Softened kudzu root and its preparation method and application

Abstract

The present application relates to the field of food processing technology, and discloses a softened kudzu root and its preparation method and application. The preparation method of the softened kudzu root of the present application first places the kudzu root in an acetic acid-sodium acetate buffer solution containing chitosan, and adds lignin peroxidase to perform the first stage enzymolysis; then adds hemicellulase and xylanase to perform the second stage enzymolysis; finally, adds acetic acid to adjust the pH to the optimal pH of cellulase, adds cellulase to perform the third stage enzymolysis, and after enzymolysis, dries to obtain the softened kudzu root. The process of the present application is based on the enzymatic method and is optimized on this basis. It can effectively soften the kudzu root fiber, avoid the problem of kudzu root fiber being difficult to chew, and at the same time retain the toughness and integrity of the kudzu root fiber to the greatest extent, avoid the generation of fiber debris, and can be extended to the production of kudzu root chewing food.

Description

Technical Field

[0001] The present application relates to the field of food processing technology, and in particular to a softened kudzu root and a preparation method and application thereof. Background Art

[0002] Puerariae lobatae Radix, the dried root of the leguminous plant Puerariae lobatae (Willd.) Ohwi, is a plant with both medicinal and edible properties. Besides starch, Puerariae contains many chemical components, including flavonoids such as puerarin, daidzein, genistin, and formononetin, as well as polysaccharides.

[0003] Because chewing betel nut carries a high risk of oral cancer, the use of kudzu root as a chewable alternative to betel nut is a new trend in the food market. However, kudzu root, the rhizome of the plant Pueraria lobata, is rich in cellulose, hemicellulose, and lignin, making it hard and difficult to chew. The current common softening method, high-temperature acid treatment, while effective, can cause significant fiber breakage, resulting in a large amount of residue after chewing, severely impacting the taste. New softening technologies are urgently needed to soften kudzu root fibers without creating excessive fiber debris. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a softened kudzu root and a preparation method thereof, so that the softened kudzu root maintains its toughness and integrity on the basis of being relatively soft, thereby avoiding excessive fiber debris generated during chewing;

[0005] Another object of the present application is to provide an application of the softened kudzu root in the preparation of kudzu root chewing products.

[0006] In order to solve the above technical problems / achieve the above objectives or at least partially solve the above technical problems / achieve the above objectives, as a first aspect of the present application, a preparation method for softened Pueraria root is provided, comprising:

[0007] S1. Place Pueraria root in an acetic acid-sodium acetate buffer solution containing chitosan and add lignin peroxidase for the first enzymatic hydrolysis step.

[0008] S2. After the first stage of enzymatic hydrolysis, hemicellulase and xylanase are added for the second stage of enzymatic hydrolysis;

[0009] S3. After the second stage of enzymatic hydrolysis, acetic acid is added to adjust the pH to the optimal pH for cellulase, and then cellulase is added to perform the third stage of enzymatic hydrolysis. After enzymatic hydrolysis, the mixture is dried to obtain softened kudzu root.

[0010] Optionally, the weight ratio of chitosan, acetic acid-sodium acetate buffer solution, Pueraria root, lignin peroxidase, hemicellulase, xylanase and cellulase is (3-6):500:(20-40):(2-4):(1-4):(1-4):(1-4).

[0011] Optionally, the pH value of the acetic acid-sodium acetate buffer solution is 5-7.

[0012] Optionally, the temperatures of the first stage enzymolysis, the second stage enzymolysis and the third stage enzymolysis are independently selected from 35-45° C., and the times are independently selected from 0.5-2 h.

[0013] Optionally, ultrasonic treatment is further included during the third stage of enzymatic hydrolysis.

[0014] As a second aspect of the present application, provided is a softened kudzu root prepared by the preparation method.

[0015] As a third aspect of the present application, provided is the use of the softened kudzu root in preparing kudzu root chewable food.

[0016] As a fourth aspect of the present application, a kudzu root chewable food is provided, wherein the surface of the softened kudzu root described in the present application is coated with weakly alkaline brine.

[0017] Optionally, the weakly alkaline brine comprises maltose, calcium hydroxide, calcium sulfate, calcium phosphate, calcium lactate, calcium silicate, water-soluble chitosan, edible flavoring, edible salt, sweetener and water.

[0018] As a fifth aspect of the present application, a method for preparing the Pueraria root chewable food is provided, comprising:

[0019] The softened kudzu root described in the present application is adjusted to a moisture content within the range of 20%-25%, and weak alkaline brine is applied to the surface of the softened kudzu root under heat preservation, dried, and then coated with weak alkaline brine again and dried, and then vacuumed and sealed for storage at room temperature and away from light.

