Brittle high-fiber low-sugar nata de coco as well as preparation method and application thereof
By employing gradient cooling to construct interpenetrating networks and porous inclusion structures in coconut jelly production, the problem of controlling the texture and sweetness in coconut jelly production was solved, enabling the preparation of crisp, high-fiber, low-sugar coconut jelly and improving the hardness and crispness of coconut jelly as well as the slow-release effect of sweetness.
Patent Information
- Application Number
- CN202511151564.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-18
- Publication Date
- 2025-11-11
AI Technical Summary
The existing coconut jelly production process has shortcomings in terms of taste experience and sweetness control, especially in pursuing the ideal crispness and chewiness as well as avoiding a lingering feeling, and further process optimization is needed.
A fiber-reinforced composite gel solution was injected into the shallow-tray fermentation system of *Acetobacter xylosiderin*. A three-stage structural regulation was achieved through gradient cooling to construct an interlocking framework of starch and cellulose. Calcium lactate was sprayed to crosslink sodium alginate to form an interpenetrating network. The solution was combined with an impregnation solution of β-cyclodextrin/zinc citrate coordination complex for sustained sweetness release and bitterness masking.
It significantly improves the crispness of coconut jelly and achieves slow release of low-sugar sweetness through a porous encapsulation structure, thereby enhancing the quality and application range of coconut jelly.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of food processing technology, specifically relating to a crispy, high-fiber, low-sugar coconut jelly, its preparation method, and its application. Background Technology
[0002] Coconut jelly, hailed as "white gold," is a unique gel-like bacterial cellulose made primarily from natural coconut water through fermentation with Acetobacter xylinum. It has a white or milky-white color, a smooth texture, and good chewiness, making it one of the best dietary fibers discovered to date. It also helps prevent constipation, has antioxidant properties, absorbs and removes toxins from food, and optimizes the digestive system environment. Due to its excellent hydrophilicity, water-holding capacity, stability, gelling properties, and complete indigestibility, coconut jelly can be used in the food industry as a thickener, colloidal filler, and food ingredient.
[0003] Due to varying technical levels and processes among coconut jelly manufacturers, the taste experience of coconut jelly products fluctuates. Some products require further process optimization to achieve the ideal oral texture (such as suitable firmness and chewiness) and avoid any lingering aftertaste. Currently, the commonly used processing method involves rinsing and deacidifying, followed by boiling in white sugar. While this method completes the basic processing, its effectiveness in fully softening the fiber and coordinating sweetness with natural flavor requires further exploration and improvement. Summary of the Invention
[0004] Technical Problem to be Solved: To address the aforementioned technical problems, the purpose of this invention is to provide a crispy, high-fiber, low-sugar coconut jelly, its preparation method, and its application. A fiber-reinforced composite gel solution is injected into a shallow-pan fermentation system of *Acetobacter xylodis*. A three-stage structural regulation is achieved through gradient cooling: first, the bacterial cellulose network expands and permeates; then, a starch-cellulose interlocking framework is induced; finally, calcium lactate is sprayed to crosslink sodium alginate to form an interpenetrating network, significantly improving crispness. The resulting coconut jelly is then immersed in an impregnation solution containing a β-cyclodextrin / zinc citrate coordination complex. The porous inclusion structure enables slow-release of sweetness and masking of bitterness, ultimately producing crispy, high-fiber, low-sugar coconut jelly.
[0005] Technical solution: A method for preparing crispy, high-fiber, low-sugar coconut jelly, comprising the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium, and let it ferment in a shallow dish at 30-37℃ for 5-6 days to obtain the initial fermentation broth; S2. After heating the initial fermentation broth to 50-55℃, inject the fiber-reinforced composite gel solution and react for 1.5-2 hours. Then, cool the broth to 38-40℃ and react for 2.5-3 hours. Finally, cool the broth to 24-26℃ and spray in a 5.5-6.5 vt% calcium lactate solution. React for 10-12 hours, allow to stand, filter, and cut to obtain coconut jelly. S3. Immerse the coconut jelly in the soaking solution, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0006] Furthermore, in step S1, the inoculation amount of *Acetobacter xylinum* seed solution is 15-20%.
