Preparation method of OSA starch sodium and OSA starch sodium prepared by using preparation method

Abstract

The invention provides a preparation method of OSA starch sodium and the OSA starch sodium prepared by the preparation method. The preparation method of the OSA starch sodium comprises the following steps: starch is pretreated, and the branched chain degree of the pretreated starch is greater than or equal to 98wt%; the preparation method comprises the following steps: mixing pretreated starch and octenyl succinic anhydride in alkaline water for esterification reaction to obtain OSA starch ester; the method comprises the following steps: adding amylase into OSA starch ester to carry out enzymolysis reaction to obtain OSA starch ester enzymatic hydrolysate; using the OSA starch ester enzymatic hydrolysate to obtain OSA enzymatic hydrolysis starch; gelatinizing the OSA enzymolysis starch; according to the method, the branched chain degree of the starch is improved, impurities in the starch are reduced, the emulsifying property of the OSA starch sodium is stable, the embedding property is good, and the turbidity of an aqueous solution of the OSA starch sodium is low.

Description

Technical Field

[0001] The present invention relates to the technical field of nutritional products, and in particular to a method for preparing sodium OSA starch and sodium OSA starch prepared by the method. Background Art

[0002] Sodium starch octenylsuccinate (OSA starch sodium) is an important modified starch, a semi-esterified product of low-substituted starch and octenylsuccinic anhydride (OSA). Due to its molecular structure containing both hydrophilic and hydrophobic groups, OSA starch sodium exhibits excellent emulsifying, stabilizing, and thickening properties. It is widely used in food, pharmaceuticals, cosmetics, and papermaking, for example as a microcapsule wall material, dairy stabilizer, and beverage emulsifier.

[0003] In 2019, Xiang Lu and others from the College of Chemistry and Life Sciences at Zhejiang Normal University published an article titled "Preparation and Properties of Waxy Corn Starch Esters of Different Molecular Weights of Octenylsuccinate" in the journal Food Industry Science and Technology. The article describes the preparation of OSA starch esters and sodium starch OSA: starch is dispersed in water, alkali is added to adjust the pH, and then OSA is added for esterification to obtain OSA starch esters. The product is then subjected to heating, gelatinization, and enzymatic hydrolysis to obtain the final product, sodium starch OSA. However, the sodium starch OSA obtained by existing preparation methods has poor encapsulation properties, making it difficult to meet the needs of high-end applications. Summary of the Invention

[0004] In response to the technical problems existing in the prior art, the present invention proposes a method for preparing OSA starch sodium, comprising: pretreating starch, wherein the branching degree of the pretreated starch is ≥98wt%; mixing the pretreated starch and octenylsuccinic anhydride in alkaline water for esterification to obtain OSA starch ester; adding amylase to the OSA starch ester for enzymatic hydrolysis to obtain OSA starch ester hydrolyzate; obtaining OSA enzymatic starch using the OSA starch ester hydrolyzate; gelatinizing the OSA enzymatic starch; and obtaining OSA starch sodium using the OSA enzymatic starch.

[0005] As described above, the step of pretreating the starch comprises: adding the starch to an alcohol aqueous solution and maintaining the solution at a predetermined temperature for a sufficient time to obtain an extract; filtering and washing the extract; and obtaining the pretreated starch.

[0006] The preparation method as described above, wherein the alcohol aqueous solution is a mixed solution of alcohol and water in a mass ratio of (0.05-0.2):1.

[0007] In the preparation method as described above, the alcohol is selected from one or more of the following components: methanol, ethanol, n-propanol, isopropanol, ethylene glycol ((CH2OH)2), and glycerol.

[0008] The preparation method as described above, wherein the mass ratio of the alcohol aqueous solution to the starch is (3-8):1.

[0009] The preparation method as described above, wherein the predetermined temperature is 30-40 degrees Celsius; and the sufficient time is no less than 20 minutes.

[0010] In the preparation method as described above, the alkaline water is selected from one or more of the following solutions: lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium carbonate, lithium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate; preferably, the alkaline water is sodium hydroxide solution.

[0011] The preparation method, wherein the amylase is β-amylase; the mass ratio of the amylase to the starch is (0.0009-0.01):1.

[0012] In the preparation method as described above, the temperature of the enzymatic hydrolysis reaction is 28-40 degrees Celsius; preferably, the temperature of the enzymatic hydrolysis reaction is 34-38 degrees Celsius.

[0013] The preparation method as described above, wherein the dry basis sugar content of the OSA starch ester enzymatic hydrolysate is 5%-20%.

[0014] In the preparation method described above, the pH value of the esterification reaction is 7.0-8.5; preferably, the pH value of the esterification reaction is 7.5-8.2; the temperature of the esterification reaction is 30-45 degrees Celsius; preferably, the temperature of the esterification reaction is 35-38 degrees Celsius.

[0015] The present application also relates to OSA starch sodium prepared according to any of the preparation methods described above.

[0016] The present application further relates to an emulsified embedded microcapsule, wherein the emulsified embedded material includes the sodium starch OSA as described above.

[0017] The microcapsules as described above, wherein the core material of the microcapsules is selected from one or more of the following components: vitamin A acetate, vitamin A palmitate, vitamin D, such as vitamin D2, vitamin D3, vitamin E acetate, vitamin E palmitate, vitamin K, β-carotene, astaxanthin, lycopene, canthaxanthin, lutein, fish oil, coenzyme Q10, B vitamins, peppermint oil, eucalyptus oil, vanillin, whey protein, pectin, DHA, EPA, cinnamaldehyde probiotics, tea polyphenols, anthocyanins, curcumin and allicin.

