Kudzuvine root and konjak gel compound and preparation method thereof

Abstract

The invention provides a preparation method of a kudzuvine root and konjak gel compound, which comprises the following steps: adding kudzuvine root starch into a buffer solution to prepare slurry, and gelatinizing the slurry for the first time; cooling the slurry subjected to primary gelatinization, then adding pullulanase for enzymolysis, inactivating after enzymolysis is completed, cooling to room temperature, washing, and freeze-drying to obtain radix puerariae resistant starch; dissolving kudzuvine root resistant starch in water, then adding konjac glucomannan, and carrying out secondary gelatinization; after moisture lost in the secondary gelatinization process is supplemented, swelling is carried out; adding dietary alkali into the swollen material, uniformly stirring, standing for forming, demolding, and boiling to obtain the kudzu vine root and konjak gel compound; the invention also provides the Konjak gel compound prepared by the method. According to the method, production nodes are easy to control, the raw material cost is low, the process is simple, complex equipment is not needed, the method is suitable for large-scale processing production, and the prepared konjak gel compound product is wide in application scene and has a very good market prospect.

Description

Technical Field

[0001] This invention relates to the field of functional gel food technology, specifically to a kudzu root and konjac gel complex and its preparation method. Background Technology

[0002] Konjac glucomannan (KGM) is a natural water-soluble dietary fiber with excellent gelling properties, showing great promise for applications in food, medicine, and other fields. However, single konjac gel has the following problems: high gel brittleness, low mechanical strength, and easy breakage, making it difficult to meet the needs of high-toughness products; poor water retention, as konjac gel is prone to dehydration and shrinkage during storage, affecting product texture and taste; poor thermal stability, as traditional konjac gel easily softens or disintegrates at high temperatures (>100℃), limiting its application in heat-processed foods; improvements to konjac gel often rely on adding chemical cross-linking agents or other colloids (such as carrageenan, sodium alginate, etc.), but these methods have problems such as high cost, complex processes, and potential food safety risks. Some processes require high temperature and high pressure conditions, increasing production costs and energy consumption. Furthermore, konjac gel mainly functions as dietary fiber, lacking additional functions such as anti-digestion and blood sugar regulation, making it difficult to meet the needs of functional foods; its effect on promoting the proliferation of intestinal probiotics is limited, and its prebiotic effect is weak.

[0003] Therefore, it is of great significance to develop a compound gel technology based on natural raw materials, with simple process and excellent performance. Summary of the Invention

[0004] To address at least some of the aforementioned technical problems, this invention provides a method for preparing a kudzu-konjac gel complex. This method involves crosslinking the amylose double helix of kudzu resistant starch with konjac glucomannan molecules through hydrogen bonding and hydrophobic interactions to form a synergistically enhanced interpenetrating network. This results in complementary gel properties between kudzu resistant starch and konjac glucomannan, leading to the preparation of a product with excellent digestibility and suitable for use as a low-GI food base.

[0005] The present invention adopts the following technical solution: A method for preparing a kudzu root and konjac gel complex includes the following steps: Primary gelatinization: Kudzu starch is added to a buffer solution to prepare a slurry, and the slurry is gelatinized once. Enzymatic hydrolysis: The slurry that has undergone the first gelatinization is cooled, and then pullulanase is added for enzymatic hydrolysis. After enzymatic hydrolysis, the enzyme is inactivated and cooled to room temperature. After washing, it is freeze-dried to obtain kudzu resistant starch. Secondary gelatinization: Dissolve kudzu root resistant starch in water, then add konjac glucomannan for secondary gelatinization; Swelling: After replenishing the water lost during the secondary gelatinization process, swelling is performed; Molding: Add edible alkali to the swollen material, stir evenly, let stand to form, then demold and boil to obtain kudzu root and konjac gel complex.

[0006] As a preferred embodiment, in the first gelatinization step, the buffer solution is a mixture of acetic acid solution and sodium acetate solution, with a buffer solution concentration of 0.15~0.25 mol / L, a pH value range of 5.0~5.5, and a slurry concentration of 8~12 %w / v.

[0007] As a preferred embodiment, the first gelatinization step includes boiling the slurry for gelatinization, with a gelatinization time of 25-35 minutes, and stirring is maintained during the gelatinization process.

[0008] As a preferred embodiment, in the enzymatic hydrolysis step, the concentration of pullulanase is 50~70 U / g, and the reaction is carried out in a water bath at 54~56℃ for 3~5 hours.

