Dried mushroom preparation method capable of increasing vitamin D content and shortening rehydration time

Abstract

The invention relates to a dried mushroom preparation method capable of increasing vitamin D content and shortening rehydration time. According to the method, under the conditions that the appearance of mushroom sporocarps is kept complete and nutrients are not lost as much as possible, the purposes of increasing the content of vitamin D2 in the dried mushrooms and rapidly rehydrating the dried mushrooms are achieved through nutrient solution spraying in the fruiting period, mushroom screening and optimization of the ultraviolet irradiation mode and the drying process, and the method has wide application prospects.

Description

Technical Field

[0001] The invention relates to a method for preparing dried shiitake mushrooms with improved vitamin D content and shortened rehydration time. Background Art

[0002] Vitamin D promotes the absorption of calcium and phosphate in the small intestine, maintains calcium function, prevents osteoporosis, and acts as a hormone. It is an important nutrient that helps prevent and treat various diseases such as Alzheimer's disease. The types of vitamin D discovered so far range from D2 to D7, among which D2 and D3 have the highest biological activity.

[0003] The recommended daily intake of vitamin D is 10μg (400IU) for children under 15 years old and women over 50 years old, and 5μg (200IU) for adults under 50 years old. The human body can synthesize vitamin D3 by basking in the sun, but the increase in indoor living time, wearing masks due to fine dust, and using sunscreens limit the exposure to ultraviolet rays, which hinders the biosynthesis of vitamin D in the skin. Vitamin D deficiency may cause rickets in growing children, osteomalacia in menopausal women and the elderly, and lead to hypocalcemia, hypothyroidism, and bone loss. Mushrooms, fish, meat, and milk contain trace amounts of vitamin D that can be ingested through diet.

[0004] Edible fungi contain a large amount of ergosterol, which is a precursor of vitamin D2. It can synthesize vitamin D2 under ultraviolet light. It is converted into biologically active calcitriol (1,25-(OH)2-D3) by the liver and kidneys, thereby realizing the various physiological functions of vitamin D2. At present, there are many articles and patents on the conversion of ergosterol into vitamin D by ultraviolet light in edible fungi. However, most of these technologies increase the vitamin D content by increasing the ultraviolet irradiation area of ​​the fruiting body by slicing or crushing, optimizing the spectral wavelength and irradiation time. However, slicing or crushing the fruiting body of edible fungi will cause nutrient loss, and the rehydration process will lead to further nutrient loss, reducing its nutritional value.

[0005] Dried shiitake mushrooms are nutritious and delicious, have multiple health functions, and are a traditional fungus food in my country. Compared with animal-derived vitamin D foods, it does not significantly increase fat and cholesterol, is more beneficial to human health, and is an excellent vitamin D nutritional supplement. The Chinese patent "Method for Preparing Vitamin D from Shiitake Mushrooms (ZL202080095867.3)" discloses a method for increasing the vitamin D content by storing and ripening at two different temperatures. However, due to the respiration of edible fungi during storage, nutrients will continue to be consumed and lost, and at the same time, fibrosis will increase and edibility will decrease. Dried shiitake mushrooms are used in many recipes after soaking and processing. Keeping the appearance of shiitake mushroom fruiting bodies intact and nutritious and delicious, increasing the vitamin D2 content, and shortening the rehydration time has become a technical challenge. Summary of the invention

[0006] The invention aims to provide a method for preparing dried shiitake mushrooms which can increase the content of vitamin D2 and shorten the rehydration time while keeping the appearance of shiitake mushroom fruiting bodies intact.