[0018] The present application provides sodium OSA starch and a preparation method thereof, which increases the degree of starch branching and reduces impurities in the starch, so that the sodium OSA starch has stable emulsification properties, good embedding properties, and low turbidity in its aqueous solution. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0020] In the following detailed description, reference may be made to the specific embodiments that are part of this application and are used to illustrate this application. Each specific embodiment of this application is described below in sufficient detail to enable a person of ordinary skill in the art with relevant knowledge and skills in the art to implement the technical solutions of this application. It should be understood that other embodiments may be utilized or that the embodiments of this application may be modified.

[0021] In order to clearly explain the technical solution, the technical terms used in this article have the following meanings:

[0022] This application defines OSA starch ester and OSA starch sodium as follows:

[0023] The "OSA starch ester" mentioned herein refers to the product obtained by the esterification reaction between starch and OSA under certain conditions, which is an intermediate product for preparing OSA starch sodium from starch.

[0024] The "OSA starch sodium" mentioned herein refers to the modified starch product obtained by further enzymatic hydrolysis of the OSA starch ester mentioned above, which has a large molecular weight and a high viscosity in aqueous solution.

[0025] The present application improves the preparation method of sodium OSA starch and enhances its embedding performance and other characteristics. Compared with sodium OSA starch prepared by the prior art method, the sodium OSA starch is not only suitable for embedding core materials known in the art, but is also more suitable for embedding core materials that are difficult to embed in the art, and can be used for the preparation of high-end products with higher embedding performance requirements.

[0026] In some embodiments, the sodium OSA starch described in the present application can be used in multiple fields such as food, medicine, and cosmetics. It can encapsulate a variety of core materials, protect the activity of the core materials, and extend the effective period of their activity; it can also be used as a sustained-release carrier for drugs, prolong the residence time of drugs in the body, increase drug absorption rate and improve its bioavailability; further, through the encapsulation of sodium OSA starch, its dispersibility and stability in water-based solutions can also be improved.

[0027] In some embodiments, the core materials that can be embedded in OSA starch sodium include but are not limited to: fat-soluble nutrients, low-boiling point or volatile molecules, large molecules or high-viscosity molecules, easily oxidized or light-sensitive molecules, highly reactive molecules, etc.

[0028] In some embodiments, fat-soluble nutrients include but are not limited to vitamin A derivatives, such as vitamin A acetate and vitamin A palmitate; vitamin D, such as vitamin D2 and vitamin D3; vitamin E derivatives, such as vitamin E acetate and vitamin E palmitate; vitamin K; β-carotene, astaxanthin, lycopene, canthaxanthin, lutein, fish oil and coenzyme Q10, etc.

[0029] In some embodiments, low-boiling-point or volatile molecules include, but are not limited to, essential oils, such as peppermint oil, eucalyptus oil, and aldehydes, such as vanillin.

[0030] In some embodiments, macromolecules or high viscosity molecules include, but are not limited to, proteins such as whey protein, polysaccharides such as pectin, certain colloids, and the like.

[0031] In some embodiments, the easily oxidized or light-sensitive molecules include, but are not limited to, polyunsaturated fatty acids, such as DHA, EPA, etc., and certain pigments, such as β-carotene, etc.

[0032] In some embodiments, highly reactive molecules include but are not limited to aldehydes, such as cinnamaldehyde, certain phenolic compounds, and the like.

[0033] In some embodiments, the core material that can be embedded in sodium OSA starch can also include probiotics, tea polyphenols, anthocyanidins, curcumin, allicin, etc.

[0034] Those skilled in the art should understand that the emulsification embedding performance is an inherent characteristic of sodium starch OSA and has little to do with the core material embedded therein. Therefore, the core material involved in the embodiments of the present application is only to illustrate the embedding performance of sodium starch OSA of the present application, rather than to limit the core material. Vitamin E is an oily liquid at room temperature. When it is used as a core material for embedding sodium starch OSA, the unembedded part will float on the water surface in an oily state and can be directly observed by the experimenter. The emulsification embedding performance of sodium starch OSA is further obtained by the oil floating height, that is, the smaller the oil floating height, the better the emulsification embedding performance. When embedding a core material in solid form, such as vitamin A, due to its physical properties, it is difficult to accurately count the amount of core material that is embedded, demulsified, or even not emulsified and embedded, making it difficult to obtain the emulsification embedding performance of sodium starch OSA. Based on this, in the embodiment of the present application, vitamin E acetate is used as the core material for emulsification and embedding of OSA starch sodium in order to facilitate the statistical analysis of the parameters of the emulsification and embedding performance (oil floating height), rather than limiting the core material that can be embedded in OSA starch sodium.

[0035] The "emulsification and encapsulation performance" mentioned in this article refers to the ability of OSA starch as an encapsulation material, also called wall material, which is the water phase, and the encapsulated core material (i.e., active ingredient) as the oil phase. The water phase and the oil phase are sheared at high speed to obtain an oil-in-water emulsion. The more stable the emulsion, the better the emulsion and encapsulation performance. The emulsion is spray-dried to obtain a structure in which the active ingredient is wrapped by the encapsulation material (also known as a microcapsule), which can prevent the active ingredient from contacting the external environment and play a role in protecting the active ingredient. Emulsions made with sodium OSA starch with good emulsification and encapsulation performance can maintain the oil-in-water state for a long time. Emulsions made with sodium OSA starch with poor emulsification and encapsulation performance quickly experience oil phase aggregation, and the stability of the active ingredients in the resulting microcapsules varies.

