Starch potassium iodide inclusion compound and preparation method thereof
Through the preparation method of starch potassium iodide inclusions, the problems of potassium iodide instability and potassium iodate safety are solved, and the stable storage and uniform addition of potassium iodide is achieved, which meets the needs of iodine enhancement of table salt and provides a safe, stable, Reliable treatment method for iodized salt.
Patent Information
- Application Number
- CN202410723399.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-05
- Publication Date
- 2024-12-17
AI Technical Summary
The use of potassium iodate as an iodine nutrition enhancer in existing table salts has potential food safety problems, and the chemical properties of potassium iodide are unstable, and food additives are needed to improve stability, but this brings negative effects.
The preparation method of starch potassium iodide inclusion is adopted to form a stable starch potassium iodide inclusion through starch toughening treatment and embedding of potassium iodide inclusion. The internal structure of starch is changed by pure physical processing, which isolates light and moisture, and enhances the storage environment of potassium iodide.
The stable storage and uniform addition of potassium iodide is achieved, which reduces the risk of thyroid disease, meets the needs of iodine fortification of table salt, and provides a safe, stable and reliable treatment method for iodized salt.
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Figure CN119138577A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of production and processing of edible iodized salt, and specifically relates to a starch potassium iodide inclusion compound and a preparation method thereof. Background Art
[0002] Iodization of salt is the most widely used method to deal with iodine deficiency in the world. Although it solves the problem of iodine deficiency in the whole population, it is followed by a large-scale exposure to thyroid diseases, such as the high incidence of thyroid nodules. The scientific basis for establishing potassium iodate as a nutritional fortifier is that it is an ideal iodine nutritional fortifier and is easy to use. However, since this century, more and more studies have shown that potassium iodate intake is positively correlated with the incidence of various diseases. Although the health department has repeatedly reduced the amount of potassium iodate added to salt, the momentum of the increase in thyroid diseases has not weakened. The reason is that the existing production technology solutions are obviously outdated, and its potential food safety is already very prominent.
[0003] Among the global iodine fortification methods, potassium iodide and potassium iodate are the only two chemical raw materials. Most developing countries, including my country, currently use potassium iodate as an iodine nutrient fortifier for table salt. The advantages are stable chemical properties, uniform addition and easy use. However, developed countries represented by the United States and the European Union have already chosen potassium iodide as the method of salt iodine fortification. They pay more attention to the food safety of potassium iodide. In order to overcome its unstable defects, food additives are used to improve its stability.
[0004] In order to avoid the negative effects caused by food additives, how to provide a safe, stable and reliable method for iodizing salt is an urgent problem to be solved. Summary of the invention
[0005] The purpose of the present invention is to provide a starch potassium iodide inclusion compound and a preparation method thereof, so as to solve the technical problem that the chemical properties of potassium iodide are unstable in the application of salt products, and the technical problem that the chemical stability can only be improved by means of food additives.
[0006] A method for preparing a starch potassium iodide inclusion compound comprises: (1) Starch toughening treatment: add appropriate amount of water to amylose to adjust the water content to 75%, mix well, bottle and seal, place in a constant temperature shaking water bath for 24 hours, control the toughening temperature to 90℃-98℃, then centrifuge at 3000r / min for 10 minutes, remove the supernatant, wash the toughened starch once with distilled water, air-dry at 30℃ for 24 hours, grind through a 100-mesh sieve, and collect the sieve to obtain toughened starch; (2) Toughened starch encapsulates potassium iodide: prepare a potassium iodide solution of a certain mass concentration, add a certain amount of toughened starch, oscillate in a constant temperature oscillating water bath at a set temperature for a certain period of time, then centrifuge at 3000 r / min for 10 min, remove the supernatant, store in a refrigerator for a certain period of time, then wash once with anhydrous ethanol water, air-dry at 30°C for 24 h, and grind through a 100-mesh sieve to obtain toughened starch-potassium iodide inclusion complex.
[0007] Furthermore, in step (1), the amylose is selected from high-amylose corn starch.
[0008] Furthermore, in step (2), the concentration of the potassium iodide solution is 5 g / L-9 g / L.
[0009] Furthermore, in step (2), the set temperature of the constant temperature oscillating water bath is controlled at 40°C-70°C.
[0010] Furthermore, in step (2), the reaction time in the constant temperature oscillating water bath is controlled within 7 h to 10 h.
[0011] Furthermore, in step (2), the mixture is stored in a refrigerator at 4°C for 3 hours.
[0012] Solid starch potassium iodide inclusion complex is obtained by applying the starch potassium iodide inclusion complex preparation method, and is applied to salt products.
