Solid-state fermentation freeze-dried gastrodia elata as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of food processing, and particularly discloses solid-state fermentation freeze-dried gastrodia elata, a preparation method and application, the freeze-dried gastrodia elata is obtained by freeze-drying fresh gastrodia elata, adding coix seed pulp, inoculating bacillus subtilis and monascus for fermentation, and freeze-drying again. The fresh gastrodia elata is freeze-dried to remove part of moisture, and is gradually rehydrated in the fermentation process, so that solid-liquid substance exchange is accelerated, and the fermentation efficiency is improved; bacillus subtilis and monascus are inoculated for synergistic fermentation, the two bacteria are fermented and metabolized to generate protease, amylase, cellulase and other enzymes, cellulose, lignin and other substances in gastrodia elata cell walls are degraded, and active ingredients in gastrodia elata are increased; on the other hand, bitter amino acids in the gastrodia elata are subjected to decarboxylation, deamination and other reactions in the fermentation process to generate alcohol compounds and the like, other ester and phenolic compounds are generated through fermentation, the content of aldehyde compounds is obviously reduced, the bitter taste and peculiar smell of the gastrodia elata are reduced, and then the loss of active ingredients is reduced through freeze drying.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and in particular relates to solid-state fermented freeze-dried Gastrodia elata, a preparation method and application thereof. Background Art

[0002] Gastrodia elata is a tuber of the orchid Gastrodia elata plant, which is rich in active ingredients such as gastrodin, p-hydroxybenzyl alcohol, and barleyson glycosides. It has a good effect on relieving various neurological symptoms and is a plant with both medicinal and edible properties. As consumers gradually shift from pursuing balanced nutrition to obtaining high-quality nutrition, plants with both medicinal and edible properties are becoming more and more popular. Many consumers choose to eat fresh Gastrodia elata, dried Gastrodia elata, etc. directly, but because Gastrodia elata contains ether substances and bitter amino acids and bitter peptides such as arginine and valine, Gastrodia elata has a "horse urine odor" and bitter taste, poor palatability, and is not easily accepted by consumers. Some consumers choose to boil Gastrodia elata in soup and only consume the soup, resulting in the waste of most of the effective ingredients in Gastrodia elata; some consumers grind Gastrodia elata into powder and add it to food for consumption, but many active ingredients in Gastrodia elata are reduced after grinding, and the human body can only absorb and utilize a small part of the nutrients. It can be seen that giving full play to the maximum advantages of nutrients and active ingredients in Gastrodia elata, as well as reducing or even removing the odor and bitterness of Gastrodia elata are issues that the industry needs to solve urgently.

[0003] Current research on improving the odor of Gastrodia elata shows that steaming, boiling and fermentation can improve the flavor of Gastrodia elata, among which the fermentation method has the best effect and also increases the content of active ingredients in Gastrodia elata. Gastrodia elata has a hard texture, so during fermentation, it is often used to inoculate probiotics after enzymatic hydrolysis of Gastrodia elata powder or to inoculate and ferment Gastrodia elata extract, which has a high degree of damage to Gastrodia elata; there are also methods of fermenting the whole Gastrodia elata, but the fermentation time is long. In the prior art, there are few methods of improving the odor of Gastrodia elata by fermentation, and finally obtaining Gastrodia elata products with relatively complete texture.

[0004] Based on this, the present invention is proposed. Summary of the invention

[0005] Based on the above reasons, one of the purposes of the present invention is to provide a sheet-like solid-state fermented freeze-dried Gastrodia elata, which has no obvious odor and bitterness and has a high content of active ingredients; the second purpose of the present invention is to provide a method for preparing solid-state fermented freeze-dried Gastrodia elata, firstly, the Gastrodia elata is sliced ​​to increase the effective area, and part of the water is removed by freeze-drying, which is beneficial to material exchange during the solid-liquid fermentation process, improves the fermentation efficiency, shortens the fermentation time, and at the same time, a composite strain is used for efficient fermentation to remove odor and bitterness, increase the content of active ingredients, and secondary freeze-drying is performed after the fermentation is completed to reduce the loss of active ingredients.

