Fermentation-method Yuring pomelo healthy preserved fruit and preparation method thereof
By processing the skin of Yuhuan pomelo through fermentation, combined with vacuum impregnation and low-temperature drying technology, the problems of difficult removal of bitter substances, uneven texture, loss of nutrients, and high production costs of Yuhuan pomelo preserves have been solved. This has resulted in the production of healthy preserves with unique flavor and texture, which meet the requirements of green food processing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG GUOHE IND CO LTD
- Filing Date
- 2026-04-03
- Publication Date
- 2026-05-12
AI Technical Summary
Existing technologies for preparing Yuhuan pomelo preserves suffer from problems such as difficulty in removing bitter substances, uneven texture, severe loss of nutrients, high production costs, and a lack of variety in product flavor. Furthermore, the environmental pollution and resource waste caused by traditional high-temperature processing are difficult to resolve.
The peel of Yuhuan pomelo is processed by fermentation. Bitter substances are degraded through fermentation with compound bacterial solution. Combined with vacuum impregnation and low-temperature drying technology, a candied fruit with unique flavor and texture is prepared.
It achieves effective degradation of bitter substances, high retention of nutrients, soft and palatable texture, rich flavor, reduces production energy consumption and resource consumption, and meets the requirements of green food processing.
Smart Images
Figure CN122004336A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of food processing technology, and in particular to a fermented Yuhuan pomelo health preserve and its preparation method. Background Technology
[0002] Yuhuan pomelo (Citrus grandis 'Tomentosa') is a superior variety of pomelo and a national geographical indication protected product. Its fruit is fragrant, juicy, and has a unique taste and high nutritional value. However, after eating it fresh or juicing it, a large amount of peel (including the spongy layer) residue is produced, accounting for about 30%-45% of the weight of a single fruit. Traditionally, this pomelo peel is mostly discarded, except for a small amount used in making local snacks or as a raw material for traditional Chinese medicine (Huajuhong), resulting in a huge waste of biomass resources and potential environmental problems due to its accumulation and decay. From a nutritional and functional perspective, pomelo peel is a raw material with high-value development potential. Its white spongy layer (white pulp) is rich in dietary fiber, flavonoids (such as naringin), vitamins, and minerals, possessing high nutritional and health value. However, pomelo peel contains a large amount of bitter substances such as naringin and has a coarse and hard texture, making it extremely unpalatable to eat directly.
[0003] Currently, there have been some attempts to make candied fruit and preserves using pomelo peel, but the following problems are common: (1) Traditional processes usually involve long-term boiling (or repeated rinsing) to remove bitterness. This process causes serious damage to the cell structure of the peel and a large loss of water-holding components such as pectin. Even after subsequent sugar boiling, the product is very easy to become soft and shapeless or dry and rough, and cannot form an ideal soft or chewy texture. Simply relying on long-term boiling with high-concentration sugar solution can easily lead to excessive gelatinization on the outside and insufficient penetration inside, resulting in uneven texture inside and outside;
[0004] (2) The traditional process of boiling or simmering for a long time removes bitter substances such as naringin, but also causes a large amount of water-soluble vitamins, minerals, soluble dietary fiber and antioxidant flavonoids to be lost with the water, resulting in a significant reduction in the nutritional value of the final product. In terms of flavor, the unique aroma of grapefruit peel is also weakened due to the volatilization and loss caused by heat.
[0005] (3) Repeated boiling, long-term sugar soaking or simmering not only has a long production cycle, but also consumes a lot of water and heat energy, resulting in high processing costs, which does not conform to the energy-saving and consumption-reducing trend of modern food processing.
[0006] (4) The grapefruit peel preserves produced by existing technologies generally have problems such as dull color (browning), prominent sweetness, bitter aftertaste, or monotonous texture, and lack high-quality products with distinctive characteristics.
[0007] In recent years, fermentation technology has been increasingly widely used in fruit and vegetable processing. Through the action of microorganisms or enzymes, bitter substances can be effectively degraded, texture improved, flavor compounds and functional components generated, while avoiding nutrient loss caused by high-temperature and long-term processing. However, there are currently no reports on the application of fermentation technology systems to the processing of Yuhuan pomelo preserves. Therefore, this invention proposes a fermentation method for making healthy Yuhuan pomelo preserves and its preparation method to solve the problems existing in the prior art. Summary of the Invention
[0008] To address the aforementioned problems, the present invention aims to propose a fermented method for preparing Yuhuan pomelo preserves and its preparation method. The present invention provides a Yuhuan pomelo preserve with a unique taste, a pleasantly sweet and sour flavor, good color, and high nutrient retention.
