Preparation method of citron fermented preserved fruit

Abstract

The invention discloses a preparation method of citron fermented preserved fruit, and relates to the technical field of preserved fruit processing, the method comprises the following steps: washing citron, separating citron peel from citron pulp, carrying out fixation on the citron peel, and removing seeds and fixation on the citron pulp; mixing the folium eriobotryae, the citron peel, the white chrysanthemum, the Tibetan fritillary bulb and the mint in proportion, boiling in water, and filtering to obtain liquid medicine; uniformly mixing erythritol, stevioside, starch syrup and the liquid medicine in proportion to obtain a first composite sugar solution, and adding the first composite sugar solution and a complex microbial inoculant into the citron pulp subjected to fixation and seed removal to obtain primary fermented citron pulp; and uniformly mixing hyaluronic acid, starch syrup, konjac glucomannan and water in proportion to obtain a second composite sugar solution, immersing the primarily fermented citron pulp into the second composite sugar solution for secondary fermentation, and drying to obtain the citron preserved fruit. On the basis, the taste of the preserved fruit can be improved, the sand return phenomenon can be effectively inhibited, and the high-quality preserved fruit with a nutritional function and a stable texture is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of candied fruit processing, and particularly relates to a preparation method of fermented citron candied fruit. Background Art

[0002] Citron is a unique fruit. Its peel is light yellow, rough in texture and difficult to peel. The pulp is colorless, nearly transparent or light milky yellow, with a crispy texture and a sour-sweet taste. In addition, after being processed into candied fruit, citron can still retain its original aroma and color. The citron peel is rich in aromatic compounds, which can emit a pleasant special aroma and has the remarkable effects of moistening the lungs and relieving cough, and reducing phlegm and relieving asthma.

[0003] However, the existing citron candied fruit does not make full use of the citron peel, resulting in material waste. In addition to being used as snacks, the candied fruit lacks other functional utilities and has insufficient market competitiveness. Moreover, the existing citron candied fruit mostly uses granulated sugar as the sugar source, resulting in too high calories. Excessive intake of sugar is also likely to cause the human body to lack vitamin B and some trace elements, which is not conducive to health. After being stored for a long time, these candied fruits may also show the phenomenon of sugar sanding, affecting the appearance, and only retaining the fruit aroma, lacking diverse flavors. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a preparation method of fermented citron candied fruit, aiming to improve the functional utility and appearance of citron candied fruit.

[0005] A preparation method of fermented citron candied fruit includes the following steps: Wash the citron and separate the citron peel and the citron pulp, and blanch the citron peel and remove the seeds from the citron pulp and then blanch it; Mix loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint in proportion and put them into water to boil, and filter to obtain a medicinal liquid; Stir and mix erythritol, stevia sugar, starch syrup, and the medicinal liquid evenly in proportion to obtain a first compound sugar solution. Add the first compound sugar solution and a compound bacterium agent to the blanched and seed-removed citron pulp, and perform a primary fermentation to obtain primary fermented citron pulp; Mix hyaluronic acid, starch syrup, konjac gum, and water evenly to obtain a second compound sugar solution. Immerse the primary fermented citron pulp in the second compound sugar solution for secondary fermentation, and then dry it to obtain citron candied fruit.

[0006] The pericarp and pulp of Citrus medica are separately subjected to blanching treatment, which not only retains the aromatic substances in the pericarp and the crispy texture of the pulp, but also inactivates enzyme activity through high temperature to effectively prevent browning. Loquat leaves, white chrysanthemum and other herbal raw materials are boiled together with the peel of Citrus medica to extract the medicinal liquid, and the discarded part of the peel is converted into an active ingredient carrier rich in the efficacy of moistening the lungs and relieving cough. Erythritol and stevioside are used to replace granulated sugar, and starch syrup is combined to adjust the sweetness and viscosity. Through fermentation with a compound bacterium agent, unique flavor substances are produced while reducing the risk of sugar intake. The specific ratio of the first compound sugar solution to the pulp ensures the balance of sugar solution penetration and bacterium agent activity. Hyaluronic acid and konjac gum form a water-retaining gel layer, and through secondary fermentation, the taste is further improved and the phenomenon of sugar sand return is effectively inhibited, and finally high-quality preserved fruits with both nutritional functions and stable texture are prepared.

[0007] Optionally, the medicinal liquid is composed of the following raw materials in parts by weight: 2-10 parts of loquat leaves, 15-25 parts of the peel of Citrus medica, 2-7 parts of white chrysanthemum, 1-6 parts of Fritillaria cirrhosa D. Don and 1-8 parts of mint.

[0008] The medicinal liquid is prepared by combining natural plant raw materials in a specific ratio, realizing the efficient utilization and functional enhancement of the peel of Citrus medica, solving the problem of discarded peel and retaining its aromatic compounds and medicinal components. Loquat leaves, as a traditional ingredient for moistening the lungs, cooperate with the peel of Citrus medica to play the role of relieving cough and reducing phlegm. The addition amount of white chrysanthemum is 2-7 parts, balancing the heat-clearing effect and flavor interference; Fritillaria cirrhosa D. Don provides saponin active substances; mint not only enhances the cool flavor but also expands the antibacterial function. By precisely controlling the proportion of each component, this compound system forms a medicinal liquid base with multiple functions such as relieving cough and asthma, antibacterial and anti-inflammatory while retaining the characteristic aroma of Citrus medica, effectively solving the technical defect of single efficacy of traditional preserved fruits.

[0009] Optionally, the first compound sugar solution is composed of the following raw materials in mass ratio: 5-20 wt% of erythritol; 5-20 wt% of stevioside; 25-40 wt% of starch syrup; 2-65 wt% of the medicinal liquid.

[0010] The compound sugar solution replaces traditional granulated sugar, reducing calories and enhancing functionality while retaining sweetness. Erythritol, as a natural sugar substitute, can reduce calorie intake, stevioside synergistically enhances sweetness and inhibits the growth of microorganisms, starch syrup prevents sugar sand return in preserved fruits through its anti-crystallization property, erythritol and stevioside ensure the sweetness threshold, and starch syrup prevents crystal separation on the premise of ensuring sufficient viscosity. Excessive starch syrup will cause the viscosity of the first compound sugar solution to be too high. The ratio control of the three takes into account both sweetness and texture stability. The medicinal liquid balances the concentration of functional components and the osmotic pressure of the sugar solution, and synergistically acts with sugars during the fermentation process, endowing the preserved fruits with the function of moistening the lungs and relieving cough, and at the same time promoting the dissolution of effective components in the peel through sugar solution penetration.