[0006] The first technical scheme of the present invention provides a solid-state fermented freeze-dried Gastrodia elata, which is prepared by freeze-drying fresh Gastrodia elata, adding coix seed paste to inoculate Bacillus subtilis and Monascus for fermentation, and freeze-drying again.

[0007] The second technical solution of the present invention provides a method for preparing the above-mentioned solid-state fermentation freeze-dried Gastrodia elata, comprising the following steps: The fresh gastrodia elata is washed, cut into gastrodia elata slices with a thickness of 0.3-0.5 cm, and freeze-dried for the first time to obtain pre-treated gastrodia elata; Adding coix seed paste to the pretreated gastrodia elata, sterilizing at high temperature to obtain a mixture to be fermented; The composite strain is inoculated into the mixture to be fermented, the solid and liquid are separated after fermentation, and the solid Gastrodia elata slices are freeze-dried for a second time to obtain solid-state fermented freeze-dried Gastrodia elata.

[0008] Furthermore, the first freeze-drying is to pre-cool the Gastrodia elata slices at -18°C for 1-1.5 hours, freeze them at -50°C for 3-4 hours, and then dry them at 40-50Pa and -25-10°C for 5-6 hours.

[0009] Furthermore, the mass ratio of the pretreated Gastrodia elata to coix seed slurry is 1:(0.5-1), and the concentration of coix seed slurry is 5-10%.

[0010] Furthermore, the composite bacteria are Bacillus subtilis and Monascus, with a mass ratio of 1: (2-3).

[0011] Furthermore, the inoculation amount of the composite bacteria is 4-6%.

[0012] Furthermore, the fermentation is an aerobic fermentation at 28-30°C for 3-5 days.

[0013] Furthermore, the second freeze-drying is to adjust the vacuum degree to 20-25 Pa and the temperature to 15-25° C. after the first freeze-drying of the fermented Gastrodia elata, and continue freezing for 12-14 hours.

[0014] The third technical solution of the present invention provides solid-state fermented freeze-dried Gastrodia elata obtained according to the above-mentioned solid-state fermented freeze-dried Gastrodia elata preparation method.

[0015] The fourth technical solution of the present invention provides the application of the above-mentioned solid-state fermented freeze-dried Gastrodia elata in food.

[0016] The present invention has the following beneficial effects: The present invention removes part of the water in the gastrodia elata through the first freeze-drying, accelerates the material exchange through the rehydration process during the solid-liquid fermentation process, and thus improves the fermentation efficiency; adds coix seed slurry to ferment with the gastrodia elata, increases the fermentable substrate, enables the bacteria to grow and reproduce rapidly, and shortens the fermentation time; since the gastrodia elata has a relatively hard texture, the composite bacteria are used for efficient fermentation, reduces the content of aldehyde compounds and bitter amino acids, and improves the flavor of the gastrodia elata. In this process, the saccharifying enzyme produced by Monascus continuously converts the fermentation substrate, and improves the fermentation efficiency; finally, the solid-state fermentation freeze-dried gastrodia elata with high gastrodia elata polysaccharide content and no obvious bitterness and peculiar smell is obtained through the second freeze-drying. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments.It should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention.In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.Unspecified conditions in the embodiments are carried out according to the conditions of normal conditions or manufacturer recommendations.Reagents used or instruments that do not specify manufacturers are conventional products that can be purchased and obtained commercially.

[0018] The first embodiment of the present invention provides a solid-state fermented freeze-dried Gastrodia elata, which is prepared by freeze-drying fresh Gastrodia elata, adding coix seed paste, inoculating Bacillus subtilis and Monascus for fermentation, and performing secondary freeze-drying to obtain the product.

