Compound gel system of low-acyl gellan gum and low-methoxyl pectin and application of compound gel system

Abstract

The invention provides a compound gel system of low-acyl gellan gum and low-methoxyl pectin and application of the compound gel system, and relates to the technical field of food processing. The compound gel system provided by the invention comprises a gel composition consisting of 30wt%-70wt% of low-acyl gellan gum and the balance of low-ester pectin, and calcium ions are not needed for gelling in the gelling process. According to the invention, gelation is carried out by virtue of strong hydrogen-bond interaction between the low-acyl gellan gum and the low-ester pectin, and calcium ions do not need to be added, so that the gelation rate is delayed, and the apparent quality and thermal stability of the gel are improved.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a compound gel system of low-acyl gellan gum and low-ester pectin and its application. Background Technology

[0002] Gellan gum is a bacterial extracellular anionic linear heteropolysaccharide. Based on its acyl group content, it can be divided into natural gellan gum (high-acyl gellan gum) and low-acyl gellan gum formed after deacylation. The former can form a highly elastic, thermally reversible gel, while the latter... 2+ Mg 2+ Under the action of cations, thermally irreversible gels with high brittleness and high hardness can be formed. For example, Chinese patent CN115778914A discloses a capsule that uses low-acyl gellan gum as a gelling agent and metal salts (potassium citrate, potassium phosphate, potassium chloride, sodium chloride, calcium chloride, magnesium chloride, etc.) as coagulant aids.

[0003] Based on the number of ester groups on the HG backbone, pectin can be divided into high-ester pectin and low-ester pectin (DE less than 50%). High-ester pectin requires a relatively harsh environment (high acid and high sugar) to form a gel by relying on the hydrophobic interaction between methoxy groups in the pectin chain and hydrogen bonds. Low-ester pectin, due to the increased carboxyl content in the pectin chain, provides more binding sites for cations, which is more conducive to the formation of a stable eggshell structure. Even in a wide range of acidity, or even in low-sugar or sugar-free environments, low-ester pectin can form a gel by binding only with cations. Moreover, the lower the degree of esterification of low-ester pectin, the more conducive it is to the formation of a gel permeation network.

[0004] However, both low-acyl gellan gum and low-ester pectin require the participation of cations during the gelation process. This dependence on cations (such as calcium ions) imposes significant limitations in production, necessitating precise control over the amount and timing of cation addition. This greatly increases production complexity. Furthermore, excessively high local cation concentrations during production can lead to excessively rapid local gelation rates, resulting in a coarse and uneven texture in the gel product, which negatively impacts product quality. Therefore, a solution is urgently needed to address these issues. Summary of the Invention

[0005] The purpose of this invention is to provide a compound gel system of low-acyl gellan gum and low-ester pectin and its application. The gel is carried out by utilizing the strong hydrogen bonding between the low-acyl gellan gum and the low-ester pectin, without the need to add calcium ions, which is beneficial to slowing down the gelation rate and improving the appearance quality and thermal stability of the gel.

[0006] In a first aspect, the present invention provides a gel composition comprising 30wt%-70wt% of low-acyl gellan gum and the balance of low-ester pectin, wherein no calcium ions are required for gelation during gelation.

[0007] Optionally, it is formed by dry mixing of low-acyl gellan gum and low-ester pectin.

[0008] Optionally, the degree of esterification of low-ester pectin is 30%-35%.

[0009] Optionally, it consists of 40wt%-60wt% of low-acyl gellan gum and the balance of low-ester pectin.

[0010] In a second aspect, the present invention provides a compound gel system of low-acyl gellan gum and low-ester pectin, wherein the low-acyl gellan gum and low-ester pectin constitute any of the above-mentioned optional gel compositions.

[0011] Optionally, the mass fraction of the gel composition in the system is 0.5%-10%.

[0012] Optionally, the liquid environment in the system includes water.

[0013] Optionally, it also includes flavor enhancers acceptable in the food industry.

[0014] Optionally, flavor enhancers include one of acidulants and sweeteners.

[0015] Thirdly, the present invention provides a gelation method for a gel composition, comprising: dissolving the gel composition in a liquid environment at 80°C-90°C to form a compound gel system, and allowing the compound gel system to stand at 20°C-30°C to gel.

