Preparation method and application of high amylose-fatty acid-calcium ternary complex

Abstract

The invention relates to a preparation method and application of a high-amylose corn starch-fatty acid-calcium ternary complex, and belongs to the technical field of food and modified starch processing. The invention provides a method for preparing a high-amylose corn starch-myristic acid derivative in a non-high-temperature and normal-pressure environment, efficient loading of calcium is completed at the same time, the method comprises the following steps: deconstructing high-amylose corn starch by adopting calcium chloride solutions with different concentrations, and after the deconstruction is completed, preparing the high-amylose corn starch-myristic acid derivative. And low-energy-consumption production of the starch derivative is realized by selecting different fatty acid adding forms. According to the method, the deconstruction degree of the high-amylose corn starch in a water phase and the complexing efficiency of the high-amylose corn starch and fatty acid can be obviously improved, the application range of the high-amylose corn starch is widened, the production cost is reduced, and a good thought is provided for realizing non-high-temperature complexing of the high-amylose corn starch and the fatty acid through a proper fatty acid adding mode.

Description

Technical Field

[0001] The invention relates to a high-amylose starch-fatty acid-calcium ternary complex and a preparation method thereof, belonging to the technical field of food and modified starch processing. Background Art

[0002] Starch is a renewable resource with a wide range of sources, economical and environmentally friendly, and can be used as one of the important sources of biodegradable materials. With the improvement of cultivation technology, the output of high-amylose corn starch has increased significantly, and the improvement of its deep utilization rate and high-value conversion rate is one of the important directions for the future development of the corn starch industry.

[0003] High-amylose starch is mainly composed of amylose, intermediate fractions and amylopectin, which has excellent retrogradation and gel properties. High-amylose corn has been widely used in many fields such as nutritional foods, food processing, drug release, biodegradable materials, etc. However, there are some limitations in the research and application of high-amylose starch. Compared with ordinary starch, high-amylose starch has a harder shell and more compact internal particles, which leads to a higher gelatinization temperature. At present, alkaline solutions, ionic liquids, dimethyl sulfoxide (DMSO), chloride solutions (zinc chloride, magnesium chloride and calcium chloride, etc.) have been proven to be gelatinizers for high-amylose corn starch. Among them, starch will inevitably undergo long-term severe shearing and heat treatment when dissolved in DMSO or alkaline solution, which will lead to a decrease in its molecular weight and a change in its chemical structure; ionic liquids are expensive and are not suitable for large-scale use in the production process. Inorganic salt solutions (zinc chloride, magnesium chloride and calcium chloride) at specific concentrations have been shown to fully decompose (2% w / vdb) high-amylose starch at moderate temperatures (<50°C). Considering its low toxicity and economic characteristics, calcium chloride solution is the most promising high-amylose starch plasticizer. High-amylose starch can form complexes with fatty acids or metal ions due to its high amylose content, but efficient complexation of the three has not yet been achieved. Summary of the invention

[0004] Based on the above problems, the present invention uses high-amylose starch as raw material, uses calcium chloride solution to construct a homogeneous reaction system, realizes efficient complexation of high-amylose starch and fatty acids, and introduces inorganic calcium into starch derivatives to prepare a new ternary complex. The method includes using calcium chloride solutions of different concentrations to deconstruct high-amylose starch, promote the destruction of the ordered structure of high-amylose starch and the dissolution of amylose starch, and realize the complexation of high-amylose starch with fatty acids under non-high temperature and normal pressure conditions.

[0005] The technical problem solved by the present invention is a new method for preparing a high-amylose starch-fatty acid-calcium ternary complex, which can be potentially applied to many fields such as packaging, coating and biomedical materials, and has both economic and environmental benefits.

[0006] The technical scheme adopted by the present invention is: adding a high-amylose corn starch suspension into a calcium chloride solution, stirring at 40-60°C for 2-4 hours; adding fatty acids, stirring at 50-80°C for 30-90 minutes to achieve complexation and obtain a sample solution; recovering the complex by a water precipitation method, separating and purifying, and obtaining the high-amylose starch-fatty acid-calcium ternary complex.

[0007] The first temperature is the dissolution temperature, and the second temperature is the complexation temperature.

[0008] In one embodiment, the raw material is high-amylose corn starch, and the amylose content is 60-80%.

[0009] In one embodiment, the concentration of the calcium chloride solution is 3-4 M, and the concentration of the high-amylose corn starch suspension is 3-6%.

[0010] In one embodiment, the fatty acid is myristic acid.