[0019] In this embodiment, fresh Gastrodia elata is freeze-dried to remove part of the moisture, and gradually rehydrated during the fermentation process, thereby accelerating the exchange of solid-liquid substances and improving the fermentation efficiency; the starch content in Gastrodia elata is about 14.5%, and the convertible and utilized substrate is relatively small, and is preferentially used for the growth and reproduction of the strain during the fermentation process. Therefore, the present invention adds coix seed paste to ferment with Gastrodia elata at the same time to increase the available substrate. Coix seed fermentation can also obtain organic acids such as fumaric acid, thereby improving the flavor of Gastrodia elata; Bacillus subtilis and Monascus are inoculated for synergistic fermentation, and enzymes such as protease, amylase and cellulase produced by the fermentation metabolism of the two bacteria degrade substances such as cellulose and lignin in the cell wall of Gastrodia elata, thereby increasing the active ingredients in Gastrodia elata. On the other hand, the bitter amino acids in Gastrodia elata are free amino acids, and alcohol compounds are generated through decarboxylation, deamination and other reactions during the fermentation process. Fermentation also generates other esters and phenolic compounds, and the content of aldehyde compounds (one of the peculiar smells) is significantly reduced, thereby improving the flavor of Gastrodia elata; finally, solid-state fermented freeze-dried Gastrodia elata with higher active substances is obtained by freeze-drying.

[0020] The second embodiment of the present invention provides a method for preparing the above-mentioned solid-state fermentation freeze-dried Gastrodia elata, comprising the following steps: The fresh gastrodia elata is washed, cut into gastrodia elata slices with a thickness of 0.3-0.5 cm, and freeze-dried for the first time to obtain pre-treated gastrodia elata; Adding coix seed paste to the pretreated gastrodia elata, sterilizing at high temperature to obtain a mixture to be fermented; The composite strain is inoculated into the mixture to be fermented, the solid and liquid are separated after fermentation, and the solid Gastrodia elata slices are freeze-dried for a second time to obtain solid-state fermented freeze-dried Gastrodia elata.

[0021] In this embodiment, fresh Gastrodia elata is washed, sliced ​​and freeze-dried. Slicing increases the contact area of ​​Gastrodia elata, accelerates the loss of water, and is beneficial to improving the efficiency of freeze-drying. The water content in Gastrodia elata is about 25-35%, and the water content after the first freeze-drying is about 15-18%. Part of the water in Gastrodia elata is removed, but it is not completely dried, which is beneficial to material exchange with the liquid substrate during the fermentation process and improves the fermentation efficiency of the strain; Job's tears slurry is added and fermented with Gastrodia elata at the same time to increase the available substrate, so that the strain can grow and reproduce rapidly in the early stage of fermentation, thereby improving the fermentation efficiency; the composite strain fermentation metabolism produces amylase, protease and pectinase, etc., and Bacillus subtilis can also produce cellulase. The combined action of multiple enzymes degrades the macromolecular components in Gastrodia elata and releases active ingredients such as polysaccharides and flavonoids. The saccharifying enzyme produced by Monascus supplements the carbon source during the fermentation process and shortens the fermentation time; the fermented Gastrodia elata slices are free of water through the second freeze-drying, which reduces the loss of active ingredients, and finally obtains dry solid-state fermented freeze-dried Gastrodia elata slices.

[0022] In some specific embodiments, the first freeze drying is to pre-cool the Gastrodia elata slices at -18°C for 1-1.5 hours, freeze them at -50°C for 3-4 hours, and then dry them at 40-50Pa and -25-10°C for 5-6 hours. The first freeze drying time of the present invention is relatively short, and part of the water in the Gastrodia elata can be removed.

