Fermentation method based on solid hydrogen storage material

Abstract

The invention discloses a fermentation method based on a solid hydrogen storage material, which comprises the following steps: S1, a pretreatment stage: pretreating a raw material to obtain a material to be fermented; s2, a fermentation stage: performing fermentation treatment on the to-be-fermented material; wherein a solid hydrogen storage material is added in the step S1 and / or the step S2; the solid hydrogen storage material comprises hydrogen storage particles and a porous base material, and the hydrogen storage particles are loaded on the porous base material. The fermentation method based on the solid hydrogen storage material can be applied to the fields of food fermentation industry, biological pharmacy and synthetic biology, agriculture, organic waste treatment and the like. According to the fermentation method, a solid hydrogen storage material is strategically used in the yellow wine fermentation process, so that the problems that gaseous hydrogen is easy to escape, unstable in concentration, limited in fermentation process and the like are solved, continuous and stable release of hydrogen is realized, and the fermentation environment is optimized.

Description

Technical Field

[0001] The present invention relates to the field of fermentation technology, and particularly to a fermentation method based on solid-state hydrogen storage materials. This fermentation method is particularly suitable for improving the quality of liquor products, especially for improving the quality of yellow rice wine. Background Art

[0002] In recent years, the biological regulatory effect of hydrogen has shown important value in the field of fermentation engineering. Research shows that hydrogen can not only optimize the fermentation microenvironment through selective antioxidant effects, but also participate in the regulation of the microbial metabolic network as an electron donor or signaling molecule, thereby inhibiting the proliferation of harmful bacteria, promoting the synthesis of target products and reducing the accumulation of by-products. In fermentation systems such as liquor, condiments, and dairy products, the intervention of hydrogen has been proven to significantly improve the flavor quality and safety of products, such as delaying lipid oxidation, protecting heat-sensitive active ingredients, and degrading potential risk substances such as ethyl carbamate. This characteristic makes hydrogen a new regulatory tool in the field of fermentation process optimization. For example, Patent CN107156566B shows that the introduction of hydrogen can significantly increase the content of 5-hydroxymethylfurfural and polyphenols in black date wine; Patent CN106635640A indicates that adding hydrogen during the fermentation process of strawberry fruit wine can significantly increase its iron content and absorption rate. These research results show that hydrogen plays an important role in improving the fermentation quality and nutritional value of liquor.

[0003] However, the traditional gaseous hydrogen application mode has inherent limitations in the fermentation scenario. The direct introduction of hydrogen or the addition of hydrogen-rich water is limited by the poor solubility and high diffusivity of hydrogen, making it difficult to form a stable concentration gradient in the liquid phase system. Although the nanobubble technology can temporarily increase the solubility of hydrogen, its preparation cost is high and the bubble stability is poor, making it difficult to meet the requirements of the entire fermentation process. The in-situ hydrogen production scheme by electrolyzing water can dynamically regulate the hydrogen supply, but it relies on complex equipment and there is a risk of electrode pollution. More critically, none of the above methods can achieve the precise matching of the hydrogen release rate and the microbial metabolic demand - there is insufficient hydrogen supply when a bacteriostatic environment needs to be quickly established in the early stage of fermentation, while there is a contradiction of premature hydrogen dissipation when a steady state needs to be maintained in the middle and late stages, resulting in a decrease in process controllability.

[0004] Huangjiu is a traditional national specialty in China and belongs to one of the three ancient fermented wines in the world. It is mainly brewed from glutinous rice and millet, with wheat koji as the saccharifying agent and yeast as the fermenting agent, and has a relatively low alcohol content. Huangjiu retains the nutrients and active substances produced during the fermentation process. In addition to ethanol and water, it also contains 21 kinds of amino acids, including 8 essential amino acids that the human body cannot synthesize on its own. The brewing process of Huangjiu depends on the action of beneficial microorganisms and related microbial communities. Enzymes such as protease and amylase degrade substances such as proteins and sugars in the substrate into small molecule nutrients during the fermentation process. With the progress of society, people's attention to health has gradually increased, especially the understanding of the negative impact of high-concentration alcohol on human health. Huangjiu, with its low alcohol content, rich nutrition and relatively healthy characteristics, has gradually gained the favor of liquor consumers, promoting the rapid development of the Huangjiu industry.

[0005] The fermentation process of Huangjiu is a complex biochemical reaction process, which depends on the metabolic activities of microorganisms and the stability of the fermentation environment. However, during the fermentation process, the generated by-products (such as biogenic amines, nitrosamines, etc.) not only affect the flavor of Huangjiu, but may also pose potential hazards to human health. Research shows that hydrogen can regulate the fermentation environment, promote microbial metabolism, and at the same time reduce the generation of harmful by-products. However, there are obvious deficiencies in the application of gaseous hydrogen during the fermentation process: on the one hand, the diffusibility of hydrogen makes it unable to act continuously and stably throughout the fermentation process; on the other hand, the uncontrollability of the release process may lead to fluctuations in hydrogen concentration, thus affecting the fermentation effect. Therefore, how to accurately release hydrogen through slow-release technology during the Huangjiu fermentation process so that it can play a stable role throughout the process has become an important direction for optimizing the Huangjiu fermentation process.

[0006] In the existing technology, the method of adding hydrogen to liquor is mainly achieved by adding hydrogen-rich water, hydrogen charging with nano microbubbles or direct electrolysis of hydrogen production, etc. However, these methods all have problems such as uncontrollable hydrogen concentration, too fast diffusion rate and high hydrogen production cost. It has been actually applied in the Baijiu brewing process. For example, invention CN118530796A discloses a method for preparing light-flavor Baijiu. This invention changes the water molecular clusters of the Baijiu original liquor into monomeric water molecules, making hydrogen dissolve evenly between each water molecule, greatly increasing the hydrogen content of the Baijiu original liquor. At the same time, monomeric water molecules are more easily absorbed by the human body. This invention locks hydrogen by increasing the solubility of hydrogen in the Baijiu original liquor through an electromagnetic field. However, hydrogen only acts on the liquor body in the subsequent treatment stage and does not participate in the brewing fermentation process of Baijiu. Therefore, the potential role of hydrogen has not been fully exerted. At the same time, gaseous hydrogen itself has problems of poor stability and easy diffusion, which has an adverse impact on the quality stability of Baijiu during long-term storage. In addition, this invention relies on an electromagnetic field generator for hydrogen charging and hydrogen locking, increasing the production cost and process complexity, and is not suitable for wide promotion.

[0007] In contrast, solid-state hydrogen storage materials, as an emerging application in recent years, have gradually attracted wide attention. Compared with traditional hydrogen production methods, solid-state hydrogen storage materials not only have strong hydrogen storage capacity, but also have more convenient transportation methods and wider application scenarios. Through slow-release technology, this material can accurately control the release rate and concentration of hydrogen, avoiding the problems of strong diffusibility and uncontrollable release of gaseous hydrogen, and providing a new solution for the application of hydrogen in the yellow rice wine fermentation process.