[0011] Optionally, the mass ratio of the scalded and pitted citron pulp to the first compound sugar solution is 1:1-3.

[0012] By controlling the contact area and infiltration depth between the sugar solution and the pulp, erythritol and stevioside in the sugar solution are evenly diffused into the pulp, replacing traditional white sugar to achieve low calories while avoiding sugar sanding. This ratio range effectively avoids excessive softening of the pulp tissue caused by excessive sugar solution, and at the same time prevents insufficient fermentation caused by insufficient sugar solution, thus ensuring stable metabolic activity of the flora during fermentation, promoting moderate degradation of pulp fibers and generation of flavor substances, and finally achieving efficient conversion of active ingredients and uniform coordination of the texture of the candied fruit. At this ratio, the viscous environment formed by the starch syrup slows down the oxidation of active ingredients, and the fritillaria cirrhosa saponin in the medicinal liquid is fully adsorbed by the pulp as the sugar solution penetrates. The bacterial agent maintains stable activity under the condition of moderate sugar concentration, promotes the decomposition of pulp fibers into soluble dietary fiber, and at the same time inhibits the reproduction of miscellaneous bacteria. When the ratio of the sugar solution is less than 1.5, the sugar film coverage on the surface of the pulp is insufficient, resulting in excessive local fermentation; when it is higher than 3, the excessive sugar solution hinders the diffusion of oxygen and inhibits the metabolic process of aerobic bacteria.

[0013] Optionally, the second compound sugar solution is composed of raw materials in the following mass ratio: Hyaluronic acid 0.5-1.5wt%; Starch syrup 1-10wt%; Konjac gum 0.1-2.0%; The balance is water; The molecular weight of the hyaluronic acid is 3000-5000 kDa.

[0014] The raw material ratio of the second compound sugar solution and the molecular weight range of hyaluronic acid synergistically solve the texture and functional problems of the candied fruit. As a natural moisturizing factor, hyaluronic acid can effectively maintain the moisture of the pulp without producing a sticky feeling; the high molecular weight hyaluronic acid with a molecular weight of 3000-5000 kDa can form a stable hydration layer. The starch syrup replaces traditional white sugar, not only significantly reducing the sweetness, but also using its anti-crystallization property to prevent sugar sanding. Konjac gum is used as a gelling agent at a low addition amount of 0.1-2.0% to construct a three-dimensional network structure, significantly enhancing the elasticity of the candied fruit. The second compound sugar solution can effectively promote the release of functional components and precisely regulate the texture during the secondary fermentation stage, and finally form a flexible and palatable candied fruit product.

[0015] Optionally, the steps of scalding the citron peel and scalding and pitting the citron pulp include: Cut the citron peel into filaments with a width of 1-3 mm and steam it at 95 °C for 3-8 min; Cut the citron pulp into slices with a thickness of 3-5 mm, remove the seeds, and place them in a container, and then heat them in a water bath at 85°C for 5-15 minutes.

[0016] Cut the citron peel into fine filaments of specific size and combine with short-term steaming with high-temperature steam, which can not only effectively destroy the rough fiber structure of the peel and release aromatic compounds, but also avoid the loss of active ingredients caused by long-term high-temperature treatment. The optimized combination of the morphology of the peel filaments and the steaming parameters can significantly improve the extraction efficiency of the medicinal liquid. The pulp is cut into thin slices and treated by water bath heating, which can not only maintain the integrity of the pulp morphology, but also soften and sterilize the pulp by precisely controlling the temperature and time, providing an ideal matrix for subsequent fermentation, ensuring the uniform penetration of the sugar solution during fermentation, and effectively avoiding the texture deterioration caused by excessive damage to the pulp.

[0017] Optionally, the steps of boiling the loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint in water and filtering to obtain the medicinal liquid include: Mix the loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint, put them into water and boil for 20-40 minutes, filter the residue, and then cool the medicinal liquid to 40°C and keep it at a constant temperature for standby.

[0018] By optimizing the preparation time and storage conditions of the medicinal liquid, the extraction efficiency and activity retention of the active ingredients are improved. The boiling time is strictly limited within the range of 20-40 minutes, which can not only fully extract the active substances in raw materials such as loquat leaves and citron peel, such as aromatic compounds and saponins, but also avoid the decomposition or volatilization of components caused by long-term high-temperature heating. The volatile components in mint will be lost due to excessive heating. After filtering the residue, cooling the medicinal liquid to 40°C not only removes the raw material residue and avoids its impact on the subsequent fermentation stability, but also reduces the temperature difference between the medicinal liquid and the fermentation environment by cooling to near the fermentation temperature, thereby reducing the risk of damage to the microbial activity. Keeping it at a constant temperature ensures the stability of the active ingredients in the medicinal liquid and prevents microbial contamination or chemical reactions caused by temperature fluctuations.

[0019] Optionally, the compound bacterium agent is a mixture of Lactobacillus plantarum and Saccharomyces cerevisiae, and the mass ratio of Lactobacillus plantarum to Saccharomyces cerevisiae is 1:0.5-2; the mass ratio of the compound bacterium agent to the blanched and de-seeded citron pulp is 1-3:100.

[0020] By defining the specific composition and ratio of the compound bacterium agent, the problem of single function of strains in the traditional candied fruit fermentation process is effectively solved. Lactobacillus plantarum can effectively inhibit the reproduction of miscellaneous bacteria and promote the softening of pulp, and Saccharomyces cerevisiae significantly enhances the generation of flavor substances through the sugar metabolism process. By defining the mass ratio, not only the balance of the activities of the strains is ensured, but also the inhibition phenomenon of metabolites caused by the imbalance of the ratio is avoided. This specific ratio can maintain the stability of the pH value of the fermentation system, promote the effective release of active ingredients such as fritillaria cirrhosa saponins, and prevent the destruction of the natural aroma of citron by over-fermentation.

[0021] Optionally, the fermentation temperature of the first fermentation is 30°C, the fermentation time of the first fermentation is 12 - 48 h, and it is stirred for 1 min every 12 h; the fermentation temperature of the second fermentation is 25°C, and the fermentation time of the second fermentation is 6 - 24 h.

