the pre-cooled mushrooms in the coating preservative for 1-3 minutes, then taking them out and letting them dry naturally at room temperature;

[0011] S4: The shiitake mushrooms that have been coated and naturally dried are packaged and sealed into ziplock bags and stored in a 4°C cold storage. The shiitake mushrooms are then divided into five groups and packed into food-grade polyethylene plastic boxes;

[0012] S5: Stored in a constant temperature and humidity refrigerator, the magnetic field is static and alternating, the static magnetic field strength is 1mT, 3mT, 5mT respectively, and the alternating magnetic field strength is 1mT.

[0013] Preferably, the raw material composition of the coating preservative is: chitosan 0.03-0.045%, glycerol 0.03-0.05%, sodium alginate 0.03-0.045%, konjac flour 0.03-0.045%, vitamin 0.025-0.04%, tea polyphenols 0.025-0.035%, and the balance is purified water;

[0014] Chitosan is a natural polymer compound with the characteristics of non-toxicity, safety, and easy film-forming. Sodium alginate is a natural polysaccharide carbohydrate that can avoid enzyme action on oxidation and prevent dehydration. Konjac flour has the characteristics of viscosity and gelation, which are conducive to film formation. The magnetic field and coating preservative are combined to extend the storage period and quality of shiitake mushrooms.

[0015] Preferably, the precooling temperature in step S2 is 4°C.

[0016] Preferably, the room temperature in step S3 is 16°C-24°C.

[0017] Preferably, in step S4, food-grade polyethylene material is used to package and seal the mushrooms.

[0018] Preferably, in step S5, the temperature in the magnetic field constant temperature and humidity incubator is 4° C. and the humidity is 80%.

[0019] Compared with the related art, the beneficial effects of the present invention are as follows: the present invention provides a method for extending the storage period of shiitake mushrooms and ensuring their quality during storage. Compared with the prior art, the present invention can slow down the water loss of shiitake mushrooms, delay the production of shiitake mushroom hydrolases, help reduce the decay rate of shiitake mushrooms during storage, maintain the quality of shiitake mushrooms, and is safer and more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a line graph showing the influence of the magnetic field and coating preservation of the present invention on the weight loss rate of shiitake mushrooms.

[0021] Figure 2 This is a statistical comparison chart of the effects of the magnetic field and the coating preservative of the present invention on the appearance of shiitake mushrooms. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] Weight loss rate determination method: Determination method reference

[0024] The weight loss rate calculation formula is:

[0025] RWL=(m1-m2)÷m1×100%,

[0026] Where: RWL is the weight loss rate, unit: %;

[0027] m1 is the mass of the sample before storage, unit: g;

[0028] m2 is the mass of the sample after storage, unit: g.

[0029] Moisture detection method: direct drying method, the moisture content of shiitake mushrooms is determined according to GB 5009.3-2016.

[0030] Determination of moisture content of shiitake mushrooms by low-field nuclear magnetic resonance analyzer

[0031] Low-field nuclear magnetic resonance method: select one mushroom from each group, select the size according to the tube mouth, remove the stem, ensure that each one is placed in the same way, face up, and place it in a clean low-field nuclear magnetic resonance test tube. Use a rubber stopper to plug the tube mouth, and then put it into the low-field nuclear magnetic resonance instrument for testing; sampling parameters: low-field nuclear magnetic resonance seed moisture measurement software, SE sequence, SW = 200KHz, TW = 1000ms, RFD = 0.02ms, DRG1 = 3, RG1 = 10, PRG = 3, delay = 0.1, TE = 100ms, NS = 8

[0032] Detection method of SOD: Reference to the study on the effect of short-wave ultraviolet rays on the post-harvest storage quality of shiitake mushrooms and its mechanism[D]Jilin University 2022.

[0033] Chop the differently treated shiitake mushrooms, mix them well, accurately weigh 0.1 g of the tissue, add 0.9 ml of normal saline into a centrifuge tube, add stainless steel beads and mix into a tissue homogenate, spin at 2500 r / min, carefully aspirate the supernatant for 10 min, dilute with normal saline to the optimal sampling concentration, and measure the absorbance at 569 nm according to the instructions.