[0023] In some specific embodiments, the mass ratio of the pretreated Gastrodia elata to coix seed slurry is 1:(0.5-1), and the concentration of the coix seed slurry is 5-10%; the polysaccharide content of Gastrodia elata increases after fermentation, but Gastrodia elata polysaccharide is easily soluble in water, so the quality of the added coix seed slurry needs to be controlled. The present invention controls the mass ratio of Gastrodia elata to coix seed slurry to be 1:(0.5-1). Under this ratio, the fermentation effect is good and the loss of Gastrodia elata polysaccharide can be reduced. The concentration of coix seed slurry ensures the growth and reproduction of the composite strain and can ferment to produce a special flavor, but has little effect on the main flavor of Gastrodia elata.

[0024] In some specific embodiments, the composite bacteria are Bacillus subtilis and Monascus, with a mass ratio of 1: (2-3). In some prior arts, exogenous amylase, cellulase and the like are first added to hydrolyze Gastrodia elata, and the converted and released substrate is then inoculated and fermented to improve the fermentation efficiency. However, the cost of exogenous enzymes is high and the process steps are increased. The present invention selects Bacillus subtilis and Monascus that can produce multiple enzymes as composite bacteria. First, the nutrients of Job's tears slurry after high-temperature saccharification are used to grow and reproduce and produce amylase, protease, cellulase and the like. These enzymes dynamically release active substances during the fermentation process to meet the fermentation requirements of Gastrodia elata, and the saccharifying enzyme and maltase produced by Monascus can continue to accumulate sugar content in the later stage of fermentation, which has a positive effect on improving the flavor of Gastrodia elata.

[0025] It can be seen that in this embodiment, slicing Gastrodia elata increases the effective area, the first freeze-drying accelerates the exchange of solid-liquid substances in the fermentation process, the addition of coix seed paste increases the fermentation substrate and is beneficial to the rapid reproduction of the bacteria, and the addition of saccharifying enzymes produced by Monascus fermentation allows the fermentation to continue. Multiple technical means support each other and ultimately improve the fermentation efficiency, shorten the fermentation time, and control the fermentation time within 5 days, ultimately obtaining solid-state fermented freeze-dried Gastrodia elata with increased Gastrodia elata polysaccharide content.

[0026] It should be noted that the high temperature sterilization of the present invention is a commonly used sterilization process in the art, that is, sterilization at 121°C for 20 minutes. The coix seed paste of the present invention is obtained by mixing coix seed powder with water, and the coix seed powder is obtained by ultrafine grinding of coix seed.

[0027] The third embodiment of the present invention provides the application of the solid-state fermented freeze-dried Gastrodia elata in food. The solid-state fermented freeze-dried Gastrodia elata obtained by the present invention is a dry flaky Gastrodia elata with low moisture content and long shelf life, and can be used as a raw material or additive in the processing of the food industry.

[0028] It can be understood that, in addition to the above special instructions, other parameters of the embodiments of the present application are obtainable by technicians in this field through experiments based on general experience or actual needs. This application does not make any special limitations, but only provides some preferred embodiments. For example, in some preferred embodiments, the inoculation amount of the composite strain is 4-6%; in some preferred embodiments, the fermentation is aerobic fermentation at 28-30°C for 3-5 days; in some preferred embodiments, the second freeze-drying is to adjust the vacuum degree to 20-25Pa and the temperature to 15-25°C after the first freeze-drying of the fermented Gastrodia elata, and continue freezing for 12-14 hours.

[0029] The following will disclose specific embodiments for implementing the present application, as well as corresponding comparative examples to demonstrate the relevant technical effects of the present application.

[0030] Example 1 Preparation of solid-state fermentation freeze-dried Gastrodia elata Pretreatment: Wash the fresh Gastrodia elata, cut it into 0.4 cm thick Gastrodia elata slices, precool the Gastrodia elata slices at -18°C for 75 min, freeze them at -50°C for 3.5 h, and dry them at 45 Pa and 4°C for 5.5 h to obtain pretreated Gastrodia elata; Fermentation: Add an equal mass of coix seed paste (concentration of 8%) to the pretreated Gastrodia elata, sterilize at 121°C for 20 min to obtain the mixture to be fermented, inoculate 5% of the composite bacteria (Bacillus subtilis: Monascus = 1:2.5), ferment aerobically at 28°C for 4 days, separate the solid and liquid after fermentation, precool the solid Gastrodia elata slices at -18°C for 75 min, freeze them at -50°C for 3.5 h, dry them at 45 Pa and 4°C for 5.5 h, adjust the vacuum degree to 25 Pa and the temperature to 20°C, and continue freezing for 13 h to obtain solid-state fermented freeze-dried Gastrodia elata.