[0036] The term "branching degree" as used herein refers to an indicator of the amount of branching structure in a starch molecule, and generally reflects the branching density of amylopectin or the distribution of branch chain lengths. Natural starch is composed of two main components: amylose, a linear molecule composed of glucose units connected by α-1,4 glycosidic bonds; and amylopectin, a highly branched molecule composed of α-1,6 glycosidic bonds every 20-25 glucose units in addition to the α-1,4 bonds. Branching density refers to the number of branching points per unit length of the main chain (e.g., the number of branches per 100 glucose units); while branch chain length refers to the average number of glucose units between branching points (typically DP 12-20 for short chains and DP 40-60 for long chains).

[0037] According to one embodiment of the present application, the degree of branching referred to herein refers to the branching density of starch.

[0038] According to one embodiment of the present application, the method for determining the degree of branching is: enzymatic hydrolysis, using a specific enzyme (such as isoamylase or pullulanase) to hydrolyze the α-1,6 bond to release the linear chain, and then performing an iodine binding experiment: the amylose forms a blue complex with iodine, and the amylopectin is purple-red, and the branching ratio is indirectly evaluated by spectrophotometry.

[0039] Turbidity, as used herein, refers to a solution's ability to scatter or absorb light, reflecting the presence of suspended particles or macromolecular aggregates in the solution. The higher the value, the more turbid the solution.

[0040] In this application, the turbidity measurement method is: dilute OSA starch sodium with water to a certain solubility, then detect the turbidity value on a turbidimeter, and determine the simple amount of insoluble matter in different OSA starch sodiums through the turbidity value.

[0041] In the application and performance evaluation of sodium starch glycolate (OSA), turbidity can be used to characterize the clarity or turbidity of its aqueous solutions and gel products. It is a key parameter for measuring the solubility and application performance of OSA sodium starch. Low turbidity is essential for the preparation of OSA sodium starch injections, transparent gels, clear beverages, or clarified dairy products. High turbidity may affect product safety, stability, and sensory quality.

[0042] The "alcohol" mentioned herein refers to a class of compounds containing a hydroxyl group bound to a carbon on a hydrocarbon or benzene ring side chain in the molecule. Its functional group is -OH (hydroxyl). The present application does not limit the alcohol used for pretreatment of starch. In some embodiments, the alcohol is selected from a monohydric alcohol, a dihydric alcohol or a polyhydric alcohol. In some embodiments, the alcohol is selected from one or more of the following alcohols: primary alcohols, secondary alcohols, tertiary alcohols, fatty alcohols, alicyclic alcohols and aromatic alcohols. In some embodiments, the alcohol is selected from one or more of the following alcohols: methanol (CH3OH), ethanol (C2H5OH), n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, n-pentanol, isopentanol, ethylene glycol ((CH2OH)2), glycerol (C3H8O3), tetratetrol, pentapentol, benzyl alcohol, chlorophylline, phenylethyl alcohol, linalool, etc. In some embodiments, the alcohol is selected from one or more of the following alcohols: methanol (CH3OH), ethanol (C2H5OH), n-propanol, isopropanol, ethylene glycol ((CH2OH)2), glycerol (C3H8O3).

[0043] The term "starch dry basis" used herein refers to the mass of starch in wet solids, expressed per unit mass of anhydrous solids, after the water content has been removed. In the chemical and food industries, to standardize starch usage, weighed mass is typically expressed on a dry basis. This ensures a consistent mass even if the moisture content of starch varies from batch to batch, by removing the water through calculation or drying.

[0044] In order to solve the problems raised in the prior art, the present application provides a method for preparing OSA starch sodium, comprising: a step of pretreating starch, wherein the branching degree of the pretreated starch is ≥98wt%; and esterifying the pretreated starch with octenylsuccinic anhydride in the presence of alkaline water.

[0045] Specifically, the preparation process is carried out according to the following steps: adding pretreated starch and water to a reactor; controlling the reaction system under a preset pH value, and simultaneously adding alkaline water and octenylsuccinic anhydride to the reactor for esterification reaction; filtering and washing the reaction system to obtain OSA starch ester.

[0046] Different from the prior art, the present application pre-treats the starting materials for preparing OSA starch ester, thereby increasing the branching degree of the starch and achieving the purpose of improving the performance of the final OSA starch sodium.

[0047] Starch is a polymer mixture that is ubiquitous in nature. Patent application CN117603368A mentions that the degree of starch branching and the amount of non-starch substances in starch may be closely related to the performance of starch. The degree of starch branching is closely related to the type of starch. Among common starches, waxy corn starch has a relatively high degree of branching, and high-quality waxy corn starch can have a degree of branching of over 95%, and also contains approximately 5% amylose. The examples of this application show that this 5% amylose has a significant impact on the emulsification and embedding properties of the final sodium starch OSA. Starch also contains trace amounts of impurities such as gelatinous substances. The examples of this application show that these impurities, the degree of starch branching, and the degree of substitution of OSA, among other factors, jointly affect the turbidity index of the sodium starch OSA aqueous solution. The greater the amount of these substances, the greater the turbidity of the final sodium starch OSA aqueous solution; the smaller the amount of these substances, the lower the turbidity of the final sodium starch OSA aqueous solution. The present application separates the amylose and some impurities in the starch by pretreatment, thereby achieving the purpose of improving the final OSA starch sodium emulsification embedding performance and reducing the turbidity of the OSA starch sodium aqueous solution.

