Sterilization method and application of sporoderm-broken ganoderma lucidum spore powder

Abstract

The invention provides a sterilization method and application of sporoderm-broken ganoderma lucidum spore powder, and belongs to the technical field of health food and medicine processing. The sterilization method comprises the following steps: pretreating wall-broken ganoderma lucidum spore powder through drying and low-temperature ultrasound; after sealing and packaging, carrying out two-section type hot-pressing sterilization treatment; and after sterilization, supercritical CO2 treatment is adopted for post-treatment. According to the invention, low-temperature vacuum drying is matched with low-temperature ultrasonic treatment to realize moisture control and uniform distribution; after sealed packaging, two-section gradient hot-pressing sterilization is adopted, and sterilization thoroughness and thermosensitive component protection are both considered; and finally, residual microorganisms are complementarily killed through supercritical CO2 aftertreatment, oxidized grease is dissolved and removed to reduce the acid value and the peroxide value, meanwhile, oxygen is replaced to delay subsequent oxidation, and no solvent is left. The method is simple and convenient to operate, feasible in industrialization and suitable for processing and production of high-quality health-care foods and medicines.

Description

Technical Field

[0001] This invention belongs to the field of health food and pharmaceutical processing technology, and particularly relates to a sterilization method and application of broken-cell wall Ganoderma lucidum spore powder. Background Technology

[0002] Ganoderma lucidum spore powder, as the core active ingredient carrier of Ganoderma lucidum, is rich in polysaccharides, triterpenes, sterols, and other effective substances. However, the active ingredients exposed after cell wall disruption are easily affected by the sterilization process, and the small particles (5-8μm) are prone to agglomeration, leading to uneven moisture distribution and posing a challenge to sterilization. Existing sterilization technologies have many shortcomings: chemical sterilization easily leaves solvent residues, affecting food safety; irradiation sterilization equipment requires large investments, its safety is questionable, and the risk of residual radiation substances is still inconclusive; dry heat sterilization has high temperatures and long times, leading to rancidity of oils and inactivation of effective ingredients; traditional moist heat sterilization (such as constant temperature high-pressure steam) has strong penetrating power, but a single temperature parameter is difficult to balance "sterilization thoroughness" and "component protection," easily resulting in local sterilization dead zones or excessive damage to heat-sensitive components; some packaging sterilization processes require high moisture conditions, requiring additional drying after sterilization, increasing the process and further damaging the components.

[0003] CN109043300A discloses a sterilization method for broken-cell wall Ganoderma lucidum spore powder, but it is not optimized for the characteristics of broken-cell wall Ganoderma lucidum spore powder, such as "extremely small particle size, high oil content, and easy agglomeration." Direct application of this method results in incomplete sterilization due to uneven moisture content and component loss due to excessively long high-temperature duration. Therefore, developing a sterilization method for broken-cell wall Ganoderma lucidum spore powder that balances sterilization effectiveness, component retention rate, and industrial feasibility has become a pressing technical challenge in this field. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a sterilization method and application for broken-cell wall Ganoderma lucidum spore powder, to improve the sterilization effect and ensure that the quality and natural components of broken-cell wall Ganoderma lucidum spore powder are not destroyed.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for sterilizing broken-cell wall Ganoderma lucidum spore powder includes the following steps: Pretreatment: The broken-cell wall Ganoderma lucidum spore powder is dried to a moisture content of 5.5-7.5% and then subjected to low-temperature ultrasonic treatment until the moisture uniformity is ≥95%; Sterilization process: The broken-cell wall Ganoderma lucidum spore powder is sealed and packaged with a high-temperature resistant film and then subjected to heat-press sterilization. The heat-press sterilization is carried out in two stages: the first stage temperature is 105~110℃ and the time is 15~20min, and the second stage temperature is 115~118℃ and the time is 25~30min. Post-treatment: After sterilization, supercritical CO2 treatment is carried out at a temperature of 38~42℃, a pressure of 20~25MPa, and a time of 35~45min. After the treatment, the pressure is slowly depressurized to atmospheric pressure at a rate of 0.3~0.6MPa per minute.

[0006] Preferably, the drying is performed using low-temperature vacuum drying, with a temperature of 39~41℃, a vacuum degree of -0.08~-0.09MPa, and a time of 2~3h.

