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In this paper, with the starch of wheat, corn and rice as raw materials, the influence of thestarch paragenesis protein, microwave processing and the starch-lipid compounds to thestarch hydrolysis rate were studied. On the basis, the preparation method of the slowlydigestible starch through the wheat starch were researched, then, the structural characteristicsand the property research of the prepared starch samples were analyzed in details.First, the influence of the starch paragenesis protein content, the enzyme degenerationtime, the monoglyceride addition and the heat treatment time to the slowly digestible starchyield were studied through single factor experiment, and the orthogonal trial was used inoptimization of technological parameters, the optimum technological condition to thepreparation of the slowly digestible starch was starch paragenesis protein content0.19%, theenzyme degeneration time3h, the monoglyceride addition0.03%, the heat treatment time8h.Then the structural characteristics of the starch samples were studied. The DSC analysisshowed that the particle structure of removing protein starch, microwave processing starch,monoglyceride-containing starch and SDS became more compact, the initial gelatinizationtemperature increased, the crystallization fields of microwave processing starch and SDSbecame chaos. X-ray diffraction analysis and synchrotron radiation light beam experimentshowed that the amorphous region structure of removing protein starch became more compact,the crystallization fields structure kept invariant, the serious chaos of the starch crystallizationfields and amorphous region was produced through microwave processing, and in contrast,the destruction to the crystallization fields was more serious, the monoglyceride addingformed a little V-type crystal, but the original starch crystal structure was not changed, thestarch crystal of SDS became not perfect, however, its amorphous region became morecompact.Then the SDS properties were studied, the results showed that after ordinary wheatstarch processing into SDS, the peak viscosity of starch paste dropped, the lowest viscosityincreased, attenuation value decreased substantially, the peak time also had a certain delay, thetransparency of starch paste increased appreciably, the retrogradation and the freeze-thawstability became poor, NaCl Solution makes the transparency and the retrogradation of starchpaste become worse, but Sucrose Solution improve its transparency and retrogradationeffectively. Therefore, with SDS as excipient, it should be mixed with sucrose, and can not add excess water (<30%), otherwise, SDS may be gelatinized so as to lose its slowlydigestibility property.
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