[0007] The present invention adopts the following technical solution: A method for preparing dried shiitake mushrooms with increased vitamin D content and shortened rehydration time comprises the following steps: (1) Management of mushroom harvesting: After the primordium of shiitake mushrooms is formed, increase the ventilation volume. Three days after the primordium is formed, spray the mushroom sticks with water nutrient solution, once every two days, 50 ml per stick each time, for a total of two sprays; one day before harvesting, use ultraviolet light to irradiate the shiitake mushroom fruiting bodies at a distance of 30 cm for 0.5 to 1 hour; harvest when the shiitake mushroom fruiting bodies are 7 to 8 open; (2) Fruiting body pretreatment: Shiitake mushrooms are sorted and stems are removed. Use a bamboo stick with a diameter of 1 to 2.5 mm to evenly pierce 5 to 13 holes, i.e. the piercing density is 1.5 to 3.9 cm 2 / hole; (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with their gills facing upward, put them in the drying room, and irradiate them on both sides with UV light at a distance of 30 cm for 1 to 2 hours. Control the temperature in the drying room at 30 to 35°C and dry them until the moisture content reaches 70%. (4) Drying treatment: heat to 40℃, heating rate 2℃ / h, drying for 2~5h to reduce the moisture content to below 50%; heat to 50℃, heating rate 1℃ / h, drying for 3~5h; heat to 55℃, drying for 2~4h to reduce the moisture content to below 30%; heat to 60℃, drying for 1h; heat to 65℃, drying for 1h to reduce the moisture content to 11~13%; obtain dried shiitake mushrooms.

[0008] Furthermore, in step (1), the water nutrient solution comprises: 15-90 ml / L of acetic acid, 2.5-10 g / L of glucose and 1-2 g / L of astragalus polysaccharide.

[0009] Preferably, in step (1), the water nutrient solution comprises: 60 ml / L acetic acid, 5 g / L glucose and 2 g / L astragalus polysaccharide.

[0010] Furthermore, in step (1), the ultraviolet lamp is a 40W ultraviolet lamp with a wavelength range of 280-320nm, and the irradiation time is 0.5h.

[0011] Furthermore, in step (2), 9 holes are evenly pierced using a bamboo stick with a diameter of 1.5 mm, i.e., the piercing density is 2.2 cm 2 / hole.

[0012] Furthermore, in step (3), the ultraviolet lamp is a 40W ultraviolet lamp with a wavelength range of 280-320nm, and the irradiation time is 2h.

[0013] The beneficial effects of the present invention are: (1) The present invention sprays nutrient solution during the fruiting period to increase the content of ergosterol in the surface layer of shiitake mushroom fruiting bodies; irradiates the shiitake mushrooms with ultraviolet rays before harvesting to promote the increase of vitamin D2 precursors; and irradiates the shiitake mushroom fruiting bodies with intact appearance with ultraviolet rays during the drying process after harvesting to convert the ergosterol in the surface layer of shiitake mushroom flesh into vitamin D2. Through the synergistic effect of multiple means, the purpose of increasing the content of vitamin D2 in dried shiitake mushrooms is achieved.

[0014] (2) The present invention is particularly targeted at light-colored shiitake mushroom fruiting bodies, which are pierced, irradiated with ultraviolet rays, and dried, thereby promoting the conversion of vitamin D2, shortening the drying time and rehydration time, maintaining the integrity of the appearance of the shiitake mushroom fruiting bodies, and avoiding nutrient loss.

[0015] (3) The dried shiitake mushroom product prepared by the present invention can be rehydrated in 20 minutes, which is convenient for cooking; it has a high content of vitamin D2, and a small amount of consumption can meet the daily vitamin D requirement of the elderly; it maintains the integrity of the appearance and natural flavor of the shiitake mushroom fruiting body, does not use organic solvents, does not significantly increase fat and cholesterol, is more beneficial to human health, and is an excellent vitamin D nutritional supplement food with broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the photochemical reaction of ergosterol to produce vitamin D2. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] In Examples 1 to 6, the shiitake mushroom fruiting bodies were collected from summer mushrooms in Chengde, Hebei. The content of vitamin D2 was determined by liquid chromatography according to the GB 5009.82-2016 method. The content of ergosterol was detected by liquid chromatography. HPLC separation conditions: chromatographic column: COSMOSIL 5C18-MS-II (4.6 mm×250 mm, 5 µm); mobile phase: 100% methanol; flow rate: 1.0 mL / min; injection volume: 5 μL; column temperature: 30°C; diode array detector, detection wavelength: 280 nm. The specification of the ultraviolet lamp is 40W power, wavelength bandwidth 280-320nm, and the main peak is 308nm. Anhydrous acetic acid is used for acetic acid. Astragalus polysaccharide uses astragalus polysaccharide injection produced by Luoyang Meibei Biotechnology Co., Ltd.