[0008] Therefore, how to develop a universal fermentation method based on solid-state hydrogen storage materials, through innovative material combinations and process designs, to achieve multi-dimensional matching of hydrogen release characteristics and the requirements of the fermentation stage, thereby systematically optimizing the functions of the microbial community, inhibiting harmful metabolic pathways, and improving product quality has become an important issue that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0009] In view of the defects existing in the above-mentioned prior art, the present invention provides a fermentation method based on solid-state hydrogen storage materials. Through innovative material design and feeding strategies, it realizes multi-dimensional matching of the hydrogen release rate and the requirements of the fermentation stage, thereby systematically optimizing microbial metabolism, improving the fermentation environment, and enhancing product quality. This method not only solves the problems of fast hydrogen diffusion, uncontrollable concentration, and strong equipment dependence in traditional hydrogen supply technologies, but also breaks through the hydrogen application bottleneck of "insufficient in the initial stage and redundant in the later stage" in the fermentation process by precisely regulating hydrogen supply in stages, providing an efficient and low-consumption technical path for the process upgrade in fields such as food brewing and biopharmaceuticals.

[0010] In the first aspect, the present invention provides a fermentation method based on solid-state hydrogen storage materials, including the following steps:

[0011] S1. Pretreatment stage: Pretreat the raw materials to obtain the material to be fermented;

[0012] S2. Fermentation stage: Ferment the material to be fermented;

[0013] Wherein, the solid-state hydrogen storage material is added in the step S1 and / or step S2;

[0014] The solid-state hydrogen storage material includes hydrogen storage particles and a porous substrate, and the hydrogen storage particles are loaded on the porous substrate.

[0015] Preferably, the solid-state hydrogen storage material further includes an adhesive, and the mass ratio of the hydrogen storage particles, the porous substrate, and the adhesive is (2 - 4):(1 - 5):(1 - 7).

[0016] The adhesive is selected from at least one of suitable natural adhesives and synthetic adhesives according to the difference in the application scenario. When applied in fields such as food and medicine, adhesive varieties with better biocompatibility and non-toxicity can be selected.

[0017] Preferably, the solid hydrogen storage material satisfies at least one of the following conditions:

[0018] (1) The hydrogen storage particles include one or more of Mg powder, magnesium hydride, magnesium hydride complex, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride, magnesium silicide, etc.; for the specific types of hydrogen storage particles, those skilled in the art can further screen according to multiple factors such as the raw materials and uses of the fermentation method;

[0019] (2) The porous substrate includes at least one of porous carbon materials and mesoporous silica; the porous carbon material is selected from at least one of biochar, carbon nanotubes, graphene oxide, etc.; mesoporous silica protects magnesium hydride from mechanical damage during the pressing process through its high mechanical strength, and its silanol groups (Si-OH) form weak bonds with hydrogen, which can delay hydrolysis;

[0020] (3) The binder includes at least one of polylactic acid and polyethylene glycol.

[0021] Preferably, the solid hydrogen storage material includes a blend granule structure and / or a core-shell structure;

[0022] The blend granule structure is prepared by mixing and granulating hydrogen storage particles, a porous substrate, and a binder;

[0023] The core-shell structure includes a hydrogen storage core and a coating layer. The hydrogen storage core includes pre-compounded hydrogen storage particles and a porous substrate. The coating layer is formed by applying a binder to the hydrogen storage core, including polylactic acid and polyethylene glycol, and polyethylene glycol accounts for 50%-85% of the total mass of the coating layer.

[0024] The blend granule structure is used for situations where a reducing environment needs to be quickly established. Through direct mixing and granulation, the preparation process is simple, the cost is low, and the hydrogen release rate is fast. The binder uniformly connects the hydrogen storage particles and the porous substrate into one body. The high specific surface area of the porous substrate effectively supports and adsorbs the hydrogen storage particles and can buffer the intensity of the hydrolysis reaction.

[0025] The solid hydrogen storage material with a core-shell structure is more suitable for processes with a longer fermentation cycle and is convenient for storage and transportation. Its hydrogen utilization rate can be increased to more than 90%, and it can prevent a sharp rise in the local pH value. The coating layer achieves diffusion control by restricting the contact between moisture and magnesium hydride. At the same time, the binder adjusts the swelling rate of the coating layer, thereby realizing the slow release of hydrogen and prolonging its action time.

[0026] The ratio of polylactic acid (PLA) to polyethylene glycol (PEG) plays a key regulatory role in the core-shell structured solid-state hydrogen storage material, directly affecting the physical and chemical properties of the coating layer, hydrogen release kinetics, and material stability. Polylactic acid is a highly rigid and hydrophobic biodegradable polyester with a high degree of crystallinity, which can provide a skeleton support and anti-permeability for the coating layer, delaying the contact of moisture with the hydrogen storage core (magnesium hydride), thereby controlling the hydrogen release rate. Polylactic acid will slowly hydrolyze in an alkaline or humid and hot environment, and its half-life is about 7-10 days. This controllable degradation characteristic enables the coating layer to gradually release hydrogen during the fermentation process without premature rupture in the initial stage. Polyethylene glycol is a flexible chain segment material with plasticizing and hydrophilic properties. It can insert between the molecular chains of polylactic acid, reduce the glass transition temperature of the coating layer, significantly improve its toughness, and increase the elongation at break by more than 50%. In addition, the hydrophilicity of polyethylene glycol can promote the penetration of water molecules and form a microporous structure through phase separation, further regulating the hydrogen release rate.

[0027] In the core-shell structure, different ratios of polylactic acid to polyethylene glycol will significantly affect the performance of the coating layer. For example, a ratio of 1:1 to 1:1.2 will form a dense structure with a porosity of less than 5% and a coating layer thickness of about 25-30 microns. This structure can achieve slow hydrogen release, with a release rate of about 3 ml / g·h and a release half-life of up to 60 hours, which is particularly suitable for the constant temperature aging stage that requires long-term stable hydrogen release. A ratio of 1:2 to 1:3.5 can form a coating layer with a medium porosity between 5% and 10%, with significantly enhanced toughness. The hydrogen release rate is balanced at 3-5 ml / g·h, which is suitable for the main fermentation period and can meet the hydrogen demand for 48-72 hours. When a ratio of 1:4 and more polyethylene glycol is used, a coating layer with a high porosity of up to 15%-20% will be formed, which can quickly respond to water penetration, and the hydrogen release rate will increase to 5-7 ml / g·h, which is basically similar to the hydrogen release effect of the blend particle structure. It can be used in the soaking or initial stage of fermentation to quickly inhibit the growth of harmful microorganisms.

[0028] The ratio of polylactic acid to polyethylene glycol achieves precise control of hydrogen release by regulating the diffusion performance and degradation rate of the coating layer. The hydrophobicity of polylactic acid dominates the barrier effect of the coating layer, while the hydrophilicity of polyethylene glycol forms hydrophilic channels through phase separation, enabling water to penetrate along the channels to the hydrogen storage core, triggering the hydrolysis reaction of magnesium hydride and releasing hydrogen. The swelling effect of polyethylene glycol further expands the pores of the coating layer and accelerates the diffusion of hydrogen. Its swelling rate is positively correlated with the content of polyethylene glycol.

[0029] Preferably, the hydrogen storage particles and the porous substrate are pre-compounded by at least one of the following methods:

[0030] Method 1: Mix the porous substrate and hydrogen storage particles evenly to obtain a hydrogen storage core;

[0031] Method 2: Add the porous substrate into a closed container and evacuate it; Blow the hydrogen storage particles into the closed container with high-pressure gas so that the hydrogen storage particles adhere to the pores and surface of the porous substrate to obtain a hydrogen storage core.