[0020] The process of this application is based on the enzymatic method and is optimized thereon. It can effectively soften the kudzu fiber, avoid the problem of the kudzu fiber being prickly in the mouth and difficult to chew, while retaining the toughness and integrity of the kudzu fiber to the greatest extent, avoiding the generation of fiber debris, and can be extended to the production of kudzu chewing food. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Shown is the appearance of untreated Pueraria root;

[0022] Figure 2 Shown is the appearance of the softened Pueraria root of Example 1;

[0023] Figure 3Shown is the appearance of the softened Pueraria root of Comparative Example 1;

[0024] Figure 4 Shown is the appearance of the softened Pueraria root of Comparative Example 2;

[0025] Figure 5 Shown is the appearance of the softened Pueraria lobata of Comparative Example 3. DETAILED DESCRIPTION

[0026] The present application discloses a softened Pueraria root and its preparation method and application. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar replacements and modifications are obvious to those skilled in the art, and they are all deemed to be included in this application. The products, processes and applications described in this application have been described through preferred embodiments. Relevant personnel can obviously modify or appropriately change and combine the products, processes and applications described herein without departing from the content, spirit and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0027] It should be noted that, in this document, if relational terms such as "first" and "second", "step 1" and "step 2", and "(1)" and "(2)" appear, they are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements. At the same time, the embodiments in this application and the features in the embodiments can be combined with each other in the absence of conflict.

[0028] In the first aspect of the present application, the present application first partially decomposes lignin using lignin peroxidase to loosen the internal mechanical structure of the vascular fibers of Pueraria root and soften the fibers; then uses hemicellulase and xylanase to partially hydrolyze the hemicellulose in the Pueraria root, reducing the degree of fiber crosslinking; finally, uses cellulase to treat a small amount of hydrolyzed cellulose for a short time to soften the Pueraria root and prevent excessive hydrolysis; supplemented by ultrasonic treatment, the cellulose, hemicellulose, and lignin components in the Pueraria root can be further effectively partially decomposed to achieve the purpose of softening the Pueraria root fibers. At the same time, the present application uses acetic acid-sodium acetate buffer as the processing medium, the overall processing environment is relatively mild, and the chitosan is used to cover it, which will not cause the Pueraria root fibers to be excessively degraded and broken into slag, and can better preserve the chewing texture of the Pueraria root blocks.

[0029] The preparation method of the softened Pueraria root described in this application specifically includes:

[0030] S1. Place Pueraria root in an acetic acid-sodium acetate buffer solution containing chitosan and add lignin peroxidase for the first enzymatic hydrolysis step.

[0031] S2. After the first stage of enzymatic hydrolysis, hemicellulase and xylanase are added for the second stage of enzymatic hydrolysis;

[0032] S3. After the second stage of enzymatic hydrolysis, acetic acid is added to adjust the pH to the optimal pH for cellulase, and then cellulase is added to perform the third stage of enzymatic hydrolysis. After enzymatic hydrolysis, the mixture is dried to obtain softened kudzu root.

[0033] In certain embodiments of the present application, lignin peroxidase, hemicellulase, xylanase, and cellulase can all be purchased from the market, and the enzyme activity is 10,000 U.

[0034] In certain embodiments of the present application, the kudzu root may be pre-treated by washing, cutting, drying, etc.

[0035] In certain embodiments of the present application, the weight ratio of chitosan, acetic acid-sodium acetate buffer solution, Pueraria root, lignin peroxidase, hemicellulase, xylanase, and cellulase is (3-6):500:(20-40):(2-4):(1-4):(1-4):(1-4). For example, the weight ratio of chitosan, acetic acid-sodium acetate buffer solution, Pueraria root, lignin peroxidase, hemicellulase, xylanase, and cellulase is 5:500:40:2:1:1:1.

[0036] In certain embodiments of the present application, the pH value of the acetic acid-sodium acetate buffer solution is 5-7, and the specific pH value can be 5, 5.5, 5.8, 6, 6.2, 6.5, 6.8 or 7.

[0037] In certain embodiments of the present application, the temperature of the first stage enzymolysis, the second stage enzymolysis and the third stage enzymolysis are independently selected from 35-45 ° C, and the time is independently selected from 0.5-2h. For example, the first stage enzymolysis and the second stage enzymolysis are both 40 ° C and 0.5h, and the third stage enzymolysis is 50 ° C and 2h. In some other embodiments of the present application, ultrasonic treatment is also included during the third stage enzymolysis. When ultrasound is used, the time of the third stage can be appropriately shortened, for example, to 0.5h. The frequency of the ultrasound is preferably around 20kHz.