[0048] In a further preferred embodiment, the mass ratio of octenylsuccinic anhydride to pretreated starch on a dry basis is (0.026-0.032):1. There are many varieties of starch, and the most commonly used raw starch for preparing sodium OSA starch is waxy corn starch. However, even the same waxy corn starch has a very different degree of branching when produced in different places. According to one embodiment of the present application, the starch is selected from at least one of corn starch, waxy corn starch, wheat starch, rice starch, and tapioca starch.

[0049] The mass ratio of octenylsuccinic anhydride to the pretreated starch dry basis determines the proportion of OSA starch bound in the final OSA starch sodium. According to relevant regulations, the proportion of OSA starch bound shall not exceed 3wt% of the total mass of OSA starch sodium. When the mass ratio of octenylsuccinic anhydride to the pretreated starch dry basis is controlled to (0.026-0.032):1, it can meet the requirements of the regulations and also prepare OSA starch sodium with good emulsification and embedding properties.

[0050] In a preferred embodiment, the base is selected from at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, lithium carbonate, lithium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate. The most commonly used base is sodium hydroxide, which has the advantages of being inexpensive and requiring little usage. Sodium hydroxide can also be combined with sodium carbonate to provide a buffering effect and more accurately control the pH value of the reaction system.

[0051] In a preferred embodiment, the preset pH value is controlled to be 7.0-9.0; the temperature of the esterification reaction is controlled to be 35-38°C. In the esterification reaction of pretreated starch and octenyl succinic anhydride, the hydrolysis reaction of octenyl succinic anhydride and its esterification reaction with pretreated starch are parallel reactions. The pH value and temperature of the reaction system directly affect the utilization rate of octenyl succinic anhydride. By controlling the pH value of the reaction system to be 7.0-9.0 and the temperature of the reaction system to be 35-38°C, a higher utilization rate of octenyl succinic anhydride can be obtained. In some preferred embodiments, the pH value of the reaction system is 7.5-8.5. Sodium octenyl succinate generated by the hydrolysis of octenyl succinic anhydride needs to be removed in the washing process after the esterification reaction is completed, otherwise it will affect the accuracy of detecting the content of OSA-bound starch.

[0052] In some embodiments, the step of pretreating starch includes: adding an alcohol-water solution to the starch to extract the starch branches; filtering and washing the extract to obtain a filter cake, which is the pretreated starch.

[0053] In some embodiments, the obtained filtrate is cooled, crystallized, filtered, and washed to obtain a filter cake of high-amylose starch.

[0054] According to the examples of this application, amylose has a greater solubility in alcoholic water than amylopectin. Therefore, adding an alcoholic aqueous solution to starch for extraction can increase its branching degree and remove impurities such as gelatinous substances. Furthermore, after cooling, crystallizing, and filtering the filtrate, the alcohol can be recovered for use in the next batch of extraction. The filter cake can be dried with airflow and used as a coating in the spray granulation of microcapsules. This allows for comprehensive starch utilization.

[0055] In a further preferred embodiment, the mass ratio of the alcohol-water solution to the starch is (3-8):1; the mass ratio of the alcohol to the water in the alcohol-water solution is (0.05-0.2):1. The present application does not limit the type of alcohol used. In some embodiments, the alcohol includes at least one of methanol and ethanol. A large amount of alcohol-water solution used in the extraction process can obtain pretreated starch with a higher degree of branching, but the extraction rate of the pretreated starch becomes smaller, and vice versa. Taking all factors into consideration, the use of the ratio as described above can achieve the purpose of comprehensive optimization and avoid losing sight of one thing while focusing on another.

[0056] In a preferred embodiment, the temperature during the extraction of starch axils is 30-40°C.

[0057] The present application also provides a method for preparing sodium OSA starch, comprising: enzymatically hydrolyzing the OSA starch ester prepared by the preparation method described above and water under the catalytic action of amylase to obtain an OSA starch ester hydrolyzate; filtering and washing the OSA starch ester hydrolyzate to obtain OSA enzymatic starch; gelatinizing the OSA enzymatic starch and water in a gelatinizer to obtain an OSA sodium starch gelatinized liquid; and spray drying the OSA sodium starch gelatinized liquid to obtain sodium OSA starch.

[0058] Different from the preparation process of the prior art, the present application adjusts the enzymatic hydrolysis reaction of OSA starch ester to be carried out before the gelatinization process. After the enzymatic hydrolysis reaction of OSA starch ester is completed, OSA starch ester enzymatic hydrolysate is obtained, and the OSA starch ester enzymatic hydrolysate is filtered and washed to obtain OSA enzymatic starch. The advantage of adopting this preparation method is that because OSA starch ester has not been gelatinized, it is still water-insoluble. After the OSA starch ester is enzymatically hydrolyzed, the main part of the OSA starch ester is still insoluble in water, so that the impurities such as small molecule sugars obtained by enzymatic hydrolysis in the OSA enzymatic starch, enzyme inactivators containing inorganic acids or inorganic alkalis, etc. can be separated by filtration to obtain OSA enzymatic starch without small molecule sugars. The OSA enzymatic starch is then subjected to gelatinization and subsequent spray drying process to finally obtain optimized OSA starch sodium. The emulsification and embedding properties of this optimized OSA starch sodium are significantly stronger than those of the OSA starch sodium prepared by the prior art.