[0007] Preferably, the low-temperature ultrasonic treatment is performed at a frequency of 25-30 kHz, a temperature of 33-37°C, and a duration of 10-15 min, while nitrogen gas is introduced at a rate of 0.5-1 L / min.

[0008] Preferably, the high-temperature resistant membrane is an oriented polypropylene microporous composite membrane, consisting of an outer layer, a middle layer, and an inner layer. The outer layer is biaxially oriented polypropylene, the middle layer is microporous polypropylene, and the inner layer is cast polypropylene, with a total thickness of 30~40μm.

[0009] More preferably, the outer biaxially oriented polypropylene layer of the high-temperature resistant film has a thickness of 12 μm, the middle microporous polypropylene layer has a thickness of 10~15 μm and a micropore diameter of 0.1~0.5 μm, and the inner cast polypropylene layer has a thickness of 8~13 μm.

[0010] Preferably, the specific operation of the sealed packaging is as follows: the pretreated spore powder is put into a high-temperature resistant film, vacuumed to -0.08~-0.09MPa, kept for 3~5 minutes to exhaust the air, and then heat-sealed. The thickness of the material after sealing is 20~40mm.

[0011] Preferably, the autoclaving is performed using a shelf with breathable partitions, and the sealed packaging is placed in a single layer with a spacing of ≥5cm between packages.

[0012] Preferably, the CO2 purity of the supercritical CO2 treatment is ≥99.99%, and the CO2 flow rate is 10~15L / h per kg of spore powder.

[0013] This invention also provides sterilized and cell-wall-broken Ganoderma lucidum spore powder prepared by the above method and its application in the preparation of health foods or medicines.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention controls the moisture content of broken Ganoderma lucidum spore powder to 5.5-7.5% through low-temperature vacuum drying, which ensures the amount of steam generated during hot pressing to enhance penetration, while avoiding excessive moisture leading to oil oxidation. Combined with low-temperature ultrasonic treatment, the cavitation effect is used to break up agglomerated particles, making the moisture uniformity ≥95%, eliminating sterilization dead zones, and laying the foundation for subsequent sterilization.

[0015] This invention employs a two-stage autoclaving process. The first stage uses low temperature and low pressure to kill heat-sensitive microorganisms, reducing the subsequent high-temperature load. The second stage uses high temperature and high pressure to kill heat-resistant spores, and the total high-temperature time is shortened. Compared with constant temperature autoclaving, the retention rate of active ingredients is increased by 2-3%, and the lipid oxidation indicators (acid value, peroxide value) are reduced by 10-15%.

[0016] This invention further employs supercritical CO2 post-treatment after sterilization to kill residual microorganisms, dissolve and remove oxidized oils to reduce acid value and peroxide value, and simultaneously replaces oxygen to reduce the rate of oil oxidation during storage. With no solvent residue, the final product has a total bacterial count ≤5 CFU / g, no detectable heat-resistant spores, and meets quality requirements even after 30 days of accelerated storage, with no solvent residue and higher safety. Detailed Implementation

[0017] This invention discloses a sterilization method for broken-cell wall Ganoderma lucidum spore powder, comprising the following steps: (1) Pretreatment: The broken Ganoderma lucidum spore powder is dried to a moisture content of 5.5-7.5% and then subjected to low-temperature ultrasonic treatment until the moisture uniformity is ≥95%.

[0018] The moisture content of broken-cell wall Ganoderma lucidum spore powder affects the subsequent hot-press sterilization effect. This invention controls the moisture content of broken-cell wall Ganoderma lucidum spore powder to 5.5-7.5% before sterilization, which can provide sufficient steam for the hot-pressing process, enhance heat penetration efficiency, and avoid excessive moisture leading to oil oxidation and deterioration after sterilization. Furthermore, low-temperature ultrasonic treatment is used to make the moisture uniformity of broken-cell wall Ganoderma lucidum spore powder ≥95%, eliminating moisture accumulation caused by agglomerated particles and avoiding incomplete local sterilization.

[0019] In this invention, it is preferred that the broken-cell wall Ganoderma lucidum spore powder is dried to a moisture content of 6%; it is further preferred that the drying is carried out by low-temperature vacuum drying, with a temperature of 39~41℃, a vacuum degree of -0.08~-0.09MPa, and a time of 2~3h; it is even more preferred that the low-temperature vacuum drying temperature is 40℃, a vacuum degree of -0.085MPa, and a time of 2.5h.

