High-yield granular seleniumized starch and a method for preparing the same

Abstract

The application discloses high-yield granular selenized starch and a preparation method thereof, and belongs to the technical field of deep processing of starch; a starch milk is prepared by using an ethanol aqueous solution as a medium, the content of ethanol, acetic acid and selenic acid in the aqueous solution is changed, the temperature and time of the reaction in the water bath are controlled, and thus the granular selenized starch is prepared; the preparation method of the high-yield granular selenized starch is innovative, and overcomes the problems of harsh reaction conditions and low yield of traditional selenized starch; the reaction system process is simple, and the reaction conditions are controllable; on the basis of not damaging the starch granules, the reaction of the starch and a selenization reagent is controlled by controlling the swelling behavior of the starch granules in the ethanol aqueous solution, high-efficiency preparation of the granular selenized starch is realized, the high-yield selenized starch can be realized in large scale, the yield of the prepared starch is higher than 80%, the selenium content is higher than 500 mu g / g, and the prepared starch can be further applied to the development of functional starch and the field of deep processing of the functional starch.

Description

Technical Field

[0001] This invention belongs to the field of starch deep processing technology, specifically relating to a high-yield granular selenized starch and its preparation method. Background Technology

[0002] Selenium is an essential trace element for the human body, playing a vital role in the prevention and treatment of various diseases, such as anti-aging, anti-tumor, anti-oxidation, and immune regulation (especially in anti-oxidation and immune regulation), and is inseparable from human health. Selenization of food components has multiple effects, including lowering blood sugar, anti-oxidation, anti-tumor, and immune regulation, making it an important modification method for the development of functional foods. Starch is an important component of staple foods and snacks such as rice, noodles, steamed buns, bread, and rice cakes, providing essential energy for the human body. To enhance the functional properties of starch products, specific functional groups can be endowed with starch through physical, chemical, and biological methods, or the multi-scale structure of starch, such as chain, helical, crystalline, layered, and granular structures, can be directionally regulated, thereby achieving targeted regulation of the physicochemical and nutritional functions of starch. However, reports on the effects of selenization on starch structure and function are still scarce. Although selenization of food components can improve the functional quality of food, reports on the preparation of selenized starch are limited.

[0003] Selenization reactions of components are generally carried out in relatively extreme reaction systems such as nitric acid, which leads to the extensive degradation of components such as polysaccharides during the reaction, resulting in low yields. In addition, the use of reagents such as nitric acid makes the reaction process highly dangerous. For the selenization modification of starch, Zhao Shuting used a dilute nitric acid reaction system to prepare selenized starch. The yield of this starch was less than 30%, and the selenium content was about 1200-2100 μg / g (Zhao Shuting. Preparation, structural characterization and in vitro bioactivity study of selenized mung bean resistant starch [D]. Heilongjiang Bayi Agricultural Reclamation University, 2022). In Chinese patent application dated April 2, 2021, with publication number CN113135998A, Yin Yanzhen et al. reported a method for preparing selenium-enriched starch. This method utilizes selenium powder and sodium borohydride to synthesize a NaSeH stock solution, which is then reacted with octenyl succinate starch ester to obtain selenized starch. This method has a complex preparation process and requires special starch to prepare selenized starch, which is not conducive to the large-scale production of selenized starch. In Chinese patent application dated January 25, 2022, with publication number CN114349875A, Zhang Ruirui et al. also reported a method for preparing cationic selenized nano starch. This method involves sulfonating nano starch in an acetonitrile system, followed by reaction with selenium and sodium borohydride under nitrogen protection to prepare nano-selenized starch. This method has harsh reaction conditions and a complex process for preparing selenized starch, which is not conducive to the large-scale preparation of selenized starch.