[0009] To achieve the objectives of this invention, the invention is implemented through the following technical solution: a fermented Yuhuan pomelo health candied fruit and its preparation method, comprising the following steps:
[0010] Step 1: Pre-treatment of raw materials: Select fresh, unrotten Yuhuan pomelos, take the white spongy layer, remove the surface oil cells, and then cut them into strips or blocks to obtain Yuhuan pomelo skin blanks.
[0011] Step 2, Fermentation treatment: Immerse the Yuhuan pomelo peel blanks in a sugar solution, then inoculate with a compound bacterial solution for fermentation. After fermentation, process to obtain fermented material.
[0012] Step 3: Prepare the mixed impregnation solution: Prepare seven components: white sugar, malt syrup, citric acid, malic acid, sodium citrate, salt and calcium lactate. Then dissolve the seven components together in water to prepare the mixed impregnation solution.
[0013] Step 4, Vacuum Impregnation: The fermented material obtained in Step 2 is immersed in the mixed impregnation solution obtained in Step 3, wherein the mass ratio of the fermented material to the mixed impregnation solution is 1:1 to 1:2, and then impregnation is carried out under vacuum conditions.
[0014] Step 5: Drying: Remove the impregnated blanks and drain them, then dry them until the moisture content is 15% to 25%.
[0015] Step 6, Packaging: Cool the dried raw material to room temperature and then vacuum or nitrogen-filled package it to obtain Yuhuan pomelo preserves.
[0016] A further improvement is made in step two, where the sugar content in the sugar solution is 2% to 10%, and the mass of the Yuhuan pomelo peel is 30% to 60% of the mass of the sugar solution.
[0017] A further improvement is that, in step two, the compound bacterial solution contains Lactobacillus plantarum, Bacillus subtilis, and yeast, and the volume ratio of Lactobacillus plantarum, Bacillus subtilis, and yeast is 2-4:1-3:1-2.
[0018] The further improvement lies in the following: In step two, the fermentation temperature is 20℃~40℃, the time is 12~72h, and the pH value is 3.0~6.0.
[0019] A further improvement is made in the following step: In step three, the mass percentage of each component in the mixed impregnation solution is as follows: 20%–50% white sugar, 10%–30% malt syrup, 0.5%–1.0% citric acid, 0.1%–0.5% malic acid, 0.1%–0.5% sodium citrate, 0.1%–0.5% salt, 0.1%–0.5% calcium lactate, and the remainder is water.
[0020] A further improvement is that the mass ratio of white sugar to maltose syrup in the mixed impregnation solution is 3:1 to 1:1.
[0021] A further improvement is made in that the vacuum impregnation conditions are: vacuum degree 0.06MPa~0.09MPa, temperature 10℃~50℃, and time 30~180min.
[0022] A further improvement is made in step five, where the drying temperature is 50℃~85℃ and the time is 4~10h.
[0023] A type of preserved pomelo from Yuhuan prepared by the method described above.
[0024] The beneficial effects of this invention are as follows:
[0025] (1) This invention uses fermentation pretreatment to enable microbial metabolism to effectively decompose bitter substances such as naringin, thereby fundamentally reducing bitterness. At the same time, the organic acids, alcohols, esters and other substances produced during fermentation can give the dried fruit a richer, smoother and more layered complex flavor, avoiding a single sweetness.
[0026] (2) The fermentation process can partially soften the fiber structure of the pomelo skin, improve its texture, and make it more palatable after subsequent vacuum impregnation and drying. At the same time, fermentation is a mild biological processing process. Therefore, this invention replaces high-temperature cooking with mild biological processing and vacuum low-temperature impregnation, which effectively reduces the loss of water-soluble vitamins, flavonoids and minerals.
[0027] (3) Because the fermentation process consumes less energy and partially replaces the chemical or physical debittering steps, it reduces water consumption and wastewater discharge, which is more in line with the green and sustainable development direction of the modern food industry.