[0022] The first fermentation temperature is set at 30°C, which provides the best metabolic environment for the synergistic action of Lactobacillus plantarum and Saccharomyces cerevisiae. This temperature not only ensures that the bacterial flora effectively decomposes the fiber structure of citron pulp and generates flavor precursor substances within 48 hours, but also avoids the risk of cell inactivation caused by too high temperature. Stirring is to control the pH value of the system to be between 4.0 - 4.5, promoting sugar conversion and the dissolution of Chinese herbal medicine components. The second fermentation adopts a low temperature condition of 25°C and a fermentation cycle of 24 hours, which not only ensures the full penetration of the hyaluronic acid and konjac gum composite sugar solution into the pulp tissue, but also reduces the risk of damage to the generated active ingredients by high temperature. At the same time, the metabolism of lactic acid bacteria further inhibits spoilage bacteria, thus promoting the formation of a stable colloidal coating structure during the second fermentation process. The temperature gradient design and time ratio of the two fermentations jointly construct a dynamic balance system for the efficient proliferation of probiotics and the preservation of heat-sensitive functional components.

[0023] Optionally, the viable count of the citron candied fruit is greater than or equal to 1×10^ 6 CFU / g, and the content of fritillaria cirrhosa saponins in the citron candied fruit is greater than or equal to 0.5 mg / g.

[0024] By the synergistic action of the two-stage fermentation process and the compound bacterium agent, the total amount of viable microorganisms in the candied fruit finished product is increased. During the first fermentation process, a specific ratio of Lactobacillus plantarum and Saccharomyces cerevisiae is mixed, which can promote the maintenance of cell activity. At the same time, during the second fermentation stage, over-sterilization is avoided through temperature control, thus ensuring the survival rate of probiotics in the final product. The content of fritillaria cirrhosa saponins refers to the concentration of active substances derived from the medicinal liquid components in the candied fruit, which can be specifically achieved through the low-temperature extraction process of fritillaria cirrhosa during the medicinal liquid decoction stage. For example, the decoction temperature is controlled below the boiling point and the heating time is shortened, so as to reduce the decomposition of saponins. At the same time, the transfer of saponins to the pulp tissue is promoted through the osmotic action of the composite sugar solution.

[0025] The beneficial effects of the present invention are as follows: By means of the liquid medicine extraction and the two - stage compound sugar liquid fermentation process, combined with the low - calorie sugar source and the functional ingredient retention technology, the problems of material waste, single flavor, high sugar content and sugar sand return in the existing citron preserves are solved, and the advantages of improving the healthiness of the product and the market competitiveness are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of a preparation method of a fermented citron preserve provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. 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 making creative efforts belong to the scope of protection of the present invention.

[0028] Figure 1 It is a flowchart of a preparation method of a fermented citron preserve provided by an embodiment of the present application. As Figure 1 shown, the method includes the following steps: S10. Wash the citron and separate the citron peel and the citron pulp, blanch the citron peel, and remove the seeds from the citron pulp and then blanch it; S20. Mix loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint in proportion and then put them into water and boil, and filter to obtain the liquid medicine; S30. Stir - mix erythritol, stevia sugar, starch syrup, and the liquid medicine evenly to obtain the first compound sugar liquid, add the first compound sugar liquid and the compound bacterium agent to the blanched and seed - removed citron pulp, and perform primary fermentation to obtain the primary - fermented citron pulp; S40. Mix hyaluronic acid, starch syrup, konjac gum, and water evenly to obtain the second compound sugar liquid, immerse the primary - fermented citron pulp in the second compound sugar liquid for secondary fermentation, and then dry it to obtain the citron preserve.

[0029] In the technical solution provided by this application, by separately performing blanching treatment on the pericarp and pulp of Citrus medica, the oxidase in the pericarp and pulp of Citrus medica is inactivated by high-temperature steam, the aromatic substances of the pericarp and the crispy texture of the pulp are retained, browning of the pericarp and pulp during subsequent processing is prevented and the original texture is retained. The pericarp is used for the preparation of medicinal liquid, converting the discarded part into a carrier of functional components; during the preparation of the medicinal liquid, the active ingredients in loquat leaves, blanched Citrus medica pericarp, white chrysanthemums, Fritillaria cirrhosa D. Don, and mint are extracted, and compounds with the efficacy of moistening the lungs and relieving cough are effectively extracted by controlling the boiling time and the ratio of raw materials; the first compound sugar solution generates organic acids and esters under the synergistic action of Lactobacillus plantarum and Saccharomyces cerevisiae, endowing the candied fruit with a unique flavor. Erythritol and stevioside in the first compound sugar solution can reduce the calories of Citrus medica, and starch syrup helps to adjust the viscosity and permeability of the sugar solution. The pulp after the first fermentation is immersed in the second sugar solution containing hyaluronic acid, and hyaluronic acid and konjac gum form a water-retaining gel layer to wrap the surface of the pulp. The residual sugar is further decomposed through the second fermentation to form a uniform sugar coating layer and improve the softness of the taste; flavor substances are generated in the pulp after the first fermentation, and the second fermentation focuses on improving the texture of the candied Citrus medica and inhibiting sugar sanding.

[0030] Optionally, the medicinal liquid is made from the following raw materials in parts by weight: 2 - 10 parts of loquat leaves, 15 - 25 parts of Citrus medica pericarp, 2 - 7 parts of white chrysanthemums, 1 - 6 parts of Fritillaria cirrhosa D. Don, and 1 - 8 parts of mint.

[0031] Loquat leaves refer to the dried leaves of the Rosaceae plant Eriobotrya japonica. Specifically, the triterpenoid compounds contained in it can be released by boiling water extraction to enhance the function of moistening the lungs and relieving cough. Citrus medica pericarp refers to the outer epidermis of the Citrus medica fruit. The volatile components such as limonene and linalool contained in it can be retained by shredding processing, serving both as a carrier of medicinal efficacy and endowing the product with characteristic aroma. White chrysanthemums refer to the dried capitula of the Compositae plant Chrysanthemum morifolium. Specifically, the content of chlorogenic acid can be maintained by low-temperature drying treatment to balance the heat-clearing efficacy and taste coordination in the formula. Fritillaria cirrhosa D. Don refers to the dried bulb of the Liliaceae plant Fritillaria cirrhosa D. Don. The dissolution of saponin substances can be promoted through crushing pretreatment to achieve the slow release of active substances at a low addition amount. Mint refers to the dried stems and leaves of the Labiatae plant Mentha haplocalyx Briq. Specifically, menthol can be extracted by distillation method, and the synergistic effect of the cool flavor and antibacterial function can be achieved by controlling the addition ratio.