[0032] Preferably, the solid hydrogen storage material includes a blend particle structure and a core-shell structure;

[0033] Add the blend particle structure in the pretreatment stage;

[0034] Add the core-shell structure in the fermentation stage.

[0035] The blend particle structure added in the pretreatment stage is made by mixing and granulating hydrogen storage particles (such as magnesium hydride), porous substrates (such as biochar or mesoporous silica), and binders (such as hydroxypropyl cellulose) in proportion. Its core principle is to use the high specific surface area of the porous substrate (300 - 500 m 2 / g, measured by BET method) to achieve uniform dispersion of the hydrogen storage particles, and fix the particle positions through the binder to avoid agglomeration. When the material contacts moisture, the hydrogen storage particles hydrolyze rapidly (for example, the reaction of magnesium hydride: MgH2 + 2H2O → Mg(OH)2 + 2H2↑), releasing more than 80% of hydrogen within 5 - 15 minutes. This process quickly establishes a local reducing environment, effectively inhibiting molds, spoilage bacteria, and aerobic heterotrophic bacteria on the surface of the raw materials. At the same time, hydrogen diffuses and penetrates into the raw materials, promoting water absorption and inhibiting the activity of oxidase, thereby reducing the loss of nutrients during the pretreatment process.

[0036] The core-shell structure added in the fermentation stage realizes slow hydrogen release through the swelling-degradation mechanism of the coating layer (such as PLA / PEG composite material). The hydrophilicity of polyethylene glycol (PEG) in the coating layer causes the material to swell in a humid environment (swelling rate 150% - 200%, measured by swelling kinetics experiment), forming nano-scale pore channels (diameter 50 - 200 nm, observed by SEM), allowing moisture to gradually penetrate into the hydrogen storage particles in the core. The hydrophobicity and degradability of polylactic acid (PLA) (degradation half-life 7 - 10 days, tested in pH 7.0 buffer solution) further regulate the hydrogen release rate to match the fermentation cycle (for example, releasing the remaining 60% - 70% of hydrogen within 5 - 7 days). This slow-release characteristic maintains a stable micro-reducing environment in the fermentation system, promotes the metabolic activity of anaerobic or facultative anaerobic microorganisms, and inhibits the proliferation of aerobic heterotrophic bacteria at the same time. In addition, the continuous release of hydrogen can scavenge free radicals and protect heat-sensitive substances (such as enzymes, vitamins) in the fermentation products from oxidative damage.

[0037] The blend granule structure in the pretreatment stage optimizes the initial state of raw materials through rapid bacteriostasis and physical penetration, while the core-shell material in the fermentation stage achieves long-term microbial regulation through a slow-release mechanism. The two form a spatio-temporal complementarity. For example, in the fermentation of organic fertilizer, the pretreatment material can reduce the putrid odor during the stacking of raw materials, while the core-shell material continuously releases hydrogen at high temperature stages (50-60 °C), accelerating the degradation of lignocellulose. In the fermentation of feed, this combination can shorten the total fermentation cycle by 20%-25% and increase the viable count of probiotics at the same time. The metal hydroxides (such as Mg(OH)2) generated in the material can also act as pH buffers to prevent the over-acidification of the fermentation broth and improve the stability of the product.

[0038] The present invention also applies the fermentation method based on solid-state hydrogen storage materials to fields such as the food fermentation industry, biopharmaceuticals and synthetic biology, and agriculture and organic waste treatment. For example, the fermentation method based on solid-state hydrogen storage materials is used to improve the quality of products such as wines and enzymes.

[0039] In particular, the present invention also applies the fermentation method based on solid-state hydrogen storage materials to the fermentation method for improving the quality of yellow rice wine, including:

[0040] S1. Pretreatment stage: Screening, washing, soaking, and steaming the raw materials of yellow rice wine to obtain the materials to be fermented;

[0041] S2. Fermentation stage: Inoculating the materials to be fermented into the vat and performing fermentation treatment to obtain the fermented product;

[0042] Wherein, the solid-state hydrogen storage material is added in at least one of the soaking and / or inoculation into the vat.

[0043] Introducing the solid-state hydrogen storage material during the soaking process of yellow rice wine raw materials, magnesium hydride reacts slowly with water to release hydrogen (MgH2 + 2H2O → Mg(OH)2 + 2H2↑), thereby creating a local micro-reducing environment. The reduction effect of hydrogen inhibits the activities of molds and spoilage bacteria, effectively reducing the mildew risk of glutinous rice during the soaking process. At the same time, it reduces the oxidative degradation of starch and protein, maintaining the natural flavor precursor substances of glutinous rice. In addition, hydrogen promotes the penetration of moisture, accelerates the water absorption and swelling process of glutinous rice, shortens the steaming time and improves the gelatinization uniformity. For the glutinous rice treated by soaking, its fatty acid value can be reduced by 15%-20%, while the reducing sugar content of the steamed rice increases by 8%-12%, providing a better substrate for the subsequent fermentation process.

[0044] Introducing solid-state hydrogen storage materials during the inoculation stage of fermented matter into the vat can regulate the microbial community structure in the initial stage of fermentation by utilizing the continuous release of hydrogen. As an electron donor, hydrogen helps to promote the balance of NADH / NAD+ in yeast, thereby accelerating the ethanol synthesis pathway, for example, by activating the activity of ADH enzyme. In addition, hydrogen can selectively inhibit the excessive proliferation of lactic acid bacteria, effectively preventing premature acidification during fermentation, reducing the pH value decline rate by 10%-15%. At the same time, hydrogen can also scavenge ROS (reactive oxygen species) generated during fermentation, protecting flavor substances (such as esters and aldehydes) from oxidative degradation. Finally, the content of ethyl acetate in the fermentation product can be increased by more than 20%, and the content of fusel oil can be reduced by more than 10%, making the taste of the wine body more pure.

[0045] Preferably, after step S2, the method for improving the quality of yellow rice wine further includes:

[0046] S3. Filter and clarify the fermented matter to obtain raw wine;

[0047] S4. Add the solid-state hydrogen storage material to the raw wine for aging to obtain the finished wine.

[0048] Preferably, the blend particle structure is added in the soaking step, and the core-shell structure is added in the vat inoculation and aging steps;

[0049] The dosage ratio of the blend particle structure to the core-shell structure is (1-10):(1-15).

[0050] Preferably, the core-shell structure includes a first core-shell material and a second core-shell material. The first core-shell material is added in the vat inoculation step, and the second core-shell material is added in the aging step;

[0051] The mass percentage of polyethylene glycol in the coating layer of the first core-shell structure is greater than that in the coating layer of the second core-shell structure.

[0052] In the core-shell structure, selecting appropriate types of polyethylene glycol and combining different proportions of polyethylene glycol coating materials can meet the differentiated requirements of various links in yellow rice wine production. For example, a 1:1 ratio with a dense coating layer of PEG600 is suitable for the constant-temperature aging stage, which can slowly release hydrogen, significantly improve the retention rate of esters in the wine body, and the free radical scavenging rate can reach over 80%. A 1:3 ratio with a medium-porosity coating layer of PEG400 is suitable for the main fermentation period and can meet the hydrogen demand for 48 - 72 hours. When the ratio is 1:4 or more polyethylene glycol and PEG200 is used, the high-porosity coating layer can reach the hydrogen release peak (1.2 ml / g) within 2 hours, which is suitable for the initial stage of vatting, and the effect is similar to the hydrogen release effect of the blended particle structure solid hydrogen storage material. By using materials with different ratios in stages, the dual goals of rapid bacteriostasis and long-term regulation of microbial metabolism can be achieved.