[0016] Optionally, dissolve by stirring at 800 rpm-1000 rpm.

[0017] Optionally, the gel can be allowed to stand at 20℃-30℃ for 0.5h-3h.

[0018] Fourthly, the present invention provides a compound gel prepared by any of the above-mentioned optional gelling methods, comprising one of gel gummies, gel carriers, and gel jellies. Attached Figure Description

[0019] Figure 1 The diagrams show the changes in the inverted morphology of the gels in Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention; wherein: A to D are the changes in the inverted morphology of the gels in Comparative Examples 1 to 4, and E to G are the changes in the inverted morphology of the gels in Examples 1 to 3.

[0020] Figure 2 The diagrams show the changes in the inverted morphology of the gels after treatment with urea and sodium dodecyl sulfate in Examples 2, 5, and 6 of the present invention; wherein: A to B are the changes in the inverted morphology and the comparison of gel strength of the gels in Comparative Examples 5 and 6, respectively, and C is the changes in the inverted morphology and the comparison of gel strength of the gel in Example 2.

[0021] Figure 3 This refers to the gelation time required for the gel systems in Examples 2, 5, and 6 of this invention to gel after being transferred from an 85°C environment to room temperature;

[0022] Figure 4 This is a schematic diagram showing the changes in storage modulus and loss modulus of the compound gel during the heating-cooling process in Embodiment 2 of the present invention;

[0023] Figure 5 This is a schematic diagram of the appearance of the gel gummy in Embodiment 4 of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0025] This invention provides a gel composition comprising 30wt%-70wt% of low-acyl gellan gum and the balance of low-ester pectin. In practice, when dissolving and gelling low-acyl gellan gum and low-ester pectin separately, gel formation is driven by hydrophobic interactions under the influence of calcium ions. However, the gel composition provided by this invention can form a stable gel using the strong hydrogen bonding between low-acyl gellan gum and low-ester pectin without the addition of calcium ions.

[0026] Furthermore, the low-acyl gellan gum and low-ester pectin used in the gel composition can both be obtained from commercially available food-grade raw materials, or extracted from raw materials using conventional extraction methods. In fact, the low-acyl gellan gum and low-ester pectin used in the gel composition can be low-acyl gellan gum and low-ester pectin modified by known modification methods, such as strengthening the hydrogen bonding between low-acyl gellan gum and low-ester pectin, or improving the solubility of low-acyl gellan gum and low-ester pectin.

[0027] In some embodiments, the low-acyl gellan gum and low-ester pectin are pre-dry mixed to form a gel composition, and then the gel composition is dried and stored for later use, which is beneficial to the uniform dissolution and diffusion of the low-acyl gellan gum and low-ester pectin in the liquid environment. In other embodiments, the low-acyl gellan gum and low-ester pectin can be dried and stored separately, and then dry mixed to form a gel composition before use. This is beneficial to adaptively adjust the mixing ratio of the low-acyl gellan gum and low-ester pectin before use.

[0028] In some embodiments, the degree of esterification of the low-ester pectin used in the gel composition is 20%-49%. Further, the degree of esterification of the low-ester pectin can also be any sub-range within the 20%-49% range, such as 25%-35%, 30%-35%, 30%-40%, etc. Specifically, the degree of esterification of the low-ester pectin can be 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, and is not limited to the values ​​listed above; other unlisted values ​​within the 20%-49% range can also achieve the purpose of this invention.

[0029] In some embodiments, the content of low-acyl gellan gum in the gel composition can be any sub-range within the range of 30wt%-70wt%, such as 30wt%-50wt%, 40wt%-60wt%, 50wt%-70wt%, etc., so that the sum of the content ratios of low-acyl gellan gum and low-ester pectin in the gel composition is 100%. Specifically, the content of low-acyl gellan gum in the gel composition can be 30wt%, 33wt%, 36wt%, 39wt%, 42wt%, 45wt%, 48wt%, 51wt%, 54wt%, 57wt%, 60wt%, 63wt%, 66wt%, 69wt%, and is not limited to the values ​​listed above. Other unlisted values ​​within the range of 30wt%-70wt% can also achieve the purpose of this invention.