[0034] Browning degree determination method: refer to Duan Ying, Geng Shengrong, Han Yongbin, etc., Screening of mushroom preservatives and their preservation effects. Food and Fermentation Industries [J]. 2004, (05): 143-6. and other methods.

[0035] Take 10g of shiitake mushrooms and put them in a small beaker. Add 100mL of phosphate buffer and use a small juicer to make a homogenate. Then filter it. Take out 10mL of filtrate and dilute it to 40mL. Centrifuge the filtrate at 3000r / min for 6min. Take the supernatant and measure the absorbance A1 at 410nm. The calculation formula of browning degree is: browning degree = A1×20

[0036] Color difference measurement method

[0037] Five mushrooms were randomly selected, and three points on the cap were randomly selected to measure the L* (brightness), a* (redness and greenness), and b* (yellowness and blueness) values ​​of the mushrooms using a colorimeter. The chromaticity coordinate x was calculated according to formula (1), and x was substituted into formula (2) to calculate the browning index (BI) of the mushrooms.

[0038]

[0039] Embodiment 1: After the fresh mushrooms are harvested and sorted, dust and impurities on the surface are removed and the mushroom stems are removed, and the mushrooms are pre-cooled for 30 minutes, and a coating liquid is prepared: chitosan 0.03-0.045%, glycerol 0.03-0.05%, sodium alginate 0.03-0.045%, konjac flour 0.03-0.045%, vitamin 0.025-0.04%, tea polyphenols 0.025-0.035%, and the balance is purified water. After stirring evenly, add them to a magnetic stirrer and stir at 60°C until they are completely dissolved. Then, the pre-cooled mushroom samples are immersed in the prepared coating liquid for 1-3 minutes, and then taken out and allowed to dry naturally at room temperature. The coated mushroom samples are placed in self-sealing bags and stored in a 4°C cold storage. The mushrooms were then divided into five groups and put into food-grade polyethylene plastic boxes with the specifications of length × width × height: 25cm × 17.5cm × 8cm. The mass of each box of mushroom samples was maintained at 500g. They were then placed in a magnetic field constant temperature and humidity incubator under the corresponding magnetic field strength. The magnetic field was a static magnetic field, and the preservation parameters were set with a magnetic field strength of 1mT, a temperature of 4°C, and a relative humidity of 80%.

[0040] The process lasts for 21 days, and the changes in various physiological indicators are detected every 2 days. The test box is equipped with corresponding temperature and humidity sensors and automatically controlled heating and cooling and humidification devices to monitor the temperature and humidity of the box at any time. If the temperature and humidity are higher or lower than the set temperature or relative humidity, the temperature and humidity sensors will automatically control cooling or heating, humidification or dehumidification according to the actual measured data to ensure that the ambient temperature and mushroom humidity meet the specifications.

[0041] At the end of the 21-day storage period, the taken-out shiitake mushrooms had the original flavor of shiitake mushrooms, and the color was quite different from the initial shiitake mushrooms. The weight loss rate was 9.1±0.2%, the moisture content was reduced, the browning index was 3.35±0.1, the SOD content was 33.8±0.1, the color difference L value was 32.2±0.1, the umbrella opening rate was 55.5%, moderate browning, the gills became darker in color, softened, and began to show symptoms of softening, with a slight odor, and the preservation effect was average.

[0042] Example 2: After the fresh mushrooms are harvested and sorted, dust and impurities on the surface are removed and the mushroom stems are removed, and then the mushrooms are pre-cooled for 30 minutes, and a coating liquid is prepared: chitosan 0.03-0.045%, glycerol 0.03-0.05%, sodium alginate 0.03-0.045%, konjac powder 0.03-0.045%, vitamin 0.025-0.04%, tea polyphenols 0.025-0.035%, and the balance is pure water. After stirring evenly, add it to a magnetic stirrer and stir at 60°C until it is completely dissolved. Then immerse the pre-cooled mushroom sample in the prepared coating liquid for 1-3 minutes, remove it and let it dry naturally at room temperature, then put the coated mushroom sample in a ziplock bag and store it in a 4°C cold storage. The mushrooms were then divided into five groups and put into food-grade polyethylene plastic boxes with the specifications of length × width × height: 25cm × 17.5cm × 8cm. The mass of each box of mushroom samples was maintained at 500g. They were then placed in a magnetic field constant temperature and humidity incubator under the corresponding magnetic field strength. The magnetic field was a static magnetic field, and the preservation parameters were set to a magnetic field strength of 3mT, a temperature of 4°C, and a relative humidity of 80%.