[0053] More preferably, the dosage of the first core-shell material is greater than that of the second core-shell material.

[0054] The vatting inoculation stage is a critical period for the rapid proliferation of the microbial community. A large amount of hydrogen is required to quickly establish a reducing environment, inhibit miscellaneous bacteria (such as molds and spoilage bacteria), and activate target strains (such as yeasts and lactic acid bacteria). To meet the initial high demand of the fermentation system, more of the first core-shell material needs to be invested to ensure sufficient hydrogen release within a short time and form a uniform reducing atmosphere.

[0055] During the aging stage, microbial metabolism tends to be stable, and the hydrogen demand turns to maintaining a slightly reducing environment and scavenging residual free radicals. A small amount of the second core-shell material can meet the long-term slow-release demand and avoid excessive hydrogen interfering with the esterification reaction or causing excessive reduction of flavor substances.

[0056] Through differential dosage design, the present invention realizes the efficient matching of hydrogen supply and the requirements of the fermentation stage: "high dosage + fast release" in the initial stage meets the explosive demand, and "low dosage + slow release" in the later stage ensures long-term stability. This strategy not only improves the hydrogen utilization rate but also avoids the supply imbalance problem caused by a single material design, providing a general solution for the precise control of the fermentation process.

[0057] The present invention has at least the following beneficial effects:

[0058] (1) By using the blended particle structure and the core-shell structure in stages, targeted regulation is achieved in different links of fermentation. In the pretreatment stage, a reducing environment is quickly established, the activity of harmful microorganisms is inhibited, and at the same time, the physical and chemical properties of raw materials are optimized; in the fermentation stage, a stable micro-oxygen environment is maintained by slowly releasing hydrogen, promoting the metabolism of target microorganisms and inhibiting the excessive proliferation of miscellaneous bacteria. The synergistic effect of the two significantly improves the fermentation success rate and avoids abnormal phenomena such as acidification and mildew.

[0059] (2) In the fermentation method provided by the present invention, the reducing property and antioxidant characteristics of hydrogen run through the whole fermentation process, effectively reducing the oxidative damage of raw materials and products and retaining natural flavor substances. At the same time, by inhibiting the generation of harmful metabolic by-products (such as fusel oil and ethyl carbamate), the purity of the product and food safety are improved. Taking yellow rice wine fermentation as an example, the addition of solid-state hydrogen storage materials in the soaking and fermentation links can effectively inhibit the growth of harmful microorganisms and optimize the microbial metabolism in the fermentation process. In the soaking stage, the hydrogen released by the reaction of magnesium hydride with water forms a local micro-reducing environment, significantly reducing the mildew risk of glutinous rice, and at the same time protecting the starch and protein in glutinous rice from oxidative degradation and maintaining their natural flavor precursors. In the fermentation stage, the continuous release of hydrogen can directionally regulate yeast metabolism, accelerate the ethanol synthesis pathway, and at the same time inhibit the excessive proliferation of miscellaneous bacteria and prevent the fermentation broth from acidifying prematurely. In this way, the content of characteristic flavor substances in yellow rice wine is significantly increased, the content of fusel oil is reduced, the taste of the wine body is purer, and the sensory score is greatly improved.

[0060] (3) The adaptable design of the staged materials in the fermentation method provided by the present invention simplifies the multi-step intervention requirements in the traditional process and shortens the pretreatment and fermentation cycles. The controllable release characteristics of the solid-state hydrogen storage materials reduce the frequency of manual regulation, and their mechanical strength and repeatability further reduce raw material loss and energy consumption. The overall process has strong compatibility and can be widely applied to fermentation fields such as food, feed, and organic fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is the process flow chart of the preparation of the solid-state hydrogen storage material of the present invention;

[0062] Figure 2 is the process flow chart of using the fermentation method based on the solid-state hydrogen storage material to improve the quality of yellow rice wine provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in combination with the specification and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0064] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0065] It should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a commodity or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such commodity or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the commodity or device comprising said element.

[0066] As Figure 1-2 , the fermentation method based on solid-state hydrogen storage materials provided by the present invention, especially for improving the quality of yellow rice wine, will be explained in detail below.

[0067] The fermentation method based on solid-state hydrogen storage materials includes the following steps:

[0068] S1. Pretreatment stage: Pretreat the raw materials to obtain the materials to be fermented;

[0069] S2. Fermentation stage: Ferment the materials to be fermented;

[0070] Among them, solid-state hydrogen storage materials are added in the step S1 and / or step S2. The solid-state hydrogen storage materials specifically include:

[0071] (1) Hydrogen storage particles, loaded on a porous substrate, including one or more of Mg powder, magnesium hydride, magnesium hydride complex, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride, magnesium silicide;

[0072] (2) Porous substrates, including at least one of porous carbon materials and mesoporous silica, and the porous carbon materials are selected from at least one of biochar, carbon nanotubes, and graphene oxide.

[0073] In the solid-state hydrogen storage materials, the hydrogen storage particles are loaded on the porous substrate. The loading can be formed by directly mixing or adsorbing the two, and more preferably, adhesive bonding or adhesive coating is used for bonding and loading;

[0074] Optionally (3) adhesives, including at least one of polylactic acid and polyethylene glycol.

[0075] When the solid-state hydrogen storage materials include adhesives, the mass ratio of the hydrogen storage particles, porous substrates, and adhesives is (2-4):(1-5):(1-7).

[0076] The solid-state hydrogen storage materials further include the following structures:

[0077] 1) Blended granule structure: By mixing and granulating the hydrogen storage particles, porous substrates, and adhesives;

[0078] 2) Core-shell structure: The core-shell structure includes a hydrogen storage core and a coating layer. The hydrogen storage core includes pre-compounded hydrogen storage particles and a porous substrate. The coating layer is obtained by applying an adhesive to the hydrogen storage core and drying and shaping it. The coating layer is formed by the adhesive and includes polylactic acid and polyethylene glycol. Preferably, polyethylene glycol accounts for 50%-85% of the total mass of the coating layer.

[0079] The application of the adhesive can optionally use the melt method or the solution drying method. Heat each raw material to 160-200°C to form a mixed melt, and extrude and granulate. This method has slightly higher energy consumption, but the types of materials are simple. Alternatively, dissolve polylactic acid and polyethylene glycol uniformly in an organic solvent to prepare an adhesive solution. When preparing the blend particle structure, the adhesive solution can be mixed uniformly with the hydrogen storage particles and the porous substrate, and granulated by a granulator, while heating to remove the solvent to obtain the blend particle structure. When preparing the core-shell structure, the adhesive solution can be evenly sprayed onto the pre-compounded hydrogen storage core. After the particle size, i.e., the thickness of the coating layer, meets the requirements, heat to remove the solvent to obtain the core-shell structure.

[0080] The hydrogen storage particles and the porous substrate are pre-compounded by at least one of the following methods:

[0081] Method 1: Mix the porous substrate and the hydrogen storage particles evenly to obtain a hydrogen storage core.