[0031] Example 2 Preparation of solid-state fermentation freeze-dried Gastrodia elata Pretreatment: Wash the fresh Gastrodia elata, cut it into 0.5 cm thick Gastrodia elata slices, precool the Gastrodia elata slices at -18°C for 1.5 hours, freeze them at -50°C for 4 hours, and dry them at 50 Pa and 10°C for 6 hours to obtain pretreated Gastrodia elata; Fermentation: Add 80% of the mass of coix seed paste (concentration of 5%) to the pretreated Gastrodia elata, sterilize at 121°C for 20 min to obtain the mixture to be fermented, inoculate 6% of the composite bacteria (Bacillus subtilis: Monascus = 1:2), ferment aerobically at 30°C for 3 days, separate the solid and liquid after fermentation, precool the solid Gastrodia elata slices at -18°C for 1.5 h, then freeze at -50°C for 4 h, and then dry at 50 Pa and 10°C for 6 h. Adjust the vacuum degree to 20 Pa and the temperature to 25°C, and continue freezing for 12 h to obtain solid-state fermented freeze-dried Gastrodia elata.

[0032] Example 3 Preparation of solid-state fermentation freeze-dried Gastrodia elata Pretreatment: Wash the fresh Gastrodia elata, cut it into 0.3 cm thick Gastrodia elata slices, precool the Gastrodia elata slices at -18°C for 1 hour, freeze them at -50°C for 3 hours, and dry them at 40 Pa and -25°C for 5 hours to obtain pretreated Gastrodia elata; Fermentation: Add 50% of the mass of coix seed paste (concentration of 10%) to the pretreated Gastrodia elata, sterilize at 121°C for 20 min to obtain the mixture to be fermented, inoculate 4% of the composite bacteria (Bacillus subtilis: Monascus = 1:3), ferment aerobically at 28°C for 5 days, separate the solid and liquid after fermentation, precool the solid Gastrodia elata slices at -18°C for 1 h, then freeze at -50°C for 3 h, and then dry at 40 Pa and -25°C for 5 h, adjust the vacuum degree to 25 Pa and the temperature to 15°C, and continue freezing for 14 h to obtain solid-state fermented freeze-dried Gastrodia elata.

[0033] Comparative Example 1 The preparation method is the same as that in Example 1, the difference is that the cutting of Gastrodia elata is omitted, and the whole Gastrodia elata is freeze-dried. At the same time, the process of the first freeze-drying is adjusted to control the moisture content of the whole Gastrodia elata after the first freeze-drying to be the same as that in Example 1.

[0034] Comparative Example 2 The preparation method is the same as that in Example 1, except that the first freeze-drying is omitted, and the fresh Gastrodia elata is cut and directly added to coix seed paste for high temperature sterilization.

[0035] Comparative Example 3 The preparation method is the same as that of Example 1, except that the coix seed paste is replaced by pure water.

[0036] Comparative Example 4 The preparation method is the same as that in Example 1, except that the inoculation of Monascus is omitted.

[0037] Comparative Example 5 The fresh Gastrodia elata is sliced ​​and freeze-dried.