[0004] It is evident that there is currently no efficient and gentle method for preparing selenized starch. Developing a simple, non-specialized method for preparing selenized starch with high yield is a key scientific problem that urgently needs to be solved in the industrial-scale production of selenized starch and the deep processing of starch. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a high-yield granular selenized starch and its preparation method. By controlling the swelling behavior of starch granules in an ethanol aqueous solution, the reaction between starch and selenizing reagent is regulated, thereby achieving efficient preparation of granular selenized starch.

[0006] The technical solution of the present invention is as follows:

[0007] One of the objectives of this invention is to provide a method for preparing high-yield granular selenized starch. The method involves preparing starch milk using an ethanol aqueous solution with an ethanol content of 65-95% as a medium, then adding acetic acid and selenic acid, and reacting the mixture in a water bath at 40-80°C for 1-10 hours. Granular selenized starch can then be obtained by separation.

[0008] Furthermore, the mass concentration of the starch milk is 1-40%.

[0009] Furthermore, the starch is commercially available granular starch.

[0010] Furthermore, the starch is any one of corn starch, potato starch, cassava starch, rice starch, wheat starch, sweet potato starch, and pea starch.

[0011] Furthermore, the selenic acid content is 0.5-6% of the volume of the ethanol aqueous solution.

[0012] Furthermore, the acetic acid content is 1-10% of the volume of the ethanol-water solution.

[0013] Furthermore, the separation method is either centrifugal separation or Buchner funnel filtration.

[0014] Furthermore, the centrifugation process involves centrifuging at 5000-5500 r / min for 3-5 min, followed by repeated washing of the precipitate with deionized water until the washing solution does not change color after the addition of ascorbic acid. The precipitate is then collected to obtain granular selenized starch.

[0015] The second objective of this invention is to provide a high-yield granular selenized starch.

[0016] Furthermore, the high-yield granular selenized starch has a selenization content higher than 500 μg / g.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention discloses for the first time a method for efficiently preparing granular selenized starch by controlling the swelling behavior of starch granules in an ethanol aqueous solution to regulate the reaction between starch and selenizing reagent without damaging the starch granules. This method allows for a wide selection of starch types, and the selenization content of the granular selenized starch is higher than 500 μg / g, which is of great significance for the large-scale production and development of high-yield selenized starch.

[0019] 2. The innovative high-yield granular selenized starch preparation method of this invention overcomes the problems of harsh reaction conditions and low yield of traditional selenized starch. The reaction system adopted is simple and the reaction conditions are controllable. No special equipment is required. It not only facilitates the directional control of starch structure and function, but also the yield of the granular selenized starch obtained is higher than 80%. It has great application potential in the field of starch deep processing and industrial production.

[0020] Figure Labels

[0021] Figure 1 This is a schematic diagram showing the morphology, yield, and selenium content of the high-yield granular selenized starch prepared in Example 1 of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0023] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0024] In the quantitative experiments in the following examples, three replicate experiments were set up, and the average value of the results was taken.

[0025] Unless otherwise specified, the experimental methods described in the following examples are conventional methods.

[0026] Example 1

[0027] This embodiment provides a high-yield granular selenized starch, the preparation method of which is as follows:

[0028] S1. Weigh 20g (dry weight) of rice starch and add it to 200mL of an ethanol aqueous solution containing 5% acetic acid (15 / 85, water / ethanol). Add 5mL of selenic acid solution and react at 70℃ for 3h.

[0029] S2. After the reaction is complete, centrifuge at 5000 r / min for 5 min, and then wash the precipitate repeatedly with deionized water until the color does not change after adding ascorbic acid to the washing solution.

[0030] S3. Collect the precipitate, dry it at 45℃, and weigh it to obtain high-yield granular selenized starch.

[0031] Example 2

[0032] This embodiment provides a method for preparing high-yield granular selenized starch, the specific steps of which are as follows:

[0033] S1. Weigh 80g (dry weight) of corn starch and add it to 200mL of an ethanol aqueous solution containing 10% acetic acid (5 / 95, water / ethanol). Add 12mL of selenic acid solution and react at 80℃ for 1h.