[0082] Method 2: Add the porous substrate into a closed container and evacuate it. Blow the hydrogen storage particles into the closed container with high-pressure gas so that the hydrogen storage particles adhere to the inside and surface of the pores of the porous substrate to obtain a hydrogen storage core.

[0083] According to the differences in the structure and composition of the solid hydrogen storage materials, the same or different solid hydrogen storage materials can be used in each stage of the process. Preferably, the solid hydrogen storage material added in the pretreatment stage is a blend particle structure, and the solid hydrogen storage material added in the fermentation stage is a core-shell structure. And according to needs, by adjusting the proportions of the hydrogen storage particles, the porous substrate, and the adhesive, as well as the proportions of polylactic acid and polyethylene glycol in the adhesive, the structure of the solid hydrogen storage material and the performance of hydrogen release can be adjusted. For example, the core-shell structure is divided into a first core-shell material and a second core-shell material. The content of polyethylene glycol in the coating layer of the first core-shell material is greater than that of the second core-shell material. Due to the pore-forming effect of polyethylene glycol, under the same conditions, the hydrogen release rate of the first core-shell material with a higher content of polyethylene glycol is higher than that of the second core-shell material. Selecting suitable materials in different process links can more synchronously meet the hydrogen demand in the fermentation process.

[0084] As a typical fermentation process, the liquor fermentation process is an application scenario with high quality requirements and high added value. The present invention provides a method for applying solid hydrogen storage materials to liquor, especially focusing on the fermentation of yellow rice wine. That is, the fermentation method based on solid hydrogen storage materials is used to improve the quality of yellow rice wine, which specifically includes the following steps:

[0085] S1. Pretreatment stage:

[0086] S1.1 Raw material screening:

[0087] Select high-quality glutinous rice with a branched starch content of ≥95% (polished rice rate ≥90%) to ensure saccharification efficiency and mellow taste of the wine body; supplement Jianhu Lake water or soft water (pH 6.8 - 7.2, hardness ≤50 mg / L) as the fermentation medium to avoid interference of metal ions with microbial activity; the distiller's yeast should contain Rhizopus (saccharification ability ≥200 U / g) and yeast (viable cell count ≥1×10 8 CFU / g), and the saccharifying enzyme activity of wheat koji should be ≥800 U / g to ensure the synergistic effect of saccharification and fermentation.

[0088] S1.2 Screening and cleaning:

[0089] Remove impurities and broken rice (broken rice rate ≤5%) through a vibrating screen and a specific gravity stoner, and then use countercurrent rinsing technology to wash until the water is clear (turbidity ≤5 NTU). After draining, let it stand for 30 - 60 minutes to make the moisture content on the surface of the rice grains ≤15%, avoiding excessive water absorption during subsequent soaking.

[0090] S1.3 Soaking:

[0091] Put the glutinous rice and the co - blended particle structure (magnesium hydride / biochar / adhesive co - blending granulation system, dosage 0.5 - 1.0 g / kg of rice) into constant - temperature water (20 - 25°C), with the water level 20 - 30 cm higher than the rice layer, and soak for 24 - 48 hours. The end point of soaking is determined by the moisture content of the rice grains reaching 25 - 30% and the release of lactic acid promoting acidification to pH dropping to 4.0 - 4.5.

[0092] S1.4 Cooking:

[0093] Cook with high - pressure steam (0.1 - 0.15 MPa) for 15 - 30 minutes to make the starch gelatinization degree ≥90% (measured by DSC), and control the moisture content at 45 - 50%. After cooking, quickly cool it to 28 - 32°C (cooling rate ≤5°C / min) to avoid starch retrogradation. Residual Mg(OH)2 of the solid - state hydrogen storage material is separated and removed through a sieve (pore size ≤0.5 mm) to ensure no physical impurities interfere with subsequent fermentation.

[0094] S2. Fermentation link:

[0095] S2.1. Vat - loading and inoculation link:

[0096] Mix the pretreated material to be fermented with the first core-shell material (dosage: 0.5 - 1.0 g / kg of rice, and the proportion of polyethylene glycol in the coating layer is 65% - 80%) and put them into the fermentation tank. Add 0.3% - 0.5% of wine yeast (including Rhizopus and yeast) and 10% - 15% of wheat koji (saccharifying enzyme activity ≥ 800 U / g) according to the mass ratio of the material to be fermented. Control the mass ratio of rice to water at 1:1.2 - 1.5. Mix the material with the auxiliary materials evenly by the method of layer-by-layer koji spreading, and form a V-shaped groove in the tank to increase the oxygen contact area and promote the initial reproduction of microorganisms and saccharification reaction.

[0097] S2.2, Pre-fermentation:

[0098] Control the initial temperature at 28 - 32 °C in the pre-fermentation stage, start fermentation (begin brewing) within 24 hours. When the product temperature rises to 33 - 35 °C, conduct the first stirring (raking) to cool down and inhibit the excessive proliferation of miscellaneous bacteria. The fermentation cycle is 5 - 7 days. During this period, stir once every 6 - 8 hours (a total of two to four raking operations), and strictly control the product temperature at ≤ 32 °C to ensure the synchronous progress of saccharification and alcohol fermentation and avoid rancidity.

[0099] S2.3, Post-fermentation:

[0100] After the pre-fermentation is completed, transfer it to a pottery jar or a closed fermentation tank, and conduct anaerobic post-fermentation in a low-temperature environment of 15 - 20 °C. The fermentation time for semi-dry yellow rice wine is 20 - 30 days, and that for dry yellow rice wine is 60 - 90 days. The final alcohol content is ≥ 14% vol, and the sugar content is controlled at ≤ 15 g / L for dry type and ≤ 40 g / L for semi-dry type. In this stage, seal off oxygen to promote the slow synthesis of flavor substances such as esters.

[0101] S3. Fermentation broth treatment

[0102] S3.1, Pressing and clarification:

[0103] Use a plate and frame filter press to conduct three-gradient pressurization (0.2 - 0.4 MPa) on the fermentation mash to separate the wine liquid from the distillers' grains, and the wine yield is 80% - 85%. Place the wine liquid in a low-temperature environment of 5 - 10 °C and let it stand for 3 - 5 days to promote the natural sedimentation of suspended proteins and impurities and initially stabilize the wine body.

[0104] S3.2, Sterilization treatment:

[0105] The wine liquid is treated by pasteurization, heated to 85 - 90 °C and maintained for 15 - 30 minutes (center temperature ≥ 80 °C) to inactivate residual microorganisms and enzymes. Immediately fill the sterilized wine into a pottery jar and seal it to avoid secondary pollution and at the same time retain the traditional flavor of yellow rice wine.

[0106] S4. Aging:

[0107] Before the sterilized raw wine is filled into the earthenware jar and sealed, add the second core-shell material (the proportion of polyethylene glycol in the coating layer is 50%-65%) according to 0.1%-0.3% of the mass of the liquor, and evenly put the second core-shell material into the bottom of the earthenware jar. The finished raw wine is aged for 1-3 years under the condition of constant temperature cellaring (temperature 10-15°C, humidity 70%-80%), and high-quality yellow rice wine requires ≥3 years. During the aging process, the wine body is further aged through slow oxidation and esterification reactions, the content of fusel alcohols decreases, the taste becomes softer, and finally the finished yellow rice wine with clear color and complex flavor is formed.

[0108] The first core-shell material put into the vat inoculation link and the second core-shell structure hydrogen storage material put into the aging link, wherein, the content of polyethylene glycol in the coating layer of the first core-shell material is greater than that of the second core-shell material.