[0032] Optionally, the first compound sugar solution is composed of the following raw materials in mass ratio: 5 - 20 wt% of erythritol, 5 - 20 wt% of stevioside, 25 - 40 wt% of starch syrup, and 20 - 65 wt% of medicinal liquid.

[0033] Erythritol refers to a natural sugar alcohol sweetener that binds to sweet receptors to produce sweetness but does not participate in the sugar metabolism pathway during metabolism. Stevioside refers to a high-sweetness natural sweetener extracted from Stevia rebaudiana, which can be achieved with steviol glycosides with a purity of ≥95%. Its sweetness is about 200-300 times that of sucrose and it is stable under acidic conditions. Starch syrup refers to a glucose syrup made by hydrolyzing corn starch, which can be specifically achieved with a liquid syrup with a DE value of 38-42. The mixture of glucose and maltose it contains can form an anti-crystallization system. The combination of erythritol and stevioside forms a synergistic sweetening system. The former provides a sense of volume and a cool sweetness, and the latter compensates for the sweetness intensity. The total proportion of the two controlled within the range of 14-70 wt% can balance the sweetness threshold and the calorie value. The minimum addition amount of 25 wt% of starch syrup forms a viscous matrix through the intermolecular hydrogen bond interaction between its glucose and maltose, effectively blocking the water migration path to prevent sugar recrystallization. The liquid medicine can ensure a sufficient concentration of plant active ingredients within the concentration range of 45-70 wt%, and at the same time avoid excessive osmotic pressure from affecting the pulp cell structure. The flavonoids it contains undergo the Maillard reaction with sugars during fermentation to generate flavor substances.

[0034] Optionally, the mass ratio of the blanched and pitted citron pulp to the first compound sugar solution is 1:1-3.

[0035] The fibrous structure of the citron pulp is conducive to the penetration of the first compound sugar solution and the attachment of microorganisms. The mass ratio of the citron pulp to the first compound sugar solution within the range of 1:1-3 can balance the osmotic pressure and the sugar concentration, ensuring that the pulp cells absorb water and swell moderately without bursting, while maintaining the nutrient supply required for the metabolism of the microbial community; when the ratio of the blanched and pitted citron pulp to the first compound sugar solution is less than 1, the sugar film coverage on the pulp surface is insufficient, resulting in excessive local fermentation; when it is higher than 3, the excessive first compound sugar solution hinders oxygen diffusion and inhibits the metabolic process of aerobic bacteria.

[0036] Optionally, the second compound sugar solution is composed of the following raw materials in mass ratio: hyaluronic acid 0.5-1.5 wt%, starch syrup 1-10 wt%, konjac gum 0.1-2.0 wt%, and the balance is water; the molecular weight of the hyaluronic acid is 3000-5000 kDa.

[0037] Hyaluronic acid refers to a natural high-molecular polysaccharide with a specific molecular weight, and the molecular weight range is controlled between 3000-5000 kDa. This molecular weight range can form a stable hydrated layer structure and play a long-term moisturizing role in candied fruits. Starch syrup can replace granulated sugar to achieve an anti-crystallization effect. Konjac gum refers to a water-soluble dietary fiber extracted from konjac tubers, which forms a three-dimensional network structure after swelling and can enhance the elasticity of candied fruits.

[0038] This solution uses starch syrup to replace granulated sugar, effectively reducing the product's calories and preventing sugar sanding during storage while maintaining the palatability of the candied fruit. The synergistic effect of hyaluronic acid and konjac gum enables the candied fruit to form a stable moist texture, while promoting the retention and release of functional components. Konjac gum can achieve texture improvement at a specific low concentration, avoiding the gelatinous texture caused by excessive addition. The introduction of starch syrup optimizes and upgrades the sugar composition while maintaining the sweetness. The reasonable ratio of water ensures that each component fully penetrates into the pulp, forming a uniform texture characteristic.

[0039] Optionally, the steps of blanching the citron peel and blanching the citron pulp after removing the seeds include: cutting the citron peel into filaments with a width of 1-3 mm and steaming them with steam at 95 °C for 3-8 min; cutting the citron pulp into slices with a thickness of 3-5 mm, removing the seeds, placing them in a container, and heating them in a water bath at 85 °C for 5-15 min. [[ID=४]]

[0040] A width of 1-3 mm for the citron peel can balance the degree of fiber structure damage and the retention rate of active ingredients. A thickness of 3-5 mm for the citron pulp is conducive to the penetration of the sugar solution and maintaining the morphological integrity of the pulp. The filamentous form increases the surface area of the peel, enabling the steam to uniformly penetrate the fiber bundle, quickly destroying the wax layer on the surface of the peel and the coarse fiber inside, and promoting the release of aromatic compounds; at the same time, short-term high-temperature treatment can avoid the browning problem caused by the continuous action of polyphenol oxidase. Through precise control of the water bath heating parameters for the thin slices of the pulp, on the premise of ensuring moderate softening of the pulp cell wall, it avoids the texture collapse caused by excessive dissolution of pectin, providing a stable matrix for the uniform penetration of the sugar solution and the microbial agent during the subsequent fermentation process.

[0041] Optionally, the step of mixing loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint, boiling them in water, and filtering to obtain the medicinal liquid includes: mixing loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint, boiling them in water for 20-40 min, filtering the residue, and cooling the medicinal liquid to 40 °C and storing it at a constant temperature for standby.

[0042] [[ID=1२]]In the stage of preparing the medicinal liquid, saponins and flavonoids in the raw materials need to be promoted to dissolve through appropriate heating, but long-term high temperature will damage volatile components. By limiting the upper limit of the boiling time, the excessive volatilization of low-boiling substances such as menthol can be avoided; the lower limit ensures the full release of poorly soluble components such as fritillaria cirrhosa saponins. Cooling the medicinal liquid to 40 °C, which is close to the subsequent fermentation temperature, can avoid the precipitation of macromolecular substances such as hyaluronic acid caused by sudden cooling, reduce the metabolic delay of the composite microbial agent due to temperature difference, further inhibit the reproduction of miscellaneous bacteria, and maintain the uniformity of the medicinal liquid components.

[0043] Optionally, the compound bacterial agent is a mixture of Lactobacillus plantarum and Saccharomyces cerevisiae, and the mass ratio of Lactobacillus plantarum to Saccharomyces cerevisiae is 1:0.5 - 2; the mass ratio of the compound bacterial agent to the blanched and pitted citron pulp is 1 - 3:100.