[0028] (4) The final product is light yellow to amber in color, semi-transparent, and has the aroma of fermentation and the sweet and sour taste of soaking. It has a chewy texture on the outside and a soft texture on the inside, with a harmonious and full flavor and no bitter aftertaste. It is a distinctive healthy snack. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the steps of the present invention. Detailed Implementation
[0030] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.
[0031] In the following examples, all raw materials were commercially purchased. The strains used in the following examples, including Lactobacillus plantarum, Bacillus subtilis, and Saccharomyces cerevisiae, are all common strains widely used in the food industry. The corresponding commercial fermentation agents or freeze-dried bacterial powders can be purchased from professional food additive suppliers, biological product companies, or microbial preparation manufacturers.
[0032] Example 1
[0033] according to Figure 1 As shown in the figure, this embodiment proposes a method for preparing Yuhuan pomelo preserves using fermentation, including the following steps:
[0034] Step 1: Pre-treatment of raw materials: Select fresh Yuhuan pomelos, take 1000g of white spongy layer, remove the surface oil cells, and cut into strips of about 1cm×4cm to obtain Yuhuan pomelo skin blanks.
[0035] Step 2: Fermentation Treatment: Prepare 2000g of a sugar solution with a sugar content of 5%. Immerse the entire dough in the solution, then inoculate with 40mL of a compound bacterial solution composed of *Lactobacillus plantarum*, *Bacillus subtilis*, and yeast in a volume ratio of 3:2:1 (inoculation amount 2%, based on the total mass of the dough and sugar solution). Ferment at 30℃ for 48 hours, allowing the pH to naturally decrease to approximately 3.8. After fermentation, remove the dough and drain.
[0036] Step 3: Preparation of the mixed impregnation solution: Weigh 900g of granulated sugar, 400g of maltose syrup, 12g of citric acid, 4g of malic acid, 4g of sodium citrate, 4g of salt, and 0.4g of calcium lactate. Add an appropriate amount of purified water, stir, and heat to 50℃ to completely dissolve the sugar. Finally, bring the volume to a total of 2000g. The mass ratio of granulated sugar to maltose syrup in the resulting mixed impregnation solution is 2.25:1.
[0037] Step 4, Vacuum Impregnation: Immerse all the drained fermented dough pieces in the above mixed impregnation solution (the mass ratio of dough pieces to impregnation solution is approximately 1:2), then seal the system and evacuate it to -0.09 MPa (absolute pressure approximately 0.01 MPa) for 60 minutes.
[0038] Step 5: Drying: Remove the soaked dough pieces, drain them, spread them flat on a drying tray, and dry them at 70℃ for 6 hours.
[0039] Step 6: Packaging: Cool the dried fruit to room temperature and vacuum pack it.
[0040] The resulting product has a moisture content of about 20%, a translucent amber color, a chewy exterior and a soft interior, a balanced sweet and sour taste, a mellow flavor from fermentation, and no bitterness.
[0041] Example 2
[0042] according to Figure 1 As shown in the figure, this embodiment proposes a method for preparing Yuhuan pomelo preserves using fermentation, including the following steps:
[0043] Step 1: Pre-treatment of raw materials: Select fresh Yuhuan pomelos, take 1000g of white spongy layer, remove the surface oil cells, and cut into strips of about 1cm×4cm to obtain Yuhuan pomelo skin blanks.
[0044] Step 2, Fermentation Treatment: Prepare 1667g of a sugar solution with a sugar content of 2%. Immerse 600g of the hide (the hide's mass is approximately 36% of the sugar solution's mass) in the solution. Inoculate with 22.7mL of a compound bacterial solution consisting of *Lactobacillus plantarum*, *Bacillus subtilis*, and yeast in a volume ratio of 2:1:1 (inoculation amount approximately 1%). Ferment at 20℃ for 12 hours, maintaining the pH at approximately 6.0. Drain after fermentation.
[0045] Step 3: Prepare the mixed impregnation solution: Weigh 400g of white sugar, 600g of malt syrup, 10g of citric acid, 2g of malic acid, 2g of sodium citrate, 2g of salt, and 2g of calcium lactate. Add water to make up to a total volume of 2000g. In the resulting mixed impregnation solution, the mass ratio of white sugar to malt syrup is 1:1.5.
[0046] Step 4, Vacuum Impregnation: Immerse the fermented dough in the mixed impregnation solution (the mass ratio of dough to impregnation solution is 1:1), then evacuate to -0.06 MPa (absolute pressure is about 0.04 MPa), and impregnate at 10℃ for 30 minutes.