[0007] Furthermore, the fermentation culture medium in step S1 is formulated as follows: sucrose 40-50 g / L, fructose syrup 10-20 g / L, coconut milk 15-20 g / L, glacial acetic acid 6-12 g / L, and soybean peptone 5-7 g / L.
[0008] Furthermore, the preparation method of the fiber-reinforced composite gel solution in step S2 is as follows: (1) Dissolve high amylose corn starch in water to prepare a starch solution of 30-35 wt%. Stir at 250-300 rpm for 30-40 min, add 0.1-0.2 M HCl, bathe in a 50℃ water bath for 1.5-2 h, and add glacial acetic acid to adjust the pH to 5 to obtain acid-hydrolyzed starch. (2) Heat the acid-hydrolyzed starch to 75-85℃, stir at 250-300rpm for 20-30min, homogenize at 120-140MPa for 2-3 times, cool in a water bath at 4℃, wash with deionized water, and dry under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. (3) Dissolve 1.8-2wt% acid-hydrolyzed-microfibrillated modified starch, 0.9-1.1wt% sodium alginate, 1.4-1.6wt% polydextrose and 0.05-0.1wt% calcium lactate in water and stir at 200-300rpm and 50-55℃ for 30-40min to obtain fiber-reinforced composite gel solution.
[0009] Furthermore, in step S2, the volume ratio of the initial fermentation broth to the fiber-reinforced composite gel solution is 1:(0.15-0.2).
[0010] Furthermore, the preparation steps of the impregnation solution in step S3 are as follows: Step 1. Dissolve 1.2-1.8 wt% β-cyclodextrin and 0.04-0.06 wt% zinc citrate in water, stir at 58-60℃ and 200-300 rpm for 25-35 min to form a β-cyclodextrin / zinc citrate coordination complex solution; Step 2. Add 0.2-0.4 wt% citric acid, 0.015-0.02 wt% sucralose and 0.08-0.12 wt% natural coconut flavoring to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained.
[0011] Furthermore, in step S3, the ratio of coconut jelly to impregnation liquid is 1:(3-3.5).
[0012] The above preparation method produces crispy, high-fiber, low-sugar coconut jelly.
[0013] The above-mentioned application of crispy, high-fiber, low-sugar coconut jelly in jelly.
[0014] Beneficial effects: 1. In this invention, a fiber-reinforced composite gel (acid-hydrolyzed-microfibrillated modified starch + sodium alginate + polydextrose) is added before the end of the coconut jelly fermentation process, and a gradient cooling treatment is performed: (1) First, the temperature is raised to 50-55℃ for 1.5-2h (fluid penetration period). Under this environment, the metabolism of *Acetobacter xyloside* stops but it does not die. Moderate acid hydrolysis can reduce the molecular weight by cutting the α-1,4 glycosidic bonds of the amorphous region of starch (controlling the degree of polymerization to about 200). After the starch is gelatinized by acid hydrolysis, it is subjected to high pressure homogenization shearing. The amylose is oriented to assemble through hydrophobic interaction to form nanofiber bundles, which form a hydrogen bond interlocking structure with bacterial cellulose (BC). In addition, the molecular chains of sodium alginate are stretched and weak cross-linked with low concentration of calcium lactate. The solubility of polydextrose increases, the viscosity of the system decreases, and the movement of starch fibers is promoted. The composite gel system is in a sol state at this time. When the bacterial cellulose obtained from the early fermentation comes into contact with the composite gel, it expands instantly and the pores are enlarged, which allows the composite gel to penetrate deeply into the pores of the bacterial cellulose network. If the acid hydrolysis is excessive, the molecular chains will be too short, the amylose will be degraded into oligosaccharides, lose the ability to self-assemble, destroy the ability of starch to form fiber bundles and microcrystalline nodes, and thus cause the systemic collapse of the coconut network structure. (2) Next, the temperature is lowered to 38-40℃ for 2.5-3h (starch skeleton construction period). At this time, the linear segments of acid hydrolysis-microfibrillation modified starch form microcrystalline nodes through hydrophobic association. The hydroxyl groups on the surface of bacterial cellulose form hydrogen bond arrays with the hydroxyl groups of acid hydrolyzed starch fibers to construct the "starch-cellulose" interlocking skeleton. (3) Finally, the temperature is lowered to 24-26℃ for 10-12 hours (network interpenetration solidification period), and calcium lactate solution is sprayed into the fermentation system to crosslink with sodium alginate, forming sodium alginate-Ca 2+ The network interweaves through the gaps in the starch-cellulose skeleton. The microcrystalline nodes of the acid-hydrolyzed and microfibrillated starch form hydrogen bonds with the sodium alginate chains, synergistically enhancing mechanical strength. Finally, a ternary interpenetrating network is formed in the fermentation system, improving the crispness of coconut jelly.