[0044] During the fermentation process, Lactobacillus plantarum preferentially consumes free sugars and reduces the environmental pH value, inhibiting the reproduction of spoilage bacteria while softening the tissue structure of citron pulp, creating suitable conditions for subsequent yeast metabolism. Subsequently, Saccharomyces cerevisiae utilizes the remaining sugars for ethanol fermentation, and the esters produced synergistically interact with the volatile components of the citron itself to form a compound flavor. When the mass ratio is controlled within 1:0.5 - 2, the growth curves of the two bacteria form a time difference, ensuring that the yeast becomes active after Lactobacillus plantarum completes the preliminary acidification, and avoiding the inhibition of lactic acid bacteria activity by premature ethanol production.

[0045] Optionally, the fermentation temperature of the first fermentation is 30 °C, and the fermentation time of the first fermentation is 12 - 48 h; the fermentation temperature of the second fermentation is 25 °C, and the fermentation time of the second fermentation is 6 - 24 h.

[0046] During the 48-hour first fermentation process at 30 °C, the enzyme system produced by the microbial community continuously acts on the citron pulp fibers, gradually decomposing pectin and cellulose to form a porous structure. At this time, the growth rate of the bacterial cells and the consumption efficiency of the substrate reach a dynamic balance, avoiding both the autolysis of bacterial cells caused by too high temperature and the fermentation lag caused by low temperature environment. After transferring to the second fermentation stage at 25 °C, the viscosity of the sugar solution moderately increases with the decrease in temperature, enabling konjac gum and hyaluronic acid to form a gel network in the pores of the pulp. This network structure can encapsulate the active substances produced during the first fermentation. The 24-hour fermentation cycle can not only ensure that the sugar solution fully infiltrates into the core area of the pulp but also reduce the thermal decomposition risk of components such as fritillaria cirrhosa saponins by shortening the high-temperature exposure time.

[0047] Optionally, the viable count of the citron candied fruit is greater than or equal to 1×10^6 CFU / g, and the content of fritillaria cirrhosa saponins in the citron candied fruit is greater than or equal to 0.5 mg / g.

[0048] In the first fermentation stage, the compound bacterial agent ferments for 48 hours at a specific temperature, and the metabolites of the bacterial cells form an acidic environment to inhibit the growth of miscellaneous bacteria, enabling the viable bacteria to stably proliferate. When decocting the medicinal liquid, the boiling time is controlled to reduce the damage to the saponin structure caused by high temperature for fritillaria cirrhosa saponins. In the second fermentation stage, a protective gel layer is formed through the compound sugar solution of hyaluronic acid and konjac gum, slowing down the oxidative loss of active ingredients and promoting the combination of saponins and pulp fibers. During the two drying processes, a gradient heating method is adopted to avoid local overheating leading to the inactivation of bacterial cells and the degradation of saponins.

[0049] The preparation method of the fermented citron candied fruit involved in the present application will be specifically described below in conjunction with specific examples and comparative examples: Example Example 1 Wash the citron and separate the citron peel and the citron pulp. Cut the citron peel into filaments with a width of 1 mm, and steam it for 3 min with steam at 95 °C for blanching. Remove the seeds from the citron pulp, cut it into slices with a thickness of 3 mm, place them in a container, and heat them in a water bath at 85 °C for 5 min for blanching; Mix 2 g of loquat leaves, 15 g of blanched citron peel, 2 g of white chrysanthemums, 1 g of fritillaria cirrhosa, and 1 g of mint, then put them into 79 g of water and boil for 20 min. Filter the residue to obtain the medicinal liquid, cool the medicinal liquid to 40 °C and keep it at a constant temperature for standby.

[0050] After stirring and mixing 5 g of erythritol, 5 g of stevioside, 25 g of starch syrup, and 65 g of the medicinal liquid evenly, obtain the first compound sugar liquid; mix 10 g of Lactobacillus plantarum and 5 g of Saccharomyces cerevisiae evenly to obtain the compound microbial agent; add 100 g of the first compound sugar liquid and 1 g of the compound microbial agent to 100 g of the blanched and de-seeded citron pulp, and ferment it in a sealed state at 30 °C and pH = 4.2 for 24 h, stirring for 1 min every 12 h; dry the citron pulp at 70 °C for 30 min to obtain the once-fermented citron pulp; Mix 0.5 g of hyaluronic acid with a molecular weight of 3000 kDa, 1 g of starch syrup, 0.1 g of konjac gum, and 98.4 g of water evenly to obtain the second compound sugar liquid. Immerse the once-fermented citron pulp in 100 g of the second compound sugar liquid and stir for 20 min, then let it stand at 25 °C for 6 h for secondary fermentation. Dry the citron pulp after secondary fermentation at 80 °C for 2 h to obtain the citron candied fruit. Finally, vacuum can the citron candied fruit and seal it with nitrogen.

[0051] Example 2 A preparation method of fermented citron candied fruit is made through the following steps: Wash the citron and separate the citron peel and the citron pulp. Cut the citron peel into filaments with a width of 3 mm, and steam it for 8 min with steam at 95 °C for blanching. Remove the seeds from the citron pulp, cut it into slices with a thickness of 5 mm, place them in a container, and heat them in a water bath at 85 °C for 15 min for blanching; Mix 10 g of loquat leaves, 25 g of citron peel, 7 g of white chrysanthemums, 6 g of fritillaria cirrhosa, and 8 g of mint, then put them into 44 g of water and boil for 40 min. Filter the residue to obtain the medicinal liquid, cool the medicinal liquid to 40 °C and keep it at a constant temperature for standby.

[0052] After stirring and mixing 20 g of erythritol, 20 g of stevioside, 40 g of starch syrup, and 20 g of medicinal liquid evenly, the first compound sugar solution is obtained; 10 g of Lactobacillus plantarum and 20 g of Saccharomyces cerevisiae are mixed evenly to obtain a compound microbial agent; 100 g of the first compound sugar solution and 3 g of the compound microbial agent are added to 100 g of the pericarpium citri sarcodactylis pulp after blanching and seed removal, and sealed fermentation is carried out at 30 °C and pH = 4.2 for 48 h, with stirring for 1 min every 12 h; the pericarpium citri sarcodactylis pulp is dried at 70 °C for 30 min to obtain the once-fermented pericarpium citri sarcodactylis pulp; 0.5 g of hyaluronic acid with a molecular weight of 3000 kDa, 1 g of starch syrup, 0.1 g of konjac gum, and 98.4 g of water are mixed evenly to obtain the second compound sugar solution. The once-fermented pericarpium citri sarcodactylis pulp is immersed in 100 g of the second compound sugar solution and stirred for 20 min, then left standing at 25 °C for 24 h for secondary fermentation. The pericarpium citri sarcodactylis pulp after secondary fermentation is dried at 80 °C for 2 h to obtain candied pericarpium citri sarcodactylis. Finally, the candied pericarpium citri sarcodactylis is vacuum canned and sealed with nitrogen.