[0038] In the second aspect of the present application, a softened kudzu root prepared by the preparation method is also provided. Compared with the softened kudzu root obtained by the traditional acid treatment and other control processes, the kudzu root has a more complete appearance, only a small amount of gaps appear between the kudzu root fibers, no burrs on the edges, and is softer overall; it is elastic when chewed, without obvious coarse fiber pricking the mouth, and only individual fragments appear after chewing for 3 minutes. The kudzu roots of other control processes have the phenomenon of small amounts or more fragments after chewing.

[0039] In the third aspect of the present application, there is provided a use of the softened kudzu root in preparing kudzu root chewable food.

[0040] In a fourth aspect of the present application, a kudzu root chewable food is provided, wherein the softened kudzu root described herein is coated with a weakly alkaline brine. The weakly alkaline brine can simulate the flavor of betel nut, making the kudzu root chewable food more flavorful while also avoiding the risk of oral cancer caused by betel nut.

[0041] In certain embodiments of the present application, the weakly alkaline brine adopts the results of previous research, which includes malt sugar, calcium hydroxide, calcium sulfate, calcium phosphate, calcium lactate, calcium silicate, water-soluble chitosan, edible flavors, edible salt, sweeteners and water. The detailed technical scheme has been recorded in the CN202311617422.9 patent, and the related schemes recorded therein can also be used as the records of this application. The weakly alkaline brine uses a reasonable proportion of four weakly alkaline calcium salts: calcium sulfate, calcium phosphate, calcium lactate and calcium silicate to replace part of the calcium hydroxide. It can perfectly simulate the flavor of traditional calcium hydroxide brine, stimulate the release of alkaloids such as kudzu flavonoids and neutralize their bitterness, while significantly reducing the alkaline irritation and oral mucosal burning caused by calcium hydroxide, and can give the brine a certain water-retaining and moisture-proof property, and significantly reduce the formation of white precipitate of calcium carbonate caused by long-term air exposure, thereby avoiding the problems of traditional brine damaging the oral mucosa, absorbing moisture and returning to brine, and turning white.

[0042] In certain embodiments of the present application, the weakly alkaline brine includes, by weight, 50-100 parts of maltose, 20-40 parts of calcium hydroxide, 20-40 parts of calcium sulfate, 20-40 parts of calcium phosphate, 10-20 parts of calcium lactate, 10-20 parts of calcium silicate, 1-5 parts of water-soluble chitosan, 1-5 parts of edible flavoring, 1-5 parts of edible salt, 1-5 parts of sweetener and 100-150 parts of water.

[0043] In certain embodiments of the present application, the method for preparing the weakly alkaline brine comprises:

[0044] Weigh calcium hydroxide, calcium sulfate and calcium phosphate, dissolve them in water and stir evenly. Weigh maltose, soften it and add it, stir and mix thoroughly to react. Add calcium lactate and food-grade calcium silicate during the reaction and continue stirring. After the reaction is completed, a reddish-brown raw brine is obtained.

[0045] After the original brine is cooled, water-soluble chitosan, edible flavoring, edible salt and sweetener are added and fully stirred, and the weak alkaline brine is obtained after grinding.

[0046] In a fifth aspect of the present application, a method for preparing the Pueraria root chewable food is provided, comprising:

[0047] The softened kudzu root described in the present application is adjusted to a moisture content within the range of 20%-25%, and weak alkaline brine is applied to the surface of the softened kudzu root under heat preservation, dried, and then coated with weak alkaline brine again and dried, and then vacuumed and sealed for storage at room temperature and away from light.

[0048] In the comparative experiments provided in this application, unless otherwise specified, other experimental conditions, materials, etc. were kept consistent except for the differences noted in each group, so as to provide comparability. The experimental materials and reagents used in the examples were all available from commercial sources unless otherwise specified.

[0049] The following further describes the softened kudzu root provided in this application, as well as its preparation method and application.

[0050] Example 1:

[0051] Chitosan (5 parts) was dissolved in acetic acid-sodium acetate buffer solution (500 parts) at pH 5.8 at 90°C. After the temperature dropped to 40°C, 40 parts of kudzu root pieces were added, 2 parts of lignin peroxidase were added, and the mixture was kept warm at 40°C for half an hour. Then, 1 part of hemicellulase and 1 part of xylanase were added. The mixture was kept warm at 40°C for another half an hour, and then 1 part of cellulase was added. The mixture was heated to 50°C and ultrasonically treated at 20 kHz for half an hour. The kudzu root pieces were taken out and dried.

[0052] Comparative Example 1:

[0053] Traditional acid treatment method: 40 parts of kudzu root pieces were placed in 500 parts of acetic acid-sodium acetate buffer solution with a pH of 3.8, and subjected to high temperature (90°C) acid treatment for 1.5 hours while simultaneously undergoing 20kHz ultrasonic treatment. The kudzu root pieces were then taken out and dried.