[0047] Step 5: Drying: Remove the soaked dough pieces, drain them, spread them flat on a drying tray, and dry them at 50℃ for 10 hours.
[0048] Step 6: Packaging: Cool the dried fruit to room temperature and vacuum pack it.
[0049] The resulting product has a moisture content of about 25%, a light yellow color, a more pliable texture, and a refreshing sweet and sour taste.
[0050] Example 3
[0051] according to Figure 1 As shown in the figure, this embodiment proposes a method for preparing Yuhuan pomelo preserves using fermentation, including the following steps:
[0052] Step 1: Pre-treatment of raw materials: Select fresh Yuhuan pomelos, take 1000g of white spongy layer, remove the surface oil cells, and cut into pieces of about 1cm×1cm to obtain Yuhuan pomelo skin blanks.
[0053] Step 2, Fermentation Treatment: Prepare 1000g of a sugar solution with a sugar content of 10%. Immerse 600g of the dough pieces in the solution (the weight of the dough pieces is approximately 60% of the weight of the sugar solution). Inoculate with 80mL of a compound bacterial solution consisting of *Lactobacillus plantarum*, *Bacillus subtilis*, and yeast in a volume ratio of 4:3:2 (inoculation amount approximately 5%). Ferment at 40℃ for 72 hours, maintaining the pH at approximately 3.0. Drain after fermentation.
[0054] Step 3: Prepare the mixed impregnation solution: Weigh 1000g of white sugar, 200g of malt syrup, 20g of citric acid, 10g of malic acid, 10g of sodium citrate, 10g of salt, and 10g of calcium lactate. Add water to make up to a total volume of 2000g. The mass ratio of white sugar to malt syrup in the resulting mixed impregnation solution is 5:1.
[0055] Step 4, Vacuum Impregnation: Immerse the fermented dough in the mixed impregnation solution (the mass ratio of dough to impregnation solution is 1:1.5), then evacuate to -0.09 MPa and impregnate at 50°C for 180 min.
[0056] Step 5: Drying: Remove the soaked dough pieces, drain them, spread them flat on a drying tray, and dry them at 85℃ for 4 hours.
[0057] Step 6: Packaging: Cool the dried fruit to room temperature and vacuum pack it.
[0058] The resulting product has a moisture content of about 15%, a deep amber color close to brown, a firmer and chewier texture, and a rich flavor.
[0059] Comparative Example
[0060] This comparative example uses a traditional sugar-cooking process: 1000g of fresh Yuhuan pomelo with white pulp, from the same source and part (white spongy layer) as in Example 1, was selected and cut into strips of the same specifications as in Example 1. The strips were then rinsed under running water for 48 hours to remove bitterness, with the water changed several times during this period. Afterward, the strips were drained and placed in a jacketed kettle. 2000g of a 60% (by mass) white sugar solution was added (sugar solution to strip mass ratio of 2:1). The mixture was heated to a gentle boil and simmered for 30 minutes. This sugar-cooking process was repeated three times, each time with a fresh 60% sugar solution, for a total simmering time of 90 minutes. Finally, the strips were removed, drained of the sugar solution, and dried at 70℃ for 6 hours until the moisture content was approximately 20%. After cooling, they were vacuum-packed.
[0061] Comparing the comparative product with the product of Example 1, in terms of appearance and color, the product of this invention is translucent amber, crystal clear, while the comparative product is opaque dark yellow or light brown, with a dull color. This indicates that the vacuum impregnation process used in this invention effectively avoids adverse reactions such as Maillard browning caused by prolonged high-temperature cooking, demonstrating the superior quality of the product in terms of color.
[0062] In terms of taste and texture, the product of this invention has a chewy exterior and a soft interior, with a uniform texture and good chewability. In contrast, the comparative product has a soft and mushy exterior and a dry and hard interior, with an uneven texture, and is easily broken or sticky. This proves that the present invention effectively protects the cell structure of the raw materials by softening the fibrous tissue through fermentation and combining it with gentle penetration under vacuum conditions, avoiding the serious damage to the texture caused by traditional boiling, and achieving the unique texture of a chewy exterior and a soft interior.