[0109] Preparation Example 1:

[0110] The solid hydrogen storage material of this preparation example is a blended particle structure, and the raw materials for preparing the solid hydrogen storage material are selected as follows:

[0111] (1) Hydrogen storage particles: Select magnesium hydride powder that is fine, uniform, and has a suitable purity (95-99%).

[0112] (2) Biochar: Biochar prepared by pyrolysis of straw. The biochar is pulverized and sieved to obtain biochar powder with uniform particle size (passing through 100-200 mesh sieve) to ensure a large contact area with magnesium hydride and uniform mixing.

[0113] (3) Polylactic acid: Select polylactic acid with high purity and low residual monomers. According to the requirements of degradation and slow release, the number average molecular weight of polylactic acid can be in the range of 1000-30000.

[0114] (4) Polyethylene glycol: Screen PEG 200, PEG 400, PEG 600, and select the polyethylene glycol with the best molecular weight by detecting the hydrogen release amount after mixing with the composite material.

[0115] (5) Organic solvent, such as dichloromethane, with a boiling point of about 40°C.

[0116] Put polylactic acid, polyethylene glycol PEG 400, and biochar into the drying oven respectively. Polylactic acid is dried at 90°C for 24h; polyethylene glycol PEG 400 is dried at 70°C for 12h; biochar can be dried to constant weight at about 105±2°C to remove moisture and volatile substances.

[0117] In the blended particle structure, the mass ratio of magnesium hydride particles, porous biochar, and binder is (2-4):(1-5):(1-7), and the polyethylene glycol in the binder accounts for about 50-75wt%. The blended particle structure is prepared by the following steps:

[0118] Prepare the adhesive solution: Weigh out polylactic acid and polyethylene glycol and dissolve them in dichloromethane to obtain the adhesive solution;

[0119] Mixing and granulation: Put the biochar, magnesium hydride, and the adhesive solution into a closed granulator, first stir and mix at low speed for 20 minutes, and then stir and granulate at high speed;

[0120] Among them, while stirring and granulating at high speed, raise the temperature of the mixing granulator to 45 °C to promote the full extraction of the solvent.

[0121] Preparation Example 2

[0122] The solid-state hydrogen storage material of this preparation example has a core-shell structure, and the types of raw materials are the same as those in Preparation Example 1. It is prepared through the following steps:

[0123] Prepare the hydrogen storage core: Mix the porous biochar and magnesium hydride particles evenly to obtain the hydrogen storage core;

[0124] Prepare the adhesive solution: Weigh out polylactic acid and polyethylene glycol and dissolve them in dichloromethane to obtain the adhesive solution, where polyethylene glycol accounts for 50%-75% of the total mass of polylactic acid and polyethylene glycol;

[0125] Spray drying: Evenly spray the adhesive solution onto the hydrogen storage core, and heat to remove the solvent to obtain the core-shell structure.

[0126] Preparation Example 3

[0127] The solid-state hydrogen storage material of this preparation example has a core-shell structure, and the types of raw materials are the same as those in Preparation Example 1. It is prepared through the following steps:

[0128] Prepare the hydrogen storage core: Add porous biochar to a closed container and evacuate it;

[0129] Blow magnesium hydride particles into the closed container with high-pressure gas so that the magnesium hydride particles adhere to the pores and surface of the porous biochar to obtain the hydrogen storage core;

[0130] Prepare the adhesive solution: Weigh out polylactic acid and polyethylene glycol and dissolve them in dichloromethane to obtain the adhesive solution; polyethylene glycol accounts for 50%-75% of the total mass of polylactic acid and polyethylene glycol;

[0131] Spray drying: Evenly spray the adhesive solution onto the pre-combined hydrogen storage core, and heat to remove the solvent to obtain the core-shell structure.

[0132] The ingredient measurement tables for each preparation example are shown in Table 1:

[0133] Table 1

[0134]

[0135] Perform hydrogen release kinetics measurements on the hydrogen storage material samples of Preparation Examples 1-1 to 3-4.

[0136] Release rate: Using the water displacement method (ISO 16111 standard), place the hydrogen storage material in a constant temperature reaction kettle (30 °C), connect a gas flow meter, record the change in hydrogen gas volume from 0 to 24 hours, and calculate the release rate (mL / g·h) of the material per unit mass. The test results are shown in Table 2.

[0137] Table 2

[0138]

[0139]

[0140] The average hydrogen release rate of the blended particle structure solid-state hydrogen storage material per unit mass is higher than that of the core-shell structure solid-state hydrogen storage material. This is mainly because on the surface of the particles with the blended particle structure, the hydrogen storage particles, porous substrate, and binder are basically evenly dispersed. When the hydrogen storage particles decompose and release hydrogen, the particle structure gradually collapses, and the dissolution of polyethylene glycol also causes the external solution to quickly enter the structure, promoting the reaction of the internal hydrogen storage particles. Correspondingly, the change in hydrogen gas volume within 24 hours is also higher. The polymer outer layer of the core-shell structure has a certain protective and isolating effect on the hydrogen storage core. As the pores are formed due to the dissolution of polyethylene glycol, the external solution gradually enters the particles and reacts with the internal hydrogen storage particles. Moreover, the porous substrate of the hydrogen storage core has a certain interval and slow-release effect on the hydrogen storage particles and also has a certain adsorption and slow-release effect on the released hydrogen. The overall hydrogen release effect is relatively uniform and stable, making it suitable for use in the fermentation stage and aging stage that take a long time.

[0141] In addition, within the same material structure, the specific hydrogen release effect of the particles will also be affected by the dosage ratios of the hydrogen storage particles, porous substrate, and binder, the dosage ratios of polylactic acid and polyethylene glycol in the binder, and the selection of the type of polyethylene glycol. The above preparation examples are not exhaustive, and in actual production, it can be adjusted according to application requirements.

[0142] Examples

[0143] Apply the fermentation method based on the solid-state hydrogen storage material to improve the quality of yellow rice wine, which specifically includes the following steps:

[0144] S1. Pretreatment stage:

[0145] S1.1 Raw material screening:

[0146] Select high-quality glutinous rice with a branched starch content ≥ 95% (polished rice rate ≥ 90%) to ensure the saccharification efficiency and the mellow taste of the wine body; supplement with Jianhu Lake water or soft water (pH 6.8 - 7.2, hardness ≤ 50 mg / L) as the fermentation medium to avoid the interference of metal ions on the microbial activity; the fermenting agent should contain Rhizopus (saccharification ability ≥ 200 U / g) and yeast (viable cell count ≥ 1×10 8(CFU / g), the glucoamylase activity of wheat koji ≥ 800 U / g to ensure the synergistic effect of saccharification and fermentation.

[0147] S1.2 Screening and cleaning:

[0148] Remove impurities and broken rice (broken rice rate ≤ 5%) through a vibrating screen and a specific gravity stoner. Subsequently, use the countercurrent rinsing technique to wash until the water is clear (turbidity ≤ 5 NTU). After draining, let it stand for 45 minutes to make the moisture content on the surface of the rice grains ≤ 15%, to avoid excessive water absorption during subsequent soaking.