[0013] The beneficial effects of the present invention are: The starch potassium iodide embedding technology adopted in this scheme is a purely physical processing method. Without the involvement of any chemical reagents, it changes the internal physical structure of starch, improves the starch quality characteristics and processing performance. The formed starch potassium iodide inclusion complex can isolate potassium iodide from light and moisture, thereby creating a stable storage environment, meeting the technical requirements for iodine fortification of salt, and promoting the transformation of iodine fortification of salt from potassium iodate to potassium iodide. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is the curve diagram of the effect of reaction temperature on KI loading; Figure 2 This is a curve diagram showing the effect of VE addition on KI loading; Figure 3 It is a curve diagram showing the effect of reaction time on KI loading; Figure 4 This is the AS-KI energy spectrum analysis diagram; Figure 5 This is the high temperature stability curve of AS-KI; Figure 6 This is the AS-KI moisture absorption stability curve; Figure 7 AS-KI light stability. DETAILED DESCRIPTION
[0015] The preferred embodiments of the present invention are described below with reference to the accompanying drawings.
[0016] A method for preparing a starch potassium iodide inclusion compound, characterized by comprising: (1) Starch toughening treatment: add appropriate amount of water to 100g of high-amylose corn starch to adjust the water content to 75%, mix well, bottle and seal, and place in a constant temperature shaking water bath for 24h. Control the toughening temperature to 90℃-98℃, preferably 95℃, and then centrifuge at 3000r / min for 10min. Remove the supernatant, wash the toughened starch once with distilled water, and then dry it at 30℃ for 24h. Grind it through a 100-mesh sieve and collect the sieve to obtain toughened starch.
[0017] (2) Toughened starch encapsulates potassium iodide: prepare a potassium iodide solution with a mass concentration range of 5g / L-9g / L, add 50g of toughened starch, and oscillate in a constant temperature oscillating water bath in the temperature range of 40℃-70℃ for 7h-10h, then centrifuge at 3000r / min for 10min, remove the supernatant, and store in a refrigerator at 4℃ for 3h. In order to clean the potassium iodide adsorbed on the starch surface, use the negative correlation between the adsorption efficiency of iodine on starch and the ethanol concentration in the solution. Wash it once with anhydrous ethanol water, dry it at 30℃ for 24h, and grind it through a 100-mesh sieve to obtain toughened starch-potassium iodide inclusion complex (hereinafter referred to as AS-KI).
[0018] Test and determination 1. Determination of Potassium Iodide Embedding Amount The amount of potassium iodide embedded was determined by redox titration. The principle is that the iodide ions in the sample are oxidized into iodate ions by sodium hypochlorite under acidic conditions, the excess sodium hypochlorite is removed by oxalic acid, and the iodate ions oxidize potassium iodide to release elemental iodine. Starch solution is used as an indicator and titrated with sodium thiosulfate standard solution to calculate the iodine content.
[0019] 2. Single factor test and load test for AS-KI: Taking potassium iodide loading as the response value, the effects of reaction temperature, potassium iodide solution concentration and reaction time on potassium iodide loading were investigated in turn. The experimental factors were as follows: reaction temperature parameter levels were 25 ℃, 40 ℃, 55 ℃, 70 ℃, and 85 ℃; potassium iodide solution concentration parameter levels were 1 g / L, 3 g / L, 5 g / L, 7 g / L, and 9 g / L; reaction time parameter levels were 2 h, 4 h, 6 h, 8 h, and 10 h. The optimal loading process conditions were optimized, and the loading capacity of high-amylose corn starch before and after toughening was compared.
[0020] 3. AS-KI spectrum analysis Energy Dispersive Spectrometer (EDS) was used to determine the mass fraction and atomic number of the main elements in the micro-area for qualitative and semi-quantitative analysis. The technical indicators of the EDS instrument were: voltage 15 000 V, electron beam 6.0 eV, and working distance 10.0 mm.
[0021] 4. AS-KI high temperature storage stability After AS-KI and toughened starch-potassium iodide physical mixture (hereinafter referred to as AS+KI) were placed in a 60 ℃ constant temperature box for 0 d, 5 d, 10 d, 15 d, and 20 d, the loading amount of potassium iodide in the samples was measured using the determination method of No. 1, and the loading amount of potassium iodide in the samples (in terms of iodine) was calculated according to formula (1): Potassium iodide loading / % = m1 / m2 × 100 (1) Where m1 is the potassium iodide loading in the sample after storage for a period of time (mg / g); m2 is the potassium iodide loading in the sample before storage (mg / kg).