[0059] It is worth noting that although impurities such as small molecule sugars and enzyme inactivators containing inorganic acids or inorganic alkalis in OSA starch sodium may cause demulsification and affect the embedding properties of OSA starch sodium, their effect on the embedding properties of ordinary core materials is relatively small, and the loss caused by the embedding properties is within an acceptable range. Therefore, those skilled in the art have no motivation to improve the process of preparing OSA starch sodium from OSA starch esters.

[0060] Furthermore, since the enzymatic hydrolysis and filtration process is relatively slow, the procedure for switching the enzymatic hydrolysis and gelatinization processes is complicated, the control difficulty increases during actual operation, and the improvement cost is high. Therefore, those skilled in the art have no motivation to switch the enzymatic hydrolysis and gelatinization processes of OSA starch ester. This operation goes against the inertial cognition of those skilled in the art, and they would not expect that switching the process would have such an unexpected improvement in the emulsification and embedding properties of OSA starch sodium.

[0061] In a preferred embodiment, for the step of obtaining an OSA starch ester enzymatic hydrolyzate by enzymolysis of OSA starch ester and water under the catalytic action of amylase, the mass ratio of water to the pretreated starch for preparing the starch ester is (1-6): 1. In the process of preparing OSA starch ester, undried OSA starch ester is obtained, which can be subjected to subsequent enzymatic hydrolysis reaction without drying. In order to control the effect of the enzymatic hydrolysis reaction, it is necessary to control the amount of water added. At this time, it is necessary to calculate the amount of water input using the amount of pretreated starch input. The amount of water input is as small as possible while satisfying the condition that the OSA starch ester can be fully dispersed, so as to reduce the amount of subsequent filtered filtrate.

[0062] In a preferred embodiment, the mass ratio of amylase to pretreated starch for preparing starch ester is (0.0009-0.05):1; preferably, the mass ratio of amylase to pretreated starch for preparing starch ester is (0.0009-0.01):1. According to one embodiment of the present application, β-amylase is used to hydrolyze OSA starch ester to prepare OSA starch sodium with better emulsification and embedding properties. The amount of β-amylase input needs to consider the price factor under the condition of considering the enzymatic reaction speed. The use of a mass ratio of β-amylase to the pretreated starch of (0.0009-0.01):1 can achieve the best overall effect and avoid losing one thing while focusing on another.

[0063] In a preferred embodiment, the temperature of the enzymatic hydrolysis reaction is controlled to be 34-38° C. to maximize the catalytic activity of the β-amylase and reduce the time of the enzymatic hydrolysis reaction.

[0064] The prior art usually controls the viscosity of the enzymolysis solution to determine the degree of enzymolysis. Different from the enzymolysis process of the prior art, in a preferred embodiment of the present application, the mass percentage content of sugar in the dry basis of the reaction system after the enzymolysis is completed is controlled to be s, and 5wt%≤s≤20wt%. The present application determines the degree of enzymolysis by detecting the sugar content of the enzymolysis solution and converting the dry basis sugar content. When the mass percentage content of sugar in the dry basis of the enzymolysis solution is controlled within the range of 5-20wt%, OSA starch sodium with the best emulsification and embedding performance can be prepared. Increasing this control index can effectively control the degree of enzymolysis reaction, control the average molecular weight of OSA starch sodium and improve the emulsification and embedding performance.

[0065] In a preferred embodiment, for the step of gelatinizing OSA enzymatic starch and water in a gelatinizer to obtain OSA sodium starch gelatinized liquid, the mass ratio of water to pretreated starch for preparing starch ester is controlled to be (2-4):1. The ratio of water to the dry basis mass of OSA enzymatic starch during gelatinization has a great influence on the energy consumption of the spray drying process, and the proportion of water during gelatinization should be reduced as much as possible. Since the dry basis mass of OSA enzymatic starch requires the detection of the dryness ratio of OSA enzymatic starch, the raw material starch of the esterification reaction, i.e., the pretreated starch, is used as the basis for the feed calculation for ease of operation. A gelatinizer similar to a plug flow process or a gelatinizer with a fully mixed flow process adapted to batch operation of extremely high viscosity systems can be used. As long as the equipment can adapt to higher viscosities, a smaller water ratio should be used as much as possible to reduce the energy consumption of spray drying.

[0066] The following specific examples will illustrate the improved method for preparing sodium starch glycolate (OSA) of the present application and verify the emulsification and embedding properties of the sodium starch glycolate (OSA) prepared according to the method. Those skilled in the art should understand that the following examples are merely illustrative of the technical solutions of the present application and are not intended to limit the scope of protection of the present application.

[0067] Example 1

[0068] Preprocessing:

[0069] To a 5000 ml four-necked flask equipped with a thermometer and a stirring paddle were added 500.0 g of waxy corn starch (441.5 g on dry basis, 95.2 wt% branching) and 2200 g of a methanol-water solution (methanol:water = 0.1:1). The flask was placed in a water bath at 35°C, stirred, and the mixture was extracted for 30 minutes.