[0015] 2. In this invention, the prepared coconut jelly is added to an impregnation solution containing a β-cyclodextrin / zinc citrate coordination complex, citric acid, sucralose, and natural coconut flavoring. The hydrophobic groups of the citric acid in the zinc citrate are embedded in the β-cyclodextrin cavity. 2+ By coordinating with the hydroxyl groups of β-cyclodextrin to form a coordination complex, the complex has a porous structure that can adsorb sweet molecules, achieving sustained release in the mouth, reducing the amount of sweetener used, and achieving low sugar content. In addition, sucralose is a commonly used sweetener in the preparation of coconut jelly, and the cavity of β-cyclodextrin is also conducive to encapsulating the residual bitter molecules of sucralose. Finally, a crispy, high-fiber, low-sugar coconut jelly is prepared, improving the quality of coconut jelly and broadening its application in products such as jelly. Detailed Implementation
[0016] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments: The fermentation medium formula is: 40 g / L sucrose, 20 g / L fructose syrup, 20 g / L coconut milk, 12 g / L glacial acetic acid, and 5 g / L soybean peptone.
[0017] Acetobacter xylodis was purchased from Wuhan Gray Algae Biotechnology Co., Ltd.
[0018] Example 1 A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch powder, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 50°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.15, react for 1.5 hours, cool to 38°C and react for 2.5 hours, then cool to 24°C and spray in 6 wt% calcium lactate solution, react for 10 hours, let stand, filter, and cut to obtain coconut jelly. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0019] Example 2 A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 50°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.2 and react for 2 hours. Then, cool the broth to 40°C and react for 2.5 hours. After cooling the broth to 24°C, spray in a 6 wt% calcium lactate solution and react for 12 hours. Allow the mixture to stand, filter, and cut to obtain coconut jelly. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0020] Example 3 A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.15, react for 1.5 hours, cool down to 38°C and react for 3 hours, then cool down to 25°C and spray in 6 wt% calcium lactate solution, react for 10 hours, let stand, filter, and cut to obtain coconut jelly. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0021] Example 4 A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 25°C and spray in 6 wt% calcium lactate solution, react for 12 hours, let stand, filter, and cut to obtain coconut jelly. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0022] Example 5 A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.2, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 26°C and spray in 6 wt% calcium lactate solution, react for 12 hours, let stand, filter, and cut to obtain coconut jelly. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3.5, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0023] Comparative Example 1 The difference between this comparative example and Example 4 is that gradient cooling was not used; the coconut jelly was prepared directly by thermosetting, as detailed below: A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation liquid to 55°C, inject the fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, then heat to 85°C to solidify for 15 minutes, let stand, filter, and cut to obtain coconut jelly. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7 Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly. Comparative Example 2
[0024] The difference between this comparative example and Example 4 is that acid-hydrolyzed-microfibrillated modified starch was not added to the fiber-reinforced composite gel solution, as detailed below: A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve 1 wt% sodium alginate, 1.5 wt% polydextrose and 0.1 wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S3. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 25°C and spray in 6 wt% calcium lactate solution, react for 12 hours, let stand, filter, and cut to obtain coconut jelly. S4. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S5. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S6. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly. Comparative Example 3
[0025] The difference between this comparative example and Example 4 lies in the addition of unmodified high amylose corn starch to the fiber-reinforced composite gel solution, as detailed below: A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve 2wt% high amylose corn starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S3. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 25°C and spray in 6 wt% calcium lactate solution, react for 12 hours, let stand, filter, and cut to obtain coconut jelly. S4. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S5. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S6. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly. Comparative Example 4