[0019] Example 1 (1) Management of mushroom harvesting: The color depth of mushroom fruiting bodies will vary significantly due to different cultivation management methods such as ventilation, humidity, and light. Select white-faced mushrooms, gray-faced mushrooms, and black-faced mushrooms of the same variety with a diameter of about 6 cm and the same size.

[0020] (2) Fruiting body pretreatment: sorting and removing the stems of shiitake mushrooms.

[0021] (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with the gills facing upward, and place them in the drying room. Irradiate the mushrooms on both sides with the UV light at a distance of 30 cm for 2 hours. Control the temperature in the drying room at 30-35℃ and dry them until the moisture content reaches 70%.

[0022] (4) Drying: Heat to 40℃, heating rate 2℃ / h, dry for 2~5h to reduce the water content to below 50%. Heat to 50℃, heating rate 1℃ / h, dry for 3~5h; heat to 55℃, dry for 2~4h to reduce the water content to below 30%. Heat to 60℃, dry for 1h; heat to 65℃, dry for 1h to reduce the water content to 11~13%. Determine the content of vitamin D2 after drying.

[0023] The results in Table 1 show that the white-faced shiitake mushrooms have the highest vitamin D2 content, reaching 53.55 ug / g, followed by the gray-faced shiitake mushrooms, and the black-faced shiitake mushrooms have the lowest vitamin D2 content, which is 29.41 ug / g. The rehydration time of the three colors of shiitake mushrooms after drying is similar, all 2h.

[0024] Table 1 Effect of Lentinus edodes fruiting body color on the conversion of vitamin D2 during drying .

[0025] Example 2 (1) Management of Shiitake mushroom harvesting: After the primordium is formed, increase the ventilation. Three days after the primordium is formed, spray the mushroom sticks with nutrient solution, once every two days, 50 ml each time, for a total of two times. When the Shiitake mushroom fruiting bodies are 7-8 open, harvest. Select Shiitake mushrooms with a diameter of about 6 cm and uniform size, cut the fruiting bodies about 3 mm from the cap with a knife, and measure the ergosterol content of the fruiting bodies and the 3 mm slices of the cap. Take the Shiitake mushrooms that were not sprayed with nutrient solution as the control.

[0026] The formula of water nutrient solution is as follows: .

[0027] (2) Fruiting body pretreatment: sorting and removing the stems of shiitake mushrooms.

[0028] (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with the gills facing upward, and place them in the drying room. Irradiate the mushrooms on both sides with the UV light at a distance of 30 cm for 2 hours. Control the temperature in the drying room at 30-35℃ and dry them until the moisture content reaches 70%.

[0029] (4) Drying: Heat to 40℃, heating rate 2℃ / h, dry for 2~5h to reduce the water content to below 50%. Heat to 50℃, heating rate 1℃ / h, dry for 3~5h; heat to 55℃, dry for 2~4h to reduce the water content to below 30%. Heat to 60℃, dry for 1h; heat to 65℃, dry for 1h to reduce the water content to 11~13%. Determine the content of vitamin D2 after drying.

[0030] The results showed (Table 2) that the addition of astragalus polysaccharide in formula 2 and formula 3 could significantly increase the ergosterol content and facilitate the adhesion of the water nutrient solution to the surface of Lentinus edodes fruiting bodies and mushroom sticks.

[0031] Table 2 Effects of spraying water nutrient solution during fruiting period on ergosterol and vitamin D2 contents of Lentinula edodes .