[0038] Test Example 1 Determination of Gastrodia elata polysaccharide content The gastrodia samples of Examples 1-3 and Comparative Examples 1-5 were weighed respectively, crushed and passed through a 60-mesh sieve, 5.0 g of the sample was taken into a round-bottom flask, and petroleum ether with a boiling range was added according to a solid-liquid ratio of 1:10, refluxed twice, each time for 2 hours, and evaporated; then 80% ethanol was added according to a solid-liquid ratio of 1:10, refluxed twice, each time for 2 hours, and evaporated; the gastrodia extract with a water-to-solid ratio of 30:1 was placed at 70°C for water extraction twice, and the water extraction time was 2 hours each time; then filtered with double gauze, the filtrate was combined and collected, and then centrifuged at a speed of 4000 r / min for 10 min, the supernatant was collected, and its total volume was measured, which was the total sugar extract, diluted to a certain multiple, and its total sugar content was measured by the phenol concentrated sulfuric acid method.

[0039] Take the above total sugar extract, add 1 / 4 Sevage reagent (chloroform: n-butanol is 4: 1), shake vigorously for 15 minutes, let it stand, discard the lower middle layer, repeat 2-3 times, centrifuge the upper layer at 4000 r / min for 2 minutes, discard the precipitate; add anhydrous ethanol, place it in a refrigerator at 4 ℃, overnight, and then centrifuge it at 4000 r / min for 5 minutes. Wash the precipitate with anhydrous ethanol, dissolve it, evaporate the ethanol, add distilled water to the dialysis bag and dialyze it for 72 hours. Rinse it with a stream of tap water on the first day, and rinse it with distilled water from the second to the third day. Change the water once every 5 hours. Collect the liquid in the dialysis bag, make it up to 40 mL for use, dilute it to a certain multiple, measure the content of crude polysaccharides by phenol concentrated sulfuric acid method, and calculate the content of crude polysaccharides in total sugars. The test results are shown in Table 1.

[0040] As can be seen from Table 1, the content of Gastrodia elata polysaccharide in the solid-state fermentation freeze-dried Gastrodia elata of Examples 1-3 all exceeded 28%, which was significantly higher than that of Comparative Example 5 (direct drying), indicating that the technical solution of the present invention is conducive to releasing and converting more active ingredients in Gastrodia elata; compared with Example 1, Comparative Example 1 may be due to the slow rate of material exchange of the whole Gastrodia elata during the fermentation process and the short fermentation time, resulting in poor fermentation effect and low conversion rate of Gastrodia elata polysaccharide; Comparative Example 2 canceled the freeze-drying pretreatment of Gastrodia elata, and the process of Gastrodia elata without rehydration during the fermentation process slowed down the rate of solid-liquid material exchange, and the fermentation time was short, and the accumulation of Gastrodia elata polysaccharide was insufficient; Comparative Example 3 did not add additional fermentation substrate, resulting in reduced fermentation efficiency, thereby affecting the accumulation of Gastrodia elata polysaccharide; Comparative Example 4 only inoculated a single strain for fermentation, the fermentation efficiency was reduced, and the fermentation time was short, affecting the accumulation of Gastrodia elata polysaccharide. In summary, it can be seen that the technical solution of the present application shortens the fermentation time and accelerates the accumulation of Gastrodia elata polysaccharide by improving the fermentation efficiency.

[0041] Table 1 Determination results of Gastrodia elata polysaccharide .

[0042] Experimental Example 2 Principal Component Analysis of Gastrodia elata According to the requirements of the standard content determination item of Gastrodia elata in the 2020 edition of the Chinese Pharmacopoeia, the total amount of gastrodin and p-hydroxybenzyl alcohol in Gastrodia elata should not be less than 0.25% calculated on the basis of the dry product. In this embodiment, the contents of gastrodin and p-hydroxybenzyl alcohol were determined by high performance liquid chromatography for the Gastrodia elata of Example 1 and Comparative Example 5, respectively. 1.000 g of Gastrodia elata sample was extracted with 40 mL of 60% ethanol at 90 ° C for 1 hour, and then filtered with a 0.22 μm organic filter membrane and then determined by HPLC. HPLC conditions: The chromatographic column is Thermo BDS C18 (4.6 mm×150 mm, 5 μm); the mobile phase is acetonitrile-0.1% H3PO4 solution (3:97); the flow rate is 0.1 mL / min; the detection wavelength is 220 nm; the column temperature is 25 ° C; and the injection is 10 μL. The experimental results are shown in Table 2.