[0020] In this invention, the preferred frequency of the low-temperature ultrasonic treatment is 25~30kHz, more preferably 28kHz; the preferred temperature is 33~37℃, more preferably 35℃; the preferred time is 10~15min, more preferably 12min; nitrogen gas is preferably introduced simultaneously with the low-temperature ultrasonic treatment to prevent the oxidation of unsaturated fatty acids in the spore powder during the ultrasonic process; and more preferably, high-purity nitrogen gas with a purity ≥99.9% is continuously introduced into the processor through a microporous gas distributor located at the bottom of the container at a flow rate of 0.5~1.0L / min·kg (based on the mass of spore powder) to ensure that the nitrogen atmosphere uniformly covers the material and effectively removes and isolates oxygen.

[0021] (2) Sterilization treatment: The broken Ganoderma lucidum spore powder is sealed and packaged with a high temperature resistant film and then subjected to heat-press sterilization treatment; the heat-press sterilization is carried out in two stages, with the first stage temperature being 105~110℃ and the time being 15~20min, and the second stage temperature being 115~118℃ and the time being 25~30min.

[0022] Autoclaving utilizes the strong penetrating power and high latent heat of steam to kill microorganisms. This invention employs a two-stage autoclaving process. The first stage has a lower temperature, which can quickly kill heat-sensitive microorganisms such as bacterial vegetative cells without damaging the components. The second stage of high-temperature sterilization is shortened, ensuring that heat-resistant spores are completely killed while reducing the damage of heat-sensitive components such as polysaccharides and triterpenes caused by high temperatures.

[0023] In this invention, the preferred high-temperature resistant membrane is an oriented polypropylene microporous composite membrane, consisting of an outer layer, a middle layer, and an inner layer. The outer layer is biaxially oriented polypropylene, providing mechanical strength and printability. The middle layer is microporous polypropylene with a uniform microporous structure (pore size 0.1~0.5μm). This structure allows post-processing supercritical CO2 gas to penetrate the entire membrane layer and contact the spore powder, while effectively blocking bacteria. The inner layer is cast polypropylene as a heat-sealing layer, which itself has a certain degree of air permeability, and together with the middle layer, allows supercritical CO2 to penetrate. The total thickness is 30~40μm. More preferably, the outer biaxially oriented polypropylene layer has a thickness of 12μm, the middle microporous polypropylene layer has a thickness of 10~15μm with a micropore size of 0.1~0.5μm, and the inner cast polypropylene layer has a thickness of 8~13μm.

[0024] In this invention, the preferred specific operation of the sealed packaging is as follows: the pretreated spore powder is loaded into a high-temperature resistant film, vacuumed to -0.08~-0.09MPa, kept for 3~5 minutes to exhaust the air, and then heat-sealed. The thickness of the material after sealing is 20~40mm; more preferably, the thickness of the material is 30mm.

[0025] In this invention, it is preferred that the first stage is autoclaving at 108°C for 18 minutes and the second stage is autoclaving at 116°C for 28 minutes.

[0026] In this invention, it is preferred that autoclaving is performed using a shelf with breathable partitions, and that sealed packaging is placed in a single layer with a spacing of ≥5cm between packages.

[0027] In this invention, it is preferred that after sterilization is completed and the material is discharged, the material is cooled to below 40°C at a cooling rate of 1~3°C / min; more preferably, the cooling rate is 2°C / min.

[0028] (3) Post-treatment: After sterilization, supercritical CO2 treatment is carried out at a temperature of 38~42℃, a pressure of 20~25MPa, and a time of 35~45min.

[0029] After sterilization, supercritical CO2 treatment is performed. The strong permeability of CO2 in its supercritical state allows it to penetrate the packaging film and contact the spore powder, further killing any heat-resistant spores that may remain after hot pressing. Simultaneously, it dissolves and removes small amounts of oxidized and deteriorated oils from the spore powder (the dissolved oils may be temporarily unevenly distributed, but will naturally redistribute themselves after standing), reducing the acid value and peroxide value. After supercritical CO2 treatment, slow depressurization is necessary: ​​depressurization should be performed at a rate of 0.3~0.6 MPa per minute to prevent the CO2 from rapidly expanding into gas from the supercritical state, which could cause the packaging film to rupture. Furthermore, supercritical CO2 can replace residual air (especially oxygen) inside the packaging, creating a low-oxygen environment that effectively slows down the oxidation rate of oils during storage. The CO2 evaporates naturally without residue, thus significantly extending the product's shelf life.