[0009] As a preferred embodiment, in the enzymatic hydrolysis step, the inactivation is carried out by boiling water bath, cooled to room temperature and stored at 3~5℃ for 90~100h, then washed with distilled water until neutral, and freeze-dried to obtain the kudzu resistant starch.

[0010] As a preferred embodiment, in the secondary gelatinization step, the mass ratio of konjac glucomannan to kudzu resistant starch is 0.2~0.6:1.

[0011] As a preferred embodiment, in the secondary gelatinization step, the secondary gelatinization temperature is 80~100℃, the gelatinization time is 15~20min, and stirring is maintained during the gelatinization process.

[0012] As a preferred embodiment, in the swelling step, after replenishing the water lost during the secondary gelatinization process, the solution is swollen at 80-90°C for 40-60 minutes.

[0013] As a preferred embodiment, in the molding step, the mass ratio of the edible alkali to the konjac glucomannan is 0.1~0.25:1; after rapid stirring, it is allowed to stand for 50~70 minutes to form the product.

[0014] The present invention also provides a kudzu root and konjac gel complex, which is prepared by any of the above-described preparation methods.

[0015] This invention has some of the following technical advantages: The preparation method of the kudzu-konjac gel complex of this invention constructs a "KRS-KGM double network gel structure" by combining kudzu resistant starch with konjac glucomannan. The linear starch double helix structure of kudzu resistant starch and the molecular chain of konjac glucomannan are cross-linked through hydrogen bonds and hydrophobic interactions to form an interpenetrating network, which significantly improves the mechanical properties and thermal stability of the gel complex product. In addition, by combining kudzu resistant starch with konjac glucomannan in this invention, the gel has anti-digestion function, and the anti-digestion characteristic of kudzu resistant starch is retained at a rate of over 97%, making it suitable for developing low-GI foods. Furthermore, the water absorption of kudzu resistant starch compensates for the insufficient water retention of konjac gel, and the water retention of the prepared gel product is improved by more than 15%.

[0016] The preparation method of the kudzu and konjac gel complex of the present invention involves compounding konjac glucomannan and kudzu resistant starch in a specific ratio, and combining low-temperature swelling with alkaline gelation to avoid high-temperature damage to the molecular chains of kudzu resistant starch. At the same time, it promotes the swelling and gelation of konjac glucomannan, promotes the formation of gel network, enhances the stability of gel network, and avoids the energy consumption problem of traditional high-temperature and high-pressure processes. Furthermore, the processing does not require chemical cross-linking agents and relies entirely on the intermolecular forces of natural raw materials, making it green and healthy.

[0017] The preparation method of the konjac gel complex described in this invention has easily controllable production nodes, low raw material costs, simple process, no need for complex equipment, and is suitable for large-scale processing and production. Moreover, the konjac gel complex products prepared have a wide range of applications, such as low-GI foods, as a base material for special diabetic diets, functional gel products, and further development of high-fiber, low-calorie jellies, puddings and other snack foods, which have a very good market prospect. Detailed Implementation

[0018] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments. Example 1

[0019] The preparation method of the kudzu root and konjac gel complex described in this embodiment includes the following steps: First gelatinization: Prepare a buffer solution with a concentration of 0.2 mol / L and a pH of 5.2 by mixing acetic acid solution and sodium acetate solution; add kudzu starch to the buffer solution to prepare a 10% w / v slurry; boil the slurry for gelatinization for 30 min, and keep stirring during the gelatinization process. Enzymatic hydrolysis: The gelatinized slurry was cooled to 55°C and maintained, and then pullulanase was added for enzymatic hydrolysis at a concentration of 60 U / g. The reaction was carried out in a water bath at 55°C for 4 hours. After the enzymatic hydrolysis was completed, the slurry was inactivated by boiling water bath for 30 minutes, cooled to room temperature, and stored at 4°C for 96 hours. Then, it was washed with distilled water until neutral, freeze-dried, and passed through a 100-mesh sieve to obtain kudzu resistant starch. Secondary gelatinization: Dissolve 5g of kudzu resistant starch in 200ml of water and stir for 10min. Then add 1g of konjac glucomannan and perform secondary gelatinization. The secondary gelatinization temperature is 80℃ and the gelatinization time is 20min. Keep stirring during the gelatinization process. Swelling: Replenish the water lost during the secondary gelatinization process, and swell at 90℃ for 50 minutes, stirring for the first 45 minutes before swelling; Molding: Add 0.25g of edible alkali to the swollen material, stir quickly for 1 minute, let stand for 60 minutes to form, then demold and boil to obtain kudzu root and konjac gel complex.