[0022] 5. AS-KI Hygroscopic Stability Multiple portions of AS-KI and AS+KI of about 20 g were weighed into 35 mm Petri dishes and placed on top of desiccators with different humidity levels. Humidity conditions were prepared by saturated solutions of the following salts: MgCl2, NaBr, NaCl, and KNO3. The desiccators of these samples were placed in a constant temperature incubator at 25°C for 20 days for hygroscopic stability testing. The choice of salts was based on reported humidity: MgCl2×6H2O—32.8%; NaBr—57.6%; NaCl—75.3%; KNO3—93.6%. Silica gel was used for 0% humidity conditions. Thymol (0.2 g) was placed in the desiccators of saturated solutions of NaCl and KCl to inhibit mold growth. The retention of potassium iodide in the samples was measured according to method No. 4.
[0023] 6. AS-KI photostability Weigh approximately 20 g of AS-KI and AS+KI physical mixtures in 35 mm culture dishes, and conduct stability tests at 0, 5, 10, 15, and 20 days under natural light and dark conditions, respectively. Measure the retention rate of potassium iodide in the samples according to method No. 4.
[0024] Results and Analysis 1. Effect of reaction temperature on potassium iodide loading As shown in Figure 1, when the reaction temperature gradually increases, the potassium iodide loading increases first and then slowly decreases. When the reaction temperature is 55 °C, the potassium iodide loading is the highest, which is 896 mg / kg. This may be because high-amylose corn starch will form a helical structure with a hydrophobic core, which can accommodate potassium iodide inside the helical cavity. As the temperature rises, the molecular movement gradually accelerates, and potassium iodide is more likely to enter the helical cavity of amylose, which also effectively promotes the inclusion of potassium iodide in amylose, so the loading amount increases; when the temperature exceeds 60 °C, the molecular movement accelerates, the amylose complex will melt at high temperature, and potassium iodide will easily overflow, which will have a certain impact on its stability. In addition, too high a temperature will cause amylose denaturation and reduce the loading amount.
[0025] 2. Effect of potassium iodide solution concentration on potassium iodide loading As shown in Figure 2, with the increase of the concentration of potassium iodide solution, the potassium iodide loading is generally gentle, showing a trend of first increasing and then tending to be gentle. When the concentration of potassium iodide solution is 7g / L, the loading reaches a high level of 810 mg / kg. This may be because the amount of potassium iodide added is small at the beginning, and the spiral cavity of amylose is not fully utilized. When the addition amount gradually increases, its loading amount also increases. When the addition amount is greater than 7g / L, the spiral cavity structure of amylose is basically in a saturated state, so it tends to be stable.
[0026] 3. Effect of reaction time on potassium iodide loading As shown in Figure 3, for AS-KI, as the reaction time increases, the potassium iodide loading increases first and then tends to be flat. When the reaction time reaches 8 h, the loading basically reaches the highest value and stabilizes at 830 mg / kg. This may be because when the reaction time is short, the toughened starch and potassium iodide fail to react fully, so the loading is low. When the reaction time reaches 8 h, the toughened starch can fully contact potassium iodide, and potassium iodide enters the spiral space of starch to undergo inclusion complexation reaction, thereby increasing the loading. When the reaction time exceeds 8 h, the spiral space of starch tends to be saturated, and the complexed and dissociated potassium iodide also tend to be balanced, which is manifested in that the loading no longer increases.
[0027] Load test analysis From the above factors, we can know that the order of influence of inclusion effect is: time > temperature > concentration, and the optimal conditions are: reaction temperature 55℃, potassium iodide solution concentration 9g / L, reaction time 10h. Loading experiment was carried out according to the optimized conditions, and the results showed that the average loading amount under the optimal conditions was 981 mg / kg.
[0028] Energy spectrum analysis The X-ray spectrometer has detected the inside of AS-KI at 15kV, and its EDS spectrum is as follows Figure 4 As shown, there are K and I atoms in the starch inclusion complex, indicating that KI enters the starch granules, and the numerous fine K and I peaks indicate that K and I are chelated with toughened starch at multiple sites. Table 1 shows the results of the energy spectrum analysis. From the mass fraction, it can be calculated that the potassium iodide embedding amount is about 800 mg / kg (in terms of iodine), which is consistent with the loading test.
[0029] Table 1 AS-KI spectrum analysis results Analysis of AS-KI Stability Test 1. High temperature stability After constant temperature storage at 60℃ for a certain period of time, the changes in the loading amount of KI in the AS-KI inclusion complex and the AS+KI physical mixture are shown in Figure 5. It can be seen that the KI loading amount of the DS-VE inclusion complex is slightly higher than that of the AS+KI physical mixture. After storage at 60℃ for 20 days, the KI retention rate in the AS-KI inclusion complex is calculated to be 98.5%, and the KI retention rate in the DS-VE physical mixture is 94.8%, indicating that DS has a better protective effect on KI in the form of inclusion. This corresponds to the results of DSC, that is, the heat resistance of the DS-VE inclusion complex is better than that of the DS-VE physical mixture.