[0054] Comparative Example 2:

[0055] Co-enzymatic hydrolysis treatment method: chitosan (5 parts) was dissolved in acetic acid-sodium acetate buffer solution (500 parts) at 90°C, and after the temperature dropped to 40°C, 40 parts of kudzu root blocks were added, and 2 parts of lignin peroxidase, 1 part of hemicellulase, 1 part of xylanase, and 1 part of cellulase were added. The mixture was kept at 40°C for 1.5 hours and ultrasonically treated at 20kHz at the same time, and then the kudzu root blocks were taken out and dried.

[0056] Comparative Example 3:

[0057] Chitosan-free treatment method: 40 parts of kudzu root pieces were placed in 500 parts of acetic acid-sodium acetate buffer solution at pH 5.8, 2 parts of lignin peroxidase were added, and the mixture was kept at 40°C for half an hour. Then, 1 part of hemicellulase and 1 part of xylanase were added. The mixture was kept at 40°C for half an hour, and then 1 part of cellulase was added. The mixture was heated to 50°C and ultrasonically treated at 20kHz for half an hour. The kudzu root pieces were taken out and dried.

[0058] Experimental example:

[0059] The untreated kudzu root, the kudzu root obtained in Example 1 and Comparative Examples 1-3 were compared in appearance and chewed by the same person. The results are shown in FIG. Figure 1-Figure 5 and Table 1;

[0060] Table 1

[0061]

[0062]

[0063] according to Figures 1 to 5 It can be seen from the actual appearance picture that the softened kudzu root obtained in Example 1 is closest to the untreated kudzu root in appearance, the kudzu root has good integrity, only a small amount of gaps between the fibers, and no burrs on the edges; while the edges of the kudzu roots in other groups all have obvious burrs and small branches.

[0064] As can be seen from Table 1, after the chewing test, except for the extremely hard untreated kudzu root, the kudzu roots of each group achieved different degrees of softening effect, but the chewing taste was different; the softened kudzu roots of Example 1 and Comparative Example 3 were elastic when chewed, and there was no obvious feeling of crude fiber pricking the mouth; the softened kudzu roots of Comparative Example 1 and Comparative Example 2 had weak or no obvious chewing elasticity, and no obvious feeling of crude fiber pricking the mouth.

[0065] A more important indicator is the degree of fragmentation after chewing. The degree of fragmentation in Example 1 is the lowest, with only individual fragments appearing. The degree of fragmentation in Comparative Example 1 is the highest, with more fragments appearing. The degree of fragmentation in Comparative Examples 2 and 3 is average, with a certain amount of fragmentation appearing.

[0066] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A method for preparing softened Pueraria root, characterized in that: include: S1. Place Pueraria root in an acetic acid-sodium acetate buffer solution containing chitosan at a pH of 5-7 and perform the first enzymatic hydrolysis with lignin peroxidase at 40°C for 0.5 h. S2. After the first enzymatic hydrolysis, hemicellulase and xylanase were added for the second enzymatic hydrolysis at 40°C for 0.5 h. S3. After the second stage of enzymatic hydrolysis, acetic acid is added to adjust the pH to the optimal pH of cellulase, and then cellulase is added for the third stage of enzymatic hydrolysis, and ultrasonic treatment is performed at the same time. The enzymatic hydrolysis temperature is 50°C, the enzymatic hydrolysis is performed for 0.5h, and the softened kudzu root is obtained by drying after enzymatic hydrolysis; wherein the weight ratio of the chitosan, acetic acid-sodium acetate buffer solution, kudzu root, lignin peroxidase, hemicellulase, xylanase, and cellulase is (3-6):500:(20-40):(2-4):(1-4):(1-4):(1-4).

2. The softened Pueraria root prepared by the preparation method according to claim 1.

3. Use of the softened kudzu root according to claim 2 in preparing kudzu root chewable food.

4. A kudzu root chewing food, characterized in that: The surface of the softened kudzu root according to claim 2 is coated with weak alkaline brine.

5. The kudzu root chewing food according to claim 4, characterized in that The weakly alkaline brine comprises maltose, calcium hydroxide, calcium sulfate, calcium phosphate, calcium lactate, calcium silicate, water-soluble chitosan, edible flavor, edible salt, sweetener and water.

6. The method for preparing the kudzu root chewing food according to claim 4, characterized in that: include: The softened kudzu root according to claim 2 is pretreated to adjust the moisture content to 20%-25%, and weak alkaline brine is applied to the surface of the softened kudzu root under heat preservation state, dried, and then coated with weak alkaline brine again and dried, and then vacuumed and sealed for storage at room temperature and away from light.

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