[0070] After the extraction was completed, the mixture was filtered while hot. The filter cake was washed with 1000 g of drinking water three times, and finally 742.4 g of clean pretreated starch (dry basis: 383.8 g, degree of branching: 99.3 wt%) was obtained.

[0071] The filtrate and washings were combined and placed in a refrigerator for cooling and crystallization at 8° C. After 12 hours of crystallization, the mixture was filtered to obtain a filter cake of 89.7 g (51.7 g on dry basis, 65.5 wt % branching). Methanol was recovered from the filtrate and used for further recycling.

[0072] Esterification reaction:

[0073] A 5000ml four-necked flask equipped with a pH meter and a stirring paddle was charged with 700.0g of pretreated starch (99.3wt%) and 2000.0g of drinking water. The flask was then placed in a waterbath to maintain an internal temperature of 36°C. 150.0g of a 3.0wt% aqueous sodium hydroxide solution was added to a first constant-pressure dropping funnel, and 11.4g of 99.2wt% octenylsuccinic anhydride was added to a second constant-pressure dropping funnel. The first and second constant-pressure dropping funnels were mounted on the feed port of the four-necked flask. A small amount of aqueous sodium hydroxide solution was first added to the 5000ml four-necked flask to adjust the pH of the reaction system to 8.0. The octenylsuccinic anhydride and aqueous sodium hydroxide solution were then added simultaneously, with the octenylsuccinic anhydride added dropwise over approximately 0.5 hours, with the sodium hydroxide addition rate maintained to maintain a pH of 8.0. After the addition of octenylsuccinic anhydride was completed, the mixture was kept at a pH of 8.0 and allowed to react for 4 hours. After the reaction was completed, 5 ml of the sample was filtered, washed, and tested for bound OSA content: 2.68 wt%.

[0074] After the esterification reaction is complete, the mixture is filtered. Drinking water is added to the filter cake for pulping and washing until the pH of the final washing solution reaches 7.0. The total amount of washing water is approximately 1500 ml. The filter cake is OSA starch ester.

[0075] Enzymatic hydrolysis reaction:

[0076] Place all of the OSA starch ester into a 5000ml four-necked flask equipped with a thermometer and add 1500g of drinking water. Place the four-necked flask in a 35°C waterbath and stir to maintain heat. Weigh 2.5g of β-amylase and 50ml of drinking water into a beaker, mix thoroughly, and pour into the four-necked flask for enzymatic hydrolysis. Maintain the internal temperature of the four-necked flask at 35°C while enzymatic hydrolysis proceeds. Sample the hydrolyzate during the hydrolysis process to determine its dry sugar content. Enzymatic hydrolysis is complete when the dry sugar content reaches 8.7wt%.

[0077] After enzymatic hydrolysis is complete, filter while hot. Add 35°C hot water to the filter cake for pulping and washing, then drain. Use about 500ml of hot water for each pulping and washing. Repeat pulping and washing three more times, for a total of four pulping and washing times.

[0078] Gelatinization reaction:

[0079] After washing, transfer the washed filter cake to a 5000ml stainless steel reactor equipped with a stainless steel ribbon stirrer. Add 1500g of drinking water to the reactor. Start stirring at 10 rpm. Heat the reactor jacket with 95°C hot water. Start timing when the internal temperature reaches 85°C. The entire gelatinization process takes approximately 30 minutes. Gelatinization should be stopped once gelatinization is complete, as determined by polarized light microscopy.

[0080] Spray drying:

[0081] After gelatinization was complete, the gelatinized liquid was transported to a spray drying tower through a high-pressure spray pump for spray drying, and finally 313.2 g of OSA starch sodium was obtained, with a combined OSA content of 2.68 wt% and a sugar content of 0.05 wt%.

[0082] Add 50g of sodium starch glycolate (OSA), 120g of drinking water, and 50g of vitamin E acetate to a beaker. Set the stator and rotor shear mechanism to 12,000 rpm and perform high-speed shear emulsification for 10 minutes. After emulsification, transfer the emulsion to a 250ml graduated cylinder with a diameter of 38mm. Allow to stand at room temperature for 48 hours. Observe the oil slick to a height of 3.3mm.

[0083] 10.0 g of sodium starch glycolate (OSA) was added to 40 g of deionized water to obtain a solution having a solid content of approximately 25 wt %. The turbidity of the solution was measured at 20° C. to 25° C. and was found to be 34 (NTU).

[0084] Example 2

[0085] The experimental equipment and parameters for Example 2 were essentially the same as those for Example 1, with the following differences: 2100 g of methanol-water solution (methanol:water = 0.05:1) was added during the pretreatment process. 744.2 g of pretreated starch (dry basis: 389.2 g, degree of branching: 99.0 wt%) was obtained. Finally, 316.1 g of sodium OSA starch was obtained. The oil float height was observed according to the verification method of Example 1: 4.5 mm, and the turbidity was 55 (NTU).

[0086] Example 3

[0087] The experimental equipment and parameters for Example 3 were essentially the same as those for Example 1, with the following differences: 2400 g of methanol-water solution (methanol:water = 0.2:1) was added during the pretreatment process. 731.5 g of pretreated starch (dry basis: 375.3 g, degree of branching: 99.5 wt%) was obtained. Finally, 310.6 g of sodium OSA starch was obtained. The oil float height was observed according to the verification method of Example 1: 3.1 mm, and the turbidity was 19 (NTU).