[0034] S2. After the reaction is complete, centrifuge at 5300 r / min for 4 min, and then wash the precipitate repeatedly with deionized water until the washing solution does not change color after adding ascorbic acid.

[0035] S3. Collect the precipitate, dry it at 45℃, and weigh it to obtain high-yield granular selenized starch.

[0036] Example 3

[0037] This embodiment provides a method for preparing high-yield granular selenized starch, the specific steps of which are as follows:

[0038] S1. Weigh 10g (dry weight) of wheat starch and add it to 200mL of an ethanol aqueous solution containing 3% acetic acid (25 / 75, water / ethanol). Add 10mL of selenic acid solution and react at 50℃ for 6h.

[0039] S2. After the reaction is complete, filter using a Buchner funnel, and then wash the filtrate repeatedly with deionized water until the washing solution does not change color after adding ascorbic acid.

[0040] S3. Collect the filtered material, dry it at 45℃, and weigh it to obtain high-yield granular selenized starch.

[0041] Example 4

[0042] This embodiment provides a method for preparing high-yield granular selenized starch, the specific steps of which are as follows:

[0043] S1. Weigh 2g (dry weight) of potato starch and add it to 200mL of an ethanol aqueous solution containing 1% acetic acid (35 / 65, water / ethanol). Add 1mL of selenic acid solution and react at 40℃ for 10h.

[0044] S2. After the reaction is complete, centrifuge at 5500 r / min for 3 min, and then wash the precipitate repeatedly with deionized water until the color does not change after adding ascorbic acid to the washing solution.

[0045] S3. Collect the precipitate, dry it at 45℃, and weigh it to obtain high-yield granular selenized starch.

[0046] Performance testing

[0047] 1. Reaction system testing

[0048] High-yield granular selenized starch was prepared according to the conditions described in Example 1. Simultaneously, 200 mL of water containing 5% acetic acid was used instead of 200 mL of ethanol aqueous solution containing 5% acetic acid (15 / 85, water / ethanol) to synthesize the test group of selenized starch in the aqueous phase. The yield and selenium content of the high-yield granular selenized starch described in Example 1 and the test group of selenized starch were calculated respectively.

[0049] The test results are shown in Table 1:

[0050] Table 1 shows the yield and selenium content of selenized starch obtained from different reaction systems:

[0051] reaction system ethanol / aqueous phase Aqueous phase Yield (%) 91.90±0.59 19.14％±1.16 Selenium content (μg / g) 1290.6±5.4 565.9±3.1

[0052] As shown in Table 1, compared with the aqueous synthesis system, the ethanol / aqueous system has a higher yield and higher selenium content in the synthesis of selenized starch, which is more conducive to the preparation of high-yield selenized starch.

[0053] 2. Ethanol ratio test

[0054] High-yield granular selenized starch was prepared according to the conditions described in Example 1, wherein the volume ratio of water to ethanol in the solution was adjusted to 5 / 95, 10 / 90, 15 / 85, 20 / 80, 25 / 75, 30 / 70, and 35 / 65, and the yield and selenium content of the selenized starch in the test groups with different ethanol ratios were calculated.

[0055] The test results are shown in Table 2:

[0056] Table 2 shows the yield and selenium content of selenized starch prepared from ethanol-water solutions of different proportions:

[0057] Water / ethanol ratio 5 / 95 10 / 90 15 / 85 20 / 80 25 / 75 30 / 70 35 / 65 Yield (%) 93.25±2.18 92.06±1.76 92.01±2.06 88.68±1.63 87.49±1.92 88.10±0.86 82.19±1.82 Selenium content (μg / g) 1025.8±2.7 1221.6±3.4 1290.6±5.4 1314.5±1.8 1352.5±4.8 1362.0±4.5 1405.9±3.6

[0058] As shown in Table 2, as the water / ethanol ratio increases, the yield of selenized starch decreases and the selenium content gradually increases.