[0030] In this invention, the preferred supercritical CO2 treatment temperature is 40°C, the pressure is 22 MPa, and the time is 40 min. After the treatment, the product is slowly depressurized as described above; more preferably, after depressurization, the product is left to stand at room temperature for 2-4 hours to allow any small amount of oil components that may have migrated due to CO2 treatment to redistribute evenly in the spore powder matrix, thus obtaining the final sterilized and broken-cell wall Ganoderma lucidum spore powder product.

[0031] In this invention, the CO2 purity of the supercritical CO2 treatment is preferably ≥99.99%, and the CO2 flow rate is 10~15L / h per kg of spore powder.

[0032] This invention also provides sterilized and cell-wall-broken Ganoderma lucidum spore powder prepared by the above method and its application in the preparation of health foods or medicines, including but not limited to the preparation of capsules, tablets, etc.

[0033] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1 A sterilization method for broken-cell wall Ganoderma lucidum spore powder, the steps of which are as follows: (1) Pretreatment: Take the broken Ganoderma lucidum spore powder with an initial cell wall breakage rate of 95.2%, and dry it for 2.5 h at 40℃ and vacuum degree of -0.085MPa using a low temperature vacuum dryer to adjust the moisture content to 6.5%; then put it into a low temperature ultrasonic cleaner and treat it for 12 min at a frequency of 28kHz and a temperature of 35℃. At the same time, nitrogen gas with a purity of ≥99.9% is introduced through a microporous gas distributor set at the bottom of the container at a flow rate of 0.8L / min·kg (based on the mass of spore powder). The moisture uniformity after treatment is 97%.

[0035] (2) Sterilization treatment: A 35μm thick oriented polypropylene microporous composite membrane was used. The pretreated spore powder was loaded into the membrane, and the vacuum was drawn to -0.085MPa. The air was exhausted after 4min. The membrane was then heat-sealed (heat sealing temperature 180℃, sealing width 6mm). The thickness of the material after sealing was 30mm. The sealed package was placed in a pressure steam sterilizer with a breathable partition. The packages were arranged in a single layer with a spacing of 5cm. The sterilization was carried out according to two-stage parameters: the first stage was sterilized at 108℃ for 18min, and the second stage was sterilized at 116℃ for 28min.

[0036] (3) Post-processing: After sterilization and discharge, the spore powder is cooled to 40°C at a cooling rate of 2°C / min. The packaged spore powder is then sent to a supercritical CO2 treatment device. Food-grade CO2 with a purity of 99.99% is introduced and treated at a flow rate of 12L / h per kg of spore powder for 40 min at 40°C and 22MPa. After treatment, the pressure is slowly reduced to atmospheric pressure at a rate of 0.5MPa per minute and allowed to stand at room temperature for 2-4 h to obtain sterilized broken Ganoderma lucidum spore powder.

[0037] Example 2 A sterilization method for broken-cell wall Ganoderma lucidum spore powder, the steps of which are as follows: (1) Pretreatment: Take the broken Ganoderma lucidum spore powder with an initial cell wall breakage rate of 95.2% and dry it for 3 hours at 39℃ and -0.08MPa using a low-temperature vacuum dryer to adjust the moisture content to 5.5%; then put it into a low-temperature ultrasonic cleaner and treat it for 15 minutes at a frequency of 25kHz and a temperature of 33℃. At the same time, nitrogen gas with a purity of ≥99.9% is introduced through a microporous gas distributor set at the bottom of the container at a flow rate of 0.5L / min·kg (based on the mass of spore powder). The moisture uniformity after treatment is 95%.

[0038] (2) Sterilization treatment: A 30μm thick oriented polypropylene microporous composite membrane was used. The pretreated spore powder was loaded into the membrane, and the vacuum was drawn to -0.08MPa. The air was exhausted after 3 minutes. The membrane was then heat-sealed (heat sealing temperature 170℃, sealing width 5mm). The thickness of the material after sealing was 25mm. The sealed package was placed in a pressure steam sterilizer with a breathable partition. The packages were placed in a single layer with a spacing of 5cm. The sterilization was carried out according to two-stage parameters: the first stage was sterilized at 105℃ for 20 minutes, and the second stage was sterilized at 115℃ for 30 minutes.

