| Starch,as a renewable resource with vast commercial potential,has been widely used in the food industry,chemical industry,and pharmaceutical industry.Since natural high molecular starch particles are not easily soluble in water,they are limited in application.In this paper,raw maize starch as raw materials,ultrasonic assisted ethanol alkali method to optimize the preparation of high water soluble granular cold water soluble maize starch,and explore its mechanism of action.Based on the above studies,we have developed anionic starch microspheres with good particle morphology and electrostatic adsorption,which has provided new ideas for the direction of pharmaceutical research.This thesis carried out the following researches.The experimental results are as follows:1.Ultrasonic assisted alcoholic-alkaline treatment of cold water soluble maize starch process optimization.On the basis of single-factor tests,experimental design and data analysis of the response surface were performed.The optimal preparation conditions were analyzed using the Design-Expert8.0.5b software based on the Box-Behnken experimental design principle: X1(volume fraction of ethanol)=80.4%.X2(sodium hydroxide concentration)= 3.98 mol/L,X3(ultrasound power)=303.73 W,and X4(ultrasound time)= 25 min.The solubility of the granular cold water soluble starch prepared under this condition was 75.17%.According to actual experimental conditions,the average solubility of granular cold-water soluble starch prepared by ultrasonic-assisted ethanol alkali method is 75.05%,which is consistent with the expected value of the response surface.2.Ultrasonic assisted alcoholic-alkaline treatment of cold water soluble maizestarch mechanism.Scanning electron microscopy,X-ray spectroscopy,and FIRT spectroscopy techniques were used to investigate the physical properties and structure of cold-water soluble starch prepared from raw starch and ethanol alkalis and ultrasound-assisted ethanol-alkaline cold-water soluble starch.The granular cold-water soluble starch prepared by the ethanol alkali method is more water-soluble than the granular cold-water soluble starch obtained by the single ethanol alkali method;the ultrasonic-assisted ethanol alkali-based cold-water soluble starch can quickly dissolve into the water and paste Low temperature,better hydration;better freeze-thaw stability and settling characteristics;and poor shear resistance,there is a stronger shear dilution phenomenon.Observation by scanning electron microscopy revealed that the original starch granules were plump and round,and the cold-water-soluble starch granules prepared by the single ethanol alkali method were crushed and swelled on the surface,while the ultrasonic-assisted ethanol-alkali prepared cold water soluble starch formed a unique three-dimensionality.Three-dimensional ring structure,and the surface damage is more obvious.X-ray analysis showed that the diffraction pattern between the two modified starches and the original starch changed significantly.The crystalline structure of the starch changed from the A-type structure of the original starch to the V-type structure.The FIRT spectrum shows that the modified starch has no new groups,but the cold-water-soluble starch prepared by ultrasonic-assisted ethanol alkali shows a significant difference and changes obviously at 3430 cm-1,indicating that the hydroxyl group is dissociated.The internal hydrogen bonds of the starch molecules are damaged,and the associative hydroxyl groups are formed on the outside,which contributes to the increase of water solubility.The gelatinization characteristic curve shows that the modified starch gelatinization curve and characteristic parameters have undergone significant changes compared with the original starch after modification,and the cold-water soluble starch prepared by ultrasonic-assisted ethanol alkali method has the highest viscosity,indicating that This kind of cold water soluble starch can quickly integrate into the water,the gelatinization temperature is low,and the hydration power is better.3.Optimization of preparation process of anionic starch microspheres.In this test,the cold-water soluble starch prepared by ultrasonic assisted ethanol alkali method was used as the raw material.The particle size of the anionic starch microspheres was used as the response index.The concentration of the starch paste,the stirring speed,and the oil-water ratio were the influencing factors.In the emulsion system,anionic starch microsphere particles are prepared by cross-linking reaction.The optimal synthesis conditions for the anionic starch microspheres were:starch concentration 5%,stirring speed 1700 rpm,oil to water ratio 5:1,and the final measured AMS starch particle size was 83.0 μm.In addition,observations by atomic force microscopy revealed that the prepared anionic starch microsphere particles maintain a complete particle morphology while having nanoscale protrusions and shrinkage on the surface.The binding experiments with amino acid molecules with different electrical properties showed that the prepared anionic starch microsphere particles can attract cationic molecules when they are in a neutral environment,and have affinity for cationic molecules in a neutral environment system.The release rate is relatively slow. |
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