[0053] Example 3 A preparation method of candied pericarpium citri sarcodactylis by fermentation is made through the following steps: The pericarpium citri sarcodactylis is washed and the pericarpium citri sarcodactylis peel and pericarpium citri sarcodactylis pulp are separated. The pericarpium citri sarcodactylis peel is cut into filaments with a width of 3 mm and steamed with steam at 95 °C for 5 min for blanching. The pericarpium citri sarcodactylis pulp is seeded-removed and cut into slices with a thickness of 5 mm, then placed in a container and water-bath heated at 85 °C for 10 min for blanching; 6 g of Folium Eriobotryae, 20 g of pericarpium citri sarcodactylis peel, 4 g of Flos Chrysanthemi, 3 g of Bulbus Fritillariae Thunbergii, and 4 g of Herba Menthae are mixed and put into 63 g of water and boiled for 30 min. After filtering the residue, the medicinal liquid is obtained. The medicinal liquid is cooled to 40 °C and kept at a constant temperature for standby.

[0054] 13 g of erythritol, 13 g of stevioside, 32 g of starch syrup, and 42 g of medicinal liquid are stirred and mixed evenly to obtain the first compound sugar solution; 10 g of Lactobacillus plantarum and 10 g of Saccharomyces cerevisiae are mixed evenly to obtain a compound microbial agent; 100 g of the first compound sugar solution and 3 g of the compound microbial agent are added to 100 g of the pericarpium citri sarcodactylis pulp after blanching and seed removal, and sealed fermentation is carried out at 30 °C and pH = 4.2 for 48 h, with stirring for 1 min every 12 h; the pericarpium citri sarcodactylis pulp is dried at 70 °C for 30 min to obtain the once-fermented pericarpium citri sarcodactylis pulp; 1.5 g of hyaluronic acid with a molecular weight of 3000 kDa, 5 g of starch syrup, 0.5 g of konjac gum, and 93 g of water are mixed evenly to obtain the second compound sugar solution. The once-fermented pericarpium citri sarcodactylis pulp is immersed in 100 g of the second compound sugar solution and stirred for 20 min, then left standing at 25 °C for 24 h for secondary fermentation. The pericarpium citri sarcodactylis pulp after secondary fermentation is dried at 80 °C for 4 h to obtain candied pericarpium citri sarcodactylis. Finally, the candied pericarpium citri sarcodactylis is vacuum canned and sealed with nitrogen.

[0055] Example 4 A preparation method of fermented citron preserves is made through the following steps: Wash the citron and separate the citron peel and the citron pulp. Cut the citron peel into filaments with a width of 3 mm, and steam it at 95 °C for 5 min for blanching. Remove the seeds from the citron pulp, cut it into slices with a thickness of 5 mm, place it in a container, and heat it in a water bath at 85 °C for 10 min for blanching; Mix 5 g of loquat leaves, 20 g of citron peel, 5 g of white chrysanthemum, 4 g of fritillaria cirrhosa, and 5 g of mint, put them into 61 g of water and boil for 30 min. After filtering the residue, obtain the medicinal liquid, cool the medicinal liquid to 40 °C and keep it at a constant temperature for standby.

[0056] After stirring and mixing 10 g of erythritol, 10 g of stevioside, 30 g of starch syrup, and 50 g of the medicinal liquid evenly, obtain the first composite sugar solution; Mix 10 g of Lactobacillus plantarum and 10 g of Saccharomyces cerevisiae evenly to obtain a composite microbial agent; Add 100 g of the first composite sugar solution and 3 g of the composite microbial agent to 100 g of the blanched and seed-removed citron pulp, and ferment it in a sealed manner at 30 °C and pH = 4.2 for 48 h, stirring for 1 min every 12 h; Dry the citron pulp at 70 °C for 30 min to obtain the once-fermented citron pulp; Mix 1.5 g of hyaluronic acid with a molecular weight of 3000 kDa, 5 g of starch syrup, 0.5 g of konjac gum, and 93 g of water evenly to obtain the second composite sugar solution. Immerse the once-fermented citron pulp in 100 g of the second composite sugar solution and stir for 20 min, then let it stand at 25 °C for 24 h for secondary fermentation. Dry the citron pulp after secondary fermentation at 80 °C for 4 h to obtain citron preserves. Finally, vacuum can the citron preserves and seal them with nitrogen filling.

[0057] Example 5 A preparation method of fermented citron preserves is made through the following steps: Wash the citron and separate the citron peel and the citron pulp. Cut the citron peel into filaments with a width of 3 mm, and steam it at 95 °C for 5 min for blanching. Remove the seeds from the citron pulp, cut it into slices with a thickness of 5 mm, place it in a container, and heat it in a water bath at 85 °C for 10 min for blanching; Mix 3 g of loquat leaves, 20 g of citron peel, 3 g of white chrysanthemum, 4 g of fritillaria cirrhosa, and 5 g of mint, put them into 65 g of water and boil for 30 min. After filtering the residue, obtain the medicinal liquid, cool the medicinal liquid to 40 °C and keep it at a constant temperature for standby.

[0058] After stirring and mixing 10 g of erythritol, 10 g of stevioside, 30 g of starch syrup, and 50 g of medicinal liquid evenly, a first composite sugar solution is obtained; 10 g of Lactobacillus plantarum and 10 g of Saccharomyces cerevisiae are mixed evenly to obtain a composite microbial agent; 100 g of the first composite sugar solution and 3 g of the composite microbial agent are added to 100 g of blanched and pitted citron pulp, and sealed fermentation is carried out at 30 °C and pH = 4.2 for 48 h, with stirring for 1 min every 12 h; the citron pulp is dried at 70 °C for 30 min to obtain once-fermented citron pulp; 1.5 g of hyaluronic acid with a molecular weight of 3000 kDa, 5 g of starch syrup, 0.5 g of konjac gum, and 93 g of water are mixed evenly to obtain a second composite sugar solution. The once-fermented citron pulp is immersed in 100 g of the second composite sugar solution and stirred for 20 min, and then left to stand at 25 °C for 24 h for secondary fermentation. The citron pulp after secondary fermentation is dried at 80 °C for 4 h to obtain candied citron. Finally, the candied citron is vacuum canned and sealed with nitrogen.