[0032] Example 3 (1) Management of Shiitake mushroom harvesting: After the primordium is formed, increase the ventilation. Three days after the primordium is formed, spray the mushroom sticks with nutrient solution, once every two days, 50 ml per stick each time, for a total of two sprays. When the Shiitake mushroom fruiting bodies are 7-8 open, harvest. Select the same variety and the same mushroom shed with a diameter of about 6 cm and the same size of gray-faced Shiitake mushrooms, cut the mushroom cap into 3mm slices with a knife, and measure the ergosterol content of the fruiting body and the 3mm slice of the mushroom cap. Take the Shiitake mushrooms that are not sprayed with nutrient solution as the control.

[0033] The formula of water nutrient solution is as follows: .

[0034] (2) Fruiting body pretreatment: sorting and removing the stems of shiitake mushrooms.

[0035] (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with the gills facing upward, and place them in the drying room. Irradiate the mushrooms on both sides with the UV light at a distance of 30 cm for 2 hours. Control the temperature in the drying room at 30-35℃ and dry them until the moisture content reaches 70%.

[0036] (4) Drying: Heat to 40℃, heating rate 2℃ / h, dry for 2~5h to reduce the water content to below 50%. Heat to 50℃, heating rate 1℃ / h, dry for 3~5h; heat to 55℃, dry for 2~4h to reduce the water content to below 30%. Heat to 60℃, dry for 1h; heat to 65℃, dry for 1h to reduce the water content to 11~13%. Determine the content of vitamin D2 after drying.

[0037] The results showed (Table 3) that spraying nutrient solution during the harvest period of Lentinus edodes spawn can increase the ergosterol content in Lentinus edodes fruiting bodies, and the ergosterol content in the 3mm slice of the cap was significantly higher than that in the fruiting body. The ergosterol content in the 3mm slice of the cap of Formula 1, Formula 2 and Formula 3 was 2.60mg / g, 2.71mg / g and 2.85mg / g, respectively, with the largest increase in Formula 3, reaching 50.8%. At the same time, it was observed that when Formula 3 was sprayed on the spawn, if the spawn was contaminated by foreign bacteria, the degree of contamination was significantly aggravated. The vitamin D2 content of Lentinus edodes fruiting bodies was positively correlated with the ergosterol content.

[0038] Table 3 Effects of spraying water nutrient solution during fruiting period on ergosterol and vitamin D2 contents of Lentinula edodes .

[0039] Example 4 (1) Management of mushroom harvesting: After the primordium is formed, increase the ventilation. When the mushroom fruiting bodies are 7-8 open, harvest. Select gray-faced mushrooms with a diameter of about 5 cm and uniform size.

[0040] (2) Fruiting body pretreatment: sort the mushrooms, remove the stems, and pierce them evenly.

[0041] Experiment 1: Use bamboo sticks with diameters of 1mm, 1.5mm, 2mm, and 2.5mm to pierce 7 holes evenly in each mushroom. Each treatment is repeated 30 times.

[0042] Experiment 2: Use a bamboo stick with a diameter of 1.5 mm to pierce 5 holes (3.9 cm 2 / hole), 7 (2.8cm 2 / hole), 9 (2.2cm 2 / hole), 11 (1.8cm 2 / hole) and 13 (1.5cm 2 Each treatment was repeated 30 times.

[0043] (3) Pre-drying and UV irradiation: 5 hours after harvesting, place the mushrooms evenly and neatly on the sieve with the gills facing upwards, and place them in the drying room. Expose the mushrooms on both sides with a UV lamp at a distance of 30 cm for 2 hours. Control the temperature in the drying room at 30-35°C and dry until the moisture content reaches 70%.

[0044] (4) Drying: Heat to 40℃, heating rate 2℃ / h, dry for 2~5h to reduce the water content to below 50%. Heat to 50℃, heating rate 1℃ / h, dry for 3~5h; heat to 55℃, dry for 2~4h to reduce the water content to below 30%. Heat to 60℃, dry for 1h; heat to 65℃, dry for 1h to reduce the water content to 11~13%. Determine the content of vitamin D2 after drying.

