The Study Of Potato Starch Esterification And Compound Modification Starch

This paper was designed to choose the rich source of potato starch as the raw material, to introduce hydrophobic groups to the starch by esterification, then the starch both had hydrophilic and hydrophic at the same time. The experiments was also carried out by alcohol alkali treatment to get amorphous starch to maintain the original particle structure, based on the increase of its water-soluble. And then on this basis, potato composite modified starch was got by the two methods. Its viscosity, solubility, freeze-thaw stability, emulsifying properties and other items was improved, and its use was further increased. This study not only expanded the potato starch deep processing methods to improve the nature of the potato starch, but also widened the scope of application of starch. Main research contents and results were as follow:The single factors and orthogonal tests were used to analysis the optimum reaction conditions of OSA Potato starch. They were:OSA was diluted by ethanol for4times, concentration of starch slurry was35%(in proportion to water, w/w), reaction time was3h. PH of reaction system was8.3-8.5, the reaction temperature was35℃. Then, the degree of substitution was0.0172. The optimum reaction conditions of alcohol alkali treatment were:ethanol concentration was75%, starch concentration was11Og/L, the addition of NaOH (3mo1/L) was17g/100ml, reaction time was1Omin, the reaction temperature was30℃, starch concentration was8%. Finally the solubility of modified starch was up to72.6%. Experiments eventually used the higher solubility of amorphous granular starch as raw material to prepare OSA-starch. The compound modified starch had a DS of up to0.0186, the solubility was79%.Compare the physical properties of three kinds of starch, compound modified starch was superior to the single denatured starch after treatment in the emulsification capacity, emulsification stability, cold water solubility, apparent viscosity and so on. Compound modified starch and amorphous starch had a good freeze-thaw stability. FT-IR analysis suggested amorphous starch was basically the same as the original starch, while Two new peaks were observed from OSA-starch and compound modified starch, one at1724cm-1and one at1572cm-1, indicating the introduction of the esterification of starch group. The scanning electron microscope found that amorphous starch and composite modified starch remain keep the structure of starch granules, but the surface was uneven, indicating the reaction was more obvious.