[0039] (3) Post-processing: After sterilization and discharge, the spore powder is cooled to 38°C at a cooling rate of 1°C / min. The packaged spore powder is then sent into a supercritical CO2 treatment device. Food-grade CO2 with a purity of 99.99% is introduced and treated at a flow rate of 10L / h per kg of spore powder for 45 minutes at 38°C and 20MPa. After the treatment, the pressure is slowly reduced to atmospheric pressure at a rate of 0.3MPa per minute and allowed to stand at room temperature for 2-4 hours to obtain sterilized broken Ganoderma lucidum spore powder.

[0040] (4) Example 3 A sterilization method for broken-cell wall Ganoderma lucidum spore powder, the steps of which are as follows: (1) Pretreatment: Take the broken Ganoderma lucidum spore powder with an initial cell wall breakage rate of 95.2%, and dry it for 2 hours at 41℃ and -0.09MPa vacuum in a low-temperature vacuum dryer to adjust the moisture content to 7.5%; then put it into a low-temperature ultrasonic cleaner and treat it for 10 minutes at a frequency of 30kHz and a temperature of 37℃. At the same time, nitrogen gas with a purity of ≥99.9% is introduced through a microporous gas distributor set at the bottom of the container at a flow rate of 1L / min·kg (based on the mass of spore powder). The moisture uniformity after treatment is 96%.

[0041] (2) Sterilization treatment: A 40μm thick oriented polypropylene microporous composite membrane was used. The pretreated spore powder was loaded into the membrane, and the vacuum was drawn to -0.09MPa. The air was exhausted after 5min. The membrane was then heat-sealed (heat sealing temperature 190℃, sealing width 7mm). The thickness of the material after sealing was 35mm. The sealed package was placed in a pressure steam sterilizer with a breathable partition. The packages were arranged in a single layer with a spacing of 5cm. The sterilization was carried out according to two-stage parameters: the first stage was sterilized at 110℃ for 15min, and the second stage was sterilized at 118℃ for 25min.

[0042] (3) Post-processing: After sterilization and discharge, the spore powder is cooled to 42°C at a cooling rate of 3°C / min. The packaged spore powder is then sent into a supercritical CO2 treatment device. Food-grade CO2 with a purity of 99.99% is introduced and treated at a flow rate of 15L / h per kg of spore powder for 35 min at 42°C and 25MPa. After treatment, the pressure is slowly reduced to atmospheric pressure at a rate of 0.6MPa per minute and allowed to stand at room temperature for 2-4 h to obtain sterilized broken Ganoderma lucidum spore powder.

[0043] Using broken-cell wall Ganoderma lucidum spore powder as raw material, experiments were conducted on heat-pressing sterilization method, pretreatment and post-treatment to study their effects on the sterilization effect of broken-cell wall Ganoderma lucidum spore powder.

[0044] 1. Test materials: (1) Broken Ganoderma lucidum spore powder: initial cell wall breakage rate 95.2%, initial total bacterial count 9.8×10 3CFU / g, mold and yeast 85 CFU / g, crude polysaccharide 1.6g / 100g, total triterpenes 3.2g / 100g, ergosterol 62mg / 100g.

[0045] (2) Reagents: food grade CO2 (purity 99.99%), glucose standard (analytical grade), oleanolic acid standard (analytical grade).

[0046] (3) Packaging material: Oriented polypropylene microporous composite film (outer layer biaxially oriented polypropylene with a thickness of 12μm, middle layer microporous polypropylene with a thickness of 13μm and a micropore diameter of 0.1~0.5μm, inner layer cast polypropylene with a thickness of 10μm).

[0047] 2. Test equipment Low-temperature vacuum dryer, low-temperature ultrasonic cleaner, pressure steam sterilizer, supercritical CO2 treatment equipment, microbial testing equipment (biosafety cabinet, constant temperature incubator) and physicochemical testing equipment (high performance liquid chromatograph, colorimeter, acid value analyzer).