[0059] Example 6 A preparation method of fermented candied citron, which is different from Example 4 in that the molecular weight of hyaluronic acid is 5000 kDa.

[0060] Example 7 A preparation method of fermented candied citron, which is different from Example 4 in that the dosage of the composite microbial agent is 1 g.

[0061] Example 8 A preparation method of fermented candied citron, which is different from Example 4 in that the dosage of the composite microbial agent is 2 g.

[0062] Comparative Example Comparative Example 1 A preparation method of fermented candied citron, which is different from Example 4 in that the first composite sugar solution further includes 10 g of lactic acid and 10 g of dried osmanthus flowers.

[0063] Comparative Example 2 A preparation method of fermented candied citron, which is different from Example 4 in that the first composite sugar solution is composed of 50 g of medicinal liquid and 50 g of granulated sugar mixed evenly.

[0064] Comparative Example 3 A preparation method of fermented candied citron, which is different from Example 4 in that the second composite sugar solution is obtained by mixing 1.5 g of hyaluronic acid with a molecular weight of 3000 kDa, 5 g of granulated sugar, 0.5 g of konjac gum, and 93 g of water evenly.

[0065] Comparative Example 4 A preparation method of fermented citron candied fruit, which is different from Example 4 in that after stirring and mixing 10 g of erythritol, 10 g of stevioside, 30 g of starch syrup and 50 g of medicinal liquid evenly, a first compound sugar solution is obtained; 100 g of the first compound sugar solution and 3 g of Saccharomyces cerevisiae are added to 100 g of citron pulp, and fermentation is carried out in a closed state at 30 °C and pH = 4.2 for 48 h, with stirring for 1 min every 12 h; the citron pulp is dried at 70 °C for 30 min to obtain the once-fermented citron pulp.

[0066] Comparative Example 5 A preparation method of fermented citron candied fruit, which is different from Example 4 in that after stirring and mixing 10 g of erythritol, 10 g of stevioside, 30 g of starch syrup and 50 g of medicinal liquid evenly, a first compound sugar solution is obtained; 100 g of the first compound sugar solution and 3 g of Lactobacillus plantarum are added to 100 g of citron pulp, and fermentation is carried out in a closed state at 30 °C and pH = 4.2 for 48 h, with stirring for 1 min every 12 h; the citron pulp is dried at 70 °C for 30 min to obtain the once-fermented citron pulp.

[0067] Comparative Example 6 A preparation method of fermented citron candied fruit, which is different from Example 4 in that the dosage of the compound bacterial agent is 10 g.

[0068] Comparative Example 7 A preparation method of fermented citron candied fruit, which is different from Example 4 in that the dosage of the compound bacterial agent is 0.1 g.

[0069] Comparative Example 8 A preparation method of fermented citron candied fruit, which is different from Example 4 in that the molecular weight of hyaluronic acid is 1000 kDa.

[0070] Comparative Example 9 A preparation method of fermented citron candied fruit, which is different from Example 4 in that the molecular weight of hyaluronic acid is 10000 kDa.

[0071] The preparation methods of the fermented citron candied fruits in Examples 2-8 and Comparative Examples 1-9 are the same as those in Example 1.

[0072] Performance detection For the citron candied fruits provided in Examples 1-8 and Comparative Examples 1-9 of the present invention, the following performance detections are carried out. Table 1 shows the performance detection results.

[0073] Sugar content (except erythritol): Take 5 g of the candied citrons of Examples 1-8 and Comparative Examples 1-9 respectively, cut them into filaments with a thickness and width less than 2 mm, add them to 50 ml of water, and heat them in a water bath for 30 min. Stir during the process to fully dissolve the samples. After cooling, transfer the solution to a 250 mL volumetric flask, make up the volume, shake well, filter, discard the initial filtrate, and collect the subsequent filtrate for standby. Titrate with Fehling's reagent, and calculate the sugar content in the sample by the following formula:

[0074] Where: F——Sugar equivalent of Fehling's reagent (mg); D——Dilution factor of the sample; V1——Volume of the sample solution consumed (mL); M——Mass of the sample (g).

[0075] Erythritol content: Take 2 g of the candied citrons of Examples 1-8 and Comparative Examples 1-9 respectively, chop them and grind them into a homogeneous paste, place them in a 50 ml centrifuge tube, add 20 mL of ultrapure water to the centrifuge tube, ultrasonically extract for 20 min at 40 °C, then centrifuge at 8000 rpm for 10 min, filter the supernatant through a 0.22 μm aqueous filter membrane, discard the initial filtrate, and collect the subsequent filtrate for standby. Use an Aminex HPX-87H chromatographic column (mobile phase: 5 mM H2SO4, flow rate: 0.6 mL / min, column temperature: 60 °C), and a refractive index detector (RID) for quantification, and calculate the erythritol content in the sample by the following formula: % Where: C——Concentration of the sample solution (mg / mL, obtained from the standard curve); V——Volume made up (mL); D——Dilution factor; M——Mass of the sample (g).

[0076] Viable count of probiotics: Take 10 g of the candied citrons of Examples 1-8 and Comparative Examples 1-9 respectively, add 90 mL of sterile normal saline (containing 0.1 g of peptone), homogenize for 2 min to make a 1:10 dilution, and continuously dilute 10-fold to 10 -6 , take each dilution and spread it on the culture medium, anaerobically culture at 37 °C for 48 h, select 30-300 CFU for plate counting, calculate CFU / g according to the dilution factor, and the viable count of probiotics = number of colonies * dilution factor * 10^sample coefficient.

[0077] Content of fritillaria cirrhosa saponins: Weigh 1 g of the candied citrons of Examples 1-8 and Comparative Examples 1-9 respectively, grind them into powder, add them to 50 ml of 70% ethanol, extract ultrasonically for 30 min, centrifuge at 4000 rpm for 10 min, take the supernatant, repeat the extraction 3 times, combine the extracts, concentrate under reduced pressure to dryness, dissolve the residue in methanol and make up the volume to 10 ml to obtain the sample solution. Take 1 ml of the sample solution + 1 ml of 5% vanillin-glacial acetic acid solution, add 2 ml of perchloric acid, heat in a water bath at 60 °C for 15 min, cool in an ice bath, add 5 ml of glacial acetic acid, measure the absorbance at a wavelength of 560 nm with a UV-visible spectrophotometer, use ginsenoside Re as the standard product to make a standard curve, and calculate the total saponin content of the sample:

[0078] Wherein: C—the saponin concentration (mg / mL) calculated from the standard curve; V—the volume of sample made up (mL); D—the dilution factor (1 if not diluted); m—the mass of the sample (g).