[0030] This invention also provides a compound gel system of low-acyl gellan gum and low-ester pectin, wherein the low-acyl gellan gum and low-ester pectin constitute the gel composition in any of the above embodiments. In fact, during the gelation process of the compound gel system, without the need for calcium ions, a stable three-dimensional gel network is formed by the strong hydrogen bonding between the low-acyl gellan gum and low-ester pectin, effectively slowing down the gelation rate and improving the uniformity and appearance quality of the gel.

[0031] In some embodiments, the mass fraction of the gel composition in the compound gel system can be from 0.5% to the solubility limit, wherein a mass fraction of 0.5% can be considered the minimum gel content. Specifically, the mass fraction of the gel composition in the system can be any sub-range within the range of 0.5% to the solubility limit, such as 0.5%-10%, 2%-8%, 3%-6%, etc. Further, the mass fraction of the gel composition can be 0.5%, 1%, 3%, 5%, 7%, 9%, etc., and is not limited to the values ​​listed above; other unlisted values ​​within the range of 0.5% to the solubility limit can also achieve the purpose of this invention.

[0032] In practice, the liquid environment in the compound gel system includes water, and the gel composition dissolves in the liquid environment to form a homogeneous gel solution. In some embodiments, when preparing the compound gel system, the gel composition can be stirred and dissolved in the liquid environment to obtain the compound gel system, or the low-acyl gellan gum can be stirred and dissolved in the liquid environment to prepare a low-acyl gellan gum solution, and the low-ester pectin can be stirred and dissolved in the liquid environment to prepare a low-ester pectin solution. The low-acyl gellan gum solution and the low-ester pectin solution are then homogenized to obtain the compound gel system.

[0033] In some embodiments, the compound gel system may also include food-grade flavor enhancers, which can provide a richer flavor to the gel when it gels. Specifically, flavor enhancers may include one of acidulants and sweeteners, such as sucrose, brown sugar, or citric acid. Furthermore, plant-derived extracts may be added to the compound gel system to increase the nutritional content of the gel and to impart a more vibrant surface color. Further, when adding other substances to the compound gel system, they must meet the conditions of being food-grade and water-soluble.

[0034] This invention also provides a gelation method for any of the above-mentioned gel compositions, comprising: forming a complex gel system by dissolving the gel composition in a liquid environment at 80℃-90℃, and then allowing the complex gel system to stand and gel at 20℃-30℃. In practice, after forming the complex gel system at 80℃-90℃, the complex gel system can be directly transferred to 20℃-30℃ for cooling. During the cooling process, the low-acyl gellan gum and low-ester pectin in the gel system form a three-dimensional gel network through hydrogen bonding. Further, the gel composition can be stirred and dissolved in a liquid environment at a speed of 800rpm-1000rpm to form a complex gel system, and then transferred to 20℃-30℃ for standing gelation for 0.5h-3h.

[0035] This invention also provides a compound gel prepared using the above-described gelling method, comprising one of gel gummies, gel carriers, and gel jellies. In practice, when preparing gel gummies, sweeteners, acidulants, and other ingredients can be added to the compound gel system to enhance the flavor and texture of the gummies.

[0036] Example 1

[0037] This embodiment 1 provides a method for preparing a compound gel, including the following steps:

[0038] S1. A polysaccharide mixture was prepared by uniformly mixing 0.3g of low-acyl gellan gum (purchased from Ningxia Shangfang Biotechnology Co., Ltd., food grade) and 0.7g of low-ester pectin (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., food grade).

[0039] S2. Add the polysaccharide mixture to 100mL of purified water and stir at 800rpm for 40min in an 85℃ water bath to ensure that the polysaccharide mixture is fully dissolved and to obtain a compound gel system.

[0040] S3. Let the compound gel system stand at room temperature (25°C) for 1 hour to form a stable compound gel.

[0041] Example 2

[0042] This embodiment 2 provides a method for preparing a compound gel, which differs from that of embodiment 1 in that, in step S1, the polysaccharide mixture is formed by uniformly mixing 0.5g of low-acyl gellan gum and 0.5g of low-ester pectin.

[0043] Example 3

[0044] This embodiment 3 provides a method for preparing a compound gel, which differs from that of embodiment 1 in that, in step S1, the polysaccharide mixture is formed by uniformly mixing 0.7g of low-acyl gellan gum and 0.3g of low-ester pectin.