[0088] Example 4

[0089] The experimental equipment and parameters for Example 4 were essentially the same as those for Example 1, except that 1500 g of methanol-water solution (methanol:water = 0.1:1) was added during the pretreatment process. 751.3 g of pretreated starch (dry basis: 391.4 g, degree of branching: 99.1 wt%) was obtained. Finally, 315.3 g of sodium OSA starch was obtained. The oil float height was observed according to the verification method of Example 1: 5.8 mm, and the turbidity was 68 (NTU).

[0090] Example 5

[0091] The experimental equipment and parameters for Example 5 were essentially the same as those for Example 1, except that 4000 g of methanol-water solution (methanol:water = 0.1:1) was added during the pretreatment process. 746.2 g of pretreated starch (dry basis: 379.8 g, degree of branching: 99.6 wt%) was obtained. Finally, 308.1 g of sodium OSA starch was obtained. The oil float height was observed according to the verification method of Example 1: 1.2 mm, and the turbidity was 18 (NTU).

[0092] Example 6

[0093] The experimental equipment and parameters for Example 6 were essentially the same as those for Example 1, except that during the pretreatment, the water bath temperature was kept low at 30°C. 756.4 g of pretreated starch (397.9 g on a dry basis, 99.0 wt% branching) were obtained. Finally, 317.3 g of sodium OSA starch was obtained. The oil slick height was observed according to the verification method of Example 1: 5.7 mm, and the turbidity was 66 (NTU).

[0094] Example 7

[0095] The experimental equipment and parameters for Example 7 were essentially the same as those for Example 1, except that during the pretreatment, the water bath temperature was maintained at 40°C. 736.4 g of pretreated starch (383.7 g on a dry basis, 99.6 wt% branching) were obtained. Finally, 316.1 g of sodium OSA starch was obtained. The oil slick height was observed according to the verification method of Example 1: 1.1 mm, and the turbidity was 17 (NTU).

[0096] Example 8

[0097] The experimental equipment and parameters of Example 8 were essentially the same as those of Example 1, except that the amount of potable water used in the enzymatic hydrolysis reaction was reduced to 700 g. The yield of pretreated starch was 741.6 g (dry basis: 384.1 g, degree of branching: 99.3 wt%). The final yield of sodium OSA starch was 313.9 g. The oil slick height was observed according to the verification method of Example 1: 3.6 mm, and the turbidity was 42 (NTU).

[0098] Example 9

[0099] The experimental equipment and parameters of Example 9 were essentially the same as those of Example 1, except that the amount of potable water used in the enzymatic hydrolysis reaction was increased to 4200 g. The yield of pretreated starch was 744.3 g (dry basis: 382.6 g, degree of branching: 99.4 wt%). The final yield of sodium OSA starch was 313.7 g. The oil slick height was observed according to the verification method of Example 1: 2.8 mm, and the turbidity was 26 (NTU).

[0100] Example 10

[0101] The experimental equipment and parameters for Example 10 were essentially the same as those for Example 1, except that the temperature in the four-necked flask was kept low at 34°C during the enzymatic hydrolysis reaction. 744.9 g of pretreated starch (384.4 g on dry basis, 99.4 wt% branching) was obtained. Finally, 313.3 g of sodium OSA starch was obtained. The oil float height was observed according to the verification method of Example 1: 2.3 mm, and the turbidity was 30 (NTU).

[0102] Example 11

[0103] The experimental equipment and parameters for Example 11 were essentially the same as those for Example 1, except that the temperature in the four-necked flask was maintained at 38°C during the enzymatic hydrolysis reaction. 736.8 g of pretreated starch (384.6 g on dry basis, 99.3 wt% branching) was obtained. Finally, 315.9 g of sodium OSA starch was obtained. The oil slick height was observed according to the verification method of Example 1: 4.6 mm, and the turbidity was 45 (NTU).

[0104] Example 12

[0105] The experimental equipment and parameters for Example 12 were essentially the same as those for Example 1, except that the amount of β-amylase used during the enzymatic hydrolysis reaction was reduced to 0.63 g. The pretreated starch yielded 743.1 g (dry basis: 383.4 g, degree of branching: 99.2 wt%). Finally, 312.4 g of sodium OSA starch was obtained. The oil slick height was observed according to the verification method of Example 1: 1.4 mm, and the turbidity was 16 (NTU).

[0106] Example 13

[0107] The experimental equipment and parameters for Example 13 were essentially the same as those for Example 1, except that the amount of β-amylase used during the enzymatic hydrolysis reaction was increased to 7.0 g. The pretreated starch yielded 743.5 g (dry basis: 382.9 g, degree of branching: 99.4 wt%). Finally, 312.7 g of sodium OSA starch was obtained. The oil slick height observed according to the verification method of Example 1 was 3.6 mm, and the turbidity was 51 (NTU).

[0108] Example 14

[0109] The experimental equipment and experimental parameters of Example 14 were basically the same as those of Example 1, except that during the enzymatic hydrolysis reaction, when the dry sugar content was equal to 5.0 wt%, the enzymatic hydrolysis was completed. The pretreated starch was obtained: 743.8 g (dry basis: 385.3 g, branching degree: 99.3 wt%). The final yield was 327.2 g of sodium OSA starch. The oil float height was observed according to the verification method of Example 1: 4 mm, and the turbidity was 32 (NTU).