[0048] Experimental Example 1 Effects of different autoclaving methods on the sterilization effect of broken-cell wall Ganoderma lucidum spore powder The broken-cell wall Ganoderma lucidum spore powder was sealed in packaging (packaging thickness 30mm), and control and experimental groups were set up and subjected to autoclaving (single layer spacing 5cm, sterilizer steam circulation rate 0.5m / s). Control group: Sterilized at a constant temperature of 115±1℃ for 40 min; Experimental group (two-stage): first stage sterilization at 108±1℃ for 18 min + second stage sterilization at 115±1℃ for 28 min.

[0049] After autoclaving, the total number of colonies and the number of heat-resistant spores, the total polysaccharide content (phenol-sulfuric acid method) and the total triterpenoid content (vanillin-glacial acetic acid method), the acid value (GB 5009.229-2016) and the peroxide value (GB 5009.227-2016), the color difference (CIELAB colorimeter system), and the odor score (blind evaluation by a 5-person sensory evaluation group, 1-5 points, 5 points: no odor, 1 point: obvious burnt smell) were measured.

[0050] As shown in Table 1, the two-stage autoclaving experimental group was significantly superior to the constant-temperature autoclaving control group in terms of sterilization effect, component retention, and sensory quality. The total bacterial count in the experimental group was only 8 CFU / g, and no heat-resistant spores were detected, while the total bacterial count in the control group was 42 CFU / g, with an occasional detection of 3 heat-resistant spores / g. In terms of component retention, the total polysaccharide and total triterpenoid contents in the experimental group were 1.59 g / 100g and 3.19 g / 100g, respectively, with retention rates of 99.4%, which were higher than the 96.9% and 97.8% of the control group. Among the lipid oxidation indicators, the acid value and peroxide value in the experimental group decreased by 13.4% and 14.8%, respectively, the color difference ΔE decreased by 41.7%, and the odor score increased by 49.9%, indicating that the two-stage autoclaving can effectively protect the active ingredients and reduce lipid oxidation while ensuring thorough sterilization.

[0051] Table 1. Effects of different autoclaving methods on the sterilization effect of broken-cell wall Ganoderma lucidum spore powder

[0052] Experimental Example 2 Effects of different pretreatments on the sterilization effect of Ganoderma lucidum spore powder The study investigated the effects of pretreatment conditions on the two-stage autoclaving effect by setting up two variables: different moisture contents (2.5%, 5.5%, 7.5%, and 10%) and with / without ultrasonic treatment (frequency 28 kHz, temperature 37 °C, time 12 min).

[0053] Moisture uniformity: Moisture content was measured at five points within the same package using a near-infrared moisture meter, and the maximum difference was calculated. Other indicators were the same as in Example 1.

[0054] As shown in Table 2, moisture content and ultrasonic treatment significantly affected sterilization efficiency, component retention, and moisture uniformity. Without ultrasonic treatment, moisture uniformity improved slightly with increasing moisture content, and the total bacterial count was generally higher in the ultrasonic-treated group. In the ultrasonic-treated group, moisture uniformity was ≤0.30%, indicating superior sterilization. The ultrasonic-treated groups with moisture contents of 5.5% and 7.5%+ performed best, with total bacterial counts of 6 CFU / g and 5 CFU / g, respectively. No heat-resistant spores were detected, and the retention rates of total polysaccharides and total triterpenes were ≥99.3%. At a moisture content of 2.5%, even with ultrasonic treatment, insufficient moisture resulted in poor heat penetration, leading to a total bacterial count of 18 CFU / g. At a moisture content of 10%, both acid value and peroxide value increased significantly regardless of ultrasonic treatment, indicating that excessive moisture easily triggers oil oxidation. In summary, a moisture content of 5.5–7.5%+ with ultrasonic treatment is the optimal combination for pretreatment.

[0055] Table 2. Effects of different pretreatments on the sterilization effect of Ganoderma lucidum spore powder.

[0056] Experimental Example 3 Effects of supercritical CO2 post-treatment on microbial control and lipid oxidation indices of Ganoderma lucidum spore powder Using a process of "6.5% moisture content + ultrasonic pretreatment + two-stage autoclaving" as the pre-process, an untreated group and a supercritical CO2 treated group (40℃, 22MPa, 40min, CO2 flow rate 12L / h, after treatment, the pressure was slowly depressurized to atmospheric pressure at a rate of 0.5MPa per minute) were set up to study the impact of post-treatment on product quality and long-term stability.