[0063] In terms of flavor, the product of this invention has a pleasantly sweet and sour taste, a harmonious and full flavor, and a mellow aroma produced by fermentation, without any bitter aftertaste; while the comparative product is excessively sweet, has a single flavor, and is accompanied by a noticeable residual bitterness. This directly confirms that the present invention, through compound bacterial fermentation, can fundamentally and effectively degrade bitter substances such as naringin and generate rich flavor components, achieving a fundamental improvement in flavor.
[0064] Regarding the retention rates of key nutrients, tests were conducted (vitamin C was determined using the 2,6-dichlorophenolindophenol titration method; total flavonoids were calculated using the aluminum nitrate-sodium nitrite colorimetric method, based on naringin, with fresh white pulp as the baseline). The vitamin C retention rate of the product of this invention was approximately 82%, and the total flavonoid retention rate was approximately 78%. In contrast, the vitamin C retention rate of the comparative product was only approximately 35%, and the total flavonoid retention rate was only approximately 42%. These data clearly demonstrate that the method of this invention can significantly reduce the loss of water-soluble and heat-sensitive nutrients, providing direct and strong experimental evidence for the core beneficial effect of "high nutrient retention rate."
[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its framework and scope of application, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.
Claims
1. A fermented healthy pomelo preserve from Yuhuan and its preparation method, characterized in that: Includes the following steps: Step 1: Pre-treatment of raw materials: Select fresh, unrotten Yuhuan pomelos, take the white spongy layer, remove the surface oil cells, and then cut them into strips or blocks to obtain Yuhuan pomelo skin blanks. Step 2, Fermentation treatment: Immerse the Yuhuan pomelo peel blanks in a sugar solution, then inoculate with a compound bacterial solution for fermentation. After fermentation, process to obtain fermented material. Step 3: Prepare the mixed impregnation solution: Prepare seven components: white sugar, malt syrup, citric acid, malic acid, sodium citrate, salt and calcium lactate. Then dissolve the seven components together in water to prepare the mixed impregnation solution. Step 4, Vacuum Impregnation: The fermented material obtained in Step 2 is immersed in the mixed impregnation solution obtained in Step 3, wherein the mass ratio of the fermented material to the mixed impregnation solution is 1:1 to 1:2, and then impregnation is carried out under vacuum conditions. Step 5: Drying: Remove the impregnated blanks and drain them, then dry them until the moisture content is 15% to 25%. Step 6, Packaging: Cool the dried raw material to room temperature and then vacuum or nitrogen-filled package it to obtain Yuhuan pomelo preserves.
2. The fermented Yuhuan pomelo health preserve and its preparation method according to claim 1, characterized in that: In step two, the sugar content in the sugar solution is 2% to 10%, and the mass of the Yuhuan pomelo peel is 30% to 60% of the mass of the sugar solution.
3. The fermented Yuhuan pomelo health candied fruit and its preparation method according to claim 1, characterized in that: In step two, the compound bacterial solution contains Lactobacillus plantarum, Bacillus subtilis, and yeast, and the volume ratio of Lactobacillus plantarum, Bacillus subtilis, and yeast is 2-4:1-3:1-2.
4. The fermented Yuhuan pomelo health candied fruit and its preparation method according to claim 1, characterized in that: In step two, the fermentation temperature is 20℃~40℃, the time is 12~72h, and the pH value is 3.0~6.
0.
5. The fermented Yuhuan pomelo health candied fruit and its preparation method according to claim 1, characterized in that: In step three, the mass percentage of each component in the mixed impregnation solution is as follows: 20%–50% white sugar, 10%–30% malt syrup, 0.5%–1.0% citric acid, 0.1%–0.5% malic acid, 0.1%–0.5% sodium citrate, 0.1%–0.5% salt, 0.1%–0.5% calcium lactate, and the remainder is water.
6. The fermented Yuhuan pomelo health preserve and its preparation method according to claim 5, characterized in that: In the mixed impregnation solution, the mass ratio of white sugar to malt syrup is 3:1 to 1:
1.
7. The fermented Yuhuan pomelo health candied fruit and its preparation method according to claim 1, characterized in that: The vacuum impregnation conditions are: vacuum degree 0.06MPa~0.09MPa, temperature 10℃~50℃, and time 30~180min.
8. The fermented Yuhuan pomelo health candied fruit and its preparation method according to claim 1, characterized in that: In step five, the drying temperature is 50℃~85℃ and the time is 4~10h.
9. A type of preserved pomelo from Yuhuan, prepared by any one of claims 1 to 8.