[0030] 2. Hygroscopic stability After a certain period of constant temperature hygroscopic storage, the changes in the loading amount of KI in the AS-KI inclusion complex and the AS, KI physical mixture are shown in Figure 6. It can be seen that the KI loading amount of the DS-VE inclusion complex is higher than that of the AS, KI physical mixture. The KI retention rate in the AS-KI inclusion complex is 96.3%, and the KI retention rate in the DS-VE physical mixture is 89.8%, indicating that the hygroscopic stability of the DS-VE inclusion complex is better than that of the DS-VE physical mixture, and the inclusion method has a better protective effect on KI. Hu et al. also reached a similar conclusion in the study of the humidity stability of drug complexes.
[0031] 3. Light stability After 20 days of photostability test, the changes in KI loading in AS-KI inclusion complex and AS, KI physical mixture are shown in Figure 7. It can be seen that the KI loading in DS-VE inclusion complex is significantly higher than that in AS, KI physical mixture. The KI retention rate in AS-KI inclusion complex is 95.4%, and the KI retention rate in DS-VE physical mixture is 76.6%, indicating that the photostability of DS-VE inclusion complex is significantly better than that of DS-VE physical mixture, and the inclusion method has a better protective effect on KI, which is consistent with the relevant literature.
[0032] in conclusion AS-KI inclusion complex was prepared with high-amylose corn starch as raw material and potassium iodide as guest molecule, and the factors affecting KI loading were studied. The optimal process conditions were reaction temperature of 55℃, potassium iodide solution concentration of 9g / L, and reaction time of 10h. Under these conditions, the average KI loading in the inclusion complex was 981 mg / kg. By comparison, it was found that the high temperature storage stability, hygroscopic stability and light stability of AS-KI inclusion complex were improved to varying degrees compared with native starch.
[0033] In accordance with the requirements of the current "National Food Safety Standard for Iodine Content in Edible Salt", the maximum iodized level of edible salt is selected to be 30 mg / kg. Calculated based on the average loading of toughened starch-potassium iodide inclusion complex of 981 mg / kg, only 15 g of inclusion complex is needed to be added to each 500 g bag of salt. This is a moderate amount that can meet the requirements of potassium iodide fortifiers for uniformity and economy of addition, and is suitable for the development of potassium iodide fortified salt products.
Claims
1. A method for preparing a starch potassium iodide inclusion compound, characterized in that: include: (1) Starch toughening treatment: add appropriate amount of water to amylose to adjust the water content to 75%, mix well, bottle and seal, place in a constant temperature shaking water bath for 24 hours, control the toughening temperature to 90℃-98℃, then centrifuge at 3000r / min for 10 minutes, remove the supernatant, wash the toughened starch once with distilled water, air-dry at 30℃ for 24 hours, grind through a 100-mesh sieve, and collect the sieve to obtain toughened starch; (2) Toughened starch encapsulates potassium iodide: prepare a potassium iodide solution of a certain mass concentration, add a certain amount of toughened starch, oscillate in a constant temperature oscillating water bath at a set temperature for a certain period of time, then centrifuge at 3000 r / min for 10 min, remove the supernatant, store in a refrigerator for a certain period of time, then wash once with anhydrous ethanol water, air-dry at 30°C for 24 h, and grind through a 100-mesh sieve to obtain toughened starch-potassium iodide inclusion complex.
2. The method for preparing a starch potassium iodide inclusion compound according to claim 1, wherein: In the step (1), the amylose is selected from high-amylose corn starch.
3. The method for preparing a starch potassium iodide inclusion compound according to claim 1, characterized in that: In the step (2), the concentration of the potassium iodide solution is 5 g / L-9 g / L.
4. The method for preparing a starch potassium iodide inclusion compound according to claim 1, wherein: In the step (2), the set temperature of the constant temperature oscillating water bath is controlled at 40°C-70°C.
5. The method for preparing a starch potassium iodide inclusion compound according to claim 1, characterized in that: In the step (2), the reaction time in the constant temperature oscillating water bath is controlled within 7 h to 10 h.
6. The method for preparing a starch potassium iodide inclusion compound according to claim 1, characterized in that: In the step (2), the mixture is stored in a refrigerator at 4°C for 3 hours.
7. A method for preparing a starch potassium iodide inclusion complex using any one of 1 to 6 above to prepare a solid starch potassium iodide inclusion complex.