[0045] The results of vitamin D2 conversion and rehydration time determination by piercing holes in shiitake mushrooms with bamboo sticks of different diameters showed (Table 4) that the larger the diameter of the bamboo stick, the higher the vitamin D2 content, the shorter the rehydration time, and the shorter the total drying time. However, piercing holes with bamboo sticks of 2 mm or more in diameter can easily cause partial tearing of the punctured holes in the shiitake mushrooms, affecting the appearance of the dried shiitake mushrooms.

[0046] Table 4 Effect of puncture diameter on vitamin D2 conversion .

[0047] According to the results in Table 4, the results of vitamin D2 conversion and rehydration time determination of Shiitake mushrooms using a 1.5 mm diameter bamboo stick showed (Table 5) that the greater the density of bamboo stick punctures, the higher the vitamin D2 content, the shorter the rehydration time, and the shorter the total drying time. However, puncturing 11 or more holes can easily cause partial tearing of the punctured mushrooms.

[0048] Table 5 Effect of puncture density on vitamin D2 conversion .

[0049] Example 5 (1) Management of mushroom harvesting: After the primordium is formed, increase the ventilation volume. One day before harvesting, irradiate with UV light at a distance of 30 cm for 0, 0.5 h and 1 h respectively. Select white-faced shiitake mushroom fruiting bodies with a diameter of about 5 cm, uniform size, and 7 to 8 folds. Each treatment was repeated 30 times.

[0050] (2) Fruiting body pretreatment: The harvested mushrooms were sorted, the stems were removed, and 9 holes were evenly pierced using a 1.5 mm diameter bamboo stick.

[0051] (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with the gills facing upward, and put them into the drying room. Expose them to UV light at a distance of 30 cm from both sides for 1 hour and 2 hours respectively. Control the temperature in the drying room at 30-35°C and dry until the moisture content reaches 70%.

[0052] (4) Drying: Heat to 40℃, heating rate 2℃ / h, dry for 2~5h to reduce the water content to below 50%. Heat to 50℃, heating rate 1℃ / h, dry for 3~5h; heat to 55℃, dry for 2~4h to reduce the water content to below 30%. Heat to 60℃, dry for 1h; heat to 65℃, dry for 1h to reduce the water content to 11~13%. Determine the content of vitamin D2 after drying.

[0053] The results showed (Table 6) that the vitamin D2 content of the four treatments was high, and the rehydration time was about 20 minutes. UV-B irradiation before and after harvesting can increase the vitamin D2 content. The treatment of irradiation with UV-B for 1 hour before harvesting and 2 hours during the pre-drying stage had the highest vitamin D2 content, reaching 72.11 ug / g, with the maximum increase of 20.1% compared with the control.

[0054] Table 6 Effects of ultraviolet irradiation methods on vitamin D2 content in shiitake mushrooms .

[0055] Example 6 (1) Management of mushroom harvesting: After the primordium is formed, increase the ventilation. Three days after the primordium is formed, spray the mushroom sticks with nutrient solution, once every two days, 50 ml per stick each time, for a total of two sprays. One day before harvesting, irradiate with ultraviolet light at a distance of 30 cm for 0.5 hours. Harvest when the mushroom fruiting bodies are 7-8 open. Select white-faced shiitake mushrooms with a diameter of about 5 cm and the same size in the same mushroom shed.

[0056] The formula of water nutrient solution is as follows: .

[0057] (2) Fruiting body pretreatment: sort the mushrooms and remove the stems. Use a 1.5 mm diameter bamboo stick to evenly pierce 9 holes.

[0058] (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with the gills facing upward, and put them into the drying room. Irradiate them with UV light on both sides at a distance of 30 cm for 2 hours. Control the temperature in the drying room at 30-35℃ and dry them until the moisture content is 70%.