[0043] It can be seen from Table 2 that after being processed by the technical scheme of the present invention, the content of the main components in the solid-state fermented freeze-dried Gastrodia elata is significantly improved, and the efficacy of Gastrodia elata is not affected. The solid-state fermented freeze-dried Gastrodia elata of the present invention meets the quality standards of Gastrodia elata.

[0044] Table 2 Results of determination of main components of Gastrodia elata .

[0045] Test Example 3 Sensory Test Sensory evaluation test. 30 professional food testers with no abnormal taste and smell were selected to evaluate the bitterness and odor of the Gastrodia elata samples of Examples 1-3 and Comparative Examples 1-5 by tasting and smelling, and the results were recorded: "-" indicates that the bitterness / odor is light or absent; "+" indicates that there is obvious bitterness / odor; "++" indicates that the bitterness / odor is strong or unacceptable. The test results are shown in Table 3.

[0046] It can be seen from Table 3 that the solid-state fermented freeze-dried Gastrodia elata of Examples 1-3 have no obvious bitterness and odor, while Comparative Examples 1-4 all show obvious bitterness and odor. It can be seen that the technical solution of adding coix lacryma-jobi slurry to inoculate Bacillus subtilis and Monascus for fermentation can effectively improve the bitterness and odor of Gastrodia elata.

[0047] Table 3 Sensory evaluation test results .

[0048] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A solid-state fermented freeze-dried Gastrodia elata, characterized in that: The product is prepared by freeze-drying fresh gastrodia elata, adding coix seed paste, inoculating Bacillus subtilis and Monascus purpureus, fermenting, and freeze-drying again.

2. The method for preparing solid-state fermented freeze-dried Gastrodia elata according to claim 1, characterized in that: The steps include: The fresh gastrodia elata is washed, cut into gastrodia elata slices with a thickness of 0.3-0.5 cm, and freeze-dried for the first time to obtain pre-treated gastrodia elata; Adding coix seed paste to the pretreated gastrodia elata, sterilizing at high temperature to obtain a mixture to be fermented; The composite strain is inoculated into the mixture to be fermented, the solid and liquid are separated after fermentation, and the solid Gastrodia elata slices are freeze-dried for a second time to obtain solid-state fermented freeze-dried Gastrodia elata.

3. The preparation method according to claim 2, characterized in that: The first freeze drying is to pre-cool the Gastrodia elata slices at -18°C for 1-1.5 hours, freeze them at -50°C for 3-4 hours, and then dry them at 40-50Pa and -25-10°C for 5-6 hours.

4. The preparation method according to claim 2, characterized in that: The mass ratio of the pretreated gastrodia elata to coix seed slurry is 1:(0.5-1), and the concentration of the coix seed slurry is 5-10%.

5. The preparation method according to claim 2, characterized in that: The composite bacteria are Bacillus subtilis and Monascus, with a mass ratio of 1: (2-3).

6. The preparation method according to claim 2, characterized in that: The inoculation amount of the composite bacteria is 4-6%.

7. The preparation method according to claim 2, characterized in that: The fermentation is carried out aerobic fermentation at 28-30°C for 3-5 days.

8. The preparation method according to claim 2, characterized in that: The second freeze drying is to adjust the vacuum degree to 20-25 Pa and the temperature to 15-25° C. after the first freeze drying of the fermented Gastrodia elata, and continue freezing for 12-14 hours.

9. The solid-state fermentation freeze-dried Gastrodia elata prepared according to any one of the preparation methods of claims 2-8.

10. Use of the solid-state fermented freeze-dried Gastrodia elata according to claim 1 or 9 in food.