[0043] The process lasts for 21 days, and the changes in various physiological indicators are detected every 2 days. The test box is equipped with corresponding temperature and humidity sensors and automatically controlled heating and cooling and humidification devices to monitor the temperature and humidity of the box at any time. If the temperature and humidity are higher or lower than the set temperature or relative humidity, the temperature and humidity sensors will automatically control cooling or heating, humidification or dehumidification according to the actual measured data to ensure that the ambient temperature and mushroom humidity meet the specifications.

[0044] At the end of the 21-day storage period, the taken-out shiitake mushrooms had the original flavor of shiitake mushrooms, the color was slightly different from the initial shiitake mushrooms, the weight loss rate was 7.5±0.2%, the moisture content was reduced, the browning index was 3.14±0.1, the SOD content was 33.1±0.1, the color difference L value was 42.8±0.1, the umbrella opening rate was 33.3%, most of the colors were normal, with slight browning, good elasticity, and some shiitake mushrooms were wrinkled, which was normal, odorless, and the preservation effect was relatively good.

[0045] Implementation Case 3: After the fresh mushrooms are harvested and sorted, dust and impurities on the surface are removed, and the mushroom stems are removed. After precooling for 30 minutes, a coating solution is prepared: chitosan 0.03-0.045%, glycerol 0.03-0.05%, sodium alginate 0.03-0.045%, konjac powder 0.03-0.045%, vitamin 0.025-0.04%, tea polyphenols 0.025-0.035%, and the balance is pure water. After stirring evenly, add it to a magnetic stirrer and stir at 60°C until it is completely dissolved. Then immerse the precooled mushroom sample in the prepared coating solution for 1-3 minutes, remove it and let it dry naturally at room temperature, then put the coated mushroom sample in a ziplock bag and store it in a 4°C cold storage. The mushrooms were then divided into six groups and put into food-grade polyethylene plastic boxes with the specifications of length × width × height: 25cm × 17.5cm × 8cm. The mass of each box of mushroom samples was maintained at 500g. They were then placed in a magnetic field constant temperature and humidity incubator under a corresponding magnetic field strength. The magnetic field was a static magnetic field, and the preservation parameters were set to a magnetic field strength of 5mT, a temperature of 4°C, and a relative humidity of 80%.

[0046] The process lasts for 21 days, and the changes in various physiological indicators are detected every 2 days. The test box is equipped with corresponding temperature and humidity sensors and automatically controlled heating and cooling and humidification devices to monitor the temperature and humidity of the box at any time. If the temperature and humidity are higher or lower than the set temperature or relative humidity, the temperature and humidity sensors will automatically control cooling or heating, humidification or dehumidification according to the actual measured data to ensure that the ambient temperature and mushroom humidity meet the specifications.

[0047] At the end of the 21-day storage period, the taken-out shiitake mushrooms had the original flavor of shiitake mushrooms, the color was slightly different from the initial shiitake mushrooms, the weight loss rate was 2.9±0.1%, the moisture content was almost unchanged, the browning index was 3.16±0.1, the SOD content was 33.2±0.1, the color difference L value was 43.3±0.1, the cap opening rate was 11.1%, the cap was fresh, yellowish brown, the gills were white, the cap was elastic, the odor was normal, there was a shiitake mushroom flavor, and the preservation effect was good.