[0011] In one embodiment, the fatty acid is added in the form of a solid or oily substance or an oily substance dissolved in anhydrous ethanol, and the amount of the fatty acid added is 6-10% based on the dry basis of starch.

[0012] In one embodiment, the recovery method is specifically as follows: the sample solution after the reaction is dripped into deionized water 2 to 3 times the volume of the sample solution at a uniform speed through a constant flow pump, and centrifuged at 3500g for 5 minutes.

[0013] In one embodiment, the separation and purification method is specifically: washing the precipitate with deionized water and freeze-drying.

[0014] In one embodiment, the method is specifically:

[0015] Step 1, preparing a 3-6% high-amylose corn starch suspension;

[0016] Step 2, prepare a 3-4M calcium chloride solution, deconstruct the high-amylose corn starch for 2-4 hours at a water bath temperature of 40-60° C., stirring continuously during the process to complete the full deconstruction of the starch; add myristic acid in the form of a solid or oily substance or an oily substance dissolved in anhydrous ethanol, adjust the composite temperature to 50-80° C., the composite time to 30-90 minutes, stirring continuously during the process to achieve complexation;

[0017] Step 3, after the compounding is completed, the composite is recovered by water precipitation method, and free calcium ions are removed by repeated washing with deionized water;

[0018] Step 4, after recovering the precipitate, freeze-drying is used for dehydration.

[0019] Beneficial effects:

[0020] First, the present invention uses high-amylose corn starch as raw material and calcium chloride solution as homogeneous system, achieving full deconstruction of high-amylose corn starch and formation of starch-fatty acid-calcium ternary complex under non-high temperature and normal pressure conditions. The present invention has obvious cost advantages, can achieve mass production, and avoids environmental and technical problems caused by composite modification.

[0021] Secondly, calcium chloride solution, as a complex system of high-amylose corn starch and fatty acids, can destroy the tight granular structure of high-amylose corn starch under mild conditions, reduce the difficulty of gelatinization of high-amylose corn starch, and promote the formation of the complex compared to water, DMSO, alkali solution and ionic liquid.

[0022] Again, choose the appropriate method of adding fatty acids to improve the complexation efficiency and achieve complex production with lower energy consumption.

[0023] Finally, the ternary complex production method described in the present invention can significantly improve the complexing efficiency of high-amylose corn starch and reduce the complexing temperature.

[0024] In summary, the calcium chloride solution used in the present invention constructs a homogeneous system to prepare a high-amylose corn starch-fatty acid-calcium ternary complex, which can achieve efficient preparation of starch derivatives and effective loading of calcium, and can be used as a raw material to develop high-value utilization in various industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 :The effect of calcium chloride solution concentration on the crystal structure of high amylose corn starch-myristic acid-calcium ternary complex (HACS-MA@CA), where 3M and 4M represent different concentrations of calcium chloride solution;

[0026] Figure 2 :Effects of calcium chloride solution concentration on high amylose corn starch-myristic acid-calcium ternary complex (HACS-MA@CA) and calcium loading, where 3M and 4M represent different concentrations of calcium chloride solution;

[0027] Figure 3 : Effect of compounding temperature on the crystal structure of high amylose corn starch-myristic acid-calcium ternary complex (HACS-MA@CA), where 60 and 75 represent the compounding temperatures of 60℃ and 75℃, respectively.

[0028] Figure 4 :Effect of fatty acid addition method on the crystalline structure of high amylose corn starch-myristic acid-calcium ternary complex (HACS-MA@CA), where S represents the fatty acid added in solid form, and L represents the fatty acid added in liquid form after being miscible with anhydrous ethanol. DETAILED DESCRIPTION

[0029] The high-amylose corn starch, myristic acid, and calcium chloride used in the preparation of the high-amylose starch-fatty acid-calcium ternary complex of the present invention can be selected from commercially available products produced by companies on the market. For example, high-amylose corn starch can be purchased from Beijing Xiangyu Biotechnology Co., Ltd., myristic acid can be purchased from Shanghai Yuanye Biotechnology Co., Ltd., and calcium chloride can be purchased from Sinopharm Chemical Reagent Co., Ltd.