[0059] 3. Acetic acid content test

[0060] High-yield granular selenized starch was prepared according to the conditions described in Example 1, wherein the acetic acid content was adjusted to 1%, 3%, 5%, 7%, 9%, and 10%, and the yield and selenium content of the selenized starch in the test groups with different acetic acid contents were calculated.

[0061] The test results are shown in Table 3:

[0062] Table 3 shows the yield and selenium content of selenized starch prepared from acetic acid with different contents:

[0063] Acetic acid content 1％ 3％ 5％ 7％ 9％ 10％ Yield (%) 94.30±1.38 92.01±2.06 90.40±1.16 86.25±2.57 85.15±1.10 84.28±0.92 Selenium content (μg / g) 627.8±5.6 985.5±4.1 1290.6±5.4 1480.4±12.2 1671.0±7.7 1725.3±4.6

[0064] As shown in Table 3, with the increase of acetic acid content, the yield of selenized starch gradually decreases and the selenium content gradually increases.

[0065] 4. Selenic acid addition test

[0066] High-yield granular selenized starch was prepared according to the conditions described in Example 1. High-yield granular selenized starch was prepared by adding 1.0 mL, 2.5 mL, 5.0 mL, 7.5 mL, 10.0 mL, and 12.0 mL of selenic acid solution, respectively. The yield and selenium content of the selenized starch in the test groups with different amounts of selenic acid were calculated.

[0067] The test results are shown in Table 4:

[0068] Table 4 shows the yield and selenium content of selenized starch prepared with different amounts of selenic acid:

[0069] Selenic acid addition amount 1.0mL 2.5mL 5.0mL 7.5mL 10.0mL 12.0mL Yield (%) 96.27±0.54 94.95±0.21 92.01±2.06 89.07±0.67 85.81±2.08 83.26±1.97 Selenium content (μg / g) 1025.7±4.2 1169.4±3.1 1290.6±5.4 1420.0±3.5 1509.0±1.8 1658.7±1.5

[0070] As shown in Table 4, with the increase of selenic acid content, the yield of selenized starch gradually decreases and the selenium content gradually increases.

[0071] 5. Reaction temperature test

[0072] Multiple groups of high-yield granular selenized starch were prepared according to the conditions described in Example 1. The starch was reacted at 40℃, 50℃, 60℃, 70℃ and 80℃ for 3 hours, respectively. The yield and selenium content of the selenized starch in the test groups at different reaction temperatures were calculated.

[0073] The test results are shown in Table 5:

[0074] Table 5 shows the yield and selenium content of selenized starch prepared at different reaction temperatures:

[0075] reaction temperature 40℃ 50℃ 60℃ 70℃ 80℃ Yield (%) 94.63±0.73 93.95±0.79 91.68±1.14 92.01±2.06 87.25±1.34 Selenium content (μg / g) 502.4±1.2 732.9±2.0 963.1±1.4 1290.6±5.4 1383.9±5.4

[0076] As shown in Table 5, the yield of selenized starch gradually decreases and the selenium content gradually increases with increasing temperature.

[0077] 6. Reaction Time Test

[0078] Multiple groups of high-yield granular selenized starch were prepared according to the conditions described in Example 1. The reactions were carried out for 1 h, 2 h, 3 h, 4 h, 5 h, and 10 h, respectively. The yield and selenium content of the selenized starch in the test groups with different reaction times were calculated.

[0079] The test results are shown in Table 6:

[0080] Table 6 shows the yield and selenium content of selenized starch prepared at different reaction temperatures:

[0081] reaction time 1h 2h 3h 4h 5h 10h Yield (%) 93.46±1.92 91.97±1.49 92.01±2.06 88.53±2.52 87.17±1.75 82.25±2.08 Selenium content (μg / g) 597.7±2.0 744.7±5.4 1290.6±5.4 1465.9±1.2 1617.3±25.8 1923.6±7.8

[0082] As shown in Table 6, with the increase of reaction time, the yield of selenized starch gradually decreased and the selenium content gradually increased.