[0057] The test indicators include total bacterial count, accelerated test (stored at 37℃ and 75% relative humidity for 30 days) total bacterial count, acid value, accelerated test acid value, and solvent residue (gas chromatography).

[0058] As shown in Table 3, the sterilization thoroughness and long-term stability of the supercritical CO2 post-treatment group were significantly better than those of the untreated group. In the untreated group, 2 heat-resistant spores / g were occasionally detected; after 30 days of accelerated treatment, the total bacterial count rose to 48 CFU / g, and the acid value reached 3.82 mg / g (close to the exceeding threshold). In the supercritical CO2 treated group, no heat-resistant spores were detected; after 30 days of accelerated treatment, the total bacterial count was only 12 CFU / g, and the acid value was 3.01 mg / g, still meeting quality requirements. Furthermore, no solvent residue was detected. This indicates that supercritical CO2 post-treatment can effectively kill residual microorganisms and significantly reduce oil oxidation indicators (acid value) during the initial and storage processes. This is mainly due to its extraction and removal effect on oxidized oils and its oxygen-displacing effect to delay oxidation, thereby significantly improving the product's storage stability and expected to effectively extend the product's shelf life.

[0059] Table 3. Effects of supercritical CO2 post-treatment on Ganoderma lucidum spore powder.

[0060] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for sterilizing broken-cell wall Ganoderma lucidum spore powder, characterized in that, Includes the following steps: Pretreatment: The broken-cell wall Ganoderma lucidum spore powder is dried to a moisture content of 5.5-7.5% and then subjected to low-temperature ultrasonic treatment until the moisture uniformity is ≥95%; Sterilization process: The broken-cell wall Ganoderma lucidum spore powder is sealed and packaged with a high-temperature resistant film and then subjected to heat-press sterilization. The heat-press sterilization is carried out in two stages: the first stage temperature is 105~110℃ and the time is 15~20min, and the second stage temperature is 115~118℃ and the time is 25~30min. Post-treatment: After sterilization, supercritical CO2 treatment is carried out at a temperature of 38~42℃, a pressure of 20~25MPa, and a time of 35~45min. After the treatment, the pressure is slowly depressurized to atmospheric pressure at a rate of 0.3~0.6MPa per minute.

2. The sterilization method according to claim 1, characterized in that, The drying process employs low-temperature vacuum drying, with a temperature of 39~41℃, a vacuum degree of -0.08~-0.09MPa, and a time of 2~3 hours.

3. The sterilization method according to claim 1, characterized in that, The low-temperature ultrasonic treatment is performed at a frequency of 25-30 kHz, a temperature of 33-37 °C, and a duration of 10-15 min, while nitrogen gas is introduced at a rate of 0.5-1 L / min.

4. The sterilization method according to claim 1, characterized in that, The high-temperature resistant membrane is an oriented polypropylene microporous composite membrane, consisting of an outer layer, a middle layer, and an inner layer. The outer layer is biaxially oriented polypropylene, the middle layer is microporous polypropylene, and the inner layer is cast polypropylene, with a total thickness of 30~40μm.

5. The sterilization method according to claim 4, characterized in that, The outer biaxially oriented polypropylene layer of the high-temperature resistant film has a thickness of 12 μm, the middle microporous polypropylene layer has a thickness of 10~15 μm and a micropore diameter of 0.1~0.5 μm, and the inner cast polypropylene layer has a thickness of 8~13 μm.

6. The sterilization method according to claim 1, characterized in that, The specific operation of the sealed packaging is as follows: the pretreated spore powder is put into a high-temperature resistant film, vacuumed to -0.08~-0.09MPa, kept for 3~5 minutes to remove the air, and then heat-sealed. The thickness of the material after sealing is 20~40mm.

7. The sterilization method according to claim 1, characterized in that, The autoclaving sterilization process uses a shelf with breathable partitions, and the sealed packaging is placed in a single layer with a spacing of ≥5cm between packages.

8. The sterilization method according to claim 1, characterized in that, The CO2 purity of the supercritical CO2 treatment is ≥99.99%, and the CO2 flow rate is 10~15L / h per kg of spore powder.

9. Sterilized Ganoderma lucidum spore powder prepared by the method according to any one of claims 1 to 8.

10. The application of the method according to any one of claims 1 to 8 or the sterilized and cell-wall-broken Ganoderma lucidum spore powder according to claim 9 in the preparation of health food or medicine.

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