[0020] In this example, the kudzu root and konjac composite gel had a water holding capacity of 85.94%, a sensory evaluation score of 84, a texture hardness of 1105.36 g, an elasticity of 85.70%, a chewiness of 710.89 J, and a hypoglycemic effect with an α-amylase inhibition rate of 43.41% and an α-glucosidase inhibition rate of 40.92%. Example 2

[0021] The preparation method of the kudzu root and konjac gel complex described in this embodiment includes the following steps: First gelatinization: Prepare a buffer solution with a concentration of 0.15 mol / L and a pH of 5.5 by mixing acetic acid solution and sodium acetate solution; add kudzu starch to the buffer solution to prepare a 12% w / v slurry; boil the slurry for gelatinization for 35 min, and keep stirring during the gelatinization process. Enzymatic hydrolysis: The gelatinized slurry was cooled to 54°C and maintained thereafter, and pullulanase was added for enzymatic hydrolysis at a concentration of 50 U / g. The reaction was carried out in a water bath at 54°C for 3 hours. After the enzymatic hydrolysis was completed, the slurry was inactivated in a boiling water bath for 20 minutes, cooled to room temperature, and stored at 3°C ​​for 90 hours. Then, it was washed with distilled water until neutral, freeze-dried, and passed through a 100-mesh sieve to obtain kudzu resistant starch. Secondary gelatinization: Dissolve 5g of kudzu resistant starch in 200ml of water and stir for 5 minutes. Then add 3g of konjac glucomannan and carry out secondary gelatinization. The secondary gelatinization temperature is 100℃ and the gelatinization time is 15 minutes. Keep stirring during the gelatinization process. Swelling: Replenish the water lost during the secondary gelatinization process, and swell at 80℃ for 40 minutes, stirring for the first 35 minutes before swelling; Molding: Add 0.3g of edible alkali to the swollen material, stir quickly for 2 minutes, let stand for 50 minutes to form, then demold and boil to obtain konjac gel complex.

[0022] In this example, the kudzu root and konjac composite gel had a water holding capacity of 83.76%, a sensory evaluation score of 81, a texture hardness of 1121.69 g, an elasticity of 83.20%, a chewiness of 689.72 J, and a hypoglycemic effect with an α-amylase inhibition rate of 42.88% and an α-glucosidase inhibition rate of 39.81%. Example 3

[0023] The preparation method of the kudzu root and konjac gel complex described in this embodiment includes the following steps: First gelatinization: Prepare a buffer solution with a concentration of 0.25 mol / L and a pH of 5.0 by mixing acetic acid solution and sodium acetate solution; add kudzu starch to the buffer solution to prepare an 8% w / v slurry; boil the slurry for gelatinization for 25 min, and keep stirring during the gelatinization process. Enzymatic hydrolysis: The gelatinized slurry was cooled to 56°C and maintained, and then pullulanase was added for enzymatic hydrolysis at a concentration of 70 U / g. The reaction was carried out in a water bath at 56°C for 5 hours. After the enzymatic hydrolysis was completed, the slurry was inactivated by boiling water bath for 40 minutes, cooled to room temperature, and stored at 5°C for 100 hours. Then, it was washed with distilled water until neutral, freeze-dried, and passed through a 100-mesh sieve to obtain kudzu resistant starch. Secondary gelatinization: Dissolve 5g of kudzu resistant starch in 200ml of water and stir for 5 minutes. Then add 2g of konjac glucomannan and perform secondary gelatinization. The secondary gelatinization temperature is 90℃ and the gelatinization time is 18 minutes. Keep stirring during the gelatinization process. Swelling: Replenish the water lost during the secondary gelatinization process, and swell at 85℃ for 45 minutes, stirring for the first 40 minutes of swelling; Molding: Add 0.45g of edible alkali to the swollen material, stir quickly for 3 minutes, let stand for 70 minutes to form, then demold and boil to obtain konjac gel complex.