[0059] (4) Drying: Heat to 40℃, heating rate 2℃ / h, dry for 2~5h to reduce the water content to below 50%. Heat to 50℃, heating rate 1℃ / h, dry for 3~5h; heat to 55℃, dry for 2~4h to reduce the water content to below 30%. Heat to 60℃, dry for 1h; heat to 65℃, dry for 1h to reduce the water content to 11~13%. Determine the content of vitamin D2 after drying.

[0060] Shiitake mushrooms harvested in the conventional way served as the control.

[0061] The results showed that spraying nutrient solution, irradiating ultraviolet rays, and piercing can significantly increase the vitamin D2 content of shiitake mushrooms and shorten the rehydration time. The rehydration time of the four treatments was 20 minutes, and the vitamin D2 content of treatment three was the highest, reaching 96.50 ug / g. It was also observed that the maturity of the shiitake mushroom fruiting bodies in treatment four was delayed and the color became darker.

[0062] Table 7 Effects of spraying water nutrient solution, irradiating ultraviolet rays, and piercing on the vitamin D2 content of shiitake mushrooms .

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing dried shiitake mushrooms with increased vitamin D content and shortened rehydration time, characterized in that: It includes the following steps: (1) Management of mushroom harvesting: After the primordium of shiitake mushrooms is formed, increase the ventilation volume. Three days after the primordium is formed, spray the mushroom sticks with water nutrient solution, once every two days, 50 ml per stick each time, for a total of two sprays; one day before harvesting, use ultraviolet light to irradiate the shiitake mushroom fruiting bodies at a distance of 30 cm for 0.5 to 1 hour; harvest when the shiitake mushroom fruiting bodies are 7 to 8 open; (2) Fruiting body pretreatment: Shiitake mushrooms are sorted, stems are removed, and holes are evenly pierced using a bamboo stick with a diameter of 1 to 2.5 mm, with a piercing density of 1.5 to 3.9 cm 2 / hole; (3) Pre-drying and UV irradiation: Arrange the mushrooms evenly and neatly on the sieve with their gills facing upward, put them in the drying room, and irradiate them on both sides with UV light at a distance of 30 cm for 1 to 2 hours. Control the temperature in the drying room at 30 to 35°C and dry them until the moisture content reaches 70%. (4) Drying treatment: heat to 40℃, heating rate 2℃ / h, drying for 2~5h to reduce the moisture content to below 50%; heat to 50℃, heating rate 1℃ / h, drying for 3~5h; heat to 55℃, drying for 2~4h to reduce the moisture content to below 30%; heat to 60℃, drying for 1h; heat to 65℃, drying for 1h to reduce the moisture content to 11~13%; obtain dried shiitake mushrooms.

2. The method for preparing dried shiitake mushrooms according to claim 1, characterized in that: The shiitake mushroom is a light-colored shiitake mushroom fruiting body.

3. The method for preparing dried shiitake mushrooms according to claim 1, characterized in that: In step (1), the water nutrient solution comprises: 15-90 ml / L of acetic acid, 2.5-10 g / L of glucose and 1-2 g / L of astragalus polysaccharide.

4. The method for preparing dried shiitake mushrooms according to claim 3, characterized in that: In step (1), the water nutrient solution includes: 60 ml / L acetic acid, 5 g / L glucose and 2 g / L astragalus polysaccharide.

5. The method for preparing dried shiitake mushrooms according to claim 1, characterized in that: In step (1), the ultraviolet lamp is a 40W ultraviolet lamp with a wavelength range of 280-320nm, and the irradiation time is 0.5h.

6. The method for preparing dried shiitake mushrooms according to claim 1, characterized in that: In step (2), use a 1.5 mm diameter bamboo stick to puncture holes evenly, with a puncture density of 2.2 cm 2 / hole.

7. The method for preparing dried shiitake mushrooms according to claim 1, characterized in that: In step (3), the ultraviolet lamp is a 40W ultraviolet lamp with a wavelength range of 280-320nm, and the irradiation time is 2h.

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