[0079] Moisture content of the finished product: Weigh 5 g of the candied citrons of Examples 1-8 and Comparative Examples 1-9 respectively, cut them into pieces and place them in a weighing dish. Put the weighing dish into a drying oven at 105 °C and dry for 4 h. Take it out and place it in a desiccator to cool for 30 min, then weigh it. Dry it again for 1 h, cool and weigh it until the difference between the two weighings is less than or equal to 0.002 g, and calculate the moisture content of the sample:

[0080] Wherein: m0—the mass of the weighing dish after constant drying (g); m1—the mass of the weighing dish + the sample before drying (g); m2—the mass of the weighing dish + the sample after drying (g).

[0081] Take 3 samples for each of the examples and comparative examples respectively, and take the average value of the test results. The specific test results are shown in Table 1.

[0082] Table 1 Performance Results

[0083] This application solves the problem of the loss of probiotic activity caused by the sterilization process in traditional citron preserves, enabling the product to have the function of regulating the intestinal flora. At the same time, by optimizing the decocting and fermentation parameters, the active ingredients of fritillaria cirrhosa d. don are effectively retained, endowing the preserves with the health care effect of moistening the lungs and relieving cough. The synergistic effect of these two indicators also improves the texture stability of the product, and no sugar sanding or flora imbalance occurs within the six-month shelf life.

[0084] Traditional preserve processing usually adopts a single high-temperature sterilization process, resulting in the number of viable bacteria in the finished product being lower than the detection limit and unable to possess probiotic functions. In the prior art, herbal components are only extracted by simple decoction without combining the fermentation process to promote the release of active substances, resulting in a loss rate of more than 60% of fritillaria cirrhosa saponins during the processing. However, in this solution, by controlling the fermentation temperature and time in stages, the survival rate of viable bacteria is increased by more than three times. At the same time, the components of the medicinal liquid gradually penetrate into the pulp tissue during the two fermentation processes, and the retention rate of saponins is increased to 85%.

[0085] In the preparation of traditional preserves, the ratio of pulp to sugar solution mostly adopts a fixed ratio of less than 1:1 or more than 1:4. The former causes the sugar solution to be unable to fully infiltrate the core of the pulp, and the latter causes sugar crystallization. By limiting the ratio range to 1:1.5 - 3, on the basis of avoiding pulp softening, the use of sugar substitutes in combination with the medicinal liquid forms a stable fermentation environment, overcoming the defects of uneven sugar solution penetration and flora inactivation in the traditional process.

[0086] Finally, it should be noted that the above are only optional examples of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing candied citron by fermentation, characterized in that, Including: Wash the citron, separate the citron peel and the citron pulp, blanch the citron peel, and remove the seeds from the citron pulp and then blanch it; Mix loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint in proportion, put them into water and boil, and obtain a medicinal liquid after filtration; Stir and mix erythritol, stevioside, starch syrup, and the medicinal liquid evenly in proportion to obtain a first compound sugar solution. Add the first compound sugar solution and a compound bacterium agent to the citron pulp that has been blanched and had its seeds removed, and perform primary fermentation to obtain primary fermented citron pulp; Mix hyaluronic acid, starch syrup, konjac gum, and water evenly in proportion to obtain a second compound sugar solution. Immerse the primary fermented citron pulp in the second compound sugar solution for secondary fermentation, and then dry it to obtain candied citron.

2. The preparation method according to claim 1, characterized in that, The medicinal liquid is made from the following raw materials in parts by weight: 2 - 10 parts of loquat leaves, 15 - 25 parts of citron peel, 2 - 7 parts of white chrysanthemum, 1 - 6 parts of fritillaria cirrhosa, and 1 - 8 parts of mint.

3. The preparation method according to claim 1, wherein, The first compound sugar solution is composed of the following raw materials in mass ratio: Erythritol 5 - 20wt%; Stevioside 5 - 20wt%; Starch syrup 25 - 40wt%; Medicinal liquid 20 - 65wt%.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the citron pulp that has been blanched and had its seeds removed to the first compound sugar solution is 1:1 - 3.

5. The preparation method according to claim 1, characterized in that, The second compound sugar solution is composed of the following raw materials in mass ratio: Hyaluronic acid 0.5 - 1.5wt%; Starch syrup 1 - 10wt%; Konjac gum 0.1 - 2.0wt%; The balance is water; The molecular weight of the hyaluronic acid is 3000 - 5000 kDa.

6. The preparation method according to claim 1, wherein, The steps of blanching the citron peel and removing the seeds from the citron pulp and then blanching it include: Cut the citron peel into filaments with a width of 1 - 3 mm, and steam it with 95°C steam for 3 - 8 min; Cut the citron pulp into slices with a thickness of 3 - 5 mm, remove the seeds, place them in a container, and heat them in a water bath at 85°C for 5 - 15 min.

7. The preparation method according to claim 1, wherein The steps of mixing loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint, putting them into water and boiling, and obtaining a medicinal liquid after filtration include: Mix loquat leaves, the blanched citron peel, white chrysanthemum, fritillaria cirrhosa, and mint, put them into water and boil for 20 - 40 min, filter the residue, and cool the medicinal liquid to 40°C and keep it at a constant temperature for standby.

8. The preparation method according to claim 1, characterized in that, The compound bacterium agent is a mixture of lactobacillus plantarum and saccharomyces cerevisiae, and the mass ratio of lactobacillus plantarum to saccharomyces cerevisiae is 1:0.5 - 2; the mass ratio of the compound bacterium agent to the citron pulp that has been blanched and had its seeds removed is 1 - 3:

100.

9. The preparation method according to claim 1, characterized in that, The fermentation temperature of the primary fermentation is 30°C, and the fermentation time of the primary fermentation is 12 - 48 h; the fermentation temperature of the secondary fermentation is 25°C, and the fermentation time of the secondary fermentation is 6 - 24 h.

10. The preparation method according to claim 1, characterized in that, The viable count of the candied citron is greater than or equal to 1×10^6 CFU / g, and the content of fritillaria cirrhosa saponin in the candied citron is greater than or equal to 0.5 mg / g.

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