[0149] S1.3 Soaking:

[0150] Put glutinous rice and the co - blended particle structure (magnesium hydride / biochar / binder system, dosage 0.8 g / kg of rice) into constant - temperature water (about 23 - 25 °C). The water level is about 25 cm higher than the rice layer, and soak for 36 hours. The end point of soaking is judged by the moisture content of the rice grains reaching about 25 - 30% and the release of lactic acid promoting acidification to pH dropping to 4.0 - 4.5.

[0151] S1.4 Steaming:

[0152] Steam with high pressure (about 0.15 MPa) for 30 minutes to make the degree of starch gelatinization ≥ 90% (measured by DSC), and control the moisture content at 45 - 50%. After steaming, quickly cool it to about 30 °C (cooling rate ≤ 5 °C / min) to avoid starch retrogradation.

[0153] Residual Mg(OH)₂ in the solid - state hydrogen storage material is separated and removed through a sieve (pore size ≤ 0.5 mm).

[0154] S2. Fermentation stage:

[0155] S2.1. Inoculation into the vat stage:

[0156] Put the pre - treated fermenting material and the co - blended particle structure or core - shell structure (dosage 0.8 g / kg of rice) into the fermentation vat. Add 0.4% of fermenting agent (containing Rhizopus and yeast) and 13% of wheat koji (glucoamylase activity ≥ 800 U / g) according to the mass ratio of the fermenting material. Control the mass ratio of rice to water at about 1:1.3. Mix the material and auxiliary materials evenly by the method of spreading koji in layers, and form a V - shaped groove in the vat to increase the oxygen contact area and promote the initial reproduction of microorganisms and the saccharification reaction.

[0157] S2.2. Pre - fermentation:

[0158] The initial temperature in the pre-fermentation stage is controlled at 28 - 32°C, and fermentation (starting fermentation) is initiated within 24 hours. When the temperature of the fermented grains rises to 33 - 35°C, the first stirring is carried out to cool down and inhibit the excessive proliferation of miscellaneous bacteria. The fermentation cycle is 6 days, during which stirring is carried out every 8 hours (a total of 3 stirring operations), and the temperature of the fermented grains is strictly controlled at ≤32°C to ensure the synchronous progress of saccharification and alcohol fermentation and avoid rancidity.

[0159] S2.3, Post-fermentation:

[0160] After the pre-fermentation is completed, it is transferred to earthen jars or airtight fermentation tanks, and anaerobic post-fermentation is carried out in a low-temperature environment of 15 - 20°C. The semi-dry yellow rice wine is fermented for 25 days, the alcohol content is ≥14% vol, and the sugar content is controlled to be semi-dry ≤40 g / L. In this stage, oxygen is isolated by sealing to promote the slow synthesis of flavor substances such as esters.

[0161] S3.1, Pressing and clarification:

[0162] The fermented mash is subjected to three-stage gradient pressing (about 0.3 MPa) using a plate-and-frame filter press to separate the liquor from the distillers grains, and the liquor yield is over 80%. The liquor is placed in a low-temperature environment of 5 - 10°C and allowed to stand for 5 days to promote the natural sedimentation of suspended proteins and impurities and initially stabilize the liquor body.

[0163] S3.2, Sterilization treatment:

[0164] The liquor is subjected to pasteurization, heated to 85 - 90°C and maintained for 20 minutes (the central temperature ≥80°C) to inactivate residual microorganisms and enzymes. After sterilization, it is immediately filled into earthen jars and sealed to avoid secondary pollution and at the same time retain the traditional flavor of yellow rice wine.

[0165] S4, Aging:

[0166] Optionally, before filling and sealing the original liquor after sterilization, 0.1% - 0.3% of the second core-shell material (Preparation Examples 3 - 4) is added according to the mass of the liquor, and the material is evenly put into the bottom of the earthen jar. The finished original liquor is sampled after aging for 1 year under constant temperature cellaring conditions (temperature 10 - 15°C, humidity 70% - 80%), and the rest of the yellow rice wine is aged for ≥3 years. During the aging process, the liquor body is further aged through slow oxidation and esterification reactions, the content of fusel alcohols decreases, and the taste tends to be mellow, and finally a finished yellow rice wine with clear color and complex flavor is formed.

[0167] Examples 1 - 4 prepare yellow rice wine according to the above fermentation method, and the specific types and dosages of raw materials are different as shown in Table 3:

[0168] Table 3

[0169]

[0170]

[0171] The following tests were conducted on Examples 1 - 4:

[0172] I. Sensory evaluation indicators, and the test results are shown in Table 4

[0173] 1. Appearance: including color and luster (such as light yellow to dark brown), clarity, and fluidity.

[0174] 2. Aroma: It is required to have the unique mellow fragrance of yellow rice wine and no abnormal or miscellaneous odors.

[0175] 3. Taste: Evaluate the thickness of the wine body, the coordination of sour, sweet, bitter, spicy, and astringent tastes, and the drinkability.

[0176] 4. Style: The uniqueness of the overall style, such as whether it reflects the "characteristics of clear wine" or the characteristics of traditional yellow rice wine.

[0177] Table 4

[0178] Appearance (25 points) Aroma (25 points) Taste (25 points) Style (25 points) Total Score Example 1 22 21 21 20 84 Example 2 24 23 23 22 92 Example 3 24 24 24 23 95 Example 4 25 25 25 24 99

[0179] II. Physical and chemical indicators, and the test results are shown in Table 5

[0180] 1. Alcohol content: Reflects the ability of yeast to metabolize alcohol during fermentation. In the new standard GB / T 13662 - 2018, the lower limit of the alcohol content of light - type yellow rice wine is adjusted to ≥6.0% vol, and the upper limit is cancelled to adapt to the trend of low - alcoholization. In the experimental study, the alcohol content is determined by the potassium dichromate oxidation colorimetric method.

[0181] 2. Content of non - sugar solids: Characterizes the solids other than sugars in the wine body (such as proteins, polyphenols, etc.), which affects the taste and nutrition. The new standard has lowered the limit value of non - sugar solids (for example, for light - type semi - dry yellow rice wine, it has dropped from ≥20.0 g / L to ≥11.0 g / L) to meet the requirements of low - alcoholization. In the research, it is determined by the gravimetric method (arbitration method), and the results are shown in Table 6.

[0182] 3. Amino acid nitrogen content: Reflects the degree of protein decomposition and the umami taste of the wine body, and is related to the nutritional value of yellow rice wine. In the new standard, the limit value of amino acid nitrogen has generally decreased (for example, for semi - dry yellow rice wine, it has dropped from ≥0.50 g / L to ≥0.40 g / L). The experiment is determined by the potentiometric titration method and is one of the core indicators for response surface optimization.

[0183] 4. Total acid content: Affects the balance of acidity and flavor of yellow rice wine. The upper limit of the total acid content of non - rice yellow rice wine has been relaxed from 7.0 g / L to 10.0 g / L to support diverse tastes. The total acid content is determined by the acid - base neutralization titration method (GB / T 13662 - 2018).

[0184] 5. Reducing sugars: Reducing sugars are sugars containing free aldehyde or ketone groups in the molecule (such as glucose and maltose). They directly affect the perception of sweetness in yellow rice wine and reflect the balance between saccharification and fermentation. Determined by the Fehling volumetric method (GB / T 15038-2006) or the DNS colorimetric method.

[0185] 6. Total ester content: Total esters are the sum of ester substances (such as ethyl acetate and ethyl lactate) in yellow rice wine, which determine the aroma complexity. Determined by the saponification-back titration method (GB / T 10345-2022) or gas chromatography.