[0030] Example 1: Preparation of high amylose corn starch-myristic acid-calcium ternary complex

[0031] (1) adding corn starch to 3M and 4M calcium chloride solutions respectively to prepare starch milk with a mass concentration of 5% (w / w), and stirring continuously at 50° C. for 4 h to obtain starch paste;

[0032] (2) weighing 10% of myristic acid based on the dry weight of starch and adding it to anhydrous ethanol, stirring continuously to completely dissolve it, to obtain a myristic acid solution;

[0033] (3) adjusting the temperature of the starch paste prepared in step (1) to 75° C. and stabilizing it at 75° C. for 5 min, slowly adding the myristic acid solution in step (2) to the starch paste, carrying out a composite reaction under continuous stirring, and controlling the reaction time to 90 min to obtain a sample solution;

[0034] (4) After the complex reaction is completed, the sample solution is slowly added dropwise into deionized water (twice the volume of the sample solution) through a constant flow pump, and the precipitate is collected after centrifugation at a centrifugal force of 3500×g for 5 min. The precipitate is washed three times with deionized water, and the precipitate is collected, followed by freeze-drying, crushing, and passing through a 100-mesh sieve to obtain a high-amylose starch-fatty acid-calcium ternary complex. The final sample is sealed and stored at 4°C.

[0035] Structural characterization of the ternary complex: The ordered structure of high-amylose corn starch is destroyed in calcium chloride solution, and linear straight chains are released. The amylose can form a single helical complex with the ligand fatty acid through the hydrophobic cavity, and its structure can be directly characterized by X-ray diffraction patterns ( Figure 1 ), wherein the diffraction peaks with diffraction angles 2θ of 7.50°, 13.50° and 20.50° are V-type crystal peaks, and the crystallinity (Xc) is calculated as the sum of the crystallinity of 13.50° and 20.50°; Figure 1 (A, B) It can be clearly seen that high-amylose corn starch can form V-shaped crystals with fatty acids in calcium chloride solution, and as the concentration of calcium chloride solution increases, Xc also increases. The diffraction peaks with diffraction angles 2θ of 21.50° and 24.00° are the crystallization peaks of free fatty acids. According to existing studies, calcium ions are mainly coordinated on the 6-CH2OH group, and its structure can be directly characterized by X-ray photoelectron spectroscopy ( Figure 2). Figure 2 (A, C) Full scan spectra of the samples, Figure 2 (B, D) are narrow scan calcium spectra of the samples, where the presence of calcium can be clearly seen, and the calcium loading is related to the calcium chloride solution. At a fixed concentration, the calcium loading is consistent.

[0036] Example 2: Preparation of high amylose corn starch-myristic acid-calcium ternary complex

[0037] (1) adding corn starch to a calcium chloride solution (4 M) to prepare a starch milk with a mass concentration of 5% (w / w), and stirring continuously at 50° C. for 4 h to obtain a starch paste;

[0038] (2) weighing 10% of myristic acid based on the dry weight of starch and adding it to anhydrous ethanol, stirring continuously to completely dissolve it, to obtain a myristic acid solution;

[0039] (3) stabilizing the starch paste prepared in step (1) at fixed temperatures of 60° C. and 75° C. for 5 min, slowly adding the myristic acid solution in step (2) to the starch paste, and performing a composite reaction under continuous stirring conditions, controlling the reaction time to 90 min, to obtain a sample solution;

[0040] (4) After the complex reaction is completed, the sample solution is slowly added dropwise into deionized water (twice the volume of the sample solution) through a constant flow pump, and the precipitate is collected after centrifugation at a centrifugal force of 3500×g for 5 min. The precipitate is washed three times with deionized water, and the precipitate is collected, followed by freeze-drying, crushing, and passing through a 100-mesh sieve to obtain a high-amylose starch-fatty acid-calcium ternary complex. The final sample is sealed and stored at 4°C.

[0041] Structural characterization of the ternary complex: The ordered structure of high-amylose corn starch is destroyed in calcium chloride solution, and linear straight chains are released. The amylose can form a single helical complex with the ligand fatty acid through the hydrophobic cavity. Its structure can be directly characterized by X-ray diffraction patterns, where the diffraction peaks with diffraction angles 2θ of 7.50°, 13.50° and 20.50° are V-type crystal peaks ( Figure 3 ), the crystallinity (Xc) is calculated as the sum of the crystallinity of 13.50° and 20.50°; Figure 3 (A, B) It can be clearly seen that high-amylose corn starch can form V-shaped crystals with fatty acids in calcium chloride solution, and as the composite temperature increases, Xc also increases. The diffraction peaks with diffraction angles 2θ of 21.50° and 24.00° are the crystallization peaks of free fatty acids. The coordination of calcium ions is mainly related to the concentration of calcium chloride solution, and its structural characterization is similar to Figure 1 similar.