[0110] Example 15

[0111] The experimental equipment and experimental parameters of Example 15 were basically the same as those of Example 1, except that during the enzymatic hydrolysis reaction, the enzymatic hydrolysis was completed when the dry sugar content was equal to 20.0 wt%. The pretreated starch was obtained: 743.4 g (dry basis: 383.6 g, branching degree: 99.4 wt%). The final yield was 272.1 g of sodium OSA starch. The oil float height was observed according to the verification method of Example 1: 4.9 mm, and the turbidity was 33 (NTU).

[0112] Comparative Example 1

[0113] The experimental equipment and parameters for Comparative Example 1 were essentially the same as those for Example 1, except that 2200 g of water was added for extraction during the pretreatment process. 757.6 g of pretreated starch (393.2 g on a dry basis, 97.8 wt% branching) was obtained. Finally, 314.4 g of sodium OSA starch was obtained. The oil float height, observed according to the verification method of Example 1, was 12.6 mm, and the turbidity was 134 (NTU).

[0114] Comparative Example 2

[0115] The experimental equipment and parameters for Comparative Example 2 were essentially the same as those for Example 1, except that 2200 g of methanol was added for extraction during the pretreatment process. 740.2 g of pretreated starch (380.5 g on dry basis, 97.9 wt% branching) was obtained. Finally, 311.2 g of sodium OSA starch was obtained. The oil float height, observed according to the verification method of Example 1, was 11.5 mm, and the turbidity was 119 (NTU).

[0116] Comparative Example 3

[0117] The experimental equipment and parameters for Comparative Example 3 were essentially the same as those for Example 1, except that 410.0 g of waxy corn starch (362.0 g dry basis, 95.2 wt% branching) was directly subjected to the subsequent esterification, enzymatic hydrolysis, gelatinization, and spray drying processes without pretreatment. The final yield was 313.3 g of sodium OSA starch. The oil slick height was observed according to the verification method of Example 1: 15.6 mm, and the turbidity was 215 (NTU).

[0118] Comparative Example 4

[0119] The experimental equipment and parameters for Comparative Example 4 were essentially the same as those for Example 1, with the following differences: 410.0 g of waxy corn starch (362.0 g dry basis, 95.2 wt% branching) was used without pretreatment. The enzymatic hydrolysis timing was adjusted, and the subsequent esterification, gelatinization, enzymatic hydrolysis, and spray drying processes were performed sequentially. The final product, 313.8 g of sodium starch OSA, was obtained. The oil slick height was observed according to the verification method of Example 1: 18.9 mm, and the turbidity was 253 (NTU).

[0120] The above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention.

Claims

1. A method for preparing sodium starch glycolate (OSA), comprising: Pretreating starch, wherein the branching degree of the pretreated starch is ≥98 wt%; The OSA starch ester is obtained by mixing the pretreated starch and octenylsuccinic anhydride in alkaline water for esterification reaction; Adding amylase to OSA starch ester to perform enzymatic hydrolysis reaction to obtain OSA starch ester enzymatic hydrolyzate; Obtaining OSA enzymatically hydrolyzed starch using the OSA starch ester enzymatic hydrolyzate; gelatinizing the OSA enzymatically hydrolyzed starch; and The OSA starch sodium is obtained by enzymatically hydrolyzing starch using the OSA.

2. The preparation method according to claim 1, wherein the step of pretreating the starch comprises: adding the starch to the alcohol aqueous solution and maintaining the temperature at a predetermined temperature for a sufficient time to obtain an extract; filtering and washing the extract; as well as The pretreated starch is obtained.

3. The preparation method according to claim 2, wherein the alcohol-water solution is a mixed solution of alcohol and water in a mass ratio of (0.05-0.20):1; preferably, the alcohol is selected from one or more of the following components: methanol, ethanol, n-propanol, isopropanol, ethylene glycol ((CH2OH)2), and glycerol; preferably, the mass ratio of the alcohol-water solution to the starch is (3.0-8.0):

1.

4. The preparation method according to claim 2, wherein the predetermined temperature is 30-40 degrees Celsius; and the sufficient time is no less than 20 minutes.

5. The preparation method according to claim 1, further comprising adding water and amylase to the OSA starch ester for enzymatic hydrolysis; wherein, The mass ratio of the water to the pretreated starch is (1-6):1; wherein the amylase is β-amylase; the mass ratio of the amylase to the pretreated starch is (0.0009-0.01):

1.

6. The preparation method according to claim 1, wherein The temperature of the enzymatic hydrolysis reaction is 28-40 degrees Celsius; preferably, the temperature of the enzymatic hydrolysis reaction is 34-38 degrees Celsius. The preparation method according to claim 1 , wherein the dry basis sugar content of the OSA starch ester enzymatic hydrolyzate is 5%-20%.

8. OSA starch sodium prepared according to the preparation method according to any one of claims 1 to 7.

9. An emulsified embedded microcapsule, wherein the emulsified embedded material comprises the sodium starch glycolate according to claim 8.

10. The microcapsule according to claim 9, wherein the core material of the microcapsule is selected from one or more of the following components: vitamin A acetate, vitamin A palmitate, vitamin D, such as vitamin D2, vitamin D3, vitamin E acetate, vitamin E palmitate, vitamin K, β-carotene, astaxanthin, lycopene, canthaxanthin, lutein, fish oil, coenzyme Q10, B vitamins, peppermint oil, eucalyptus oil, vanillin, whey protein, pectin, DHA, EPA, cinnamaldehyde probiotics, tea polyphenols, anthocyanins, curcumin and allicin.