[0186] 7. pH value: Determined by potentiometric titration, which affects the microbial activity and fermentation stability.

[0187] 8. Higher alcohols content: The total content of the mixture of higher alcohols in the wine body other than ethanol, mainly including isoamyl alcohol, isobutanol, etc. Excessive amounts can cause discomfort after drinking. Each monomer alcohol is separated and quantified by gas chromatography (GB / T10345-2022), and the sum is the higher alcohols content.

[0188] 9. Polyphenol content: Polyphenols are an important class of functional components with antioxidant activity in yellow rice wine, mainly including phenolic acids, flavonoids (such as catechin and quercetin), tannins and other compounds. Determined by the Folin-Ciocalteu method or high performance liquid chromatography (HPLC).

[0189] Table 5

[0190]

[0191]

[0192] In the brewing process of yellow rice wine of the present invention, by precisely controlling the use of magnesium hydride, the quality of the wine body is significantly improved. The alcohol content is stably controlled within the range of 14.0-15.5% vol, the metabolic efficiency of yeast is enhanced, meeting the requirements of the new national standard for semi-dry yellow rice wine. At the same time, the content of non-sugar solids is optimized to 9.5-13.0 g / L, the thoroughness of fermentation is improved, providing strong technical support for the low-alcohol trend of yellow rice wine.

[0193] The amino acid nitrogen content is increased to 0.72-0.85 g / L, confirming the deep strengthening of protein decomposition and becoming the core source of umami substances. The reducing sugars remain precisely at 20.0-30.0 mg / mL, achieving a delicate balance between sweetness and fermentation control. The synergistic effect of total acid and pH value is particularly prominent. The total acid of 4.0-5.0 g / L and the pH environment of 3.8-4.2 not only inhibit the growth of miscellaneous bacteria but also stabilize the flavor framework.

[0194] After introducing the magnesium hydride process into yellow rice wine, the polyphenol content increased significantly from 231.7 μg / mL in Example 1 to 331.2 μg / mL in Example 4 (an increase of 43%), the total ester content increased significantly to more than 3.5 g / L, and the ethyl acetate content exceeded 2.4 g / L, making the wine body emit a rich fruity aroma and the aroma level improved fundamentally. The above quality leap is attributed to the dual effects of the slow release of hydrogen by magnesium hydride and the activity of magnesium ions, which not only optimized the fermentation kinetic process but also enhanced the synthesis of flavor substances through redox regulation.

[0195] Based on the data of each example, it can be seen that for the semi-dry yellow rice wine fermented by adding solid-state hydrogen storage materials in the present invention, the reducing sugar content is stably in the ideal range of 31.3 - 37.8 mg / mL, the total ester content reaches an excellent level of 3.5 - 5.2 g / L, and the fusel oil is controlled within the safe range of 240 - 380 mg / L. All indicators are significantly better than those of the traditional process. In the sensory evaluation, all examples scored higher than 80 points. Examples 2 - 4, which were configured with different solid-state hydrogen storage materials at different stages, scored above 90 points. In particular, Example 4 verified the value of process innovation with an excellent performance of 99 points. The amber wine body is bright and clear, with rich aged aroma levels and a soft and harmonious taste, showing the unique charm of the integration of traditional yellow rice wine and modern brewing technology.

[0196] This fermentation method not only solves the problems of easy oxidation and unstable flavor in traditional yellow rice wine brewing but also realizes a comprehensive improvement in quality through precise regulation of microbial metabolism, providing a safe and reliable quality upgrade solution for the yellow rice wine industry.

[0197] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the present invention is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention.

Claims

1. A fermentation method based on solid-state hydrogen storage materials, characterized in that, It includes the following steps: S1. Pretreatment stage: Pretreat the raw materials to obtain the material to be fermented; S2. Fermentation stage: Carry out fermentation treatment on the material to be fermented; Wherein, a solid hydrogen storage material is added in the step S1 and / or step S2; The solid hydrogen storage material includes hydrogen storage particles and a porous substrate, and the hydrogen storage particles are loaded on the porous substrate.

2. The fermentation method according to claim 1, wherein The solid hydrogen storage material further includes an adhesive, and the mass ratio of the hydrogen storage particles, the porous substrate and the adhesive is (2 - 4):(1 - 5):(1 - 7).

3. The fermentation method according to claim 2, wherein The solid hydrogen storage material satisfies at least one of the following conditions: (1) The hydrogen storage particles include one or more of Mg powder, magnesium hydride, magnesium hydrogen complex, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride, magnesium silicide; (2) The porous substrate includes at least one of porous carbon materials and mesoporous silica; (3) The adhesive includes at least one of polylactic acid and polyethylene glycol.

4. The fermentation method according to claim 3, wherein The solid hydrogen storage material includes a blend particle structure and / or a core - shell structure; The blend particle structure is prepared by mixing and granulating the hydrogen storage particles, the porous substrate and the adhesive; The core - shell structure includes a hydrogen storage inner core and a coating layer. The hydrogen storage inner core includes pre - compounded hydrogen storage particles and a porous substrate, and the coating layer is formed by applying the adhesive to the hydrogen storage inner core, including polylactic acid and polyethylene glycol, and polyethylene glycol accounts for 50% - 85% of the total mass of the coating layer.

5. The fermentation method according to claim 4, characterized in that, The hydrogen storage particles and the porous substrate are pre - compounded by at least one of the following methods: Method 1: Mix the porous substrate and the hydrogen storage particles evenly to obtain a hydrogen storage inner core; Method 2: Add the porous substrate into a closed container and evacuate it; blow the hydrogen storage particles into the closed container with high - pressure gas so that the hydrogen storage particles adhere to the pores and surface of the porous substrate to obtain a hydrogen storage inner core.

6. The fermentation method according to claim 5, wherein Using the blend particle structure and the core - shell structure includes: Adding the blend particle structure at least in the pretreatment stage; Adding the core - shell structure at least in the fermentation stage.

7. The fermentation method according to any one of claims 4 to 6, characterized in that, The method is used to improve the quality of rice wine, wherein: S1. Pretreatment stage: Screen, wash, soak and steam the rice wine raw materials to obtain the material to be fermented; S2. Fermentation stage: Inoculate the material to be fermented into the vat and carry out fermentation treatment to obtain a fermented product; Wherein, the solid hydrogen storage material is added in at least one of the soaking and / or inoculating into the vat links.

8. The fermentation method according to claim 7, wherein, After step S2, the method for improving the quality of rice wine further includes: S3. Filter and clarify the fermented product to obtain raw wine; S4. Add the solid hydrogen storage material to the raw wine for aging to obtain the finished wine.

9. The fermentation method according to claim 8, characterized in that, The blend particle structure is added in the soaking link, and the core - shell structure is added in the inoculating into the vat and aging links; The dosage ratio of the blend particle structure to the core - shell structure is (1 - 10):(1 - 15).

10. The fermentation method according to claim 9, characterized in that, The core - shell structure includes a first core - shell material and a second core - shell material. The first core - shell material is added in the inoculating into the vat link, and the second core - shell material is added in the aging link; The mass percentage of polyethylene glycol in the coating layer of the first core - shell material is greater than the mass percentage of polyethylene glycol in the coating layer of the second core - shell material.

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