[0042] Example 3: Preparation of high amylose corn starch-myristic acid-calcium ternary complex

[0043] (1) adding corn starch to a calcium chloride solution (4 M) to prepare a starch milk with a mass concentration of 5% (w / w), and stirring continuously at 50° C. for 4 h to obtain a starch paste;

[0044] (2) weighing two portions of myristic acid accounting for 10% of the dry weight of starch, retaining one portion in solid form, and adding the other portion into anhydrous ethanol, stirring continuously to completely dissolve the myristic acid, to obtain a myristic acid solution;

[0045] (3) stabilizing the starch paste prepared in step (1) at fixed temperatures of 60° C. and 75° C. for 5 min, slowly adding the myristic acid solid and the myristic acid solution in step (2) to the starch paste, and performing a composite reaction under continuous stirring conditions, controlling the reaction time to 90 min, to obtain a sample solution;

[0046] (4) After the complex reaction is completed, the sample solution is slowly added dropwise into deionized water (twice the volume of the sample solution) through a constant flow pump, and the precipitate is collected after centrifugation at a centrifugal force of 3500×g for 5 min. The precipitate is washed three times with deionized water, and the precipitate is collected, followed by freeze-drying, crushing, and passing through a 100-mesh sieve to obtain a high-amylose starch-fatty acid-calcium ternary complex. The final sample is sealed and stored at 4°C.

[0047] Structural characterization of the ternary complex: The ordered structure of high-amylose corn starch is destroyed in calcium chloride solution, and linear straight chains are released. The amylose can form a single helical complex with the ligand fatty acid through the hydrophobic cavity. Its structure can be directly characterized by X-ray diffraction patterns, where the diffraction peaks with diffraction angles 2θ of 7.50°, 13.50° and 20.50° are V-type crystal peaks ( Figure 4 ), the crystallinity (Xc) is calculated as the sum of the crystallinity of 13.50° and 20.50°; Figure 4 (A, B) It can be clearly seen that high-amylose corn starch can form V-shaped crystals with fatty acids in calcium chloride solution. At a lower composite temperature, adding fatty acids after dissolving can significantly increase Xc, and the increase in Xc represents the increase in the complexation rate of high-amylose corn starch and fatty acids. The diffraction peaks with diffraction angles 2θ of 21.50° and 24.00° are the crystallization peaks of free fatty acids. The coordination of calcium ions is mainly related to the concentration of calcium chloride solution, and its structural characterization is similar to Figure 1 (C, D) are similar.

Claims

1. A method for preparing a high-amylose starch-fatty acid-calcium-ternary complex, characterized in that: The high-amylose starch is added to a calcium chloride solution, and stirred at 40-60° C. for 2-4 hours; fatty acids are added, and stirred at 50-80° C. for 30-90 minutes to achieve complexation and obtain a sample solution; the complex in the sample solution is recovered by a water precipitation method, and separated and purified to obtain the high-amylose starch-fatty acid-calcium ternary complex.

2. The method for preparing a high-amylose starch-fatty acid-calcium ternary complex according to claim 1, characterized in that: The raw material is high-amylose corn starch, and the amylose content is 60-80%.

3. The method for preparing a high-amylose starch-fatty acid-calcium ternary complex according to claim 1, characterized in that: The concentration of the calcium chloride solution is 3-4M, and the concentration of the high-amylose corn starch suspension is 3-6%.

4. The method for preparing a high-amylose starch-fatty acid-calcium ternary complex according to claim 1, characterized in that: The fatty acid is myristic acid.

5. The method for preparing a high-amylose starch-fatty acid-calcium ternary complex according to claim 1, characterized in that: The fatty acid is added in the form of solid or oily substance or oily substance dissolved in anhydrous ethanol, and the amount of fatty acid added is 6-10% based on the dry basis of starch.

6. The method for preparing a high-amylose starch-fatty acid-calcium ternary complex according to claim 1, characterized in that: The specific recovery method is: the sample solution after the reaction is dripped into deionized water 2 to 3 times the volume of the sample solution at a uniform speed through a constant flow pump, and centrifuged at 3500×g for 5 minutes.

7. The method for preparing a high-amylose starch-fatty acid-calcium ternary complex according to claim 1, characterized in that: The separation and purification method is specifically: washing the precipitate with deionized water and freeze-drying.

8. Use of the high-amylose starch-fatty acid-calcium complex prepared according to any one of claims 1 to 7 in the fields of food, medicine and health food.

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