[0045] Example 4

[0046] This embodiment 4 provides a method for preparing gel gummies, including the following steps:

[0047] S1. A polysaccharide mixture is prepared by uniformly mixing 1.0g of low-acyl gellan gum and 1.0g of low-ester pectin.

[0048] S2. Add the polysaccharide mixture to 100mL of purified water and stir to dissolve in an 85℃ water bath. Then add 50g of sucrose and stir to dissolve. Then add 1.2g of anhydrous citric acid and continue stirring to dissolve. Concentrate the mixture to a mass of 100g to obtain the compound gel system.

[0049] S3. After injecting the compound gel system into the gummy candy mold, let it stand at room temperature of 25°C for 1 hour to form a stable compound gel.

[0050] Comparative Example 1

[0051] Comparative Example 1 provides a method for preparing a low-acyl gellan gum, comprising: adding 1.0 g of low-acyl gellan gum to 100 mL of purified water and stirring at 800 rpm for 40 min in an 85°C water bath to ensure that the low-acyl gellan gum is fully dissolved to obtain a gellan gum solution; and allowing the gellan gum solution to stand at room temperature for 1 h.

[0052] Comparative Example 2

[0053] Comparative Example 2 provides a method for preparing low-ester pectin gel, comprising: adding 1.0 g of low-ester pectin to 100 mL of purified water and stirring at 800 rpm for 40 min in an 85°C water bath to promote the full dissolution of the low-ester pectin to obtain a pectin solution; and allowing the pectin solution to stand at room temperature for 1 h.

[0054] Comparative Example 3

[0055] Comparative Example 3 provides a method for preparing a compound gel, which differs from Example 1 in that, in step S1, the polysaccharide mixture is formed by uniformly mixing 0.2g of low-acyl gellan gum and 0.8g of low-ester pectin.

[0056] Comparative Example 4

[0057] Comparative Example 4 provides a method for preparing a compound gel, which differs from Example 1 in that, in step S1, the polysaccharide mixture is formed by uniformly mixing 0.8g of low-acyl gellan gum and 0.2g of low-ester pectin.

[0058] Comparative Example 5

[0059] Comparative Example 5 provides a method for preparing a low-acyl gelling gel, which differs from Comparative Example 1 in that 1 mL of a 100 mmol / L calcium chloride solution is added, stirred, and then allowed to stand at room temperature for 1 h.

[0060] Comparative Example 6

[0061] Comparative Example 6 provides a method for preparing low-ester pectin gel, which differs from Comparative Example 2 in that 1 mL of a 100 mmol / L calcium chloride solution is added, stirred, and then allowed to stand at room temperature for 1 h.

[0062] Performance testing:

[0063] The gels prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were inverted, and the morphological changes were observed as follows: Figure 1As shown; in the preparation process of Examples 2, 5, and 6, urea and sodium dodecyl sulfate (SDS) were added to the compound gel system, respectively, and the final concentrations of urea and sodium dodecyl sulfate were set to 4 mol / L and 50 mmol / L, respectively. A system without added urea and SDS was used as a control. The system was left to stand at room temperature for 1 hour, and changes in gel morphology and gel strength were observed using an inverted experiment. Figure 2 As shown.

[0064] In the preparation processes of Examples 2, 5, and 6, the starting point was the transfer of the composite gel system from an 85°C water bath to room temperature. The gelation point was defined as the point where no sloshing occurred on the surface of the composite gel system. The time taken from the starting point to the gelation point was recorded. Figure 3 As shown; the changes in storage modulus (G') and loss modulus (G'') of the composite gel in Example 2 during the heating-cooling process from 25℃ to 90℃ to 25℃ were monitored using a rheometer. Figure 4 As shown; the appearance of the gel gummies prepared in Example 4 was photographed as follows. Figure 5 As shown.

[0065] Results analysis:

[0066] from Figure 1 As can be seen, the gels in Comparative Examples 1 to 2 are aqueous phases, indicating that neither low-acyl gellan gum nor low-ester pectin can form a gel without the participation of calcium ions. However, the gels in Comparative Examples 3 and 4 show obvious mobile phases, indicating that when there is an excess of low-acyl gellan gum or low-ester pectin in the polysaccharide mixture, the gel performance will be reduced. The compound gels in Examples 1 to 3 exhibit a stable gel structure.