[0024] In this example, the kudzu root and konjac composite gel had a water holding capacity of 86.34%, a sensory evaluation score of 85, a texture hardness of 1109.18 g, an elasticity of 87.37%, a chewiness of 722.51 J, and a hypoglycemic effect with an α-amylase inhibition rate of 44.23% and an α-glucosidase inhibition rate of 42.47%. Example 4

[0025] The preparation method of the kudzu root and konjac gel complex described in this embodiment includes the following steps: First gelatinization: Prepare a buffer solution with a concentration of 0.18 mol / L and a pH of 5.1 by mixing acetic acid solution and sodium acetate solution; add kudzu starch to the buffer solution to prepare an 11% w / v slurry; boil the slurry for gelatinization for 28 min, and keep stirring during the gelatinization process. Enzymatic hydrolysis: The gelatinized slurry was cooled to 55°C and maintained thereafter, and pullulanase was added for enzymatic hydrolysis at a concentration of 65 U / g. The reaction was carried out in a water bath at 55°C for 4.5 h. After the enzymatic hydrolysis was completed, the slurry was inactivated by boiling water bath for 30 min, cooled to room temperature, and stored at 4°C for 95 h. Then, it was washed with distilled water until neutral, freeze-dried, and passed through a 100-mesh sieve to obtain kudzu resistant starch. Secondary gelatinization: Dissolve 5g of kudzu resistant starch in 200ml of water and stir for 5 minutes. Then add 1.5g of konjac glucomannan and carry out secondary gelatinization. The secondary gelatinization temperature is 95℃ and the gelatinization time is 16 minutes. Keep stirring during the gelatinization process. Swelling: Replenish the water lost during the secondary gelatinization process, and swell at 88℃ for 55 minutes, stirring for the first 50 minutes of swelling; Molding: Add 0.35g of edible alkali to the swollen material, stir quickly for 1 minute, let stand for 65 minutes to form, then demold and boil to obtain konjac gel complex.

[0026] In this example, the kudzu root and konjac composite gel had a water holding capacity of 85.02%, a sensory evaluation score of 83, a texture hardness of 1116.48 g, an elasticity of 84.2%, a chewiness of 694.64 J, and a hypoglycemic effect with an α-amylase inhibition rate of 42.19% and an α-glucosidase inhibition rate of 39.03%.

[0027] 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 invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a kudzu root and konjac gel complex, characterized in that, Includes the following steps: Primary gelatinization: Kudzu starch is added to a buffer solution to prepare a slurry, and the slurry is gelatinized once. Enzymatic hydrolysis: The slurry that has undergone the first gelatinization is cooled, and then pullulanase is added for enzymatic hydrolysis. After enzymatic hydrolysis, the enzyme is inactivated and cooled to room temperature. After washing, it is freeze-dried to obtain kudzu resistant starch. Secondary gelatinization: Dissolve kudzu root resistant starch in water, then add konjac glucomannan for secondary gelatinization; Swelling: After replenishing the water lost during the secondary gelatinization process, swelling is performed; Molding: Add edible alkali to the swollen material, stir evenly, let stand to form, then demold and boil to obtain kudzu root and konjac gel complex.

2. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the first gelatinization step, the buffer solution is a mixture of acetic acid solution and sodium acetate solution with a concentration of 0.15~0.25 mol / L and a pH range of 5.0~5.

5. The concentration of the slurry is 8~12 %w / v.

3. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, The gelatinization step includes boiling the slurry for gelatinization, with a gelatinization time of 25-35 minutes, and stirring is maintained during the gelatinization process.

4. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the enzymatic hydrolysis step, the concentration of pullulanase is 50~70 U / g, and the reaction is carried out in a water bath at 54~56℃ for 3~5 hours.

5. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the enzymatic hydrolysis step, the inactivation is carried out by boiling water bath, cooled to room temperature and stored at 3-5°C for 90-100 hours, then washed with distilled water until neutral, and freeze-dried to obtain the kudzu resistant starch.

6. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the secondary gelatinization step, the mass ratio of konjac glucomannan to kudzu resistant starch is 0.2~0.6:

1.

7. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the secondary gelatinization step, the secondary gelatinization temperature is 80~100℃, the gelatinization time is 15~20min, and stirring is maintained during the gelatinization process.

8. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the swelling step, after replenishing the water lost during the secondary gelatinization process, the solution swells at 80-90°C for 40-60 minutes.

9. The method for preparing the kudzu root and konjac gel complex according to claim 1, characterized in that, In the molding step, the mass ratio of the edible alkali to the konjac glucomannan is 0.1~0.25:1; after rapid stirring, it is allowed to stand for 50~70 minutes to form the product.

10. A kudzu root and konjac gel complex, characterized in that, The kudzu root and konjac gel complex is prepared by any one of the preparation methods described in claims 1 to 9.