[0026] The difference between this comparative example and Example 4 is that the calcium lactate solution was not sprayed in, as detailed below: A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 55°C, inject the fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 25°C and react for 12 hours. After standing, filtering and cutting, the coconut jelly is obtained. S6. Dissolve 1.5wt% β-cyclodextrin and 0.05wt% zinc citrate in water, stir at 58℃ and 200rpm for 35min to form a β-cyclodextrin / zinc citrate coordination complex solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavor to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly. Comparative Example 5
[0027] The difference between this comparative example and Example 4 is that β-cyclodextrin was not added to the impregnation solution, as detailed below: A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 25°C and spray in 6 wt% calcium lactate solution, react for 12 hours, let stand, filter, and cut to obtain coconut jelly. S6. Dissolve 0.05wt% zinc citrate in water and stir at 58℃ and 200rpm for 35min to form a zinc citrate solution; S7. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavoring to the zinc citrate solution, stir, and the impregnation solution is obtained; S8. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly. Comparative Example 6
[0028] The difference between this comparative example and Example 4 is that the β-cyclodextrin / zinc citrate coordination complex was not added to the impregnation solution, as detailed below: A method for preparing crispy, high-fiber, low-sugar coconut jelly includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium at an inoculation amount of 20%, and let it ferment in a shallow dish at 33°C for 6 days to obtain the initial fermentation broth; S2. Dissolve high amylose corn starch in water to prepare a 33wt% starch solution. Stir at 300 rpm for 30 min, add 0.15 M HCl, incubate in a 50℃ water bath for 2 h, and adjust the pH to 5 with glacial acetic acid to obtain acid-hydrolyzed starch. S3. The acid-hydrolyzed starch was heated to 85℃, stirred at 300rpm for 30min, homogenized under high pressure at 140MPa three times, cooled in a water bath at 4℃, washed with deionized water, and dried under vacuum at 40℃ to obtain acid-hydrolyzed-microfibrillated modified starch. S4. Dissolve 2wt% acid-hydrolyzed-microfibrillated modified starch, 1wt% sodium alginate, 1.5wt% polydextrose and 0.1wt% calcium lactate in water, stir at 250 rpm and 50℃ for 35 min to obtain fiber-reinforced composite gel solution. S5. After heating the initial fermentation broth to 55°C, inject fiber-reinforced composite gel solution at a volume ratio of 1:0.18, react for 2 hours, cool down to 40°C and react for 3 hours, then cool down to 25°C and spray in 6 wt% calcium lactate solution, react for 12 hours, let stand, filter, and cut to obtain coconut jelly. S6. Add 0.3wt% citric acid, 0.02wt% sucralose and 0.1wt% natural coconut flavoring to water and stir to obtain the impregnation solution; S7. Immerse the coconut jelly in the soaking solution with a material-to-liquid ratio of 1:3, vacuum penetrate at -0.08MPa for 30 minutes, soak at normal pressure for 2 hours, and drain to obtain crispy high-fiber low-sugar coconut jelly.
[0029] Performance testing: (1) Texture characteristics The texture of coconut jelly was analyzed using a British SMS TA .XTPlus texture analyzer (TA .XTPlus physical property tester). A P / 25 cylindrical probe was selected, the test speed was 10 mm / s, the compression ratio was 30%, the residence time was 50 s, and the initial force was 30 g. The coconut jelly was placed on the test platform and squeezed twice. The average value was taken to determine the hardness, elasticity, and brittleness.
[0030] Table 1. Texture properties of the crispy, high-fiber, low-sugar coconut jelly prepared in Examples 1-5 and Comparative Examples 1-6
[0031] As shown in Table 1, the high hardness and brittleness of the coconut jelly prepared in the examples are due to the interpenetrating network constructed by gradient cooling. The construction of the interpenetrating network in the examples restricts the deformation recovery ability of the polymer chain, sacrificing some elasticity in exchange for increased brittleness. Comparative Examples 1-4 lack a rigid skeleton, the network is softer, it is easy to recover after compression, and has better elasticity, while the hardness and brittleness are significantly reduced.