[0083] 7. Starch type test

[0084] Multiple groups of high-yield granular selenized starch were prepared according to the conditions described in Example 2. Corn starch, potato starch, cassava starch, wheat starch, sweet potato starch, and pea starch were used as reaction raw materials, and the yield and selenium content of the selenized starch in the test groups with different reaction times were calculated.

[0085] The test results are shown in Table 7:

[0086] Table 7 shows the yield and selenium content of selenized starch prepared at different reaction temperatures:

[0087] Types of starch corn starch Potato starch Tapioca starch Wheat starch Sweet potato starch Pea starch Yield (%) 85.65±2.05 87.73±0.82 83.21±1.62 86.28±1.94 84.28±1.66 85.64±1.68 Selenium content (μg / g) 1849.9±1.8 1547.6±3.3 1643.6±4.0 1587.5±2.1 1628.9±6.2 1656.9±8.1

[0088] As shown in Table 7, when different types of starch are used as reaction raw materials to prepare selenized starch, the starch type has a significant impact on the yield and selenium content of selenized starch, but the yield and selenium content of selenized starch are always higher than 80% and 500 μg / g, respectively.

[0089] 8. Starch concentration test

[0090] Multiple groups of high-yield granular selenized starch were prepared according to the conditions described in Example 3, with starch granule concentrations of 1%, 5%, 10%, 20%, 30%, and 40%, respectively. The yield and selenium content of the selenized starch in the test groups with different reaction times were calculated.

[0091] The test results are shown in Table 8:

[0092] Table 8 shows the yield and selenium content of selenized starch prepared at different reaction temperatures:

[0093] starch concentration 1％ 5％ 10％ 20％ 30％ 40％ Yield (%) 95.23±1.87 96.18±1.25 94.95±2.01 96.28±1.78 96.59±2.01 96.62±1.88 Selenium content (μg / g) 556.2±4.9 563.9±8.2 562.4±3.7 549.5±2.8 532.6±3.6 516.4±2.5

[0094] As shown in Table 8, the yield of selenized starch did not change significantly with the increase of starch concentration, while the selenium content showed a gradual decreasing trend.

[0095] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing high-yield granular selenized starch, characterized in that, The preparation method uses an ethanol aqueous solution with an ethanol content of 65-95% as a medium to prepare starch milk, then adds acetic acid and selenic acid and reacts in a water bath at 40-80 ℃ for 1-10 h, and then separates to obtain granular selenized starch. The selenic acid content is 0.5-6% of the volume of the ethanol aqueous solution; The acetic acid content is 1-10% of the volume of the ethanol aqueous solution.

2. The method for preparing high-yield granular selenized starch as described in claim 1, characterized in that, The starch milk has a mass concentration of 1-40%.

3. The method for preparing high-yield granular selenized starch as described in claim 1, characterized in that, The starch is commercially available granular starch.

4. The method for preparing high-yield granular selenized starch as described in claim 3, characterized in that, The starch is any one of corn starch, potato starch, cassava starch, rice starch, wheat starch, sweet potato starch, and pea starch.

5. The method for preparing high-yield granular selenized starch as described in claim 1, characterized in that, The separation method is either centrifugal separation or Buchner funnel filtration.

6. The method for preparing high-yield granular selenized starch as described in claim 5, characterized in that, The centrifugation process involves centrifuging at 5000-5500 r / min for 3-5 min, followed by repeated washing of the precipitate with deionized water until the washing solution does not change color after adding ascorbic acid. The precipitate is then collected to obtain granular selenized starch.

7. A high-yield granular selenized starch obtained by the high-yield granular selenized starch preparation method according to any one of claims 1-6.

8. The high-yield granular selenized starch as described in claim 7, characterized in that, The high-yield granular selenized starch has a selenization content of over 500 μg / g.

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