[0048] Implementation Case 4: After the fresh mushrooms are harvested and sorted, dust and impurities on the surface are removed, and the mushroom stems are removed. After precooling for 30 minutes, a coating liquid is prepared: chitosan 0.03-0.045%, glycerol 0.03-0.05%, sodium alginate 0.03-0.045%, konjac powder 0.03-0.045%, vitamin 0.025-0.04%, tea polyphenols 0.025-0.035%, and the balance is pure water. After stirring evenly, add it to a magnetic stirrer and stir at 60°C until it is completely dissolved. Then immerse the precooled mushroom sample in the prepared coating liquid for 1-3 minutes, remove it and let it dry naturally at room temperature, then put the coated mushroom sample in a ziplock bag and store it in a 4°C cold storage. The mushrooms were then divided into six groups and put into food-grade polyethylene plastic boxes with the specifications of length × width × height: 25cm × 17.5cm × 8cm. The mass of each box of mushroom samples was maintained at 500g. They were then placed in a magnetic field constant temperature and humidity incubator under the corresponding magnetic field strength. The magnetic field was an alternating magnetic field, and the preservation parameters were set with a magnetic field strength of 1mT, a temperature of 4°C, and a relative humidity of 80%.

[0049] The process lasts for 21 days, and the changes in various physiological indicators are detected every 2 days. The test box is equipped with corresponding temperature and humidity sensors and automatically controlled heating and cooling and humidification devices to monitor the temperature and humidity of the box at any time. If the temperature and humidity are higher or lower than the set temperature or relative humidity, the temperature and humidity sensors will automatically control cooling or heating, humidification or dehumidification according to the actual measured data to ensure that the ambient temperature and mushroom humidity meet the specifications.

[0050] At the end of the 21-day storage period, the taken-out shiitake mushrooms had the original flavor of shiitake mushrooms, and the color was slightly different from the initial shiitake mushrooms. The weight loss rate was 2.7±0.1%, the moisture content decreased less, the browning index was 3.17±0.1, the SOD content was 40.6±0.1, the color difference L value was 38.8±0.1, the cap opening rate was 22.2%, and most of the shiitake mushrooms had fresh caps, yellowish brown, white gills, good cap elasticity, normal odor, and a shiitake flavor, with a good preservation effect.

[0051] Comparative Example 1: The difference is that the shiitake mushroom samples were treated by refrigeration without applying a magnetic field or adding a coating preservative. The results showed that at the end of the 21-day storage period, the surface became sticky, and the quality was reduced compared with the shiitake mushroom samples at the beginning of storage; the weight loss rate was 5.5±0.1%. The moisture content was low, the moisture loss was high, the browning index was 3.77±0.1, the SOD index was 45.8±0.1, the color difference L value was 37.8±0.1, the umbrella opening rate was 66.67%, severe browning, the gills were rotten, soft, water-stained, and had a strong odor. Compared with the initial storage, the difference was significant, and the shiitake mushroom samples were not fresh.

[0052] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative, characterized in that: The following steps are involved: S1: remove dust and impurities from the stem part and the surface of shiitake mushrooms; S2: pre-cool the mushrooms for 30 minutes; S3: soaking the pre-cooled mushrooms in the coating preservative for 1-3 minutes, then taking them out and letting them dry naturally at room temperature; S4: The shiitake mushrooms that have been coated and naturally dried are packaged and sealed into ziplock bags and stored in a 4°C cold storage. The shiitake mushrooms are then divided into five groups and packed into food-grade polyethylene plastic boxes; S5: Stored in a constant temperature and humidity refrigerator, the magnetic field is static and alternating, the static magnetic field strength is 1mT, 3mT, 5mT respectively, and the alternating magnetic field strength is 1mT.

2. The method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative according to claim 1, characterized in that: The raw materials of the coating preservative are as follows: 0.03-0.045% chitosan, 0.03-0.05% glycerol, 0.03-0.045% sodium alginate, 0.03-0.045% konjac flour, 0.025-0.045% vitamins, 0.025-0.035% tea polyphenols, and the balance is purified water.

3. The method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative according to claim 1, characterized in that: The precooling temperature in step S2 is 4°C.

4. The method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative according to claim 1, characterized in that: The room temperature in step S3 is 16°C-24°C.

5. The method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative according to claim 1, characterized in that: In the step S4, the mushrooms are packaged and sealed using food-grade polyethylene material.

6. The method for preserving shiitake mushrooms by combining a magnetic field and a coating preservative according to claim 1, characterized in that: In step S5, the temperature in the magnetic field constant temperature and humidity incubator is 4° C. and the humidity is 80%.

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