[0032] (2) Determination of dietary fiber content The enzyme-gravimetric method was used for determination. Coconut samples were pulverized and passed through a 100-mesh sieve. 50 mL of phosphate buffer was added, and the mixture was vortexed. Then, 0.1 mL of heat-stable α-amylase was added, and the mixture was incubated at 95°C for 30 min. After cooling to 60°C, 0.1 mL of protease was added to hydrolyze the protein, and the mixture was incubated at 60°C for 30 min. The pH was adjusted to 4.5, and 0.1 mL of amylase was added. The mixture was incubated at 60°C for 30 min, and then 4 times the volume of 95% ethanol was added to precipitate the fiber. The mixture was allowed to stand at room temperature for 1 h, then vacuum filtered. The residue was washed successively with 78% ethanol, 95% ethanol, and acetone. The residue was dried in a 105°C oven to constant weight, cooled, and weighed to obtain the residue mass m1. The total dietary fiber content was calculated by subtracting ash (m2) and protein (m3) using the following formula:
[0033] The ash dry weight was determined according to GB 5009.4-2016 "National Food Safety Standard - Determination of Ash in Food", and the protein dry weight was determined according to GB 5009.5-2016 "National Food Safety Standard - Determination of Protein in Food".
[0034] Table 2. Dietary fiber content of the crispy, high-fiber, low-sugar coconut jelly prepared in Examples 1-5 and Comparative Examples 1-6
[0035] Table 2 shows that the dietary fiber content of the crispy high-fiber low-sugar coconut jelly prepared in Examples 1-5 is 8.0-8.5%, while the dietary fiber content of traditional coconut jelly (Comparative Example 1) is only 4.2%. Comparative Example 2 did not add acid-hydrolyzed-microfibrillated modified starch, lacked a starch skeleton, and could not bridge bacterial cellulose through hydrogen bonds, resulting in a low dietary fiber content. Comparative Example 3 added unmodified starch, but the unmodified starch particles were much larger than the BC pores and could not penetrate into the BC network, only physically adhering to the BC surface. The starch particles were easily detached during subsequent washing and cutting, leading to a decrease in the total fiber content. Comparative Example 4 did not spray-inject calcium lactate solution, and could not achieve the reaction of sodium alginate and Ca. 2+The cross-linking of the fibers resulted in the absence of a fiber network; changes in the impregnation solutions of Comparative Examples 5 and 6 did not affect the fiber structure.
[0036] (3) Brix content The total sugar content was determined using the phenol-sulfuric acid method.
[0037] Table 3 Total sugar content of crispy high-fiber low-sugar coconut jelly prepared in Examples 1-5 and Comparative Examples 1-6
[0038] As shown in Table 3, the total sugar content of the coconut jelly prepared in the examples was 1.7-2.0%, which was generally lower than that of the comparative examples. This is because the coconut jelly impregnation solution contained a β-cyclodextrin / zinc citrate coordination complex. The complex has a porous structure that can adsorb sweet molecules and achieve oral sustained release, thereby achieving low sugar content.
[0039] (4) Sensory evaluation The crisped, high-fiber, low-sugar coconut jelly prepared in Example 4 and Comparative Examples 1-6 was used for sensory evaluation. 50g of each sample was placed in a white coded cup at room temperature. Twenty evaluators who passed the basic taste test were selected to taste the jelly in turn. Rinsing the mouth was required before each tasting.
[0040] Table 4 Scoring Criteria
[0041] Table 5 Sensory evaluation results of coconut jelly prepared in Example 4 and Comparative Examples 1-6
[0042] As shown in Table 5, the crispy high-fiber low-sugar coconut jelly prepared in Example 4 had the best light transmittance due to the uniformity of its interpenetrating network. The impregnation solution contained a β-cyclodextrin / zinc citrate coordination complex, which utilized a porous inclusion structure to achieve sustained sweetness release and bitterness shielding, resulting in the highest overall score. Comparative Examples 1-4 had reduced appearance and crispness due to structural defects. Comparative Examples 5-6 lacked β-cyclodextrin, so their sweetness was higher, and their overall acceptability was correspondingly lower.