[0067] Combination Figure 1 and Figure 2 It can be seen that low-acyl gellan gum solutions and low-ester pectin solutions can form gel structures under the action of calcium ions, while from Figure 2 As shown in A, the addition of urea and sodium dodecyl sulfate to the low-acyl gellan gel solution (Comparative Example 5) both lead to a decrease in gel strength, with sodium dodecyl sulfate having a greater effect. This indicates that the main driving force for the gelation of low-acyl gellan gel is hydrophobic interaction, followed by hydrogen bonding. Figure 2 As can be seen from B in the figure, the addition of urea to the low-ester pectin solution (Comparative Example 6) will reduce the gel strength, while the system will not gel when sodium dodecyl sulfate is added. This indicates that the main driving force for the gelation of low-ester pectin is hydrophobic interaction, followed by hydrogen bonding.

[0068] from Figure 2As can be seen from C, after mixing low-acyl gellan gum and low-ester pectin, the present invention can form a stable gel structure without the addition of calcium ions. However, the system cannot gel in the presence of urea, and can gel in the presence of sodium dodecyl sulfate, but the strength decreases. This indicates that the main driving force for gelation of the compound gel system provided by the present invention is hydrogen bonding, and hydrophobic interactions have little effect on gelation. Therefore, the gelation mechanism of the compound gel system provided by the present invention is different from that of low-acyl gellan gum and low-ester pectin.

[0069] from Figure 3 As can be seen, the low-acyl gellan gum solution forms a gel after standing at room temperature for about 10 minutes under the action of calcium ions, while the low-ester pectin gels rapidly after standing at room temperature for about 1 minute. This indicates that both low-acyl gellan gum and low-ester pectin gel rapidly under the action of calcium ions, while the compound gel system provided by this invention requires standing at room temperature for about 35 minutes to form a gel. This shows that this invention can effectively reduce the gelation rate, which is beneficial for controlling the gel and for the industrial application of the gel.

[0070] from Figure 4 As can be seen from the data, in Example 2, the storage modulus (G') of the composite gel is greater than the loss modulus (G'') during the heating-cooling process. This indicates that the composite gel maintains a good gel structure and has good thermal stability during the heating-cooling process. Figure 5 As can be seen, the gel gummies made from low-acyl gellan gum and low-ester pectin have high transparency, regular shape, and uniform texture. This is due to the high transparency of low-acyl gellan gum after gelation and the relatively slow and controllable gelation rate of the compound gel system.

[0071] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A gel composition, characterized in that, It consists of 30wt%-70wt% low-acyl gellan gum and the balance low-ester pectin, and does not require calcium ions for gelation during gelation; preferably, it is formed by dry mixing of low-acyl gellan gum and low-ester pectin.

2. The gel composition according to claim 1, characterized in that: The degree of esterification of the low-ester pectin is 30%-35%; and / or, it consists of 40wt%-60wt% of low-acyl gellan gum and the balance of low-ester pectin.

3. A compound gel system of low-acyl gellan gum and low-ester pectin, characterized in that, The low-acyl gellan gum and the low-ester pectin constitute the gel composition as described in claim 1 or 2.

4. The compound gel system according to claim 3, characterized in that: The mass fraction of the gel composition in the system is 0.5%-10%; and / or, the liquid environment in the system includes water.

5. The compound gel system according to claim 3, characterized in that: It also includes flavor enhancers acceptable in the food industry; preferably, the flavor enhancers include one of acidulants and sweeteners.

6. A gelling method for the gel composition according to any one of claims 1 to 2, characterized in that, include: The gel composition is dissolved in a liquid environment at 80℃-90℃ to form a compound gel system, and the compound gel system is allowed to stand at 20℃-30℃ to gel.

7. The gelation method according to claim 6, characterized in that: Dissolve by stirring at 800 rpm-1000 rpm; and / or, allow the gel to stand at 20°C-30°C for 0.5 h-3 h.

8. A compound gel prepared by the gelation method according to claim 6 or 7, characterized in that, Compound gels include one of the following: gummy candies, gel carriers, and gel jellies.

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