[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the present invention.
Claims
1. A method for preparing crispy, high-fiber, low-sugar coconut jelly, characterized in that, Includes the following steps: S1. Inoculate the seed culture of Acetobacter xyloside into the fermentation medium, and let it ferment in a shallow dish at 30-37℃ for 5-6 days to obtain the initial fermentation broth; S2. After heating the initial fermentation broth to 50-55℃, inject the fiber-reinforced composite gel solution and react for 1.5-2 hours. Then, cool the broth to 38-40℃ and react for 2.5-3 hours. Finally, cool the broth to 24-26℃ and spray in a 5.5-6.5 vt% calcium lactate solution. React for 10-12 hours, allow to stand, filter, and cut to obtain coconut jelly. S3. Immerse the coconut jelly in the soaking solution, vacuum permeate, soak under normal pressure, and drain to obtain crispy, high-fiber, low-sugar coconut jelly.
2. The method for preparing crispy, high-fiber, low-sugar coconut jelly according to claim 1, characterized in that: In step S1, the inoculation amount of *Acetobacter xylodis* seed solution is 15-20%.
3. The method for preparing crispy, high-fiber, low-sugar coconut jelly according to claim 1, characterized in that, The fermentation medium formula in step S1 is as follows: sucrose 40-50g / L, fructose syrup 10-20g / L, coconut milk 15-20g / L, glacial acetic acid 6-12g / L, and soybean peptone 5-7g / L.
4. The method for preparing crispy, high-fiber, low-sugar coconut jelly according to claim 1, characterized in that, The preparation method of the fiber-reinforced composite gel solution in step S2 is as follows: (1) Dissolve high amylose corn starch in water to prepare a starch solution of 30-35 wt%. Stir at 250-300 rpm for 30-40 min, add 0.1-0.2 M HCl, bathe in a 50℃ water bath for 1.5-2 h, and add glacial acetic acid to adjust the pH to 5 to obtain acid-hydrolyzed starch. (2) Heat the acid-hydrolyzed starch to 75-85℃, stir at 250-300rpm for 20-30min, homogenize at 120-140MPa for 2-3 times, cool in a water bath at 4℃, wash and dry to obtain acid-hydrolyzed-microfibrillated modified starch. (3) Dissolve 1.8-2wt% acid-hydrolyzed-microfibrillated modified starch, 0.9-1.1wt% sodium alginate, 1.4-1.6wt% polydextrose and 0.05-0.1wt% calcium lactate in water and stir at 200-300rpm and 50-55℃ for 30-40min to obtain fiber-reinforced composite gel solution.
5. The method for preparing crispy, high-fiber, low-sugar coconut jelly according to claim 1, characterized in that, In step S2, the volume ratio of the initial fermentation broth to the fiber-reinforced composite gel solution is 1:(0.15-0.2).
6. The method for preparing crispy, high-fiber, low-sugar coconut jelly according to claim 1, characterized in that, The preparation steps of the impregnation solution in step S3 are as follows: Step 1. Dissolve 1.2-1.8 wt% β-cyclodextrin and 0.04-0.06 wt% zinc citrate in water, stir at 58-60℃ and 200-300 rpm for 25-35 min to form a β-cyclodextrin / zinc citrate coordination complex solution; Step 2. Add 0.2-0.4 wt% citric acid, 0.015-0.02 wt% sucralose and 0.08-0.12 wt% natural coconut flavoring to the β-cyclodextrin / zinc citrate coordination complex solution, stir, and the impregnation solution is obtained.
7. The method for preparing crispy, high-fiber, low-sugar coconut jelly according to claim 1, characterized in that, In step S3, the ratio of coconut jelly to soaking liquid is 1:(3-3.5).
8. Crispy, high-fiber, low-sugar coconut jelly prepared by the preparation method according to any one of claims 1-7.
9. The application of the crisped high-fiber, low-sugar coconut jelly as described in claim 8 in jelly.